Department of Microbiology, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil.
United States Department of Agriculture, Agricultural Research Service, Natural Products Utilization Research University, MS 38677, USA.
Molecules. 2017 Jan 21;22(1):175. doi: 10.3390/molecules22010175.
is a rare, ancient, and endemic neotropical plant present in the Brazilian Rupestrian grasslands. The dichloromethane extract of adventitious roots was phytotoxic against , , and , and showed larvicidal activity against . Phytotoxicity bioassay-directed fractionation of the extract revealed one new isopimaradiene, 8(9),15-isopimaradien-1,3,7,11-tetraone, and three new cleistanthane diterpenoids, 7-oxo-8,11,13-cleistanthatrien-3-ol, 3,20-epoxy-7-oxo-8,11,13-cleistanthatrien-3-ol, and 20-nor-3,7-dioxo-1,8,11,13-cleistanthatetraen-10-ol. These new structures are proposed based on interpretation of ¹H, C, COSY, NOESY, HSQC, and HMBC NMR data. 8(9),15-isopimaradien-1,3,7,11-tetraone was especially phytotoxic with an IC value (30 μM) comparable to those of commercial herbicides clomazone, EPTC, and naptalam. In addition, 7-oxo-8,11,13-cleistanthatrien-3-ol provided 100% mortality at a concentration of 125 ppm against one-day-old larvae. Our results show that ancient and unique plants, like the endangered narrowly endemic neotropical species present in the Rupestrian grasslands, should also be protected because they can be sources of new bioactive compounds.
是一种罕见的、古老的、地方特有的新热带植物，存在于巴西的岩生草原中。不定根的二氯甲烷提取物对 、 、 和 具有植物毒性，并对 具有杀幼虫活性。提取物的植物毒性生物测定导向分离揭示了一种新的异戊二烯，8(9)，15-异戊二烯-1,3,7,11-四酮，和三种新的开环二萜，7-酮-8,11,13-开环萜烯-3-醇，3,20-环氧-7-酮-8,11,13-开环萜烯-3-醇和 20-降-3,7-二酮-1,8,11,13-开环萜四烯-10-醇。这些新结构是基于对 ¹H、C、COSY、NOESY、HSQC 和 HMBC NMR 数据的解释提出的。8(9)，15-异戊二烯-1,3,7,11-四酮具有特别的植物毒性，IC 值（30 μM）与商业除草剂氯唑酮、EPTC 和萘丙胺相当。此外，7-酮-8,11,13-开环萜烯-3-醇在 125 ppm 浓度下对 1 天龄的 幼虫提供 100%死亡率。我们的研究结果表明，古老而独特的植物，如濒危的新热带地区特有植物 ，也应该受到保护，因为它们可能是新的生物活性化合物的来源。
