Antioxidant and hepatoprotective properties of polyphenol extracts from Telfairia occidentalis (fluted pumpkin) leaves on acetaminophen induced liver damage.

In this study the antioxidant and hepatoprotective properties of free and bound polyphenols from Telfairia occidentalis (darkish green leafy vegetable popularly used in soup and folk medicine for the management of many diseases in Nigeria) leaves were compared. Free soluble polyphenols were extracted with 80% acetone, while the bound polyphenols were extracted from the acid and alkaline hydrolyzed residue of the leaf from free soluble polyphenols using ethyl acetate. The total phenol, DPPH free radical scavenging ability and reducing property were determined; subsequently the ability of the extracts to prevent acetaminophen (megadose) induced liver damage in rats were also assessed. Change in serum Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT), alkaline phosphatase (ALP), albumin, total protein and bilirubin were also determined. The results of the study revealed that the free soluble polyphenols content in the vegetable were significantly higher (p<0.05) than the bound polyphenols. Also, the free soluble polyphenols had a significantly higher antioxidant activity as typified by their higher reducing Power (0.28 OD700) and free radical scavenging ability (83.3%) than the bound polyphenols [reducing power (0.22 OD700), free radical scavenging ability (66.6%)]. Daily intubation of wistar strain albino rat's with 100 mg/mL/day for 7 days caused a significant increase (p<0.05) in serum alkaline phosphatase (ALP), Glutamate Oxaloacetate Transaminase (GOT) and Glutamate Pyruvate Transaminase (GPT), while there was no significant change (p>0.05) in serum bilirubin, albumin, globulin and total proteins in the rats. However, simultaneous intubations of some of the rat with 10 mg or 20 mg mL(-1) of T. occidentalis leaf extract (free soluble or bound polyphenols) along side with the acetaminophen caused a significant decrease (p<0.05) in serum ALP, GOT and GPT (except those intubated with bound polyphenols). Free soluble polyphenols had higher protective effect on the liver than the bound polyphenols; however there action were not dose-dependent. It could be inferred that both soluble free and bound polyphenols extracts of T. occidentails leaf have antioxidant and hepatoprotective properties, however soluble free polyphenols had significantly higher antioxidant and hepatoprotective properties than the bound polyphenols.