Bitter melon juice may be efficacious against pancreatic cancer, according to the results of in vitro and animal studies conducted at the University of Colorado.1
Although no clinical trials in patients with cancer have been conducted, bitter melon (Momordica charantia), which is commonly consumed in parts of Asia and Africa, has previously been shown to have activity against breast, prostate, and colon cancer cells.
In the University of Colorado studies, four pancreatic cell lines were treated with juice obtained from bitter melons purchased in a local store. A single 24-hour treatment reduced the viability of the various cell lines by 54% to 98% after 72 hours, suggesting significant, broad spectrum anti-cancer activity.
Two cell lines were tested to determine if treatment with bitter melon juice increased apoptotic cell death compared with untreated cells. Apoptosis increased from 12% to 32% in one cell line and from 11% to 34% in the other cell line.
Western blot analysis showed that bitter melon juice activated two regulators of apoptosis, caspase-3 and caspase-9, and upregulated several proapoptotic molecules in both cell lines; overall the bitter melon juice also had variable effects on several antiapoptotic molecules.
Adenosine monophosphate-activated protein kinase (AMPK), which is activated when cell energy is restricted, was more active in treated cells than in untreated cells, suggesting that bitter melon juice was starving them of energy.
To study the effects in vivo, the researchers next grafted human pancreatic cells from a single line to athymic nude mice and administered bitter melon juice orally for 6 weeks, with apparently positive results: at the end of the study period, xenograft volume and weight were both significantly lower in treated mice than in controls. The mice that received bitter melon juice had no weight loss and there were no apparent harmful effects on the pancreas or liver.
Apoptosis is regulated by a balance between proapoptotic and antiapoptotic molecules. Compared with tumor cells from untreated mice, tumor cells from mice given bitter melon juice showed an increase in proapoptotic proteins and a decrease in antiapoptotic proteins, supporting the results found in vitro.
The researchers’ interest in the effect of bitter melon juice on pancreatic cancer was sparked by the observation that the juice has mild hypoglycemic effects and has been used in traditional medicine to treat diabetes, a disease that increases the risk for pancreatic cancer (Related: Relationship of Type 2 Diabetes and Cancer Risk). They speculated that, even in the absence of diabetes, bitter melon juice might have favorable effects on pancreatic tumors.
“Three years ago researchers showed the effect of bitter melon extract on breast cancer cells only in a Petri dish,” said Rajesh Agarwal, PhD, co-program leader of Cancer Prevention and Control at the Colorado University Cancer Center and professor at the Skaggs School of Pharmacy and Pharmaceutical Sciences, Denver, CO.
“This study goes much, much further. We used the juice—people especially in Asian countries are already consuming it in quantity. We show that it affects the glucose metabolism pathway to restrict energy and kill pancreatic cancer cells.”
1. Kaur M, Deep G, Jain AK, et al. Bitter melon juice activates cellular energy sensor AMP-activated protein kinase causing apoptotic death of human pancreatic carcinoma cells. Carcinogenesis. 2013;34:1585-92.