PAPER TITLE :COMPARATIVE STUDIES ON THE EFFECT OF FREE AND BOUND PHENOLIC EXTRACTS FROM SELECTED EGGPLANT (SOLANUM SPP) FRUITS ON CARBOHYDRATE HYDROLYSIS ENZYMES

FUTA JOURNAL OF RESEARCH IN SCIENCE | VOLUME 15 NUMBER 2 2019

Paper Details

  • Author(s) : 1Nwanna E.E, 1Obadaye T.S, 2Shodehinde S.A and 1Ojo R.O
  • Abstract:

Tropical Eggplant (Solanum spp) fruits are known to have numerous therapeutic properties, however little information is known on the distribution of phenolic constituents of these selected eggplant Solanum melongena depressum (green), Solanum gilo (white) and Solanum melogena (purple) fruits commonly found in Nigeria. Most literature only report free phenolic content while bound phenolic content is not included. Therefore this study aims to determine the anti-diabetic and anti-hypertensive effect of free and bound phenolics from these eggplant fruits in-vitro. The dried pulverised fruits were subjected to solvent extraction, base digestion, and solid-phase extraction process using 80% acetone and ethyl acetate for free and the bound phenolics. The extracts were used to determine total phenol, total flavonoid, ferric reducing antioxidant capacity (FRAP), as well as their inhibitory effect on carbohydrate hydrolysis enzymes (α-glucosidase and α-amylase) and angiotensin-I-converting enzyme (ACE) linked to hypertension. Results show that the free phenolic significantly (P<0.05) had higher total phenol, total flavonoid than bound phenolic, in the same vein free phenolics inhibited α-amylase, α-glucosidase, and ACE activities more than the bound phenolics. Free phenolic extract from Solanum depressum had the highest inhibitory effect on α-amylase (EC50= 79.48µg/mL) while its bound phenolic extract had the highest inhibitory effect on α-glucosidase (EC50= 170.24µg/mL) as well as on ACE (EC50= 98.68µg/ml) activities. This study revealed that these eggplants are rich sources of free and bound phenolics which could serve as a good bioactivity index for dietary diabetes and hypertension prevention.

Keywords: eggplant, free phenolic, bound phenolic, α-amylase; α-glucosidase