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.

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.

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.

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. In vitro and animal studies indicate anticancer ^{(3) (7) (8)}, antiviral ^{(9) (10)}, and lipid lowering ⁽¹¹⁾ effects. Bitter melon exerted significant hypoglycemic effects in both healthy and diabetic patients ^{(1) (2)}, but had no effect on natural killer cell activity in a study of cervical cancer patients ⁽⁶⁾.
Children and pregnant women should not use bitter melon because of its potential toxicity.
There is a potential for additive effect when bitter melon is combined with insulin or oral hypoglycemic agents.

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⁾

The compounds present in bitter melon including vicine, charantin, and polypeptide-P 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) and 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.
^{(1) (2) (3)}. Bitter melon also inhibits P-glycoprotein and can alter the pharmacokinetics of drugs by inhibiting the P-glycoprotein-mediated efflux ⁽¹²⁾.

Red arils (covering on seed) are reportedly toxic in children, causing vomiting, diarrhea, and death.
⁽¹⁾

Bitter melon is contraindicated in pregnant women as it can induce bleeding, contractions, and abortion.

Hypoglycemia and hepatotoxicity were reported in animal studies.

Toxicity: Ingestion of vicine (seed) may cause favism characterized by headache, fever, abdominal pain, and coma.
⁽⁴⁾

Insulin: Bitter melon may have an additive effect when used concomitantly.
Hypoglycemics: Bitter melon may have additive effect when used concomitantly.
^{(4) (5)}