Abstract

A new abietane-type diterpenoid, rubesanolidic acid (1), alongside six known compounds including β-sitosterol (2), lupeol (3), betulinic acid (4) ursolic acid (5), β-sitosterol 3-O-β-D-glucopyranoside (6) and stigmasterol 3-O-β-D-glucopyranoside (7) were isolated from the roots of Burkea africana through column chromatography. Their structures were elucidated from spectroscopic analyses (UV, IR, MS, 1D and 2D NMR) data and by comparison with data from previous studies. The extract and compounds were tested for their α-amylase inhibition. The extract was more active than the isolated compounds with a percentage inhibition of 51.0 ± 2.5% at 400 µg/mL and was the only sample showing above 50% inhibition at this dose. Amongst the isolated compounds and at the dose of 400 µg/mL, the new diterpenoid Rubesanolidic acid exibited the highest percentage inhibition of α-amylase of 38.2 ± 2.0% while β-sitosterol showed the lowest inhibition of 9.6 ± 0.5%. The results indicate that B. africana is a potential source of antidiabetic compounds.

摘要

一种新的枞树烷型二萜，rubesanolidic acid ( 1 )，以及六种已知化合物，包括β-谷甾醇( 2 )、羽扇豆醇 ( 3 )、白桦脂酸 ( 4 ) 熊果酸 ( 5 )、β-谷甾醇 3 -O-β- D-吡喃葡萄糖苷( 6 )和豆甾醇3 -O-β-D-吡喃葡萄糖苷( 7 )通过柱层析从非洲布克根中分离得到。它们的结构通过光谱分析（UV、IR、MS、1D 和 2D NMR）数据以及与先前研究的数据进行比较来阐明。对提取物和化合物进行了测试α-淀粉酶抑制。在 400 µg/mL 时，提取物比分离的化合物更有活性，抑制百分比为 51.0 ± 2.5%，并且是唯一一个在该剂量下显示出超过 50% 抑制的样品。在分离的化合物中，在 400 µg/mL 的剂量下，新的二萜类甜菜酸对α-淀粉酶的抑制百分比最高，为 38.2 ± 2.0%，而β-谷甾醇的抑制百分比最低，为 9.6 ± 0.5%。结果表明，非洲双歧杆菌是抗糖尿病化合物的潜在来源。