Biological properties of lemon basil seeds extract, legumes extract, sesame seeds extract and the inhibitory activity of the combination of lemon basil seeds extract with rice volatiles compounds against α-glucosidase, α-amylase and tyrosinase

This research was conducted to evaluate the bioactive compounds content and biological activity of legume extract (mung bean (MB), job’s tears (JT), red kidney bean (RB) and black bean (BB)), sesame extract (white sesame (WS) and black sesame (BS)) and lemon basil seed extract (LB). The research also investigated the combined LB extract with kojic acid, acarbose and five rice volatile compounds against α-glucosidase, α-amylase and tyrosinase activity. The inhibitory activity of three enzymes and the extracts’ antioxidant capacity was closely related to the total phenolic and total flavonoid content. LB methanol extract (LB(ME)) had the highest total phenolic content, total flavonoid content and antioxidant capacity. LB water extract (LB(WE)) with the IC₅₀ of 0.04 ± 0.004 and 0.14 ± 0.01 mg/mL had the highest inhibition potent against α-glucosidase and tyrosinase enzymes. In comparison, LB(ME) with the IC₅₀ of 0.13 ± 0.01 mg/mL represented the highest inhibition potent on the α-amylase enzyme. Five rice volatile compounds with the α-glucosidase, α-amylase and tyrosinase inhibitory activity, low cytotoxicity and high anti-nitric oxide production were combined with LB extract to investigate the enzymatic inhibitory effect. The results indicated that LB(WE)/2-methoxy-4-vinylphenol and LB(WE)/2-pentyl furan had a synergic effect on α-glucosidase activity. We also investigated LB extract combined with acarbose and kojic acid against these enzymes. The results showed that LB(ME)/acarbose had the highest inhibition potent on α-glucosidase and α-amylase activity and LB(WE)/kojic acid had the highest on tyrosinase activity. Thus, these results suggest that using LB extract and the combined may be a useful therapeutic approach for diabetes and melanogenesis treatment.