Published Research - K

A B G H K M N P S T

Karela

Botanical name: Momordica charantia

Karela has been used in the folk medicine in China, India, Africa, the West Indies and elsewhere, from ancient times. The fruits are pickled and used as a relish and the seed as a condiment. The bitterness can be reduced by steeping them in salt water, removing the outer skin and cooking. For use out of season, the fruits are preserved after slicing and drying.

Hypoglycaemic activity
Extracts of Momordica charantia rapidly decreased and normalised blood sugar levels in alloxan- or streptozotocin-induced diabetes mellitus. The water-soluble peptide fraction (named MC6) was found to be effective on oral administration.

Source: Ng TB, Li WW, Yeung HW 1987 - Effects of ginsenosides, lectins and Momordica charantia insulin-like peptide on corticosterone production by isolated rat adrenal cells. Journal of Ethnopharmacology 21(1):21

The effect of the insulin-like peptide on the lipid profile is not clear since it had no action on steroidogenesis, but other studies showed fractions with anti-lipolytic activity.

Source: Ng TB, Wong CM, Li WW, Yeung HW 1986 - Insulin-like molecules in Momordica charantia seeds. Journal of Ethnopharmacology 15(1):107

Fruit extracts reversed some of the complications of diabetes in the liver and kidney in experimental diabetes, with effective glucose control, and reversed the effect of chronic diabetes on the modulation of both P450-dependent mono-oxygenase activities and GSH-dependent oxidative stress.

Source: Baquer NZ, Gupta D, Raju J 1998 - Regulation of metabolic pathways in liver and kidney during experimental diabetes: effects of anti-diabetic compounds. Indian Journal of Clinical Biochemistry 13(2):63

Raza H, Ahmed I, John A, Sharma AK 2000 - Modulation of xenobiotic metabolism and oxidative stress in chronic streptozotocin-induced diabetic rats fed with Momordica charantia fruit extract. Journal of Biochemical and Molecular Toxicology 14(3):131

In a clinical study of Momordica in diabetic patients, hypoglycaemic effects were accompanied by significant adaptogenic properties indicated by a delay in the appearance of cataracts and other secondary complications of diabetes.

Source: Srivastava Y, Venkatakrishna-Bhatt H, Verma Y, Venkaiah K, Raval BH 1993 - Anti-diabetic and adaptogenic properties of Momordica charantia extract: an experimental and clinical evaluation. Phytotherapy Research 7(4):285

Hepatoprotective activity
Feeding Karela to diabetic rats brought levels of aminopyrene N-demethylase close to that of control animals, while ethoxycoumarin-O-deethylase was further reduced to 60% of the control value, with the normalisation of cytosolic glutathione.

Source: Raza H, Amed I, Lakhani MS, Sharma AK, Pallot D, Montague W 1996 - Effect of bitter melon (Momordica charantia) fruit juice on the hepatic cytochrome P-450-dependent mono-oxygenases and glutathione S-transferases in streptozotocin-induced diabetic rats. Biochemistry and Pharmacology 52(10):1639

It involved in vitro metabolic activation of aflatoxin B1 and benzo(a)pyrene and demonstrates that the fruits contain monofunctional phase II enzyme inducers and compounds capable of repressing some mono-oxygenases, especially those involved in the metabolic activation of chemical carcinogens. This shows potential as a chemopreventive agent.

Source: Kusamran WR, Ratanavila A, Tepsuwan A 1998 - Effects of Neem flowers, Thai and Chinese bitter gourd fruits and sweet basil leaves on hepatic mono-oxygenases and glutathione S-transferase activities, and in vitro metabolic activation of chemical carcinogens in rats. Food Chemistry and Toxicology 36(6):475

Anti-cancer activity
The aqueous extract killed human leukaemic lymphocytes in a dose-dependent manner, whilst not affecting the viability of normal human lymphocytes. A partially purified factor showed an inhibitory action on both viral and host cell RNA and on protein synthesis. This factor was found to be a single component with a molecular weight of 40,000 daltons.

Source: Takemoto DJ, Jilka C, Rockenbach S, Hughes JV 1983 - Purification and characterisation of a cystostatic factor with anti-viral activity from the bitter melon. Preparative Biochemistry 13(5):391

Application of Momordica proteins to MDA-MB-231 breast cancer cells resulted in inhibition of cell proliferation as well as inhibition of the expression of the HER2 gene in vitro, suggesting a potential therapeutic use against carcinoma of the breast.

Source: Lee-Huang S, Huang PL, Sun Y et al 2000 - Inhibition of MDA-MB-231 human breast tumor xenografts and HER2 expression by anti-tumour agents GAP31 and MAP30. Anticancer Research 20(2A):653