Bitter melon (Momordica charantia) and MAP30
Natural Standard Bottom Line Monograph, Copyright © 2013 (www.naturalstandard.com). Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.
While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.
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Bitter melon (Momordica charantia L. Curcurbitaceae) has traditionally been used as a remedy for lowering blood sugar in patients with diabetes. Preliminary data exists on bitter melon use in HIV and cancer. Extracts and powdered formulations of the fruit are most frequently used, although teas made from the stems and leaves are sometimes recommended.
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.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
MAP30, a protein isolated from bitter melon extract, has been reported to possess anti-cancer activity, although potential anti-cancer effects have not been studied in humans. Additional study is needed before a strong recommendation can be made.
Diabetes mellitus (hypoglycemic agent)
Preliminary study has indicated that bitter melon may decrease serum glucose levels; however, reports are mixed. Because safety and efficacy have not been established, bitter melon should be avoided by diabetics except under the strict supervision of a qualified healthcare professional, including a pharmacist, with careful monitoring of blood sugars.
Human immunodeficiency virus (HIV)
Early studies have shown that a protein in bitter melon called MAP30 may have antiviral activity, but this has not been studied in humans. Further research is needed before a strong recommendation can be made.
*Key to grades:A: Strong scientific evidence for this use; B: Good scientific evidence for this use; C: Unclear scientific evidence for this use; D: Fair scientific evidence against this use (it may not work); F: Strong scientific evidence against this use (it likely does not work).
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.
Abortion, analgesia (pain relief), anorexia, antifungal, antimicrobial, antioxidant, antiparasitic, antitumor, antiviral, chemopreventive, contraception, diabetic neuropathy, disorders of the stomach and intestines (diabetic gastopathy), gastrointestinal cramps, glaucoma, hemorrhoids, herpes, high cholesterol, immunomodulation, infertility, pain, psoriasis, respiratory infections, retinopathy, rheumatoid arthritis, sinusitis, stomach cramps.
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (over 18 years old)
Due to the wide variations in preparation techniques of bitter melon, the proper dosing cannot be determined at the present time. Bitter melon has sometimes been administered as a fruit juice in doses of 50 milliliters or 100 milliliters in diabetic patients. Juice formulations have been reported to have more potent effects on blood sugar and lab values than the powder of the sun-dried fruit. However, safety and efficacy have not been established for any specific dose(s) of bitter melon.
Subcutaneous administration of bitter melon has been studied in humans, although safety, efficacy, and dosing have not been clearly established.
Children (under 18 years old)
There is not enough scientific data to recommend bitter melon for use in children. Caution is advised, based on two case reports of hypoglycemic coma in children following the ingestion of bitter melon tea.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Individuals with allergies to plants related to the bitter melon or members of the Curcurbitaceae (gourd or melon) family, including Persian melon, honeydew, casaba, muskmelon, and cantaloupe, may have allergic reactions to bitter melon.
Side Effects and Warnings
Headaches have been reported after the ingestion of bitter melon seeds. However, details regarding severity and duration of headaches are limited. Considerable increases in liver enzymes have been observed in animals after drinking bitter melon fruit juice and seed extract. These increases, however, have not been associated with significant damage or changes in the liver. The clinical relevance in humans has not been studied, so caution is advised, particularly in patients with underlying liver disease. The seeds and outer-rind of bitter melon contain a toxic chemical (lectin), which inhibits protein synthesis in the intestinal wall. Although this has not been correlated with signs or symptoms in humans, ingestion of bitter melon seeds or outer rind should be avoided due to potential adverse effects.
Bitter melon may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia (low blood sugar) and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare provider, and medication adjustments may be necessary. Two case reports have documented hypoglycemic coma and convulsions in children after the administration of a bitter melon tea.
Ingestion of bitter melon (or bitter melon seeds) should be avoided in patients with glucose-6-phosphate dehydrogenase (G6PDH) deficiency, due to the risk of hemolytic reaction and "favism." Favism is the onset of hemolytic anemia with symptoms including headache, fever, stomach pain, and coma. G6PDH deficiency and favism are most common in people from the Mediterranean and the Middle East.
The fertility rate of mice that were fed with daily bitter melon juice dropped from 90% to 20% in one study. Sperm production was inhibited in dogs that were fed a bitter melon fruit extract for 60 days. However, studies of a protein isolated from bitter melon seeds, called MAP30, have found that they do not affect sperm motility in laboratory studies.
Pregnancy and Breastfeeding
Bitter melon is not recommended during pregnancy; two proteins isolated from the raw fruit possess properties that may cause an abortion in animals. Lowered fertility rates are also possible.
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
Bitter melon may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist.
Elevations in liver enzymes have been reported. Theoretically, bitter melon may interact with drugs metabolized by or affecting the liver.
The antiviral protein of bitter melon may enhance the therapies of the HIV antagonists, dexamethasone and indomethacin. Bitter melon may have antiviral and immunomodulating effects and therefore may have additive effects with other drugs with similar activity.
Bitter melon leaf extracts have been observed to reverse chemotherapy drug resistance.
Bitter melon may lower triglyceride levels and therefore may have additive effects with other drugs with similar activity.
Absorption, distribution, metabolism, and elimination (pharmacokinetics) of other drugs may be altered by bitter melon.
Bitter melon may induce abortion, reduce fertility rates, or inhibit production of sperm. Caution is advised in patients taking fertility agents or antifertility agents.
In theory, bitter melon may interact with medications used to treat parasites (anthelmintics).
Interactions with Herbs and Dietary Supplements
Bitter melon may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood sugar levels may require monitoring, and doses may need adjustment.
Elevations in liver enzymes have been reported. Theoretically, bitter melon may interact with herbs or supplements metabolized by or affecting the liver.
Bitter melon leaf extracts have been observed to reverse chemotherapy drug resistance.
Bitter melon may lower triglyceride levels and therefore may have additive effects with other herbs or supplements with similar activity.
Absorption, distribution, metabolism, and elimination (pharmacokinetics) of other herbs or supplements may be altered by bitter melon.
Bitter melon may induce abortion, reduce fertility rates, or inhibit production of sperm. Caution is advised in patients taking herbs or supplements with proposed fertility or antifertility effects.
In theory, bitter melon may also interact with herbs or supplements that suppress or enhance the immune system. Furthermore, bitter melon may interact with herbs or supplements used to treat parasites (anthelmintics), although human evidence is lacking in this area.
This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.
Basch E, Gabardi S, Ulbricht C. Bitter melon (Momordica charantia): a review of efficacy and safety. Am J Health Syst Pharm 2003;60(4):356-359. View Abstract
Bourinbaiar AS, Lee-Huang S. The activity of plant-derived antiretroviral proteins MAP30 and GAP31 against herpes simplex virus in vitro. Biochem Biophys Res Commun 1996;219(3):923-929. View Abstract
Bourinbaiar AS, Lee-Huang S. Potentiation of anti-HIV activity of anti-inflammatory drugs, dexamethasone and indomethacin, by MAP30, the antiviral agent from bitter melon. Biochem Biophys Res Commun 1995;208(2):779-785. View Abstract
Dans AM, Villarruz MV, Jimeno CA, et al. The effect of Momordica charantia capsule preparation on glycemic control in type 2 diabetes mellitus needs further studies. J Clin Epidemiol 2007;60(6):554-559. View Abstract
Das P, Sinhababu SP, Dam T. Screening of antihelminthic effects of Indian plant extracts: a preliminary report. J Altern Complement Med 2006;12(3):299-301. View Abstract
Day C, Cartwright T, Provost J, et al. Hypoglycaemic effect of Momordica charantia extracts. Planta Med 1990;56(5):426-429. View Abstract
Krawinkel MB, Keding GB. Bitter gourd (Momordica Charantia): A dietary approach to hyperglycemia. Nutr Rev 2006;64(7 Pt 1):331-337. View Abstract
Leatherdale BA, Panesar RK, Singh G, et al. Improvement in glucose tolerance due to Momordica charantia (karela). Br Med J (Clin Res Ed) 1981;282(6279):1823-1824. View Abstract
Lee-Huang S, Huang PL, Chen HC, et al. Anti-HIV and anti-tumor activities of recombinant MAP30 from bitter melon. Gene 1995;161(2):151-156. View Abstract
Lee-Huang S, Huang PL, Huang PL, et al. Inhibition of the integrase of human immunodeficiency virus (HIV) type 1 by anti-HIV plant proteins MAP30 and GAP31. Proc Natl Acad Sci USA 1995;92(19):8818-8822. View Abstract
Leung SO, Yeung HW, Leung KN. The immunosuppressive activities of two abortifacient proteins isolated from the seeds of bitter melon (Momordica charantia). Immunopharmacology 1987;13(3):159-171. View Abstract
Limtrakul P, Khantamat O, Pintha K. Inhibition of P-glycoprotein activity and reversal of cancer multidrug resistance by Momordica charantia extract. Cancer Chemother Pharmacol 2004 Dec;54(6):525-30. View Abstract
Raman A, Lau C. Anti-diabetic properties and phytochemistry of Momordica charantia L. (Cucurbitaceae). Phytomedicine 1996;2(4):349-362.
Rebultan SP. Bitter melon therapy: an experimental treatment of HIV infection. AIDS Asia. 1995 Jul-Aug;2(4):6-7. View Abstract
Virdi J, Sivakami S, Shahani S, et al. Antihyperglycemic effects of three extracts from Momordica charantia. J Ethnopharmacol 2003;88(1):107-111. View Abstract
Copyright © 2013 Natural Standard (www.naturalstandard.com)
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.
March 22, 2017