|Ferreira, Mariana - Universidade Federal De Minas Gerais|
|Ali, Abbas - University Of Mississippi|
|Rosa, Luiz - Universidade Federal De Minas Gerais|
Submitted to: Molecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2017
Publication Date: 1/21/2017
Citation: Ferreira, M.C., Cantrell, C.L., Duke, S.O., Ali, A., Rosa, L.H. 2017. New phytotoxic diterpenoids from Vellozia gigantea (Velloziaceae), an endemic neotropical plant living in the endangered Brazilian biome Rupestrian grasslands. Molecules. 22:175. doi:10.339/molecules22010175.
Interpretive Summary: Brazil has a rich biodiversity of plant species, which includes rare and endemic taxa. Among the typical biomes from Brazil, the Espinhaço mountain range has the Rupestrian grasslands (“campo rupestre”) that shelter different plant species with a high richness of endemism. Vellozia gigantea is a rare, ancient and endemic neotropical plant present in the Brazilian Rupestrian grasslands. The dichloromethane extract of V. gigantea adventitious roots was phytotoxic against lettuce, bentgrass, and duckweed, and showed larvicidal activity against the vector for Zika virus. From the extract of adventitious roots of V. gigantea, we isolated four new diterpenes with phytotoxic activities. These compounds might be used as scaffolds to develop new herbicides and other pesticides.
Technical Abstract: Vellozia gigantea is a rare, ancient and endemic neotropical plant present in the Brazilian Rupestrian grasslands. The dichloromethane extract of V. gigantea adventitious roots was phytotoxic against Lactuca sativa, Agrostis stolonifera and Lemna paucicostata, and showed larvicidal activity against Aedes aegypti. 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. 8(9),15-isopimaradien-1,3,7,11-tetraone was especially phytotoxic with and an IC50 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 1-day-old Ae. aegypti larvae. Our results show that ancient and unique plants, like the endangered narrowly endemic neotropical species V. gigantea present in the Rupestrian grasslands, should also be protected because they can be sources of new bioactive compounds.