Antioxidant and pro-oxidant activity of Mucuna pruriens leaf extract (MPLE) and potential anti-diabetic and cancer chemopreventive benefits

Background: Mucuna pruriens is used traditionally for anaemia, diabetes and cancer. The aim of this study was to investigate the potential health benefit of tea made from the leaves.

Methods: Xanthine/xanthine oxidase and NADH/PMS superoxide generating system were used to assay for anti-oxidant activity. The MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] [1] assay and 2′,7′-dichlorofluorescin (DCFH₂) [2] assay were used to determine cell viabilty and ROS generation in EA.hy926 cell lines respectively.

Results: 0.1 mg, 0.8 mg, 1.6 mg MPLE showed dose dependent antioxidant activity in both xanthine oxdiase/xanthine and NADH/PMS superoxide generating systems. 1.6 mg MPLE antioxidant activity was comparable to antioxidant activity of 1.7 mg Tempol (recognized superoxide scavenger) in xanthine oxidase/xanthine superoxide generating system. 1.6 mg MPLE antioxidant activity was better than anti-oxidant activity of 1.7 mg Tempol in NADH/PMS superoxide generating system. 0.2 mg MPLE induced significant intracellular ROS generation and 0.1 mM Cu²⁺ enhanced the toxicity of 0.1 mg and 0.2 mg MPLE in EA.hy926 cells.

Discussion: Antioxidant activity of MPLE could be due to the prescence of polyphenols and other nutritional phytochemicals. 0.1 mM Cu²⁺ was not toxic to the cells. Enhanced toxicity of MPLE in the presence of Cu²⁺ indicates the presence of polyphenols in MPLE. Cu²⁺ serum levels are known to be increased within the environment of cancer cells and it has been implicated in angiogenesis. Due to its interaction with Cu²⁺, it could be angiostatic and consumption of MPLE could be beneficial for cancer chemoprevention. Pro-oxidant activity is commonly associated with polyphenols [3]. Polyphenol-rich foods are known to have anti-hyperglycemic effect and can delay/prevent cardiovascular complications in diabetic conditions [4].

Conclusion: MPLE showed antioxidant and pro-oxidant activity. The activity of MPLE suggest it could be useful for prevention of diabetic complications and cancer.

Keywords: Reactive oxygen species (ROS), Mucuna pruriens leaf extract (MPLE), polyphenols, diabetic complication and cancer chemoprevention

References:

[1] Mosmann T. (1983). Journal of Immunological Methods. 65(1 – 2): 55 – 63.

[2] Wang H. and Joseph J. A. (1999). Free Radical Biology and Medicine. 27(5 – 6): 612 – 616.

[3] Halliwell B. (2008). Arch Biochem Biophys. 15; 476(2): 107 – 12.

[4] PJ Curtis et al. (2012). Diabetes Care 35; (2): 226 – 232.