Abstract:
Objective: To explore whether the extracts of Zijuan tea has the potential to anti-hypertensive, anti-hyperglycemic and anti-obesity. Methods: The crude polyphenol fraction ( defined as ZTE
1) was extracted from Zijuan tea. ZTE
1 was then separated to the precipitated ( defined as ZTE
2) and the soluble ( defined as ZTE
3) with ethyl acetate.Subsequently, delphinidin-3-O-β-D- ( 6- ( E) -p-coumaroyl) galactopyranoside ( AN
3) and cyanidin-3-O-β-D- ( 6- ( E) -p-coumaroyl) galactopyranoside ( AN
4) were purified from ZTE
2. The inhibitory activities of the three crude fractions and two anthocyanins towards angiotensin converting enzyme ( ACE) , α-amylase and pancreatic lipase were evaluated comparing with epigallocatechin gallate ( EGCG) .The inhibitory type of AN
3 and AN
4towards ACE, α-amylase and pancreatic lipase was also explored.Results: All the Zijuan tea extracts had inhibitory activities towards the three enzymes.The inhibitory activities of ZTE
3 towards the three enzymes, ZTE1 towards α-amylase and pancreatic lipase, ZTE
2 towards α-amylase were stronger than EGCG.Furthermore, ZTE
3 had the highest inhibitory acitivity against ACE, whereas ZTE
2 and ZTE
1 had the highest inhibitory acitivity against α-amylase and pancreatic lipase, respectively. And the inhibitory activity of AN
3 towards α-amylase was not significantly different to EGCG.The inhibitory activity of AN
3 was higher than AN
4 towards all the three enzymes. In addition, AN
3 and AN
4 were noncompetitive inhibitors of ACE, α-amylase and pancreatic lipase with Ki values of 0.33, 0.37 mmol/L, 0.39, 0.41 mg/m L and 0.22, 0.78 mg/m L.Conclusion: The extracts of Zijuan tea has the potential to anti-hypertensive, antihyperglycemic and anti-obesity.