This word document was downloaded from http://www. worddocx. com/ please remain this link information when you reproduce , copy, or use it. word documents Author: W Ethan Basch, Steven Gabardi and Catherine Ulbricht Type of Publication: Review Date of Publication: February 15, 2003 Publication: Am J Health-Syst Pharm—Vol. 60, February 15, 2003 Abstract: The pharmacology, clinical efficacy, adverse effects, drug interactions and place in therapy of bitter melon are described. Bitter melon (Momordica charantia) is an alternative therapy that has primarily been used for lowering blood glucose levels in patients with diabetes mellitus.
Components of bitter melon extract appear to have structural similarities to animal insulin. Antiviral and antineoplastic activities have also been reported in vitro. Four clinical trials found bitter melon juice, fruit and dried powder to have a moderate hypoglycemic effect. These studies were small and were not randomized or double-blind, however. Reported adverse effects of bitter melon include hypoglycemic coma and convulsions in children, reduced fertility in mice, a favism-like synrome, increases in ? -glutamyltransferase and alkaline phosphatase levels in animals and headaches.
Bitter melon may have additive effects when taken with other glucose-lowering agents. Adequately powered, randomized, placebo-controlled trials are needed to properly assess safety and efficacy before bitter melon can be routinely recommended. Bitter melon may have hypoglycemic effects, but data are not sufficient to recommend its use in the absence of careful supervision and monitoring. Bitter melon (Momordica charantia) is used primarily as an alternative therapy for diabetes. A member of the Cucurbitaceae family, the plant grows in tropical areas, including parts of the Amazon Basin, Africa, Asia, the Caribbean and South America.
The bitter melon is a vine with green leaves and yellow flowers; the fruit itself is oblong and green, resembling a cucumber. Bitter melon has a long history of use as a hypoglycemic agent in Asia, Africa, and Latin America, where the plant extract has been referred to as vegetable insulin. Data from in vitro, animal, and several poorly designed human studies do suggest that bitter melon and some of its crude extracts have a moderate hypoglycemic effect. More recently, bitter melon has been proposed as an antiviral and antineoplastic agent; in particular, a 30-kDa protein isolated from bitter melon seeds, MAP30, has shown promise.
1-4 However, despite some positive results in vitro, there are no reliable human trials showing efficacy for these latter indications. Folkloric uses have included a myriad of other indications, including psoriasis, infertility, gastrointestinal cramps, infections, and cancer and as an abortifacient. Extracts and powdered formulations of the fruit are used most frequently; less frequently, teas are made from the stems and leaves of the plant. Bitter melon is also consumed as a foodstuff and is found as an ingredient in some south Asian curries.
The raw fruit is available in specialty Asian markets, where it is known as karela. Other names and related substances include African cucumber, balsam-apple, balsam-birne, balsam pear, balsamo, beta-momorcharin, bitter apple, bitter cucumber, bitter gourd, bittergurke, carilla gourd, charantin, chinli-chih, cundeamor, kakara, kuguazi, k’u-kua, lai margose, MAP30, Momordica angustipala, momordique, pavakkachedi, pepino montero, p’u-t’ao, sorosi, sushavi, vegetable insulin and wild cucumber. This article describes the pharmacology, clinical efficacy, adverse effects, drug interactions and place in therapy of bitter melon.
Pharmacology Hypoglycemic activity. Multiple mechanisms have been proposed as the cause of bitter melon’s hypoglycemic properties. Components of bitter melon extract appear to have structural similarities to animal insulin, as measured by electrophoresis and infrared-spectrum analysis. $ Preliminary investigations have suggested some insulin-like properties of bitter melon. 5-7 other evidence indicates that bitter melon may decrease hepatic gluconeogenesis, increase hepatic glycogen synthesis, and increase peripheral glucose oxidation in erythrocytes and adipocytes.
8 Welihinda et al.9 reported that bitter melon increases pancreatic insulin secretion. It has been theorized that bitter melon extract increases beta-cell production in the pancreas; however, this mechamism has not been confirmed by studies. 10,11 Although several constituents of bitter melon have been fund to have hypoglycemic properties, most interest has focused on a polypeptide isolated from the seeds called polypeptide-p and a mixture of two steroid glycosides referred to as charantin. 12, 13 Antiviral activity. The antiviral activity observed in vitro has been attributed to MAP30.
this protein has been reported to inhibit HIV viral integrase and to cause irreversible relaxation of supecoiled viral nucleic acids. 3 these changes render viruses unable to integrate themselves into host cell genomes. Reduced rates of T-lymphocyte infection with HIV type-1 and reduced rates of viral replication in infected cells have also been reported in vitro. 3 The MAP30 gene has been cloned and expressed, and the recombinant protein re-MAP30 has properties in vitro similar to those of native MAP30. however, the antiviral activity of MAP-30 has not been studied in humans. Antineoplastic activity.
MAP-30 has been reported to have antineoplastic effects in vitro. These effects have been attributed to reduced expression of growth factor receptors, such as the transmembrane tyrosine kinase receptor encoded by the HER2 oncogene (also known as neu and c-erb-2), which has been implicated in breast cancer. 4, 14 MAP-30 was originally identified as a single-chain ribosome-inactivating protein, but its in vitro activities appear to be unrelated to its effect on ribosomes. 2, 4, 14 Again, the activities of this protein have not been studied in humans.
Clinical trials Bitter melon has been observed to decrease serum glucose levels in animal experiments and in a few methodologically weak human studies. 15-18 these investigations were neither randomized nor blinded, and dosage, toxicity and adverse effects have not been systematically assessed. Preparation techniques varied, and potency and chemical constituents may have varied accordingly.
Nonetheless, the human, animal and in vitro evidence collectively suggests a moderate hypoglycemic effect of bitter melon and some of its crude extracts. Reductions in serum glucose levels may occur as soon a 30 minutes after ingestion, peak at 4 hours, and persist for at least 12 hours.
Baldwa et al. 15 studied the effects of bitter melon on blood sugar levels in patients with diabetes. Nineteen subjects were enrolled, including 14 patients with type-1 or type-2 diabetes mellitus. An extraction method was performed to isolate vegetable insulin, which was suspended in sterile water and made available in a subcutaneous form with a concentration of 1. 8 mg of vegetable insulin per 40-unit dose.