In vitro Antioxidant and Biological Activities of Extract and Fractions from Telfairia occidentalis Stems

Telfairia occidentalis (TO) Hook is a widely consumed vegetable in Nigeria. This study investigated the antioxidant and antidiabetic activities of stem ethanol extract (ETTO) and fractions (hexane, HTO; dichloromethane, DTO; ethylacetate, ETO; methanol, MTO and aqueous, Aq.TO) from Telfairia occidentalis by measuring the scavenging activity, reducing power, total phenolic content (TPC), total flavonoid content (TFC), and the in vivo alpha amylase and glucosidase inhibitory effects. The ethanol stem extract exhibited significant (p < 0.05) reduction in blood glucose levels of treated rats. ETO exhibited the highest radical scavenging (EC50 = 116.256 µg/mL) and reducing (EC50 = 55.218 µg/mL) activity. Contents of total phenolics and flavonoids were highest in ETO (22.17 mg GAE/ g and 129.56 RE/ g respectively), while HTO showed the lowest radical scavenging and reducing activity (EC50 = 249.159 µg/mL and 97.781 µg/mL respectively). Gass chromatography-mass spectrum (GC-MS) analysis of the fractions revealed that saturated fatty acids, polyunsaturated fatty acids, amino acids, alcohols, amides and straight chain hydrocarbons were the major constituents. This research demonstrates that the stem extract and fractions of TO may alleviate oxidative-stress related diseases and exhibit antidiabetic activity, potentially through the inhibition of alpha amylase and alpha glucosidase enzymes, which may be attributed to its phytochemical constituents.