Larvicidal and Adulticidal Activity of Essential Oils from Four Cuban Plants against Three Mosquito Vector Species.

Mosquitoes are one of the main vectors of many important diseases and their degree of resistance to chemical insecticides has increased. Nowadays, it has become crucial to identify novel plant larvicides with an eco-friendly impact. The components of essential oils from Croton linearis Jacq. (EO-Cl), Lantana involucrata L. (EO-Li), Ocimum sanctum var. cubensis M. Gómez. (EO-Os), and Zanthoxylum pistaciifolium Griseb. (syn. Zanthoxylum flavum subsp. pistaciifolium (Griseb.) Reynel (EO-Zp) were determined using gas chromatography-mass spectrometry (GC-MS) analysis. Larvicidal and adulticidal bioassays against Aedes aegypti, Anopheles albitarsis and Culex quinquefasciatus, were performed according to the World Health Organization standard methods. A high diversity of compounds was identified in the four oils, with a total of 152 compounds (33-70 components). EO-Cl, EO-Li, and EO-Os were classified as active against both insect forms, larvae and adults. Lantana involucrata showed the best results, with LC50 values from 33.8 to 41.7 mg/L. In most of the cases, it was not possible to associate the main compounds with the measured activity, supporting the hypothesis about probable synergistic interactions among major and minor compounds. The results indicate EO-Cl, EO-Os, and EO-Li as good eco-friendly insecticides with potential.

Novel flavonol-3-O-methylethers from Zanthoxylum pistaciifolium Griseb. (Rutaceae).

Zanthoxylum pistaciifolium Griseb. is a tree endemic to Cuba, occasionally used in herbal medicine. Previously, the antitrypanosomal activity of a n-hexane-2-butanone extract of Z. pistaciifolium leaves and of its constituent skimmianine were published. In the current study a more thorough examination of the respective extract is performed, which led to the isolation and identification of three flavonoids, more specifically, the flavonol-3-O-methylethers kaempferol-3-O-methylether (1) and novel compounds kaempferol-3-O-methylether-5-O-ß-D-glucoside (2) and kaempferol-8-hydroxy-3,7-O-dimethylether-5-O-ß-D-glucoside (3). All compounds were screened for their antimicrobial and antiprotozoal activity and cytotoxicity towards MRC-5 SV2 cells. Compound 1 showed a moderate to weak activity against Trypanosoma cruzi (IC50 30.8 µM), T. brucei (IC50 15.4 µM) and Plasmodium falciparum (IC50 53.8 µM), but also showed cytotoxicity (CC50 19.0 µM). Compounds 2 and 3 did not display activity in any of the assays (IC50 and CC50 > 64 µM).[Formula: see text].