In vitro antioxidant, antiglycation, and enzymatic inhibitory activity against α-glucosidase, α-amylase, lipase and HMG-CoA reductase of Terminalia boivinii Tul.

Abstract Phytoantioxidants from Terminalia boivinii Tul. are of medical interest given their potential inhibitory capacity against the formation of glycation end products and key enzymes associated with metabolic syndrome. The present study investigated and compared the polyphenolic content and biological properties of ethyl acetate, n-butanol and aqueous solvent fractions of T. boivinii fruits, leaves, stem and bark methanolic extracts. The total bioactive content of the tested materials was evaluated by spectrophotometric methods. The antioxidant activity was analyzed using DPPH, superoxide anion radical, metal chelation and FRAP assays. The enzyme inhibitory properties were tested on α-glucosidase, α-amylase, lipase and HMG-CoA reductase enzymes, while antiglycation activities were evaluated by the bovine serum albumin (BSA) - methylglyoxal (MG) method. Phytochemical analysis indicated that the ethyl acetate fractions had high levels of phenols (40.58 ± 2.94 mg GAE/g DW of leaves) and flavonoids (20.32 ± 1.62 mg QE/g DW of leaves) compared to the other extracts, which is directly related with their significant antiradical, reducing power, α-glucosidase, lipase and HMG-CoA reductase inhibitory ability. However, the water fraction with the lowest polyphenol content was more active in metal chelation. Moreover, the antiglycation activities followed a similar pattern to the radical scavenging activities. Our results showed that T. boivinii is a viable source of natural bioactive antioxidant and enzyme-inhibiting chemicals that maybe considered for commercial exploitation.