Center for Eco-friendly New Materials , Korea Research Institute of Chemical Technology , Daejeon 34114 , Korea.
Department of Medicinal Chemistry and Pharmacology , University Science and Technology , Daejeon 34113 , Korea.
J Agric Food Chem. 2019 Jul 10;67(27):7706-7715. doi: 10.1021/acs.jafc.9b02236. Epub 2019 Jun 27.
While searching for new antifungal compounds, we revealed that a methanol extract of plant species has a potent antifungal activity against rice blast fungus . To identify the antifungal substances, the methanol extract of was extracted by organic solvents, and consequently, six active compounds were isolated from the -butanol layer. The isolated compounds were five new acylated triterpenoid saponins including maejaposide I (), maejaposides C-1, C-2, and C-3 (-), and maejaposide A-1 (), along with a known one, maejaposide A (). These chemical structures were determined by NMR and a comparison of their NMR and MS data with those reported in the literature. Based on the antifungal bioassay, the five compounds (-) exhibited strong antifungal activity against with MIC values ranging from 4 to 32 μg/mL, except for maejaposide I () (MIC > 250 μg/mL). When the compounds were evaluated at concentrations of 125, 250, and 500 μg/mL for an antifungal activity against rice blast, compounds - strongly reduced the development of blast by at least 85% to 98% compared to the untreated control. However, compound did not show any antifungal activity up to a concentration of 500 μg/mL. Taken together, our results suggest that the methanol extract of and the new acylated triterpenoid saponins can be used as a source for the development of natural fungicides.
在寻找新的抗真菌化合物时，我们发现植物物种的甲醇提取物对稻瘟病菌具有很强的抗真菌活性。为了鉴定抗真菌物质，用有机溶剂提取了的甲醇提取物，随后从正丁醇层中分离出六种活性化合物。从分离得到的化合物中，鉴定出了五种新的酰化三萜皂苷，包括麦角甾苷 I（）、麦角甾苷 C-1、C-2 和 C-3（-）以及麦角甾苷 A-1（），以及一种已知的化合物，麦角甾苷 A（）。这些化学结构通过 NMR 确定，并通过与文献中报道的 NMR 和 MS 数据进行比较来确定。基于抗真菌生物测定，化合物（-）对稻瘟病菌表现出很强的抗真菌活性，MIC 值范围为 4 至 32 μg/mL，除了麦角甾苷 I（）（MIC > 250 μg/mL）。当化合物在 125、250 和 500 μg/mL 浓度下评估对稻瘟病的抗真菌活性时，与未处理的对照相比，化合物（-）至少将病害发展减少了 85%至 98%。然而，化合物（）在 500 μg/mL 浓度下没有表现出任何抗真菌活性。总之，我们的研究结果表明，植物的甲醇提取物和新的酰化三萜皂苷可以作为开发天然杀菌剂的来源。
