Chemistry Department, College of Natural and Applied Sciences, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania.
Department of Chemistry - BMC, Uppsala University, SE-751 23 Uppsala, Sweden.
Fitoterapia. 2021 Jun;151:104857. doi: 10.1016/j.fitote.2021.104857. Epub 2021 Feb 11.
The new isoflavonoid kirkinone A (1) and biflavonoid kirkinone B (2) along with six known compounds (3-8) were isolated from the methanolic extract of the root bark of Ochna kirkii. The compounds were identified by NMR spectroscopic and mass spectrometric analyses. Out of the eight isolated natural products, calodenin B (4) and lophirone A (6) showed significant antibacterial activity against the Gram-positive bacterium Bacillus subtilis with MIC values of 2.2 and 28 μM, and cytotoxicity against the MCF-7 human breast cancer cell line with EC values of 219.3 and 19.2 μM, respectively. The methanolic crude extract of the root bark exhibited cytotoxicity at EC 8.4 μg/mL. The isolated secondary metabolites and the crude extract were generally inactive against the Gram-negative Escherichia coli (MIC ≥400 μg/mL). Isolation of biflavonoids and related secondary metabolites from O. kirkii demonstrates their chemotaxonomic significance to the genus Ochna and to other members of the family Ochnaceae.
从 Ochna kirkii 的根皮的甲醇提取物中分离得到了新的异黄酮基克林酮 A（1）和双黄酮基克林酮 B（2）以及六种已知化合物（3-8）。通过 NMR 光谱和质谱分析鉴定了这些化合物。在所分离的八种天然产物中，calodenin B（4）和 lophirone A（6）对革兰氏阳性菌枯草芽孢杆菌具有显著的抗菌活性，MIC 值分别为 2.2 和 28 μM，对 MCF-7 人乳腺癌细胞系的细胞毒性 EC 值分别为 219.3 和 19.2 μM。根皮的甲醇粗提取物在 EC 8.4 μg/mL 时表现出细胞毒性。分离的次生代谢物和粗提取物对革兰氏阴性大肠杆菌（MIC≥400 μg/mL）通常没有活性。从 Ochna kirkii 中分离出双黄酮类化合物和相关的次生代谢产物，证明它们对 Ochna 属和 Ochnaceae 科的其他成员具有化学生态分类学意义。
