Ramabulana Tshifhiwa, Ndlovu Musawenkosi, Mosa Rebamang A, Sonopo Molahlehi S, Selepe Mamoalosi A
Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa.
Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa.
ACS Omega. 2022 Mar 31;7(14):11964-11972. doi: 10.1021/acsomega.2c00096. eCollection 2022 Apr 12.
In the study, ultraperformance liquid chromatography-quadrupole time-of-flight-mass spectrometry analysis of leaf and stem extracts led to the identification of various classes of compounds. Further chromatographic purifications resulted in the isolation of 22 compounds that consisted of a new triterpenoid named leucosidic acid A (), an acetophenone derivative , a phloroglucinol derivative , three chromones , seven pentacyclic triterpenoids , a phytosterol glucoside , a flavonoid , and seven flavonoid glycosides . Nineteen of these compounds including the previously undescribed triterpenoid are isolated for the first time from . The structures of the isolated compounds were assigned based on their high-resolution mass spectrometry and nuclear magnetic resonance data. Some of the isolated triterpenoids were evaluated for inhibitory activity against α-amylase, α-glucosidase, and pancreatic lipase. Of the tested compounds, 1-hydroxy-2-oxopomolic acid () and pomolic acid () showed higher potency on α-glucosidase than acarbose, which is used as a positive control in this study. The two compounds inhibited α-glucosidase with IC values of 192.1 ± 13.81 and 85.5 ± 6.87 μM, respectively.
在该研究中，对叶和茎提取物进行超高效液相色谱-四极杆飞行时间质谱分析，从而鉴定出各类化合物。进一步的色谱纯化分离出了22种化合物，其中包括一种名为白果酸A的新三萜类化合物（）、一种苯乙酮衍生物、一种间苯三酚衍生物、三种色酮、七种五环三萜类化合物、一种植物甾醇糖苷、一种黄酮类化合物以及七种黄酮糖苷。这些化合物中的19种，包括之前未描述的三萜类化合物，首次从……中分离得到。根据高分辨率质谱和核磁共振数据确定了分离出的化合物的结构。对一些分离出的三萜类化合物进行了α-淀粉酶、α-葡萄糖苷酶和胰脂肪酶抑制活性的评估。在所测试的化合物中，1-羟基-2-氧代坡模酸（）和坡模酸（）对α-葡萄糖苷酶的抑制活性高于本研究中用作阳性对照的阿卡波糖。这两种化合物抑制α-葡萄糖苷酶的IC值分别为192.1±13.81和85.5±6.87μM。
