About Herbs

Bottom Line: Bitter melon might be able to lower blood glucose levels, but it should not be used to treat diabetes because it is not known how it interacts with insulin or other medications. There is NO proof that bitter melon can treat cancer or any other medical condition.

Several active substances in bitter melon have been studied in both animals and humans. These experiments show that these substances act in the same way as insulin, by increasing the entry of glucose into cells and promoting its processing and storage in the liver, muscle, and fat. Bitter melon also prevents the conversion of stored nutrients to glucose and the release of this glucose into the blood. However, researchers have not established the correct dosage of bitter melon for effectively treating the high blood glucose levels in diabetes, and therefore it cannot be recommended as a replacement therapy for insulin or hypoglycemic drugs.

Bitter melon extracts are able to kill leukemia cells in the laboratory and slow the growth of breast cancer in mice, but it is unknown whether these effects occur in humans. A study in humans showed bitter melon had little effect on the immune system of cervical cancer patients. In laboratory tests, bitter melon extracts also inhibit the ability of HIV to insert its DNA into the chromosomes of human cells, but it is also not known whether this effect would occur in humans.

Diabetes:
A handful of small, poorly-designed clinical trials have evaluated the ability of bitter melon to lower blood glucose levels in diabetics, but no definitive conclusions can be drawn from them about bitter melon's effectiveness.

Eighteen newly diagnosed adults with diabetes took part in a clinical trial evaluating the ability of bitter melon to lower blood glucose levels after a glucose tolerance test (GTT). None of these patients were yet taking insulin or hypoglycemic medications for their diabetes. Thirty minutes before the GTT, half the patients took a bitter melon extract and half did not. Overall, 73% of the volunteers had a significant reduction in blood glucose levels when they were given bitter melon compared to taking nothing at all. These results are promising, but larger clinical trials in which the volunteers are randomly assigned to different groups should be performed. In addition, the long-term safety and effects of bitter melon are still not known.

Researchers have not established the correct dosage or long-term effects of bitter melon for treating the high blood glucose levels in diabetes, and therefore it cannot be recommended as a replacement therapy for insulin or hypoglycemic drugs.

Momordica charantia

Bitter gourd, bitter apple, wild cucumber, bitter cucumber, balsam apple, balsam pear, margose, la-kwa, leprosy gourd, karela

Derived from the fruit and seed of the tree. Bitter melon has been used to treat diabetes, cancer, viral infections, and immune disorders. Data suggest that a significant hypoglycemic effect occurs in both healthy and diabetic patients. However, bitter melon should not be used in place of mainstream therapies. In vitro and animal studies indicate antiviral activity against HIV and herpes, cytotoxic effects against leukemic cells, and cytostatic effects in breast cancer, but related human studies have not been conducted. Children and pregnant women should not use bitter melon because of its potential toxicity. Reported adverse effects include hypoglycemia and hepatotoxicity. There is a potential for additive effect when bitter melon is combined with insulin or oral hypoglycemic agents. A clinical trial demonstrated no effect on natural killer cell activity in cervical cancer patients ⁽⁶⁾.

Fruit:

Glycosides: momordin, charantin

Alkaloids: momordicin

Others: polypeptide-P

Oils (seed only): stearic, linoleic, oleic acids

Glycoproteins: alpha-momorcharin, beta-momorcharin, lectins

Others: vicine (pyrimidine nucleoside), protein MAP30
⁽¹⁾

Vicine, charantin, and polypeptide-P in both animals and humans increase glucose uptake and glycogen synthesis in the liver, muscle, and adipose tissue, and improve glucose tolerance. Studies with hepatic enzymes in mice revealed reduction in glucose-6-phosphatase and fructose-1,6-bisphosphatase activity, and increased glucose oxidation by G6PDH pathway. Bitter melon displays cytotoxic activity against leukemic cells in vitro (guanylate cyclase inhibitor). The MAP30 extract has a cytostatic effect on MDA-MB-231 human breast cancer cells xenografted into mice. MAP30 also demonstrates dose-dependent inhibition of HIV-1 integrase leading to poor viral DNA integration, thus inhibiting T lymphocyte and monocytes.
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Red arils (covering on seed) are reportedly toxic in children, causing vomiting, diarrhea, and death.
⁽¹⁾

Pregnant woman should not use - may induce bleeding, contractions, and abortion.

Reported: Hypoglycemia, hepatotoxicity (animal studies)
Toxicity: Ingestion of vicine (seed) may cause favism characterized by headache, fever, abdominal pain, and coma.

Insulin: Bitter melon may have an additive effect when used concomitantly.
Hypoglycemics: Bitter melon may have additive effect when used concomitantly.
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Only small, uncontrolled human trials have evaluated the hypoglycemic properties of bitter melon.

Welihinda J, et al. Effect of momordica charantia on the glucose tolerance in maturity onset diabetes. J Ethnopharmacol 1986;17:277-82.
A prospective evaluation of 18 newly diagnosed adult diabetics comparing blood glucose level with and without bitter melon administration 30 minutes prior to an oral glucose tolerance test (GTT). Patients had not started any hypoglycemic therapy (e.g. insulin or sulfonylureas). A statistically significant reduction in blood sugar after administration of bitter melon, approximately 20-30%, was demonstrated. Larger randomized trials are necessary to establish long-term effects.