Bitter melon

Momordica charantia is a tropical and subtropical vine of the family Cucurbitaceae, widely grown for edible fruit, which is among the most bitter of all vegetables. The best substantiated use to date is that of bitter melon for people with diabetes mellitus. Several preliminary (non-randomized, non-blinded) clinical trials suggest this benefit, though controlled trials are necessary for confirmation. In the Philippines, bitter melon tea is used in blood sugar control.

Momordica (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.

Clinical Studies

Effect of Momordica charantia on lipid profile and oral glucose tolerance in diabetic rats

Phytother Res. 2004 Nov;18(11):954-6.
Department of Biological Sciences, Faculty of Science, University of Botswana, Gaborone, Private Bag 0022, Botswana

In this study, the methanol extract of Momordica charantia fruit extract was administered to diabetic rats to assess the long term effect of the extract on the lipid profile and the oral glucose tolerance test. Treatment for 30 days showed a significant decrease in triglyceride, low density lipoprotein and a significant increase in high density lipoprotein level. A significant effect on oral glucose tolerance was also noted. Chronic administration showed an improvement in the oral glucose tolerance curve. The effect was more pronounced when the test was done in rats fed the extract on the day of the test compared with tests done in rats which were not fed the extract on the same day.


Studies evaluating bitter melon in the treatment of diabetes

The largest study, published in a 1999 issue of the Bangladesh Medical Research Council Bulletin, used an aqueous suspension of bitter melon vegetable pulp in 100 patients with type 2. The authors evaluated the effect at one hour after bitter melon was administered and then two hours after a 75-gram oral glucose tolerance test.

The average blood glucose was 222 mg/dl, which was lower than the previous day’s two-hour value of 257 mg/dl.

In another study, published in a 1981 issue of the Journal of Natural Products, bitter melon was prepared as an injectable “plant insulin” and injected into five patients with type 1 and six patients with type 2. There was a control group of six patients 6 with type 1 and two patients with type 2 who did not receive any bitter melon.

In type 1s, average glucose decreased from 304 to 169 mg/dl four hours after injection; this effect was maintained at six and eight hours after injection.


The effect of Momordica charantia capsule preparation on glycemic control in Type 2 Diabetes Mellitus needs further studies

Department of Medicine, Philippine General Hospital Medicine, Taft Avenue, Manila, Philippines.

BACKGROUND AND OBJECTIVES: Momordica charantia, locally known as Ampalaya, is being widely used and advertised for its hypoglycemic effects. However, to date, no large clinical trial has been published on the efficacy of any type of preparation. The main objective of this study is to determine if addition of M. charantia capsules to standard therapy can decrease glycosylated hemoglobin (hemoglobin A1c or HbA1c) levels in diabetic patients with poor sugar control. STUDY DESIGN AND SETTING: A randomized, double-blind, placebo-controlled trial was conducted between April and September 2004 at the outpatient clinics of the Philippine General Hospital. The trial included 40 patients, 18 years old and above, who were either newly diagnosed or poorly controlled type 2 diabetics with A1c levels between 7% and 9%. On top of the standard therapy, the patients were randomized to either M. charantia capsules or placebo. The treatment group received two capsules of M. charantia three times a day after meals, for 3 months. The control group received placebo at the same dose. The primary efficacy endpoint was change in the A1c level in the two groups. The secondary efficacy endpoints included its effect on fasting blood sugar, serum cholesterol, and weight. Safety endpoints included effects on serum creatinine, hepatic transaminases (Alanine aminotransferase/ALT and Aspartate aminotransferase/AST), sodium, potassium, and adverse events. RESULTS: Baseline characteristics between the treatment and control groups were similar. The difference in mean change in A1c between the two groups was 0.22% in favor of M. charantia (95% CI: -0.40 to 0.84) with P=0.4825.There was no significant effect on mean fasting blood sugar, total cholesterol, and weight or on serum creatinine, ALT, AST, sodium, and potassium. There were few adverse events and these were generally mild. CONCLUSION: This is the first randomized controlled trial to shed light on the issue concerning the hypoglycemic effects of M. charantia. The investigators targeted a 1% decline in A1c at the outset with an estimated power of 88%. With the observed decline of 0.24%, the achieved power was only 11%. For this reason, we are unable to make a definite conclusion about the effectiveness of M. charantia. However, the results of this study can be used estimate the sample size for bigger studies.

PMID: 17493509 [PubMed - in process]


The reparative effects of Momordica Charantia Linn. extract on HIT-T15 pancreatic beta-cells

Institute of Biotechnology, Fuzhou University, 523 Gongye Road, Fuzhou, Fujian, China 350002.

The aim of this study is to investigate the cell reparative effects of Mormordical Charantia Linn. boiling water extract (MCE) on the HIT-T15 Hamster Pancreatic beta-cells. Furthermore, the superoxide dismutase (SOD) activity of MCE was determined. 0.02% MCE (w/v) achieved the highest cell proliferation rate of 45.6% (p<0.01) on alloxan damaged HIT-T15 cells while 0.2% MCE increased the proliferation of the normal cells by 35.4% (p<0.05). The high molecular weight fraction of MCE (MHMF, MW>3 kDa) showed the stronger effects in repairing alloxan damaged cells (cell proliferation rate=32.1%, p<0.05) than that of the low molecular weight fraction (MLMF, MW< or =3 kDa), while the latter showed the higher activity on increasing insulin secretion of normal or damaged cells. 2%MCE and MLMF showed the highest SOD activities, 19.74 NU/mL and 19.84 NU/mL, but they failed to improve the proliferation rate of alloxan damaged cells. These results indicated MCE has significant repairing effects on HIT-T15 cells against superoxide anion radicals, which did not correlate to MCEfs SOD activity. It was hypothesized that the different fractions of MCE may make different contributions to MCE's cell repairing activity and its ability of stimulating insulin secretion.

PMID: 17392113 [PubMed - in process]