Regulation of lipid metabolism by polyphenols derived from non-edible part

从花生（ArachishypogaeaL.）皮中鉴定出表儿茶素-（4 b->6）-表儿茶素-（2b->O->7，4 b->8）-儿茶素（EEC，一种原花色素三聚体）。EEC比原花青素A1（二聚体）在体外表现出更强的胆固醇胶束降解活性。因此，在我们先前的实验中，花生皮多酚对高胆固醇饮食大鼠的高胆固醇血症抑制作用可能主要是由于肠道中的胶束降解作用。然后，我们发现花生皮提取物降低了给予淀粉，蔗糖或葡萄糖的大鼠的血糖水平。结果表明，EEC对α-淀粉酶活性有明显的抑制作用，而（+）-儿茶素和原花青素A1对α-淀粉酶活性无明显的抑制作用。这些结果表明，不同聚合度的原花青素对胆固醇胶束的降解活性和糖消化酶的活性不同。

We identified epicatechin-(4b->6)-epicatechin-(2b->O->7, 4b->8)-catechin (EEC, a proanthocyanidin trimer) in the skin of the peanut (Arachis hypogaea L.). EEC showed more potent cholesterol micelle-degrading activity than procyanidin A1 (a dimer) in vitro. The hypercholesterolemia suppressing effect of a peanut skin polyphenol on rats fed high-cholesterol diet in our preceding experiments might thus have been due primarily to a micelle-degrading effect in the intestine. Then we showed peanut skin extracts reduces blood glucose levels in rats administered starch, sucrose or glucose. Then inhibition activities of sugar digestion enzyme by proanthocyanidins from peanut skin were investigated and EEC inhibited alpha-amylase activity in a dose-dependent manner, while (+)-catechin and procyanidin A1 did not. These results indicate that procyanidins of different degrees of polymerization will different activities of cholesterol micelle-degrading activity and sugar digestion enzyme.