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 […]


ANTIINFLAMMATORY AGENTS are drugs that are used to reduce inflammatory responses in the body. Although inflammation is essentially a normal defensive mechanism (a reaction to tissue injury, infection, inhalation of foreign proteins), the manifestations may be so serious and inappropriate or involve such discomfort, that treatment with antiinflammatory agents is required. Inflammatory conditions can be acute (as in insect stings) or chronic (chronic asthma, dermatitis and other skin conditions, rheumatoid conditions). A wide range of drugs may be used to treat one or other inflammatory condition, and potential toxicity in relation to the medical condition is an important determinant of choice. The NSAID ANALGESIC group has the widest antiinflammatory use, and their inhibitory antiinflammatory property is due to their cyclooxygenase activity (see CYCLOOXYGENASE INHIBITORS). Here the associated relief of pain is largely attributable to some degree of correction of the underlying inflammatory condition. Some of this group are relatively non-toxic and are available without prescription for use for relatively trivial complaints, e.g. aspirin and ibuprofen. (Paracetamol has insufficient antiinflammatory action to be useful Read more […]