Evaluation of L-dopa, proximate composition with in vitro anti-inflammatory and antioxidant activity of Mucuna macrocarpa beans: A future drug for Parkinson treatment

Objective: To investigate L-3, 4-dihydroxyphenylalanine (L-dopa, anti-Parkinson drug), anti-inflammatory activity, proximate nutritional composition and antioxidant potential of Mucuna macrocarpa (M. macrocarpa) beans. Methods: L-dopa content was determined and quantified by high performance thin layer chromatography and reversed phase high-performance liquid chromatography (RP-HPLC) methods. Anti-inflammatory activity was performed by in vitro protein denaturation inhibition and human red blood cell membrane stabilisation activity. Proximate composition and elemental analysis were also investigated. The antioxidant potential (2,2-diphenyl-1-picrylhydrazyl, N-N-dimethyl-phenylenediamine and ferric-reducing antioxidant power) of M. macrocarpa beans were evaluated by using different extraction solvents. The RP-HPLC analysis also quantified significant phenolics such as gallic acid, tannic acid, p-hydroxybenzoic acid and p-coumaric acid. Results: RP-HPLC quantification revealed that M. macrocarpa beans contain a high level of L-dopa [(115.41 +/- 0.985) mg/g] which was the highest among the Mucuna species from Indian sub-continent. Water extract of seed powder showed strong anti-inflammatory and antioxidant potential. Proximate composition of M. macrocarpa beans revealed numerous nutritional and anti-nutritional components. RP-HPLC analysis of major phenolics such as tannic acid (43.795 mg/g), gallic acid (0.864 mg/g), p-coumaric acid (0.364 mg/g) and p-hydroxybenzoic acid (0.036 mg/g) quantified successfully from M. macrocarpa beans respectively. Conclusions: This study suggests that M. macrocarpa is a potential source of L-dopa with promising anti-inflammatory, antioxidant and nutritional benefits.