Actinodiscaceae

The Chrysophyta has three classes, one of which is the Bacillariophyceae (Diatomeae), containing some 10 000 species of diatom. They are unicellular algae, have a silica skeleton, and show infinite variety in shape and in the sculpturing of the cell wall. There are two main types: the subclass Centricae (in which Discales is one of the orders) and subclass Pennatae (which includes the order Pennatales). The Centricae are centric or discoid in shape and generally marine, while the Pennatae are pennate or naviculoid and more often occur in fresh water.

An example of the family Actinodiscaceae is Arachnoidiscus, found in Japanese agar (q.v.) and other genera are found in the fossil deposits of diatomite or kieselguhr (q.v.).

Fragilariaceae and Naviculariaceae

Species of these two families occur in diatomite and are illustrated in Fig. 34.1.

Laminariaceae

The brown algae are mainly marine and vary from microscopic branched filaments to leathery frond-like forms up to 60 m in length. They owe their brown colour to the carotenoid pigment fucoxanthin, which masks the other pigments.

Many of the 30 species of Laminaria are used in coastal districts for agricultural purposes. They are used for the manufacture of alginic acid (q.v.), mannitol and iodine.

Fucaceae and Sargassaceae

Examples of the Fucaceae are Fucus (about 30 spp.) and Pelvetia; and of the Sargassaceae about 250 species of Sargassum. These are collected on a large scale in many parts of the world for the production of alginic acid and its derivatives. The species have been much investigated for biologically active properties; F. vesiculosus, for example, gives water-soluble extracts that inhibit the activity of the HIV reverse-transcriptase enzyme.

Gelidiaceae

The red algae are divided into 11 orders. The 3000 species are mainly marine and are particularly abundant in the tropics and subtropics. Most are relatively small. Their plastids contain chlorophyll, the red pigment phycoerythrin (usually in sufficient quantity to mask the other pigments), and sometimes the blue pigment phycocyanin.

Important genera of the Gelidiaceae are Gelidium (about 40 spp.) and Pterocladia (5 spp.). Many of these are used in the preparation of agars (q.v.).

Gracilariaceae and Gigartinaceae

Gracilaria (100 spp.) is a source of agar, particularly G. lichenoides, found in the Indian Ocean. In the Gigartinaceae Chondrus crispus yields carageen or Irish moss (q.v.); Gigartina stellata has been investigated as a source of British agar.

Mucoraceae

These fungi have an aseptate mycelium; members include Phytophthora infestans, which causes potato blight. In the Mucoraceae we have Mucor (40 spp.) and Rhizopus (8 spp.), which are among the moulds associated with badly stored food products. Some Rhizopus species are used industrially for the saccharification of starchy material and for producing D-lactic acid from glucose; they are important in the microbiological conversions of steroids (q.v.).

Saccharomycetaceae

This group includes the yeasts, some 30 species of Saccharomyces. Dried yeast (q.v.) is prepared from a strain of S. cerevisiae. A member of the related family Cryptococcaceae is Candida utilis, which produces torula yeast, a rich source of proteins and vitamins.

Aspergillaceae

In this order the conidial stage is more prominent than the ascal stage. Penicillium (over 100 spp.) yields important antibiotics (q.v.) such as penicillin and griseofulvin; also the immunosuppressant mycophenolic acid. P. islandicum forms emodin. Among the 60 species of Aspergillus may be noted A. oryzae, used in the manufacture of soya sauce; A. fumigatus, producing the antibiotic fumagillin; and A. flavus producing aflatoxin in poorly stored feeding materials.

Hypocreaceae

Gibberella (10 spp.) produces the plant growth regulators known as gibberellins, first isolated from G. fugikuroi, see Chapter 12.

Clavicipitaceae

Like other Ascomycetes, the ascospores are produced in a sac or ascus. Claviceps (10 spp.) includes ergot, the sclerotium of C. purpurea; Cordyceps (100 spp.) includes C. sinensis, one of the most valued species in Chinese traditional medicine but limited in use by a shortage of supply. C. militaris has similar properties and efforts are devoted to its artificial culture; R. Yu et al., have purified and identified four polysaccharides from cultured material (Fitoterapia, 2004, 75, 662).

Polyporaceae

The Polyporaceae includes Polyporus, Polystichus, Fomes, Ganoderma and Boletus (200 spp.). Polyporus officinalis (white agaric) and P. fomentarius were formerly used in medicine. Ganoderma lucida has long been used in Chinese medicine and its biologically active triterpenoids have attracted attention. Boletus edulis is edible.

Tricholometaceae

The Tricholometaceae contains Clitocybe (80 spp.), species of which produce muscarine (q.v.). Other families of the order contain Stropharia, Psilocybe and Conocybe, which produce hallucinogenic substances (q.v.) such as psilosin and psilocybin.

Amanitaceae

The family includes Amanita (50–60 spp.) and Pluteus; Amanita muscaria (fly agaric) and A. pantherina contain muscarine (q.v.).

Agaricaceae

This family includes the common mushroom, Agaricus campestris. The genus Agaricus (Psalliota) contains about 30 species.

Phallinaceae

The Phallinaceae takes its name from Phallus (10 spp.). Phallus impudicus is the stinkhorn.

Dematiaceae

The family Dematiaceae contains Helminthosporium (150–200 spp.), a species of which, H. graminium, produces helminthosporin (q.v.). Another family of the group, the Tuberculariaceae, contains Fusarium (65 spp.). Fusarium lini will transform digitoxigenin into digoxigenin.

Fungal spores are a common source of allergens.

Cycadaceae

The order contains only 10 genera and about 100 species. The family Cycadaceae contains the single genus Cycas, with 20 species. A sago (not to be confused with that from certain palms) is obtained from the pith of Cycas circinalis and C. revolula.

Ginkgoaceae

With the exception of Ginkgo biloba, the maidenhair-tree, the plants of this order are found only as fossils. In recent years, owing to their increasing use for the treatment of various diseases associated with the ageing process, the leaves of the ginkgo tree have been extensively investigated. For further details see ‘Diterpenoids’.

Pinaceae

All members of the order are trees or shrubs; mostly evergreen with needle-like leaves; monoecious or dioecious. Sporophylls usually in cones. Resin ducts occur in all parts.

The Pinaceae are trees, rarely shrubs. Important genera are: Abies (50 spp.), Pseudotsuga (7 spp.), Tsuga (15 spp.), Picea (50 spp.), Larix (11 spp.), Cedrus (4 spp.), and Pinus (70–100 spp.). They are abundant in the northern hemisphere and extend southwards to Indonesia and Central America. Apart from their great value as timber and paper-making material, many species (e.g. Pinus) yield oleoresin (see ‘Colophony Resin and Crude Turpentine’). Other species are Abies balsamea, yielding Canada balsam; Pseudotsuga taxifolia (Douglas fir); Picea abies (Norway spruce); and Larix europaeus (larch). The barks of larch and hemlock spruce are tanning materials. Pinus pinea (the umbrella pine) produces large edible seeds (pignons). An extract of the bark of P. pinaster (P. maritima) var. atlantica containing bioflavonoids, particularly procyanidins (q.v.), is marketed as a food supplement (Pycnogenol®) having antioxidant properties. Some members of the family are a potential source of shikimic acid (q.v.).

Taxodiaceae

A small family of 10 genera, including Sequoia, Taxodium, Cryptomeria, Tetraclinis, Taiwania and Cunninghamia; 16 species.

The resin sandarac is produced in North Africa and Spain from Tetraclinis articulata. Some of the family contain antifungal diterpenes, others alkaloids.

Cupressaceae

A family of 19 genera and 130 species of trees and shrubs.

Members differ from the Pinaceae in that the leaves and cone-scales are usually opposite or whorled and the ovules erect. The genera include Callitris (16 spp., Australasia), Thuja (5 spp., China, Japan and North America), Cupressus (15–20 spp.), Chamaecyparis (7 spp.), Juniperus (60 spp., northern hemisphere). Juniperus communis yields juniper berries and volatile oil (q.v.); J. virginiana, the red cedar wood used for pencils; and J. sabina, volatile oil of savin; J. oxycedrus, by destructive distillation, yields oil of cade, which was formerly much used in veterinary work. This tar-like oil contains cadinene and phenols. Various diterpenes and flavonoids of the family have been studied.

Araucariaceae

Two genera and 38 species of trees, which sometimes have pungent leaves.

Araucaria (18 spp.) provides useful timbers; and Agathis (20 spp.), the resins known as copals or animes, which are used for varnish. Manila copal is obtained from the Malaysian Agathis alba; and kauri copal from A. australis, the kauri pine, in Australia and New Zealand. The best copals are usually those found in the ground long after the trees are dead.

Podocarpaceae

Six genera and 125 species of trees and shrubs. The largest genus, Podocarpus (100 spp.), extends from tropical to temperate zones and yields valuable timbers. A characteristic chemical feature of this genus is the widespread occurrence of norditerpene and bisnorditerpene dilactones; these compounds exhibit a variety of biological activities (see I. Kubo et al., Phytochemistry, 1992, 31, 1545).

Cephalotaxaceae

A family of one genus (Cephalotaxus) and seven species of trees and shrubs (plum yews) found from the eastern Himalayas to Japan. They have been intensively studied for their antitumour constituents in particular, the alkaloids harringtonine and homoharringtonine from C. harringtonia.

Taxaceae

An order of only one family, which includes the genera Taxus (10 spp.), Pseudotaxus, Torreya, Austrotaxus and Amentotaxus.

The common yew, Taxus baccata, produces valuable wood. The fruit has a fleshy red aril. All parts of the plant are very poisonous, and cattle and horses can die very rapidly after eating the leaves and stems. In addition to alkaloids, a cyanogenetic glycoside and antitumour agent have been reported in the genus.

Taxus brevifolia (the Pacific yew). The bark of this species yields the anticancer drug taxol, a nitrogenous diterpene. Low yields from the bark and the scarcity of raw material leading to damage to forests by, often illegal, over-collection hampered the development of the drug. The investigation of alternative sources led to tissue culture procedures for the production of taxol but the yields are still low. A development involving a renewable source has been the isolation of 10-deacetylbaccatin from the fresh needles of T. baccata in up to 0.1% yield and its chemical conversion to taxol. T. media, T. cuspidata and T. chinensis are other species investigated for taxane alkaloids.

Ephedraceae

The order consists of three families (Gnetaceae, Ephedraceae and Welwitchiaceae), three genera and about 70–75 species.

The Ephedraceae contains the single genus Ephedra (q.v.), about 40 species of shrubs. They occur in arid regions of the subtropics and tropics. Their seed, with two cotyledons, is enclosed in a perianth which becomes woody. Various species yield the drug ephedra (q.v.) and the alkaloid ephedrine.

Myricaceae and Juglandaceae

The order contains only these two small families.

The Myricaceae has three or four genera of trees and shrubs with unisexual flowers. Some members contain volatile oil (e.g. Myrica gale, the bog myrtle).

The Juglandaceae has seven or eight genera and the best-known species is the walnut, Juglans regia, which produces timber and edible nuts. Juglans contains the naphthoquinone juglone, the sugars raffinose and stachyose, flavonoids and phenolic acids.

The leaves and pericarp of J. regia have long been used as extracts in traditional medicine and pharmacologically demonstrated to be antihelmintic, antidiarrhoeal, antifungal, astringent, hypoglycaemic and, more recently, sedative; see M. Girzu et al., Pharm. Biol., 1998, 36, 280.

Salicaceae

The single family of the order contains only two genera, Salix (500 spp.) and Populus (35 spp.). The dioecious flowers are in catkins.

Both genera contain phenolic glycosides such as fragilin, salicin and populin. Salicin, formerly used in medicine, has been replaced by other drugs. Willow charcoal is the chief kind of wood charcoal used in Britain. Osiers (Salix purpurea and S. viminalis) are used for basket-making, and S. alba var. caerulea is used for cricket-bats. Species of Populus contain raffinose and stachyose. The dried winter buds of various species of poplar (P. nigra, P. candicans, P. tacamahaca) constitute Balm of Gilead Bud BHP 1996, BHC Vol 1, 1992. It is used as an expectorant and contains flavonoids, phenolic esters and free acids (caffeic acid, etc.). The hive product propolis may be derived from poplar bud exudates.

Betulaceae and Fagaceae

These families consist of monoecious trees and shrubs. Their classification together is confirmed by similarities in constituents.

The Betulaceae has two genera, Alnus (35 spp.) and Betula (60 spp.). Constituents include many phenolic substances such as myricetin, delphinidin and ellagic acid; also terpenoids such as lupeol and betulin. The wood of Betula alba is used for charcoal.

The Fagaceae has eight genera and about 900 species. Fagus (10 spp.) includes the beech, F. sylvatica, the nuts of which are expressed to yield oil; Castanea (12 spp.) includes the sweet chestnut, C. sativa, which yields timber and a bark used for tanning. The edible nut serves as a component of a gluten-free diet in cases of coeliac disease and in paediatrics for the treatment of gastroenteritis. For the isolation of a pyrrole alkaloid from the seeds, see A. Hiermann et al., Fitoterapia, 2002, 73, 22. Quercus (450 spp.) provides valuable timber. Different Quercus spp. contain shikimic acid (a cyclitol), methyl salicylate and terpenoids. The cupules and unripe acorns of Q. aegelops (valonia) are used in tanning. Q. ilex and Q. robur yield tanning barks and Q. tinctoria, a yellow dye. Q. suber affords the commonly used cork, in an industry worth (1987) some £120 million p.a. to Portugal’s economy; because there was no planned re-afforestation the industry now faces a decline. An extract of Q. stenophylla has been marketed for the acceleration of the elimination of renal and urethral calculi. Turkish galls (q.v.), an important source of tannic acid, are vegetable growths formed on the young twigs of the dyer’s oak, Q. infectoria, as a result of the activity of a gall-wasp. Similar galls are produced on the English oak, Q. robur.

Ulmaceae, Moraceae, Cannabinaceae, Urticaceae

The Cannabinaceae, originally included in the Moraceae, is now regarded as a separate family.

Proteaceae

The single family of the order, the Proteaceae, contains 62 genera and 1050 species. Shrubs and trees are particularly abundant in Australia, New Zealand and South Africa. Many species have been examined chemically, and the constituents reported include cyanogenetic compounds, alkaloids, tannins, leucoanthocyanins, arbutin and the sugar alcohol polygalitol. Genera include Protea (130 spp.), Grevillea, Persoonia, Hakea and Knightia.

Olacaceae, Santalaceae, Loranthaceae

The order contains seven families of which only four need be mentioned.

The Olacaceae has about 27 genera and 250 species. Few have been examined chemically. Acetylenic acids occur in Olax stricta.

The Santalaceae contains about 30 genera and 400 species. Of the genera, Santalum contains 25 species and Thesium about 325 species. Monoterpenes and sesquiterpenes occur in several genera. The plants are hemiparasitic herbs, shrubs and small trees. Santalum album yields sandalwood and sandalwood oil (q.v.) and is rich in sesquiterpene alcohols. Australian sandalwood and its oil are obtained from another member of the family, Eucarya spicata.

The Loranthaceae is a fairly large family of 36 genera and 1300 species. The genus Viscum consists of about 60 species of parasitic evergreen shrubs, which often contain cyclitols. The dried aerial parts of the common mistletoe, Viscum album, which grows on apple and other trees are included in the BHP 1996 and are used for various circulatory conditions. It contains glycoproteins (the mistletoe lectins), polypeptides (viscotoxins), lignans, flavonoids, etc. The flavonoid glycosides involve glucose, apiose and trans-cinnamic acid; for glycoside isolations from V. album ssp. atlantica grown on apricot (Armeniaca vulgaris) in Turkey, see D. Deliorman Orhan et al., Pharm. Biol., 2002, 40, 380.

Polygonaceae

This one-family order occupies an isolated position. It has about 40 genera and 800 species, mostly herbs. About 29 species are indigenous to Britain. Genera include Rheum (50 spp.), Rumex (about 180 spp.), Fagopyrum (15 spp.), Coccoloba (150 spp.) and Polygonum. The fruit is a one-seeded, usually three-winged nut (e.g. dock and buckwheat). Anthocyanin pigments are common; also flavones and flavonols—for example, buckwheat, Fagopyrum esculentum, is a commercial source of rutin. Quinones (anthraquinones, phenanthraquinones, anthrones and dianthrones) are found in many species of Rheum (q.v.), Rumex and Polygonum. The root of Rumex crispus (yellow dock, curled dock), BHP 1983, contains hydroxyanthraquinone derivatives; it is indicated for the treatment of chronic skin diseases, obstructive jaundice and psoriasis.

Phytolaccaceae, Caryophyllaceae, Chenopodiaceae

The order contains 13 families which show a passage from the monochlamydeous type of flower (e.g. Phytolaccaceae and Chenopodiaceae) to the dichlamydeous type of flower (e.g. Caryophyllaceae). Most families of the order, except the Caryophyllaceae, produce characteristic betacyanin and betaxanthin pigments, which indicate affinity with the Cactales (the next order, below).

The Phytolaccaceae is a family of 12 genera and 100 species; herbs, shrubs and trees, found particularly in tropical America and South Africa. Phytolacca (35 spp.) includes Phytolacca americana (Poke root), the leaves and roots of which have been found as an adulterant of belladonna: its berries contain a dyestuff. The roots which contain saponins are included in the BHP (1996) for the treatment of rheumatic diseases; however, arising from its toxicity the drug is not strongly recommended and excessive use should be avoided. The toxicity is primarily due to mitogenic proteins (lectins) and triterpene saponins. Other species have been shown to have molluscicidal activity.

The Caryophyllaceae has 70 genera and about 1750 species, mostly herbs, and is wide-spread. Genera include Saponaria, Stellaria, Arenaria, Spergularia, Herniaria, Silene, Lychnis, Gypsophila (125 spp.) and Dianthus (300 spp.). Many of these plants are rich in saponins. The root of Saponaria officinalis has been included in many pharmacopoeias. It contains about 5% of saponins and is widely used as a domestic detergent.

The Chenopodiaceae contains 102 genera and 1400 species; most grow naturally in soils containing much salt (halophytes). Genera include Beta (6 spp.), Chenopodium (100–150 spp.), Salicornia, Atriplex and Anabasis. From the wild Beta vulgaris (sea-beet) have been derived garden beetroot, sugar-beet and the mangold-wurzel. Chenopodium anthelminticum yields the anthelmintic Mexican tea or ‘wormseed’ and its oil of chenopodium (q.v.).

Cactaceae

The Cactaceae is the only family of the order and contains from 50 to 150 genera and about 2000 species. The plants are xerophytes and, with possibly one exception, are all native to the Americas. They will not grow where there is virtually no rainfall, but thrive in deserts where there is a reasonable rainfall even if rain occurs very infrequently. Some cacti occur in rain forests, where they are often epiphytes (e.g. Epiphyllum). The majority are succulent and store water in their stems. The plant body is usually globular or cylindrical and bears wool, spines and flowers, but in Epiphyllum the stems are flattened and consist of jointed segments, which are often mistaken for leaves. Among the genera are Epiphyllum (21 spp.), Opuntia (250 spp.), Cephalocereus (48 spp.), Cereus (50 spp.) and Echinocereus (75 spp.). The leaves of Opuntia and Nopolea provide food for cochineal insects (q.v.). Opuntia ficus-indica, the prickly-pear, is sometimes grown as a hedge but can become a troublesome weed. Dried cactus flowers (Opuntia spp.) are used as an astringent herbal remedy. O. dillenii finds various medicinal uses in India. Lophophora williamsii is the plant producing peyote, anhalonium or ‘mescal buttons’; it contains mescaline (q.v.). Several genera contain simple isoquinoline alkaloids; cyanogenetic glycosides are very rare or absent; most species contain abundant mucilage.

Magnoliaceae, Winteraceae, Annonaceae, Myristicaceae, Canellaceae, Schisandraceae, Illiciaceae, Monimiaceae, Lauraceae and Hernandiaceae

This order contains 22 families.

Ranunculaceae, Berberidaceae, Menispermaceae and Nymphaeaceae

Of the seven families in this order the above four are of medicinal interest. The families show a considerable variety of plant constituents and alkaloids are very common. In the four named families the alkaloids are often based on benzylisoquinoline, bisbenzylisoquinoline or aporphine.

Piperaceae

Four families are included in the Piperales; only the Piperaceae is considered here.

The Piperaceae (excluding the Peperomiaceae) consists of four genera and about 2000 species. The plants are tropical, mostly climbing shrubs or lianes, with swollen nodes and fleshy spikes of flowers. The leaves contain oil cells. The one-celled ovary has a single basal ovule and develops into a berry. The seeds contain endosperm and abundant perisperm. The four genera are Piper (about 2000 spp.), Trianaeopiper (18 spp.), Ottonia (70 spp.) and Pothomorphe (10 spp.). In addition to the above, Engler includes in the Piperaceae the Peperomiaceae with its four genera and about 1000 species of succulent herbs and subshrubs. All but 5 of its species belong to the genus Peperomia. The Piperaceae contains phenolic esters and ethers; pyrrolidine alkaloids; volatile oils and lignans. The peppers (q.v.) are widely used as condiments. Cubebs, Piper cubeba, was formerly used in medicine but is now obsolescent. In the South Pacific islands an aqueous extract of the roots of P. methysticum (kava-kava) is consumed as a ritual stimulant; large doses cause intoxication. In herbal medicine the root is used as a diuretic, stimulant and tonic. the active principles are pyrone derivatives (kava lactones); a number of piperidine alkaloids, including pipermethysticine, have also been isolated (K. Dragull et al., Phytochemistry, 2003, 63, 193).

Aristolochiaceae

The order comprises three families, of which only the Aristolochiaceae is of importance.

The Aristolochiaceae has seven genera and about 500 species. Members occur in the tropics and warm temperate zones, excluding Australia. Most are herbs or climbing shrubs. Oil-secreting cells occur throughout the family, often forming transparent dots on the leaves. The principal genera are Aristolochia (350 spp.) and Asarum (70 spp.). Constituents of the family include alkaloids (aporphine and protoberberine), aristolochic acid, phenolic esters and ethers, volatile oils and flavonoids. Some species show tumour-inhibiting properties. Asarum europaeum, asarabacca root, was formerly used in European medicine.

Paeoniaceae, Dipterocarpaceae, Theaceae, Guttiferae

Of the 16 families in the order, only the four above need be noted.

Sarraceniaceae, Nepenthaceae, Droseraceae

The three small families of insectivorous plants forming this order are of minor pharmaceutical interest.

The Sarraceniaceae consists of three genera and 17 species of pitcher-plants. The Nepenthaceae has two genera and 68 species, of which 67 belong to Nepenthes. In these plants, which occur mainly in tropical Asia, the leaves are modified into pitchers, which attract insects by their colour and honey-like secretion. The Droseraceae has four genera and 105 species. Of these, 100 belong to Drosera, which is represented in Britain by three sundews. The European sundew, Drosera rotundifolia, has long been employed in folk medicine and has been included in some pharmacopoeias (BHP 1983). In Italy it is an ingredient of a liqueur. It contains the naphthoquinone plumbagone, which has antimicrobial activity.

Papaveraceae, Fumariaceae, Capparaceae, Cruciferae

An order of seven families, if the Fumariaceae is separated from the Papaveraceae. The Papaveraceae belongs to the suborder Papaverineae and the Capparaceae and Cruciferae to the Capparineae. Some workers regard the Papaveraceae as related to the Ranunculales and the Capparineae as derived from the Cistales. Chemical support for this view is that alkaloids of the Papaveraceae are related to those of the Ranunculaceae, and that thiogluconates are absent from the Papaveraceae but present in the other two families.

Hamamelidaceae, Crassulaceae, Saxifragaceae, Rosaceae, Leguminosae, Krameriaceae

The order Rosales consists of 19 families divided into four suborders. The families to be considered fall into the suborders as follows: Hamamelidineae (Hamamelidaceae); Saxifragineae (Crassulaceae, Saxifragaceae and Pittosporaceae); Rosineae (Rosaceae); Leguminosineae (Leguminosae and Krameriaceae). The flowers are usually hermaphrodite (rarely bisexual by abortion: e.g. kousso flowers from Brayera); hypogynous, perigynous or epigynous. The sepals and petals are usually free; stamens and carpels free or united.

Geraniaceae, Zygophyllaceae, Linaceae, Erythroxylaceae, Euphorbiaceae

The order Geraniales consists of nine families.

Rutaceae, Simaroubaceae, Burseraceae, Meliaceae, Malpighiaceae, Polygalaceae

This order is closely allied to the Geraniales. The chief difference is that in the Rutales the plants are mainly shrubs or trees. The flowers have a disc between the androecium and the gynaecium. Oil glands are of general occurrence. The order contains 12 families and is divided into three suborders. Of the families mentioned above, the Rutaceae, Simaroubaceae, Burseraceae and Meliaceae all belong to the same suborder, the Rutineae.

Anacardiaceae, Aceraceae, Sapindaceae, Hippocastanaceae

The Sapindales consist of 10 families.

Aquifoliaceae, Celastraceae, Buxaceae

An order of 13 families; trees and shrubs with simple leaves.

Rhamnaceae, Vitaceae

The order contains three families.

Elaeocarpaceae, Tiliaceae, Malvaceae, Bombacaceae, Sterculiaceae

An order of seven families. Herbs, shrubs or trees; tropical and temperate. Many species contain mucilage; alkaloids are rare.

Thymelaeaceae, Elaeagnaceae

An order of five families.

Flacourtiaceae, Violaceae, Turneraceae, Passifloraceae, Cistaceae, Bixaceae, Tamaricaceae, Caricaceae

An order of 20 families. It includes herbs, shrubs and trees; tropical and temperate. Cyanogenetic glycosides occur in some of the families (e.g. Flacourtiaceae, Turneraceae and Passifloraceae), but are absent from others (e.g. Violaceae).

Cucurbitaceae

An order containing the single family Cucurbitaceae.

A family of about 110 genera and 640 species; abundant in the tropics; mostly herbs climbing by tendrils, with abundant sap and very rapid growth. Flowers are generally unisexual, regular and pentamerous, except in the gynaecium, which is reduced to three. The fruit is the fleshy type seen in the cucumber. Most members have bicollateral vascular bundles. Genera include Cucurbita (5 spp.), Cucumis (25 spp.), Ecballium (1 sp.), Citrullus (3 spp.), Luffa (6 spp.), Bryonia (4 spp.) and Momordica (45 spp.), Cucurbita pepo is vegetable marrow; C. maxima, great pumpkin; Cucumis melo, the melon; C. sativus, the cucumber; Ecballium elaterium, the squirting cucumber, yields the purgative elaterium; Citrullus colocynthis yields colocynth; C. lanatus, the water melon. The vascular network of the pericarp of Luffa is used as a bath sponge (loofah). The fruits and seeds of L. acutangula contain saponins and are used in Ayurvedic medicine. Bryony root, from Bryonia dioica, was formerly used as a purgative and for the treatment of gout; it contains saponins and sterols. Bryonia alba contains antitumour substances. The enzyme elaterase hydrolyses the bitter glucosides of the family to cucurbitacins and glucose. The cucurbitacins are triterpenoid bitter principles named A to Q, and the compound formerly known as alpha;-elaterin is cucurbitacin-E. For their formation in tissue cultures of Ecballium elatarium see G. A. Attard and A. Scicluna-Spiteri, Fitoterapia, 2001, 72, 146; G. Toker et al., Fitoterapia, 2003, 74, 618.

Lythraceae, Myrtaceae, Punicaceae, Rhizophoraceae, Combretaceae, Onagraceae

An order of 17 families. Many members rich in tannins.

Alangiaceae, Cornaceae, Garryaceae, Araliaceae, Umbelliferae

An order of seven families. All, except the Umbelliferae and Araliaceae, are small. Acetylenic compounds occur throughout the order.

The main umbelliferous fruits and their volatile oils used in pharmacy are fennel, Foeniculum vulgare; caraway, Carum carvi; dill, Anethum graveolens; coriander, Coriandrum sativum; aniseed, Pimpinella anisum; and cumin, Cumminum cyminum. Bupleurum falcatum roots contain oleanene saponins and are an important antihepatotoxic drug in oriental medicine. Visnaga, from Ammi visnaga, yields khellin, a dimethoxyfuranochromone. Among poisonous plants of the family may be mentioned Conium maculatum, the spotted hemlock, which contains the alkaloid coniine; and Oenanthe crocata, the hemlock waterdropwort, which contains oenanthotoxin. Other well-known plants of the family are celery, Apium graveolens; parsley, Petroselinum crispum; parsnip, Pastinaca sativa; and carrot, Daucus carota. Constituents of the family, other than volatile oils and resins, include coumarins (e.g. umbelliferone), furocoumarins, chromono-coumarins, terpenes and sesquiterpenes, triterpenoid saponins and acetylenic compounds. Alkaloids occur (e.g. coniine) but are rare.

Ericaceae

An order of five families, including the Pyrolaceae, Epacridaceae and Ericaceae. Only the last family, the largest, will be described.

Ericaceae. A family of about 80 genera and 2000 species; particularly common on moors and peaty soils. Members are shrubs or small trees. The genera include Rhododendron (500–600 spp.), Ledum (10 spp.), Erica (over 500 spp.), Calluna (1 sp.), Vaccinium (300–400 spp.), Gaylussacia (49 spp.), Gaultheria (about 210 spp.), Pieris (10 spp.), Lyonia (30 spp.), Arbutus (20 spp.) and Arctostaphylos (71 spp.). In addition to the well-known garden plants, the family includes the wintergreen, Gaultheria procumbens, which yields natural oil of wintergreen (now generally replaced by synthetic methyl salicylate); and bearberry leaves from Arctostaphylos uva-ursi, which contain the phenolic glycoside arbutin and are again official. The medicinal properties of Vaccinium myrtillus (bilberry, blueberry, whortleberry) have been utilized since the Middle Ages and have been reviewed (P. Morazzoni and E. Bombardelli, Fitoterapia, 1996, 67, 3); the fruits are included in the BP/EP. The family produces phenolic acids, phenolic glycosides (e.g. arbutin), aucubin glycosides, diterpenoids (grayanotoxin), triterpenoids (ursolic acid), cyclitols and leucoanthocyanins. A few species are cyanogenetic; saponins are absent.

Myrsinaceae, Primulaceae

An order of three families.

The Primulaceae consists of 20 genera and about 1000 species of herbaceous perennials with rhizomes or tubers. Especially common in the north temperate regions. Many members are cultivated as garden plants. Genera include Primula (500 spp.), Cyclamen (15 spp.), Anagallis (31 spp.) and Dionysia (41 spp.). The dried flowers of Primula veris (the cowslip) are used in herbal medicine for insomnia and as a sedative in combination with other herbs. The flowers are particularly rich in flavonoids. Saponins are present in some species; also phenolic esters and ethers. Alkaloids appear to be absent. Anthocyanin pigments are common, but not betacyanins or betaxanthins.

Plumbaginaceae

The Plumbaginaceae is the only family of the order, and contains 19 genera and about 775 species. Members are herbs or shrubs often found on sea coasts or salt steppes. Genera include Plumbago (12 spp.) and Ceratostigma. Roots of Plumbago spp. are used in traditional Indian medicine; immunosuppressive and antitumour activities have been demonstrated. Constituents found in the family include phenolic acids, tannins, anthocyanin pigments and naphthoquinones (e.g. plumbagin).

Sapotaceae, Ebenaceae, Styracaceae

An order of seven families consisting mainly of trees and shrubs.

Oleaceae

The Oleaceae is the only family of the order. It is widely distributed, and contains 29 genera and about 600 species. Genera include Olea (20 spp.), Forsythia (7 spp.), Fraxinus (70 spp.), Syringa (30 spp.), Osmanthus (15 spp.), Jasminum (300 spp.) and Ligustrum (40–50 spp.). Many species are grown in Britain (e.g. Syringa vulgaris, the lilac). The manna of present-day commerce is obtained by making incisions in the stem of the manna ash, Fraxinus ornus. F. oxyphylla and F. excelsior afford Ash Leaf BP/EP. Of great economic importance is the olive, Olea europoea. In addition to olive oil (q.v.), the family produces sugar alcohols (e.g. the mannitol of manna), saponins, tannins, coumarins and iridoid glycosides. Alkaloids are rare.

Loganiaceae, Gentianaceae, Menyanthaceae, Apocynaceae, Asclepiadaceae, Rubiaceae

An order of seven families which is of medical and chemical interest. All the families contain alkaloids, but important glycoside-containing genera also occur.

Polemoniaceae, Convolvulaceae, Boraginaceae, Verbenaceae, Labiatae, Solanaceae, Scrophulariaceae, Bignoniaceae, Acanthaceae, Pedaliaceae, Gesneriaceae, Myoporaceae

An order of six suborders and 26 families containing many important drugs. The families considered below fall into the following suborders:

Members of these families are usually herbs with alternate or opposite simple leaves. The flowers are generally bisexual and often zygomorphic. They usually have two or four epipetalous stamens and a bicarpellary superior ovary.

5 Labiatae (Lamiaceae). A family of about 200 genera and 3300 species; aromatic, annual or perennial herbs or undershrubs. The family is well represented in the Mediterranean area and in Britain. The flowers are bisexual, zygomorphic, usually have the floral formula K(5), C(5), A4, G(2), and are arranged in verticillasters. The corolla is bilabiate and the stamens didynamous. With the exception of Rosmarinus, the genera have a gynobasic style and the four nutlets have only a small surface of contact with one another. Rosemary also differs from most genera in having only two stamens. The herbaceous members of the family have square stems. The leaves and other aerial parts have clothing hairs (see Fig. 42.4) and glandular hairs (Fig. 42.5), which secrete the volatile oil. The genera include Ajuga (40 spp.), Teucrium (300 spp.), Rosmarinus (3 spp.), Scutellaria (300 spp.), Lavandula (28 spp.), Marrubium (40 spp.), Nepeta (250 spp.), Lamium (40–50 spp.), Ballota (35 spp.), Stachys (300 spp.), Salvia (700 spp.), Monarda (12 spp.), Satureja (30 spp.), Origanum (15–20 spp.), Thymus (300–400 spp.), Mentha (18 spp. and 13 hybrid spp.), Pogostemon (40 spp.), Ocimum (150 spp.), Leonurus (14 spp.) and Leonotis (41 spp.). Many members of the family are used as culinary or medicinal herbs, as sources of volatile oils and in some cases for the preparation of constituents of the volatile oils such as menthol and thymol; chemical races are common. In addition to those drugs described elsewhere, note pennyroyal (Mentha pulegium), patchouli (Pogostemon patchouli), germander (Teucrium chamaedrys), wood sage (T. scorodonia), wood betony (Stachys officinalis), sweet basil (Ocimum basilicum), holy basil (O. sanctum), savory (Satureja spp.), and hyssop (Hyssopus officinalis). Also, thyme (Thymus vulgaris) and Monarda punctata are both important sources of thymol. Patchouli oil obtained from Pogostemon cablin (P. patchouli) is used medicinally in China, and also cultivated in India. Of the 41 constituents of the volatile oil, α-guaiene (ca. 21%) and α-bulnescene (ca. 16%) have been reported as the principal components, with alpha;-bulnescene being active against PAF-induced platelet aggregation (Y.-C. Tsai et al., Fitoterapia, 2007, 78, 7).

In addition to the volatile oils, constituents of the family include diterpenoids and triterpenoids, saponins, a few pyridine and pyrrolidine alkaloids, insect-moulting hormones, polyphenols and tannins, iridoids and their glycosides, quinones, furanoids, cyclitols, coumarin, and the sugars raffinose and stachyose.

Liliaceae, Agavaceae, Hypoxidaceae, Amaryllidaceae, Dioscoreaceae, Iridaceae

The order is divided into five suborders and 17 families. Some botanists favour further subdivision—for example, the separation from the Liliaceae of Smilax and Ruscus into separate families, the Smilaceae and Ruscaceae respectively.

Many members of the group are perennial herbs having a bulb, corm or rhizome. The flowers are hermaphrodite, regular or zygomorphic, and typically have the floral formula P 3 + 3, A 3 + 3 or 3 + 0, G(3). The perianth is usually petaloid; the ovary superior (e.g. Liliaceae) or inferior (e.g. Iridaceae). Fruit a capsule or berry.

Bromeliaceae

The Bromeliaceae is the only family of the order and contains about 44 genera and 1400 species; mainly tropical and subtropical, xerophytes and epiphytes. Fruit a berry or capsule. These interesting plants vary very much in size and habitat; many are grown as house-plants or in greenhouses. Genera include Bromelia (40 spp.) and Ananas (5 spp.). Ananas comosus (syn. A. sativus) is the pineapple, the juice of which contains bromelain, a protein-splitting enzyme which can be used as an adjunct in the treatment of trauma and oedema arising from surgery and for soft tissue inflammation. It is cited as an aid to digestion and studies (Gut, 1998, 43, 196) have suggested it as a possible cure for travellers’ diarrhoea. The chemistry of the family requires more study, but many species contain gums and mucilages and there are reports of tannins, phenolic acids and flavonoids.

Gramineae

An order of one family.

The Gramineae contains about 620 genera and 10 000 species. Mostly herbs with fibrous roots; rarely shrubs or trees. Annuals, biennials and perennials almost universally distributed and many of great economic importance. Leaves alternate, with sheath; blade usually long and narrow; veins normally parallel. Inflorescence of numerous spikelets, with scales. Flowers bisexual, protected by palea; stamens usually three; ovary unilocular with one ovule. Fruit one-seeded, usually a caryopsis (rarely a nut or berry). Some important genera are Bambusa (70 spp.), Arundinaria (150 spp.), Oryza (25 spp.), Arundo (12 spp.), Triticum (about 20 spp.), Agropyron (100–150 spp.), Hordeum (20 spp.), Secale (4 spp.), Avena (70 spp.), Sorghum (60 spp.), Zea (1 sp.), Saccharum (5 spp.) and Andropogon (113 spp.), Cymbopogon (60 spp.), Phalaris (20 spp.) and Vetiveria (10 spp.). Products include bamboos of many different sizes, from species of Bambusa and Arundinaria, rice from Oryza sativa, wheat from Triticum, barley from Hordeum, rye from Secale, millet or guinea corn from Sorghum vulgare, maize or Indian corn from Zea mays and sugar cane from Saccharum officinarum. The tribe Paniceae, which includes Andropogon, Cymbopogon and Vetiveria, is rich in volatile oils. These grass oils are relatively cheap and are much used in perfumery, especially for scenting soap. They include citronella oils, lemon-grass and palmarosa (geranium) oils from species of Cymbopogon; oil of vetivert from Vetiveria zizanioides. The roots of the latter plant, khus-khus, are used both in perfumery and as a drug and are also woven into fragrant-smelling mats and fans.

The Gramineae contains a very wide range of constituents but a large proportion of the chemical work has been devoted to the above-mentioned foodstuffs, starches, sugar and volatile oils. Other constituents include 11 different classes of alkaloid (for details see R. D. Gibbs, Chemotaxonomy of Flowering Plants, Montreal, Canada: McGill University Press), saponins, cyanogenetic substances, phenolic acids, flavonoids and terpenoids.

Palmae

The order contains the single family Palmae.

The Palmae has 217 genera and about 2500 species. Widely distributed in the tropics and subtropics. Mostly trees with an unbranched stem bearing a crown of large, often branched leaves. The flowers are usually unisexual and regular, consisting of two trimerous whorls of small perianth leaves, six stamens and three superior carpels. The carpels may be free or united and develop into a berry, drupe or nut. The seeds contain a very small embryo but abundant endosperm. Important genera are Phoenix (17 spp.), Sabal (25 spp.), Copernicia (30 spp.), Metroxylon (15 spp.), Calamus (375 spp.), Areca (54 spp.), Elaeis (2 spp.), Cocos (1 sp.), Phytelephas (15 spp.), Serenoa (1 sp.) and Daemonorops (100 spp.). Of economic interest are the date palm, Phoenix dactylifera; sago from the stems of Metroxylon rumpii and M. laeve; rattan canes from species of Calamus; areca or betel nuts from Areca catechu; palm oil and palm kernel oil from Elaeis guineensis; coconut from Cocos nucifera; carnauba wax from Copernicia cerifera. The resin from species of Daemonorops gives the East Asian dragon’s blood and this appears (1997) to be the only available commercial source; the constituents investigated are of flavonoid origin, some derived from 5-methoxyflavan-7-ol and 5-methoxy-6-methylflavan-7-ol. Isolated compounds have been named dracoflavans (A. Arnone et al., J. Nat. Prod., 1997, 60, 971). For the botany, chemistry and therapeutic uses of this, and other types of dragon’s blood (species of Croton, Dracaena and Pterocarpus), see D. Gupta et al., J. Ethnopharm., 2008, 115, 361. The fruits of Serenoa repens (saw-palmetto) native to the S.E. coastal states of North America are a popular remedy for male impotence and are used in the treatment of the symptoms of benign prostate hyperplasia (q.v.). Seeds of Phytelephas spp. (P. aequatorialis in Ecuador) are the basis of the vegetable ivory industry (for a report see A. S. Barfod et al., Econ. Bot., 1990, 44, 293).In addition to the fixed oil, carbohydrates and leaf wax mentioned above, the family contains saponins, tannins, catechins, flavonoids, terpenoids and ketones. Alkaloids occur in Areca, but few have been found in other genera. Steroidal substances occur (e.g. estrone in the pollen of Phoenix).

Araceae

The order consists of two families, the Araceae and the Lemnaceae. The latter, which contains only six genera and 30 species of aquatic herbs, is of little importance.

The Araceae has 115 genera and about 2000 species; mainly herbs or climbing shrubs and over 90% tropical; many members contain poisonous latex, the poison being destroyed by heat. The genera include Acorus (2 spp.), Arum (15 spp.), Monstera (50 spp.), Dracuncula, Amorphophallus and Cryptocoryne. Calamus or sweet flag rhizome is derived from the perennial herb Acorus calamus, which is widely distributed in damp situations in Europe and North America. Arum, also known as lords and ladies, cuckoo-pint and wake robin, is Arum maculatum, a common hedgerow plant in England. It and other species of Arum are poisonous; these plants contain amines and cyanogenetic compounds. Species of Monstera are often grown as house-plants. The rhizome of Cryptocoryne spiralis is known as ‘Indian ipecacuanha’. Amorphophallus campanulatus is the elephant-foot yam. Many members of the family are cyanogenetic. Alkaloids, either pyridine or indole types, are reported in a few genera. Other constituents include saponins, tannins, phenolic acids, amines and terpenoids.

Cyperaceae

The order contains the single family.

The Cyperaceae has about 90 genera and 4000 species; widely distributed herbs. Genera include Cyperus (550 spp.), Scirpus (300 spp.) and Carex (150–200 spp.). Formerly official in a number of pharmacopoeias were the rhizomes of Carex arenaria and Cyperus rotundus. Papyrus, used in ancient times as paper, is derived from Cyperus papyrus. Like some members of the Gramineae, certain species of Scirpus and Ampelodesma serve as host plants for species of Claviceps and produce ergot-like sclerotia. Other family constituents include volatile oils, tannins, phenolic acids, flavonoids and sesquiterpenoids.

Musaceae, Zingiberaceae, Cannaceae, Marantaceae

An order of five families.

Orchidaceae

The order contains a single family.

The Orchidaceae is one of the largest families of flowering plants, with some 735 genera, over 17 000 species and many hybrids. Cosmopolitan perennial herbs, some terrestrial but many tropical epiphytes (e.g. Vanilla). The ovary is inferior and the fruit a capsule; seeds very small and light. Genera include Orchis (35 spp.), Cypripedium (50 spp.), Phalaenopsis (35 spp.), Dendrobium (1400 spp.), Liparis (250 spp.), Malaxis (300 spp.), Vanda (60 spp.), Cryptostylis (20 spp.) and Vanilla (90 spp.). The glycosides of vanilla, which produce vanillin and other aromatic substances by slow enzymic change, have long been known. More recently, attention has been directed to the numerous alkaloids present in the family. Some of these are of an unusual indolizidine type, others are derivatives of indole, pyrrolidine and pyrrolizidine. Other constituents include phenolic acids, tannin, flavonoids, coumarins and terpenoids.

(Sponges)

Metabolites include bromophenols (antibacterial properties), cyclic peroxides and peroxyketals (antimicrobial, ichthyotoxic, cytotoxic activities), modified sesquiterpenes (antimalarial, antifungal, antibacterial, anticancer activities). Siliceous sponge spicules are often found in samples of kieselguhr and agar (q.v.).

(Jellyfishes, sea anemones, corals)

The soft coral Plexaura homomalla is a rich source of prostaglandin A₂ and Sarcophyton glaucum contains diterpenoids (sarcophytols A and B) which inhibit tumour promotion. As with the sponges there is much current biochemical interest in this phylum.

(Flatworms)

This phylum includes the Trematodes (the parasitic flukes such as the liver fluke and Schistosoma) and the Cestoda (tapeworms).

(Roundworms)

Some are parasitic in man and animals.

(Segmented worms)

Earthworms, lugworms and leeches (q.v.) belong to this phylum. The potent neurotoxic agent nereistoxin is obtained from the Japanese species Lumbriconereis heteropoda.