Seasonal variation in phytochemicals and nutraceutical potential of Begonia nelumbiifolia consumed in Puebla, México.

Begonia nelumbiifolia is a traditional edible plant consumed and commercialized in the northern highlands of Puebla, México. The present study reports the seasonal variation in proximate analysis as well as organic acids, carotenoids and flavonoids content in both leaves and stalks of this plant. The stalks contained low concentrations of protein (~3%), fiber (~1.5%) and nitrogen free extract (~0.26%) during the time of study. Both organs showed contents of oxalic acid (91-103 mg 100 g-1 FW), ascorbic acid (50-65 mg 100 g-1 FW), lutein (1-2.5 mg 100 g-1 FW), β-carotene (1-3 mg 100 g-1 FW), quercetin (1.3-2.7 mg 100 g-1 DW) and rutin (0.5-1.7 mg 100 g-1 DW). Antioxidant activity against DPPH was observed by the stalk extracts from 30% methanol (IC50, 0.21-0.37 mg L-1), pure methanol (IC50, 0.14-0.21 mg L-1) and hexane: acetone (IC50, 0.77-1.21 mg L-1). In vitro anti-HMG-CoA reductase (IC50, 0.07-0.36 mg L-1) and anti-alpha-glucosidase (IC50, 0.28-0.43 mg L-1) activities were observed in extracts from the edible stalks from pure methanol and 30% methanol. The leaf extracts from 30% methanol inhibited the growth of Pseudomonas syringae pv. tabaci TBR2004 (MIC, 254 µg mL-1), P. syringae pv. tomato DC3000 (MIC, 423 µg mL-1), P. syringae pv. glycinea (MIC, 605 µg mL-1) and Clavibacter michiganensis AB299158 (MIC, 162 µg mL-1). B. nelumbiifolia contained valuable phytochemicals associated to nutraceutical and biological properties. However, the consumption of the fresh stalks must be carefully considered because of the high oxalate content.