Asteraceae: Drug Interactions, Contraindications, And Precautions

Patient survey data from Canada, the U.S., and Australia show that one in five patients use prescription drugs concurrently with CAM. The inherent polypharmaceutical nature of complementary and alternative medicine increases the risk of adverse events if these complementary and alternative medicine either have pharmacological activity or interfere with drug metabolism. Since confirmed interactions are sporadic and based largely on case reports, advice to avoid certain drug-CAM combinations is based on known pharmacological and in vitro properties. Known Hypersensitivity to Asteraceae Cross-reactive sesquiterpene lactones are present in many, if not all, Asteraceae. Patients with known CAD from one plant may develop similar type IV reactions following contact with others. Affected patients are often advised to avoid contact with all Asteraceae, yet this advice is based on limited knowledge of cross-reactivity between relatively few members of this large family. Some authorities recommend avoiding Asteraceae-derived complementary and alternative medicine if, for example, the patient is known to have IgE-mediated inhalant allergy to ragweed. While a reasonable approach, this ignores a number of important facts: (1) Read more […]

Natural products in Helicobacter pylori research

(in-vitro data) In most developing countries, plant-based medicines are commonly used to treat gastrointestinal ailments, including gastritis, peptic ulcer disease and diarrhea. Thus, considering the strong association between these conditions and Helicobacter pylori infections, it should not be surprising that some plant-based medicines would have activity against Helicobacter pylori in vitro. The first investigation of the in-vitro efficacy of plant extracts against Helicobacter pylori was published in 1991. This group reported that extracts of 13 Malagasy medicinal plants were effective against a number of clinical strains of Helicobacter pylori in vitro. In 1996, Fabry and coworkers reported that a number of east African medicinal plant extracts had inhibitory effects on the growth of Helicobacter pylori in vitro. One plant, Terminalia spinosa was reported to be the most active, with a minimum inhibitory concentration (MIC) range of 62.5-500 µg/mL. Extracts of Tbymus vulgaris (aqueous extract) and Cinnamonum zeylanicum (alcohol extract) were also reported to inhibit the growth of the bacterium at concentrations of 3.5 mg/mL. In 1997, investigators discovered that common food plants such as garlic, soybean Read more […]

Herb-Drug Interactions: Liquorice

Qycyrrhiza glabra L. (Fabaceae) Synonym(s) and related species Licorice. Spanish and Italian liquorice is Glycyrrhiza glabra var typica Reg. et Herd. Persian or Turkish liquorice is Glycyrrhiza glabra L var violacea Boiss. Russian liquorice is Glycyrrhiza glabra L var glanduli-fera. Chinese liquorice is the closely related Glycyrrhiza uralensis Fisch., also known as Gancao. Pharmacopoeias Licorice (US Ph 32); Liquorice (British Ph 2009); Liquorice Dry Extract for Flavouring Purposes (British Ph 2009); Liquorice Liquid Extract (British Ph 2009); Liquorice Root (European Ph 2008); Liquorice Root for use in THM (British Ph 2009); Powdered Licorice (US Ph 32); Powdered Licorice Extract (US Ph 32); Processed Liquorice Root for use in THMP (British Ph 2009); Standardised Liquorice Ethanolic Liquid Extract (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4). Constituents Liquorice has a great number of active compounds of different classes that act in different ways. The most important constituents are usually considered to be the oleanane-type triterpenes, mainly glycyrrhizin (glycyrrhizic or glycyrrhizinic acid), to which it is usually standardised, and its aglycone glycyrrhetinic 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 […]

Ginger: Background. Actions

Historical Note Ginger has been used as both a food and a medicine since ancient times. Confucius wrote about it in his Analects, the Greek physician, Dioscorides, listed ginger as an antidote to poisoning, as a digestive, and as being warming to the stomach in De Materia Medica, and the Koran, the Talmud and the Bible all mention ginger. Records suggest that ginger was highly valued as an article of trade and in 13th and 14th century England, one pound of ginger was worth the same as a sheep. Ginger is still extremely popular in the practice of phytotherapy, particularly in TCM, which distinguishes between the dried and fresh root. It is widely used to stimulate circulation, treat various gastrointestinal disorders and as a stimulant heating agent. Other Names African ginger, Indian ginger, Jamaica ginger, common ginger, rhizoma zingiberis, shokyo (Japanese) Botanical Name / Family Zingiber officinale Roscoe (family Zingiberaceae) Plant Part Used Rhizome Chemical Components The ginger rhizome contains an essential oil and resin known collectively as oleoresin. The composition of the essential oil varies according to the geographical origin, but the chief constituents, sesquiterpene hydrocarbons, which are Read more […]


ANTIBIOTICS are, strictly speaking, natural products secreted by microorganisms into their environment, where they inhibit the growth of competing microorganisms of different species. In common usage, the term is generally applied to a wide range of chemicals, whether directly isolated from mould ferments, their semisynthetic derivatives, or synthetic chemicals showing some structural similarities. Also, in everyday language the term is used to denote drugs with a selectively toxic action on bacteria or similar non-nucleated single-celled microorganisms (including chlamydia, rickettsia and mycoplasma), though such drugs have no effect on viruses. In this loose parlance even the sulphonamides may, incorrectly, be referred to as antibiotics because they are antimicrobial. More confusing is the fact that a number of antibiotics are used as cytotoxic agents in cancer chemotherapy (e.g. bleomycin): see ANTICANCER AGENTS. Further, partly because of the recent development of high-throughput screens for lead chemicals, a number of new drug chemical classes have arisen from antibiotic leads (e.g. the CCK antagonist asperlicin and derivatives, from Aspergillus spp.). The antimicrobial antibiotics have a selectively toxic Read more […]