Phaseolus lunatus(lima beans) abates Fe2+‐induced hepatic redox imbalance; inhibits intestinal glucose absorption and major carbohydrate catabolic enzymes; and modulates muscle glucose uptake

Abstract

The antioxidative and antidiabetic effects of the aqueous extract of Phaseolus lunatus were investigated in vitro and ex vivo. The seeds were subjected to aqueous extraction, after defatting with n-hexane. The extract (15, 30, 60, 120, 240 µg/ml) showed significant (p < 0.05) free radical scavenging and enzyme inhibitory activities in vitro. It significantly (p < 0.05) elevated glutathione level with concomitant depletion of malondialdehyde level as well as increased superoxide dismutase and catalase activities in rat liver. Fe2+-induced hepatic DNA fragmentation was also significantly (p < 0.05) suppressed. The extract significantly inhibited intestinal glucose absorption and increased muscle glucose uptake with and without insulin. The inhibitory activities and reversion of hepatic redox imbalance, as well as inhibition of intestinal glucose absorption and increased muscle glucose uptake by P. lunatus suggest an antihyperglycemic and antioxidative effect. These can be ascribed to the synergistic effect of the phytochemicals and amino acids identified in the extract. Practical applications Lima beans (Phaseolus lunatus) is among the many underutilized legumes with reported nutritional benefits. It is utilized locally in Nigeria in treating and managing diabetes and its complications, but without any scientific proof. The ability of the legume to inhibit digestive enzymes linked to postprandial blood glucose spike, as well as inhibition of intestinal glucose absorption and increased muscle glucose uptake substantiates its antidiabetic folkloric uses. The amino acid constituents also indicate its nutritional properties. These findings will promote its utilization not only as an antidiabetic functional food but also as a nutritional meal.