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
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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. These new structures are proposed based on interpretation of
1H,
13C, COSY, NOESY, HSQC, and HMBC NMR data. 8(9),15-isopimaradien-1,3,7,11-tetraone was especially phytotoxic with an IC
50 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
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.
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