Plant Bioactives Group, Post-Harvest and Agro-processing Technologies, Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch, South Africa.
Department of Food Science, Stellenbosch University, Stellenbosch, South Africa.
Planta Med. 2021 Apr;87(4):325-335. doi: 10.1055/a-1265-1945. Epub 2020 Nov 3.
Fractions of an ultrafiltered extract, respectively enriched in xanthones and benzophenones, were previously shown to inhibit mammalian -glucosidase The present study investigated intestinal transport of these fractions, using excised porcine jejunal tissue, to determine whether the gut could be a predominant site of action. The major bioactive compounds, the xanthones (mangiferin, isomangiferin) and benzophenones (3--D-glucopyranosyliriflophenone, 3--D-glucopyranosyl-4---D-glucopyranosyliriflophenone) exhibited poor permeation in the absorptive direction with a relatively high efflux ratio (efflux ratio > 1). The efflux ratio of 3--D-glucopyranosyl-4---D-glucopyranosyliriflophenone (3.05) was similar to rhodamine 123 (2.99), a known substrate of intestinal P-glycoprotein 1 efflux transporters. Low epithelial membrane transport rates, coupled with efflux mechanisms, would effectively concentrate these bioactive compounds at the target site (gut lumen). Storage stability testing and moisture sorption assays of the xanthone-enriched fraction, benzophenone-enriched fraction, and ultrafiltered extract were performed to determine their susceptibility to physical and chemical degradation during storage. Hygroscopicity of the powders, indicated by moisture uptake, decreased in the order: benzophenone-enriched fraction (22.7%) > ultrafiltered extract (14.0%) > xanthone-enriched fraction (10.7%). 3--D-Glucopyranosylmaclurin, a minor benzophenone, was the least stable of the compounds, degrading faster in the benzophenone-enriched fraction than in ultrafiltered extract, suggesting that the ultrafiltered extract matrix may provide a degree of protection against chemical degradation. Compound degradation during 12 wk of storage at 40 °C in moisture-impermeable containers was best explained by first order reaction kinetics.
先前的研究表明，一种经超滤得到的提取物，分别富含黄烷酮和二苯甲酮类化合物，能抑制哺乳动物的 -葡萄糖苷酶。本研究使用离体猪空肠组织，研究了这些提取物在肠道中的转运情况，以确定肠道是否可能是主要的作用部位。主要的生物活性化合物，黄烷酮（芒果苷、异芒果苷）和二苯甲酮（3--D-吡喃葡萄糖基异夫拉定、3--D-吡喃葡萄糖基-4---D-吡喃葡萄糖基异夫拉定）在吸收方向的渗透性差，外排率相对较高（外排率＞1）。3--D-吡喃葡萄糖基-4---D-吡喃葡萄糖基异夫拉定（3.05）的外排率与肠道 P 糖蛋白 1 外排转运体的已知底物罗丹明 123（2.99）相似。低的上皮膜转运率加上外排机制，将有效地使这些生物活性化合物在靶部位（肠腔）浓缩。对富含黄烷酮的部分、富含二苯甲酮的部分和超滤提取物进行储存稳定性测试和水分吸附试验，以确定它们在储存过程中对物理和化学降解的敏感性。通过水分吸收来表示的粉末吸湿性，按以下顺序降低：富含二苯甲酮的部分（22.7%）＞超滤提取物（14.0%）＞富含黄烷酮的部分（10.7%）。3--D-吡喃葡萄糖基马库林是一种较少的二苯甲酮，在富含二苯甲酮的部分中比在超滤提取物中降解得更快，这表明超滤提取物基质可能在一定程度上提供了对化学降解的保护。在不透水容器中于 40°C 下储存 12 周期间，化合物的降解最好用一级反应动力学来解释。
