Herb-Drug Interactions: Valerian

Valeriana officinalis L. (Valerianaceae) Synonym(s) and related species All-heal, Belgian valerian, Common valerian, Fragrant valerian, Garden valerian. Many other Valerian species are used in different parts of the world. Pharmacopoeias Powdered Valerian (The United States Ph 32); Powdered Valerian Extract (The United States Ph 32); Valerian (British Ph 2009, The United States Ph 32); Valerian Dry Aqueous Extract (European Ph 2008); Valerian Dry Hydroalcoholic Extract (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4); Valerian Root (European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4); Valerian Tablets (The United States Ph 32); Valerian Tincture (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4). Constituents Valerian root and rhizome contains a large number of constituents which vary considerably according to the source of the plant material and the method of processing and storage. Many are known to contribute to the activity, and even those that are known to be unstable may produce active decomposition products. The valepotriates include the valtrates, which are active constituents, but decompose on storage to form other Read more […]

Herb-Drug Interactions: St John’s wort

Hypericum perforatum L. (Clusiaceae) Synonym(s) and related species Hypericum, Millepertuis. Hypericum noeanum Boiss., Hypericum veronense Schrank. Pharmacopoeias St John’s Wort (British Ph 2009, European Ph 2008, US Ph 32); St John’s Wort Dry Extract, Quantified (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4). Constituents The main groups of active constituents of St John’s wort are thought to be the anthraquinones, including hypericin, isohypericin, pseudohypericin, protohypericin, protopseudohypericin and cyclopseudohypericin, and the prenylated phloroglucinols, including hyperforin and adhyperforin. Flavonoids, which include kaempferol, quercetin, luteolin, hyperoside, isoquercitrin, quercitrin and rutin; biflavonoids, which include biapigenin and amentoflavone, and catechins are also present. Other polyphenolic constituents include caffeic and chlorogenic acids, and a volatile oil containing methyl-2-octane. Most St John’s wort products are standardised at least for their hypericin content (British Pharmacopoeia 2009), even though hyperforin is known to be a more relevant therapeutic constituent, and some preparations are now standardised for both (The United Read more […]

Herb-Drug Interactions: Saw palmetto

Serenoa repens (Bartram) J.K. Small (Arecaceae) Synonym(s) and related species American dwarf palm, Sabal, Serenoa. Brahea serrulata H.Wendl., Sabal serrulata (Michx.) Schult f., Sabal serrulatum Schult f., Serenoa serrulata (Michx.) Hook. f. ex B.D. Jacks. Pharmacopoeias Powdered Saw Palmetto (US Ph 32); Saw Palmetto (US Ph 32); Saw Palmetto Capsules (US Ph 32); Saw Palmetto Fruit (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4). Constituents The fruit of saw palmetto contains about 25% fatty acids (extracts are often standardised to a minimum of 11% total fatty acids) consisting of capric, caprylic, lauric, palmitic, oleic, linoleic and linolenic acids in the form of fixed oils. Sterols including campesterol, stig masterol and beta-sitosterol are also present, as are long-chain alcohols, carotenoids, various polysaccharides and some flavonoids, including rutin, isoquercetin and kaempferol. Use and indications The main contemporary use of saw palmetto fruit is to treat the urological symptoms of benign prostatic hyperplasia. It has also been used as a diuretic, a sedative, an endocrine agent, an antiseptic and for treating disorders involving the sex hormones. Pharmacokinetics Saw Read more […]

Herb-Drug Interactions: Milk thistle

Silybum mahanum (L.) Gaertn. (Asteraceae) Synonym(s) and related species Lady’s thistle, Marian thistle, Mediterranean milk thistle, St Mary’s thistle. Carduus marianus, Mariana lactea Hill. Pharmacopoeias Milk Thistle (US Ph 32); Milk Thistle Capsules (US Ph 32); Milk Thistle Fruit (British Ph 2009, European Ph 2008); Milk Thistle Tablets (US Ph 32); Powdered Milk Thistle (US Ph 32); Powdered Milk Thistle Extract (US Ph 32); Refined and Standardised Milk Thistle Dry Extract (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4). Constituents The mature fruit (seed) of milk thistle contains silymarin, which is a mixture of the flavonolignans silibinin (silybin), silicristin (silychristin), silidianin (silydianin), isosilibinin and others. It may be standardised to contain not less than 1.5% (European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4), or not less than 2% (The United States Ph 32) of silymarin, expressed as silibinin (dried drug). Standardised extracts, containing high levels of silymarin, are often used. Milk thistle fruit also contains various other flavonoids, such as quercetin, and various sterols. Note that milk thistle leaves do not contain silymarin, Read more […]

Herb-Drug Interactions: Goldenseal

Hydrastis canadensis L. (Ranunculaceae) Synonym(s) and related species Hidrastis, Hydrastis, Orange root, Yellow root. Xanthorhiza simplicissima Marsh. Pharmacopoeias Goldenseal (US Ph 32); Goldenseal Rhizome (European Ph 2008); Goldenseal Root (British Ph 2009); Powdered Goldenseal (US Ph 32); Powdered Goldenseal Extract (The United States Ph 32). Constituents The rhizome of goldenseal contains the isoquinoline alkaloids hydrastine and berberine, to which it may be standardised, and also berberastine, hydrastinine, canadine (tetrahydroberberine), canalidine and others. Use and indications Used for inflammatory and infective conditions, such as amoebic dysentery and diarrhoea; gastric and liver disease. The alkaloids are antibacterial, amoebicidal and fungicidal. For details on the uses of berberine, a major constituent of goldenseal, see berberine. Pharmacokinetics In several in vitro studies, goldenseal root has been identified as a potent inhibitor of the cytochrome P450 isoenzyme CYP3A4, but more modest inhibitory effects were seen clinically with the CYP3A4 probe substrate, midazolam. Two studies in healthy subjects, found that goldenseal, given for 14 to 28 days, reduced the metabolism or urinary Read more […]

Herb-Drug Interactions: Ginseng

Panax ginseng C.A.Mey (Araliaceae) Synonym(s) and related species Many species and varieties of ginseng are used. Panax ginseng C.A.Mey is also known as Asian ginseng. Chinese ginseng, Korean ginseng, Oriental ginseng, Renshen. Panax quinquefolius L. is also known as American ginseng. Other species used include: Panax notoginseng (Burkill) F.H.Chen ex C.Y.Wu & K.M.Feng known as Sanchi ginseng, Tienchi ginseng and Panax pseudo-ginseng Wall, also known as Himalayan ginseng. It is important to note that Siberian ginseng (Eleutherococcus senticosus Maxim.) is often used and marketed as a ginseng, but it is from an entirely different plant of the Araliaceae family and possesses constituents that are chemically different. It will be covered in this monograph with distinctions made throughout. Not to be confused with ashwagandha, which is Withania somnifera. This is sometimes referred to as Indian ginseng. Not to be confused with Brazilian ginseng, which is Pfaffia paniculata. Pharmacopoeias American Ginseng (US Ph 32); American Ginseng Capsules (US Ph 32); American Ginseng Tablets (US Ph 32); Asian ginseng (US Ph 32); Asian Ginseng Tablets (US Ph 32); Eleuthero (US Ph 32); Eleutherococcus (British Read more […]

Herb-Drug Interactions: Ginkgo

Ginkgo biloba L. (Ginkgoaceae) Synonym(s) and related species Fossil tree, Kew tree, Maidenhair tree. Salisburia adiantifolia Sm., Salisburia biloba Hoffmanns. Pharmacopoeias Ginkgo (US Ph 32); Ginkgo capsules (US Ph 32); Ginkgo dry extract, refined and quantified (British Ph 2009, European Ph 2008); Ginkgo leaf (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4); Ginkgo tablets (US Ph 32); Powdered ginkgo extract (The United States Ph 32). Constituents Ginkgo leaves contain numerous flavonoids including the biflavone glycosides such as ginkgetin, isoginkgetin, bilobetin, sciadopitysin, and also some quercetin and kaempferol derivatives. Terpene lactones are the other major component, and these include ginkgolides A, B and C, and bilobalide, Ginkgo extracts may be standardised to contain between 22 and 27% flavonoids (flavone glycosides) and between 5 and 12% terpene lactones, both on the dried basis. The leaves contain only minor amounts of ginkgolic acids, and some pharmacopoeias specify a limit for these. The seeds contain ginkgotoxin (4-O-methylpyridoxine) and ginkgolic acids. Use and indications The leaves of ginkgo are the part usually used. Ginkgo is often used Read more […]

Herb-Drug Interactions: Garlic

Allium sativum L. (Alliaceae) Synonym(s) and related species Ajo, Allium. Pharmacopoeias Garlic (US Ph 32); Garlic Delayed Release Tablets (US Ph 32); Garlic Fluid Extract (US Ph 32); Garlic for Homeopathic Preparations (British Ph 2009, European Ph 2008); Garlic Powder (European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4, British Pharmacopoeia 2009); Powdered Garlic (US Ph 32); Powdered Garlic Extract (The United States Ph 32). Constituents Garlic products are produced from the bulbs (cloves) of garlic and are usually standardised according to the content of the sulphur-containing compounds, alliin, allicin (produced by the action of the enzyme alliinase on alliin) and/or γ-glutamyl-(S)-allyl-L-cysteine. Other sulphur compounds such as allylmethyltrisulfide. allylpropyldisulfide, diallyldisulfide, diallyltrisulfide, ajoene and vinyldithiines, and mercaptan are also present. Garlic also contains various glycosides, monoterpenoids, enzymes, vitamins, minerals and flavonoids based on kaempferol and quercetin. Use and indications Garlic has been used to treat respiratory infections (such as colds, flu, chronic bronchitis, and nasal and throat catarrh) and cardiovascular disorders. It is believed Read more […]