Podophyllum spp.

Lignans, as natural products, are distributed widely in the plant kingdom. More than 200 compounds in this general class have been identified. Lignans have aroused considerable interest because some of them display antitumor activities. This is particularly true of the podophyllotoxin group of lignans, which are constituents of the medical resin extracted from Podophyllum species. Podophyllotoxins are a particularly instructive class of natural products for consideration in the design and synthesis of potential anticancer agents based upon natural product prototypes. History The medical use of Podophyllum species dates back over 1000 years. At that time the roots of wild chervil were used in a salve for treating cancer in England. About 400-600 years ago, the natives of the Himalayas and the American Indians independently discovered that the aqueous extracts of the roots (podophyllin) from Podophyllum species was a canthartic and poison. After the American Indians introduced the use of podophyllin to the American colonists, it became such a popular drug that it was included in the US Pharmacopoeia in 1820 as a canthartic and cholagog and remained until 1942, when it was removed because of its severe toxicity. However, Read more […]

Dysosma pleiantha (Hance) Woodson

Dysosma comprises seven species distributed from central and southern China to Taiwan. Among them, Dysosma pleiantha (Hance) Woodson (Berberidaceae), highly prized by the mountain tribes of Taiwan for its medicinal properties, is a herbaceous, rhizomatous perennial. It is an interesting species discovered by Watters in Taiwan in 1881 and described by Hance in 1883 as Podophyllum pleianthum (). It was later introduced as the synonyms P. versipelle Hance, P. onzoi Hayata, etc.. Woodson (1928) compared the floral and vegetative features of P. pleiantha and those of other species of Podophyllum in herbarium material, and indicated some features which are quite different, and suggested this herb as D. pleiantha (Hance) Woodson. This plant, distributed from Himalayan districts to Taiwan through the mountainous parts of China, was rarely cultivated in any of the European and American botanical gardens until earlier in this century. So, contrary to its related species Podophyllum peltatum L. and P. Emodi Wall., its morphological and histological studies have been rather neglected, although some descriptions were given by Kumazawa (1936), Ying (1979), and Terabayashi (1983). Studies on its heteromorphic karyotype have been documented. Several Read more […]

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 […]

Taxol (Paclitaxel) and Cancer Chemotherapy

Taxol is an antineoplastic agent. This compound, first isolated from the bark of the Western yew tree in 1971, exhibits unique pharmacological actions as an inhibitor of mitosis, differing from the vinca alkaloids and colchicine derivatives in that it promotes rather than inhibits microtubule formation. Following its introduction into clinical trial, the drug was approved for treatment of cisplatin-refractory ovarian cancer in 1992 and has promising activity against cancers of the breast, lung, esophagus, and head and neck. Malignant neoplastic diseases may be treated by various approaches: surgery, radiation therapy, immunotherapy, or chemotherapy, or a combination of these. The extent of a malignant disease (staging) should be ascertained in order to plan an effective therapeutic intervention. Plants have antineoplastic activities. A significant portion of the product derived from plants serve either as protective agents against various pathogens (e.g., insects, fungi, or bacteria) or growth regulatory molecules (e.g., hormonelike substances that stimulate or inhibit cell division and morphogenesis). Chemical Groups Of Natural Products With Anticancer Properties Cancer Chemotherapy Before discussing the specific Read more […]

Herb-Drug Interactions: Cannabis

Cannabis sativa L. (Cannabaceae) Synonym(s) and related species Bhang, Dagga, Ganja, Hashish, Indian hemp, Marihuana, Marijuana. Cannabis indica Lam. Constituents Cannabis herb contains a wide range of cannabinoids, which are the major active compounds. The main psychoactive constituent is delta9-tetrahydrocannabinol (THC; dronabinol), and it is the cause of many of the pharmacological effects elicited by the consumption of cannabis. However, other cannabinoids, which do not possess psychoactive properties, such as cannabidiol, cannabinol (a decomposition product of delta9-tetrahydrocannabinol), cannabigerol and cannabichromene, are increasingly being investigated for their pharmacological and therapeutic properties. Cannabinoids are often found in the plant as their acid metabolites, e.g. ll-nor-9-carboxy-delta9-tetrahydrocannabinol, cannabidiol acid and others, especially if the plant has been grown in a cooler climate. These decarboxylate to the parent cannabinoid at high temperatures, such as during smoking. Most medicinal cannabis products have been heat treated to ensure that the cannabinoids are present only in the non-acid form. Use and indications Cannabis has no current established use in herbal Read more […]

LIGNANS AND LIGNINS

Lignans are composed of two phenylpropanoid units joined together to form an 18-carbon skeleton. Many other functional groups can then be added by the plant to modify this base structure. Generally, these molecules are lipophilic and function within plant cell membranes to provide rigidity, strength, and water impermeability. Most lignans are relatively safe. Few generalizations can be made about this class of compounds beyond these statements, in part because of the lack of research. As interest in lignans grows, more information will surely become available. Several lignans have demonstrated intriguing and important clinical activity. Podophyllotoxin from Podophyllum peltatum (mayapple) acts as a cathartic laxative that is distinct from the anthraquinone glycosides; it inhibits human papillomavirus (HPV) and is antineoplastic. The semisynthetic chemotherapy drugs teniposide and etoposide are derived directly from this molecule. The lignans in Linum usitatissimum (flax), such as sec-oisolariciresinol, are transformed by the gut flora to enterodiol and enterolactone, known phytoestrogenic constituents that clearly are active in vivo. Flax seeds have definite anticancer effects, as has been documented in the results 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: Glucosamine

2-Amino-2-deoxy-beta-D-glucopyranose Types, sources and related compounds Chitosamine, Glucosamine hydrochloride, Glucosamine sulfate potassium chloride, Glucosamine sulfate sodium chloride. Pharmacopoeias Glucosamine Hydrochloride (US Ph 32); Glucosamine Sulfate Potassium Chloride (US Ph 32); Glucosamine Sulfate Sodium Chloride (US Ph 32); Glucosamine Tablets (The United States Ph 32). Use and indications Glucosamine is a natural substance found in chitin, mucoproteins and mucopolysaccharides. It can be made by the body, and is found in relatively high concentrations in cartilage, tendons and ligaments. The primary use of supplemental glucosamine is for the treatment of osteoarthritis and other joint disorders. It is sometimes given with chondroitin. Glucosamine in supplements may be prepared synthetically, or extracted from chitin. Pharmacokinetics The oral bioavailabihty of glucosamine has been estimated to be about 25 to 50%, probably due to first-pass metabolism in the liver. Glucosamine is rapidly absorbed and distributed into numerous tissues, with a particular affinity for articular cartilage. Interactions overview Glucosamine supplements have modestly increased the INR in a few patients taking Read more […]

Herb-Drug Interactions: Flavonoids

Bioflavonoids The flavonoids are a large complex group of related compounds, which are widely available in the form of dietary supplements, as well as in the herbs or foods that they are originally derived from. They are the subject of intensive investigations and new information is constantly being published. You may have come to this monograph via a herb that contains flavonoids. Note that the information in this general monograph relates to the individual flavonoids, and the reader is referred back to the herb (and vice versa) where appropriate. It is very difficult to confidently predict whether a herb that contains one of the flavonoids mentioned will interact in the same way. The levels of the flavonoid in the particular herb can vary a great deal between specimens, related species, extracts and brands, and it is important to take this into account when viewing the interactions described below. Types, sources and related compounds Flavonoids are a very large family of polyphenolic compounds synthesised by plants that are common and widely distributed. With the exception of the flavanols (e.g. catechins) and their polymers, the proanthocyanidins, they usually occur naturally bound to one or more sugar molecules Read more […]

Echinacea: Uses

Clinical Use Clinical trials using echinacea have used various preparations, such as topical applications, homeopathic preparations, injectable forms and oral dose forms, characteristics that should be noted when reviewing the data available. Overall, the majority of clinical studies performed in Europe have involved a commercial product known as Echinacin (Madaus, Germany), which contains the fresh-pressed leaf juice of Echinacea purpurea stabilised in ethanol. UPPER RESPIRATORY TRACT INFECTIONS Overall, clinical studies support the use of echinacea in URTIs, such as bacterial sinusitis, common cold, influenza-like viral infections and streptococcal throat. Evidence is strongest for use of echinacea in adults as an acute treatment; however, results in children have been disappointing. A 1999 review of 13 clinical trials consisting of 9 treatment studies and 4 prevention studies concluded that 8 of 9 treatment trials produced positive results whereas 3 of 4 prevention trials suggested modest effects. In other words, current evidence is stronger for supporting the use of echinacea as acute treatment in URTIs than as prophylactic treatment. In 2000, a Cochrane review was published that had assessed the evidence Read more […]