Environmental and Biochemical Sciences Group, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
Food Funct. 2018 Jan 24;9(1):502-510. doi: 10.1039/c7fo01690e.
A polyphenol-rich extract (PRE) from the edible seaweed, Ascophyllum nodosum, inhibited pancreatic lipase activity in an oil-based turbidimetric assay with an IC of 200 μg gallic acid equivalents (GAE) perassay) [∼230 μg DW] whereas the known inhibitor, Orlistat, gave an IC at 0.4 μg per assay. A phlorotannin-enriched fraction (TRF) purified from the PRE was more potent with an IC = 60 μg GAE per assay (∼65 μg DW). When the assay was started by the addition of lipase, both Orlistat and TRF were much less effective which suggests that pre-incubation of enzyme and inhibitor improved inhibition. Based on phenol content, water extracts from Ascophyllum were more potent lipase inhibitors than PRE (IC ∼ 150 μg GAE per assay). However, this was equivalent to ∼580 μg DW and these extracts contained polysaccharides (e.g. alginate content = 110 μg mL) which may also contribute to inhibition. Indeed, a polysaccharide-enriched fraction obtained by ethanol precipitation gave an IC of 1000 μg DW which was equivalent to 130 μg GAE and 420 μg alginate per assay. Therefore a >3 fold increase in alginate content did not markedly improve inhibition. Re-precipitation increased alginate content and reduced polyphenol content but lipase inhibition was markedly reduced (i.e. IC at ∼1100 μg DW per assay, 700 μg alginate and 25 μg GAE). Purifying the polysaccharide fraction by ion exchange removed all phenolics but the IC increased to >2500 μg DW, equivalent to >1970 μg alginate per assay. In conclusion, polysaccharides and phlorotannins may inhibit lipase in an additive fashion, with phlorotannins apparently more effective in vitro. However, interactions between these components may be important when food products containing this edible seaweed are consumed.
一种从食用海藻泡叶藻（Ascophyllum nodosum）中提取的富含多酚的提取物（PRE），在基于油的浊度测定法中抑制了胰脂肪酶的活性，IC 为 200μg 没食子酸当量（GAE）/测定法）[∼230μg DW]，而已知的抑制剂奥利司他的 IC 为 0.4μg/测定法。从 PRE 中纯化得到的富含岩藻黄质的馏分（TRF）的活性更强，IC = 60μg GAE/测定法（∼65μg DW）。当通过添加脂肪酶启动测定法时，奥利司他和 TRF 的效果都要差得多，这表明酶和抑制剂的预孵育可改善抑制作用。基于酚含量，从泡叶藻中提取的水提取物比 PRE（IC∼150μg GAE/测定法）更有效地抑制脂肪酶。但是，这相当于∼580μg DW，并且这些提取物含有多糖（例如褐藻酸盐含量= 110μg mL），这也可能有助于抑制。实际上，通过乙醇沉淀获得的富含多糖的馏分的 IC 为 1000μg DW，相当于 130μg GAE 和 420μg 褐藻酸盐/测定法。因此，褐藻酸盐含量增加 3 倍以上不会明显改善抑制作用。再沉淀增加了褐藻酸盐的含量并降低了多酚的含量，但脂肪酶抑制作用明显降低（即 IC 约为 1100μg DW/测定法，700μg 褐藻酸盐和 25μg GAE）。通过离子交换对多糖馏分进行纯化去除了所有酚类，但 IC 增加到>2500μg DW，相当于 1970μg 褐藻酸盐/测定法。总之，多糖和岩藻黄质可能以累加的方式抑制脂肪酶，而岩藻黄质在体外显然更有效。但是，当食用含有这种食用海藻的食品产品时，这些成分之间的相互作用可能很重要。
