GC-MS ANALYSIS, ANTIOXIDANT AND ENZYME INHIBITORY ACTIVITIES OF VOLATILE AND SOLVENT EXTRACT OF Pteris togoensis

Abstract

Pteris togoensis is a fern commonly used in west Africa for management of medical conditions resulting from metabolic disorder and oxidative stress. In this study, the essential oil of P. togoensis was obtained using hydrodistillation method while the alcoholic extract was obtained using aqueous methanol. The alcoholic extract was thereafter silylated using N, O-bis-(trimethylsilyl) trifluoroacetamide containing 1% trimethylchlorosilane. Both the essential oil (PTEO) and silylated extract (PTSE) were analysed on GC-MS and investigated for antioxidant and enzyme inhibitory activities using DPPH, alpha-glucosidase and porcine pancreatic lipase enzyme. Principal classes of compound identified in PTEO were monoterpenoids (12.30%), sesquiterpenoids (24.14%) and diterpenoids (21.26%) while the PTSE indicated preponderance of sugar and fatty acids, with fructofuranose (20.31%), mannose (24.14%) and palmitic acid (6.32%) as major constituents. The IC50 of DPPH radical scavenging potentials of PTEO (435.81±1.25 µg/mL) and PTSE (280.09±1.14 µg/mL) indicated that both extracts exhibited mild activities which were lower than the standard ascorbic acid (32.61 ± 2.60 µg/mL). Also, hypoglycemic activities of PTEO (308.26±3.67 µg/mL) and PTSE (363.45±2.55 µg/mL) were fairly comparable to the acarbose (279 ± 4.21 µg/mL). PTSE showed no inhibition on porcine pancreatic lipase while PTEO had IC50 of 111.71±2.12 µg/mL compared to 0.88 ± 0.12 µg/mL orlistat.