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Duke, J.A. 1990. Promising phytomedicinals. p. 491-498. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

Promising Phytomedicinals

James A. Duke*


  1. INTRODUCTION
  2. IMPORTANT MEDICINAL PLANT SPECIES
  3. CONCLUSIONS
  4. REFERENCES
  5. Table 1

INTRODUCTION

Two hundred and fifty years ago, there were few or no synthetic medicines. The 250,000-300,000 species of higher plants were the main source of drugs for the world's population. Today, 75% of the world's population, the poor 3/4ths, still relies on those plants and other tools of traditional medicine. In the U.S. and Europe the ecological movement has brought about a renewed interest in traditional medicines. High inflation rates in the third world have caused some citizens to return to or begin using herbal remedies. In Bolivia, the Ministry of Health and the Faculty of Medicine of the National University have given official and moral support for the return to native medicines (Healy 1986). Life expectancy of the poor has not increased quite so much as with the richer quarter of the world's population, who depend on non-traditional medicine. Even among prescription drugs, at least 25% contain at least one compound derived from higher plants. The percentage might be higher if we include over-the-counter (OTC) drugs. Today, many avant garde North American citizens, too, are beginning to seek natural alternatives to iatrogenic synthetics. The prescription drug market is around $40 billion** today, suggesting a value of about $10 billion for those drugs containing at least one compound derived from higher plants. Ironically, illicit drugs, mostly natural generate more revenue than prescription drugs, United States markets alone for illicit drugs are estimated at more than $150 billion.

In the 250 years when the "developed" quarter of the world shifted largely from naturals to synthetics, life expectancy and population nearly doubled, especially among the "developed" quarter. Who, then, would argue that natural drugs are better than synthetics? Some advocates of natural medicine tend to opt for the natural given a choice between a natural and synthetic of equal efficacy and toxicity. They argue that humans and our hominid ancestors coevolved with the natural compounds. Our genes and immune system also coevolved with many of the natural compounds, but have not experienced any of tomorrow's synthetics.

IMPORTANT MEDICINAL PLANT SPECIES

Table 1 was compiled mostly from published lists (Morton 1977, Farnsworth et al. 1985, Duke 1985a, and Tyler 1987). It lists 250 of the more important medicinal species, including those from which many of our prescription drugs are derived. Though more than half, maybe even more than three quarters, of the world's plant species are tropical, only about half of these 250 medicinal species are tropical. Why should half of the medicinal species be temperate? Simply because developed countries developed most drugs and, with the peculiar exception of the United States, developed countries tended to study their local flora first enabling them to rely on their own domestic supply. However, the United States imports much of its crude drug supply. Because of the high cost of labor in the United States, it is cheaper to import such things as chamomile from Europe, psyllium from India, and even jimson weed. But finished pharmaceutical products, like agricultural products, are among the few non-deficit columns in the United States export-import balance sheet.

I agree with others, such as Norman Farnsworth, America's most outspoken pharmacognoscist, who believe that somewhere in the plant kingdom there is a remedy for everything. But we may have to wait for the Japanese to develop and promote these remedies. In 1986, Japan developed 40% of the new drugs reaching the market, while the United States, United Kingdom, Germany, and France all together came up with only 40%, leaving 20% for the rest of the world. In 1987, Japan captured 56% of the natural product patents summarized in Phytotherapy Research.

Evolution argues quietly for the natural drug, while economics argues loudly for the unnatural drug. It now costs $125 million to bring a new drug to market in the United States. Out of 4,000 starts, only one makes it to market. Drug companies are not inclined to invest $125 million to prove an herb safe and efficacious. If we grow our medicine and self-medicate, the drug companies could not recoup their $125 million. Pharmaceutical firms do actively study potential medicinal plants, discovering bioactive compounds, which, with some molecular modifications, become proprietary, enabling them to recoup their investment

Podophyllotoxin and/or deoxypodophyllotoxin occur in such diverse genera as Anthriscus, Hernandia, Juniperus, Linum, and Podophyllum, some temperate, some tropical. Podophyllotoxin has been converted to etoposide (or vepeside) by a pharmaceutical firm (Bristol Myers). Etoposide was approved for cancer of the testicles in 1984 and for small cell cancer of the lungs in 1986. We assume, since the drug is approved, that it is safe and efficacious. It is said to be more safe and efficacious than the natural compound from which it derives. As with aspirin, etoposide may have fewer side effects than the natural compound from which it derives. But if the natural compound podophyllotoxin were safer and/or more efficacious, Bristol Myers would not be obligated to tell us. They could legally, and with economic good sense, withhold that information until the patent on etoposide expires. Who knows? Conceivably they may already have better naturals and semisynthetics! Why should they introduce them until they've recouped their investment on etoposide? Drug companies' fiscal health necessarily comes before your physical health.

All plant species contain poisonous, medicinal and nutritional compounds. For example, the nutritional value of herb teas is not to be discounted. Almost any foliar herb tea, with its vitamin C, could have prevented scurvy, scourge of sailors of the day of long voyages. In the tropics, 25-50 million children may be suffering from xerophthalmia, which could be alleviated or corrected by beta-carotene. A single large carrot may provide four times the vitamin A recommended daily allowance (RDA) (as beta-carotene). Fresh leafy vegetables average about 4,000 ug beta-carotene per 100 g. Foliar herbs used in herb teas also contain relatively high levels of betacarotene. On a zero-moisture basis (ZMB, water removed by calculation), the average herb is richer than 3% milk (ZMB) in fiber, calcium, iron, vitamin A, thiamin, niacin, and vitamin C (Duke and Atchley 1986).

We credit our forefathers with the intelligence to have discovered which species around them were poisonous and which were edible. Yet we sometimes seem reluctant to credit them with discovering those intermediate properties we call medicinal activities. Our forefathers discovered many, if not most of the important medicinal species tabulated herein. Farnsworth et al. (1985) calculated that 74% of 119 plant-derived drugs were discovered as a result of chemical studies to isolate the active substances responsible for their traditional use. In other words, we are indebted to our fore fathers empirical observations for about 75% of these currently used botanicals. We may expect new discoveries and uses among these same species, this year, next decade, next century. Only in this decade did we learn, e.g., about antiretroviral activities of hypericin, and anticirrhotic activity of colchicine, compounds rather common in temperate species.

We obtain our berberine, ephedrine (also synthesized), hypericin, papaverine (also synthesized), podophyllotoxin, sanguinarine, scopolamine, mostly from temperate species, but, we could get all of them from tropical species. With greater species diversity in the tropics, it follows that there is also a greater diversity in biologically active compounds in the tropics.

We've been cautioned by conservationists that tropical species (and their contained compounds) are jeopardized by habitat destruction. Such habitat destruction could endanger sources of some of our current medicines (i.e. Physostigma) and pesticides (i.e. Ryania) in genera confined to the tropics. The world will benefit from conservation of these species. The future discovery of new products from unexplored plants is dependent upon such conservation.

In Table 1, I've attempted to estimate the relative rarity of the medicinal plant germplasm in the United States. In Column 3 (Germplasm Availability) a Y (for Yes) indicates that germplasm is readily available, M (for Maybe) indicates that germplasm is limited, while an N (for No) indicates a perceived scarcity or nonexistence of public germplasm in the United States. Species scored M and N should be obtained through germplasm exploration or exchange.

In a computer data base, entitled Father Nature's Farmacy, I am compiling the surprising array of new medicinal uses for old (and some new) medicinal plants and the biologically active compounds contained therein. Firmly convinced that we could reduce the greenhouse effect significantly I urge the use of natural medicinal and pesticidal compounds (with biomass fuel as a byproduct in lieu of fossil fuels). Recently, there was near hysteria over traces of daminozide (Alar) (LD50 8,400 mg/kg orally in rats) in apples which contain several natural pesticides more toxic than alar. If Americans are going to get hysterical over traces of relatively non-toxic pesticides and growth regulators in the food chain, perhaps the much more copious natural pesticides should be removed from the food chain and put in the pesticide can, leaving the synthetics in the minds of man rather than the mouths of babes.

Reforestation of 100 million hectares with medicinal, pesticidal, and energy species, could tie up enough CO2 to halt the increase in CO2, hence retard or nullify the greenhouse warming (Duke 1985b). Two billion hectares in oil palm could provide us with enough oil (50 billion barrels) which, transesterified, could satisfy the world's energy needs renewably. There's much to be said for growing energy oils in the tropical zone and food oils (less saturated) in the temperate zone.

Elsewhere, I have detailed hundreds of new medicinal developments, the majority with old well-known medicinal species, the minority with species like Castanospermum australe A. Cunn. et Fras for which I find no folk medicinal data in the literature.

Here are just a few reported new uses for compounds from well-known old medicinal species: anabasine as antifumitory, artemisinin for malaria, chymopapain for disc problems, colchicine for cirrhosis, cynarin for choleretic activity, huperzine for anticholinesterase activity, hypericin for antiretroviral activity, gammalinolenic acid for atopic eczema, lobeline as an antifumitory, pilocarpine for xerostomia, polygodiol for antiyeast activity, psoralen for leukemia, sanguinarine for antiplaque activity, silymarin for hepatitis, taxol for antitumor activity, tetrahydrocannabinol for glaucoma, and yohimbine for serotinergic activity.

If forced to name the most important tropical medicinal species, I would apologetically list, with caveats, the following: Catharanthus, Cephaelis, Cinchona, Datura, Dioscorea, Erythroxylum, Physostigma (or Dioclea), Pilocarpus, Psoralea, and Rauwolfia. Collectively these have played a big role in dozens of major disorders. The United States is deficient in germplasm for more than half of these.

CONCLUSIONS

Once we have investigated and analyzed the tropical species as intensively as temperate species, I predict we'll find many more important medicinal species in the tropics. Already there are hundreds of well-known biologically active compounds from the thousands of tropical species that are used as folk or proven medicines. But fewer than 2% of these tropical species have been analyzed. It seems our duty as plant scientists and custodians of Planet Earth is to study carefully these plants. The value of products they can produce will exceed by a magnitude or more the cost of preserving them from extinction.

Somewhere in the tropics, there are probably compounds that will alleviate or correct every ailment known to mankind. Let's only hope someone finds them before the species and Tropical Medicine Chest become extinct. The survival of mankind is intimately dependent on the survival of forests. The more diverse tropical floras, containing more biologically active compounds, are even more threatened than the better studied temperate floras.

REFERENCES


*New Crops Botanist Modified from a lecture, Pharmacological Value of Tropical Medicinal Plants, first presented at American Society of Horticultural Science, Orlando, Florida, November 10, 1987, revised, expanded, and amended for presentation at this First National Symposium on New Crops. Acknowledgment to Steven Foster, Izard Ozark Natives, P.O. Box 106, Eureka Springs, Arkansas 72632, for valuable comments on Chinese medicinal species and Arthur O. Tucker, Department of Agriculture and Natural Resources, Delaware State College, Dover, Delaware, for help with the plant nomenclature.
**Sittig's Pharmaceutical Manufacturing Encyclopedia (1988) recently gauges the worldwide pharmaceutical market at more than $100 billion.
Table 1. Important medicinal plant species.

Species Habitz Germplasm
availabilityy
Some active ingredient(s)
Acacia senegal Tr T X M Gum acacia
Acokanthera schimperi Tr T X N Ouabain (cardiac)
Aconitum napellus Te P X Y Aconitine (CNS-active)
Adonis vernalis Te P X Y Adonoside (cardiotonic)
Aesculus hippocastanum Te T X Y Aescin (anti-inflammatory)
Agathosma betulina Tr S X N Limonene, pulegone, rutin, diosmin
Agave spp. Tr P EX YM Steroids
Agrimonia eupatoria Te P X Y Catechin,, Agrimophol (anthelmintic)
Ailanthus altissima Te T X Y Quassinoids (antimalarial)
Allium ssp. Te P X Y Alan, Allicin, Ajoene
Aloe vera Tr P X Y Aloin, aloe-emodin
Althaea officinalis Te P X Y Mucilage (demulcent)
Ammi majus Te A X Y Xanthotoxin (antipsoriac)
Ammi visnaga Te A X Y Khellin (antiasthmatic)
Anabasis aphylla Te S X M Anabasine (antismoking, myorelaxant)
Anadenanthera peregrina Tr T X Y Tryptamines
Anamirta cocculus Tr L X M Picrotoxin (analeptic)
Ananas comosus Tr P X Y Bromelain (proteolytic)
Andira araroba Tr T X N Chrysorobin (antipsoriac)
Andrographis paniculata Tr A X M Andrographolide, neoandrographolide (antidysenteric)
Angelica archangelica Te P X Y Imperatorin
Angelica polymorpha Te P X M Phthalides (sedative)
Anisodus tanguticus Te A X N Anisodine (anticholinergic)
Apocynum cannabinum Te P E Y Apocannoside, cymarin
Arctium lappa Te B X Y Arctiin inulin
Arctostaphylos uva-ursi Te P E Y Arbutin (anticystitic)
Ardisia japonica Tr S X M Bergenin (antitussive)
Areca catechu Tr T X M Arecoline (anthelmintic)
Artemisia annua Tr A X Y Artemisinin (antimalarial)
Artemisia maritima Te S X M Santonin (ascaricide)
Aspidosperma spp. Tr T X N Yohimbine (aphrodisiac)
Astragalus gummifer Te P X Y Tragacanth
Atropa belladonna Te P X Y Atropine
Avena sativa Te A X Y Fiber
Banisteriopsis caapi Tr L X Y Harmine, harmaline
Belamcamda chinensis Te P X Y Shikonin (antibacterial antitussive)
Berberis spp. Te S EX YM Berberine (antidysenteric)
Betula lenta Te T E Y Methyl salicylate
Bocconia spp. Tr T X M Sanguinarine (antiseptic)
Borago officinalis Te A X Y Gamma-linolenic-acid (anti-PMS)
Brassica nigra Te A X Y Allyl isothiocyanate (rubefacient)
Brunfelsia uniflorus Tr T X M Manacine, manaceine
Calendula officinalis Te A X Y Calendula oil
Camellia sinesis Tr T X Y Caffeine, theophylline
Camptotheca acuminata Te T X M Camptothecin, etc. (antitumor)
Cannabis sativa Te A X Y Delta-9-tetrahydrocannabinol (antiglaucomic, antemetic)
Capsicum spp. Tr A X Y Capsaicin
Carica papaya Tr S X Y Papain, chymopapain (proteolytic)
Castanospermum australe Tr T X Y Castanospermine
Catha edulis Tr S X Y Cathine, cathinine
Catharanthus roseus Tr P X Y Leurocristine (vincristine) and vinca leukoblastine (vinblastine)
Centella asiatica Tr P X E Y Asiaticoside (vulnerary)
Cephaelis ipecacuanha Tr P X N Emetine (amebicide, emetic)
Cephalotaxus spp. Te S X M Harringtonine, etc. (antitumor)
Chamaemelum nobile Te P X Y Chamazulene
Chelidonium majus Te P X Y Berberine, chelidonic acid
Chenopodium ambrosioides Tr A X E Y Ascaridole, methyl salicylate
Chimaphila spp. Te P E Y Arbutin
Chondodendron tomentosum Tr L X M Tubocurarine (myorelaxant)
Chrysanthemum cinerariaefolium Te P X Y Pyrethrins (insecticide)
Chrysanthemum parthenium Te P X Y Parthenolides (antimigraine)
Cinchona calisaya Tr T X M Quinine, quinidine
Cinchona ledgeriana Tr T X M Quinine, quinidine
Cinchona pubescens Tr T X M Quinine, quinidine
Cinnamomum camphora Tr T X M Camphor (rubefacient)
Cissampelos pareira Tr L X M Cissampeline (myorelaxant)
Citrullus colocynthis Tr V X Y Citrullol, elaterin
Citrus limon Tr T X Y Pectin
Citrus sinensis Tr T X Y Citrus bioflavonoids, limonene
Cnicus benedictus Te A X Y Polyacetylenes
Colchicum autumnale Te P X Y Colchicine, colchiceine amide, demecolcine
Coleus forskohlii Tr P X M Forskolin (cardiovascular)
Commiphora abyssinica Tr T X N Myrrh gum
Commiphora molmol Tr T X N Myrrh gum
Convallaria majalis Te P X Y Convallatoxin (cardiotonic)
Copaifera langsdorfii Tr T X M Oleoresin
Coptis spp. Te P X E Y Berberine (antidysenteric), palmatine (antipyretic, detoxicant)
Corydalis ambigua Te X M (±)-Tetrahydropalmatine (analgesic, sedative)
Crataegus oxyacantha Te T X Y Amines
Crotalaria sessiliflora Tr P X M Monocrotaline (antitumor)
Croton tiglium Tr S X M Croton oil
Curcuma longa Tr P X Y Curcumin (choleretic, anticoagulant)
Cynara scolymus Te P X Y Cynarin (choleretic)
Cytisus scoparius Te S X Y Sparteine
Daphne genkwa Te S X N Yuanhuacine (ecbolic) yuanhuadine (antitumor)
Datura stramonium Tr A X Y Scopolamine, hyoscyamine, atropine
Digitalis lanata Te B X Y Digoxin, lanatoside C, acetyidigoxin
Digitalis purpurea Te B/P X Y Digitoxin and digitalis whole leaf
Dioscorea spp. Tr L X Y Diosgenin
Drimys winteri Tr T X N Polygodiol (fungicide)
Duboisia myoporoides Tr S X N Atropine, hyoscyamine, scopolamine
Echinacea spp. Te P E Y Echinacein: arabinogalactan
Eleutherococcus senticosus Te T X Y Eleutherosides
Ephedra spp. Te S X M Ephedrine, pseudephedrine, norpseudephedrine
Erythroxylum coca Tr T X Y Cocaine
Erythroxylum novogranatense Tr T X Y Cocaine
Eucalyptus spp. Tr T X Y Eucalyptol (cineole), eucalyptus oil
Fagopyrum esculentum Te A X Y Rutin
Filipendula ulmaria Te P X Y Salicylates
Frangula alnus Te T X Y Frangula bark
Fraxinus rhynchophylla Te T X M Aesculetin (antidysenteric)
Gaultheria procumbens Te P E Y Methyl salicylate (rubefacient)
Gelsemium sempervirens Te L E Y Gelsemium extract
Gentiana spp. Te P E Y Gentiamarin, gentisic acid
Ginkgo biloba Te T X Y Superoxide dismutase
Glaucium flavum Te A X Y Glaucine (antitussive, hypotensive)
Glycine max Te A X Y Sitosterols
Glycyrrhiza glabra Te P X Y Licorice extract
Gossypium Tr A X Y Gossypol (male contraceptives)
Guaiacum officinale Tr T X Y Guaiaretic acid, guaiaconic acid
Guarea rusbyi Tr T X M Cocillana extract
Hamamelis virginiana Te S E Y Tannins
Heliotropium indicum Tr A X Y Heliotrine (antitumor, hypotensive)
Hemsleya amabilis Tr L X N Hemsleyadin (antidysenteric, antipyretic)
Holarrhena antidysenterica Tr T X M Conessine (amebicide, anesthetic), conkurchine (hypotensive, vasodilator)
Humulus lupulus Te V X Y Humulone, gamma-linolenic-acid
Huperzia serrata Te P X N Huperzine (anticholinesterase)
Hydnocarpus kurzii Tr T X M Chaulmoogric acid, hydnocarpic acid
Hydrastis canadensis Te P E Y Hydrastine (hemostat), berberine
Hyoscyamus spp. Te P X M Hyoscyamine, hyoscine, atropine
Hypericum spp. Te AP X E Y Hypericin (antiretroviral)
Ipomoea purga Tr V X M Ipurolic acid, scammonin
Jateorrhiza columba Tr L X M Jateorrhizine
latropha curcas Tr S X Y Curcin
Juglans spp. Te T E X Y Juglone (anthelmintic)
Juniperus oxycedrus Te S X Y Terpineol
Justicia adhatoda Tr S X M Vasicine (oxytocic, expectorant)
Larrea divaricata Tr S E Y Nordihydroguariaretic acid (antioxidant)
Lavendula officinalis Te P X Y Lavender oil
Linum usitatissimum Te A X Y Linseed oil podophyllotoxin ALA
Liquidambar styraciflora Te T E Y Storax
Liquidambar orientalis Te T X M Storax
Lobelia spp. Te A E Y Lobeline (antismoking)
Lophophora williamsii Tr P E Y Mescaline
Lycoris squamigera Te P X M Galanthamine (cholinesterase-inhibitor)
Macleaya cordata Te P X Y Sanguinarine (antiplaque)
Malus sylvestris Te T X Y Pectin
Matricaria recutita Te A X Y Azulenes
Melaleuca cajuputi Tr T X Y Cajeput oil
Melissa officinalis Te P X Y Rosmarinic acid
Mentha arvensis Te P X Y Menthol
Mentha x piperita Te P X Y Menthol (rubefacient anesthetic)
Mentha spicata Te P X Y Menthol (rubefacient anesthetic)
Momordica charantia Tr V X Y Charantin (antidiabetic)
Montanoa spp. Tr P X M Extracts (contraceptive)
Morus alba Te T X Y Morin (myorelaxant)
Mucuna deeringiana Tr L X Y Bufotenine (anticholinesterase), L-Dopa (antiparkinsonian)
Mucuna pruriens Tr L X Y Bufotenine (anticholinesterase), L-Dopa (antiparkinsonian)
Musa paradisiaca Tr P X Y Fruit pulp (antiulcer)
Myristica fragrans Tr T X Y Nutmeg oil
Myroxylon balsamum Tr T X M Tolu balsam, benzyl benzoate
Myroxylon balsamum var. pereirae Tr T X M Peru balsam
Narcissus tazetta Te P X Y Tazettine, lycorine
Nardostachys jatamansi Te P X M Jatamansone (tranquilizer for hyperkinesis)
Nepeta cataria Te P X Y Nepetalactone
Nicotiana tabacum Te A E Y Nicotine (insecticide)
Ocotea glaziovii Tr T X N Glaziovine (antidepressant)
Oenothera biennis Te B E Y Gamma-linolenic acid
Olea europaea Tr T X Y Olive oil (mono-unsaturates)
Paeonia albiflora Te P X Y Paeoniflorin (antiinflammatory)
Panax ginseng Te P X Y Ginsenosides
Panax quinquefolius Te P E Y Ginsenosides
Papaver somniferum Te A X Y Codeine, morphine, noscapine, papaverine
Papaver bracteatum Te P X Y Thebaine
Passiflora spp. Tr V X E Y Harmalines
Paullinia cupana Tr L X M Caffeine
Pausinystalia yohimbe Tr T X M Yohimbine
Peganum harmala Tr P X Y Harmalines
Peumus boldus Tr T X M Boldine, benzylbenzoate (scabicide)
Phyllanthus spp. Tr T X E M Phyllanthoside (antitumor)
Physalis spp. Te P XE YMN Withanolides
Physostigma venenosum Tr L X N Physostigmine (eserine)
Picrasma excelsa Tr T X M Picrasmin neoquassin
Picrorrhiza kurroa Tr P X M Kuskin, cinnamic acid, vanillic acid, apocyanin (choleretic, laxative)
Pilocarpus spp. Tr T X MN Pilocarpine
Pimpinella anisum Te A X Y Anise oil
Pinus elliottii Te T E Y Turpentine
Pinus palustris Te T E Y Turpentine
Piper cubeba Tr S X M Cubebin, 1,4-cineole
Piper methysticum Tr S X M Kawain
Plantago indica Tr A X M Psyllium husks, mucilage (hypocholesterolemic)
Plantago ovatum Tr A X Y Psyllium husks, mucilage (hypocholesterolemic)
Plantago psyllium Tr A X Y Psyllium husks, mucilage (hypocholesterolemic)
Platycodon grandiflorum Te P X Y Platycodin (analgesic, antitussive)
Podophyllum spp. Te P E Y Podophyllin, podophyllotoxin
Polygala senega Te P E Y Senega fluid extract
Populus spp. Te T E Y Salicin
Populus balsamifera Te T E Y Poplar bud
Prunus domestics Te T E Y Prune concentrate
Prunus virginiana Te T E Y Wild cherry bark
Psoralea corylifolia Tr P X M Psoralen, bakuchicol isopsoralen
Pterocarpus marsupium Tr T X M Epicatechin (antidiabetic)
Punica granatum Tr S X M Pelletierine
Quassia amara Tr S X M Quassin
Quercus infectoria Te T X M Tannic acid
Quisqualis indica Tr T X Y Quisqualic acid (ascaricide)
Rauvolfia serpentina Tr S X M Reserpine
Rauvolfia spp. Tr S X M Deserpidine, reserpine, rescinnamine, ajmaline
Rhamnus spp. Te T E Y Anthraquinones, emodim casanthranol, danthron
Rheum spp. Te P X M Anthraquinones (emodin)
Rheum rhaponticum Te P X Y Anthraquinones (emodin)
Rhododendron molle Te S X M Rhomitoxin (hypotensive, tranquilizer)
Ribes spp. Te S X E Y Gamma-linolenic acid
Ricinus communis Tr S X Y Castor oil, ricinoleic acid, ricin
Rorippa indica Te A X Y Rorifone (antitussive)
Rosa gallica Te S X Y Rose petal infusion
Ruta graveolens Te P X Y Rutin, bergapten, psoralen
Salix alba Te T E Y Salicin, salicylic acid (analgesic)
Sanguinaria canadensis Te P E Y Sanguinarine
Sassafras albidum Te T E Y Safrole, eugenol
Saussurea lappa Tr P X Y Saussurine (bronchiorelaxant)
Scutellaria lateriflora Te P E Y Scutellarin
Senna alexandrina Tr S X Y Sennosides A + B, danthron
Serenoa repens Tr S E Y Sitosterol
Sesamum indicum Tr A X Y Sesame oil
Silybum marianum Te P X Y Silymarin (antihepatotoxic)
Simarouba glauca Tr T X M Glaucarubin (antiamebic)
Smilax spp. Tr L X E Y M N Steroids
Sophora pachycarpa Tr T X M Pachycarpine (oxytocic), sparteine (oxytocic), rutin
Stephanie tetrandra Tr L X M Tetrandrine (hypotensive)
Sterculia urens Tr T X Y Karaya gum
Strophanthus gratus Tr L X N Ouabain
Strophanthus kombe Tr L X N Ouabain
Strychnos nux-vomica Tr T X M Strychnine, brucine
Styrax benzoin Tr T X M Benzoin gum
Styrax paralleloneurus Tr T X N Benzoin gum
Symphytum spp. Te P X Y Allantoin (vulnerary)
Syzygium aromaticum Tr T X Y Clove oil (antiseptic)
Tabebuia spp. Tr T X Y Lapachol (antitumor)
Tabernanthe iboga Tr S X M Ibogaine
Taxus brevifolia Te T E Y Taxol (antitumor)
Tecoma stans Tr T X Y Lapachol, tecomine
Terminalia chebula Tr T X M Ellagitannins
Theobroma cacao Tr T X Y Theobromine, caffeine (CNS, stimulant)
Thymus vulgaris Te P X Y Thymol (spasmolytic)
Trichosanthes kirilowii Tr V X M Trichosanthin (abortifacient)
Trigonella foenum-graecum Te A X Y Fenugreekine
Tripterygium wilfordii Te L X Y Wilfordine (antitumor)
Urginea maritima Te P X Y Scillaren A (cardiotonic)
Urtica dioica Te P E Y Acetylcholine, histamine, tryptamine
Vaccinium myrtillus Te S X Y Anthocyanosides
Vale,riana officinalis Te P X Y Valepotriates (tranquilizer)
Veratrum viride Te P E Y Cryptennamine, protoveratrine
Vinca minor Te P X Y Vincamine (cerebrotonic, hypotensive)
Viscum album Te P X Y Viscin
Warburgia ugandensis Tr T X M Polygodiol (antifeedant antiyeast)
Withania somniferum Tr P X Y Withanolide
Zea mays Te A X Y Cornsilk (diuretic)
Zingiber officinale Tr P X Y Borneol (analgesic, antiinflammatory, antipyretic), shogoal, zingerone
Ziziphus jujube Te T X Y Oleanolic acid, C-AMP (antiallergic)
zTr = Tropical, Te = Temperate, A = Annual, B = Biennial P = Perennial, S = Shrub, T = Tree, L = Liana (woody), V = Vine (herbaceous).
yX = Exotic to U.S.; E = Endemic to U.S.; Y = Yes (sufficient germplasm), M = Maybe (questionable sufficiency of germplasm), N = No (insufficient germplasm in the United States).


Last update March 25, 1997 by aw