Jefferson Q. Lima

Chemical composition and larvicidal activity of Rollinia leptopetala (Annonaceae)

The aim of present study was to describe the chemical composition of the essential oils from the leaf and stem of Rollinia leptopetala R. E. Fries (Annonaceae) and to evaluate the larvicidal activities of these essential oils, of the methanol extract from roots of this plant and of the oxoaporphine alkaloid, liriodenine (1) against the third-instar of Aedes aegypti larvae. The methanol extract from the roots showed larvicidal activity with LC 50 64.6 ± 1.5 ppm. Higher activity was observed for the isolated alkaloid liriodenine (1), LC 50 3.6 ± 0.4 ppm. The essential oils from the leaves and stems, also exhibited larvicidal activity with LC 50 104.7 ± 0.2 and 34.7 ± 0.3 ppm, respectively. These results suggest R. leptopetala as a source of natural larvicidal compounds. This is the first report about the chemical composition and larvicidal activity of the leaf and stem essential oils of R. leptopetala.

Estudo químico e biológico de Tephrosia toxicaria Pers.

The ethanol extracts from leaves, stems, pods and roots were assayed against the 3rd instar Aedes aegypti larvae and the highest activity was observed in the roots extracts (LC50 47.86 ppm). This extract was submitted to partition with hexane, chloroform, ethyl acetate and methanol. The respective fractions were bioassayed and the best larvicidal activities were identified in the hexane (LC50 23.99 ppm) and chloroform (LC50 13.80 ppm) fractions. Antioxidant activity (DDPH method) was observed in the ethanol extract (IC50 276 µg/mL) from roots of T. toxicaria. Fractions from this extract were also tested and the highest antioxidant activity (IC50 89 µg/mL) was found in the methanol fraction. The flavonoids iso-obovatin (1), obovatin (2), 6a,12a-dehydro-β-toxicarol (3), 6a,12a-dehydro-α-toxicarol (4) and α-toxicarol (5) were isolated and bioassayed against A. aegypti. The flavonoid 5 showed the best larvicidal activity (LC50 24.55 ppm). The antioxidant activity of 2 was investigated and showed IC50 3.370 µg/mL. The antioxidant and larvicidal activities of Tephrosia toxicaria are reported for the first time.

Rotenoids from Tephrosia toxicaria with larvicidal activity against Aedes aegypti, the main vector of dengue fever

In the search for new larvicides from plants, we have investigated the potential activity of the rotenoids deguelin (1), 12a-hydroxy-α-toxicarol (2) and tephrosin (3), isolated from the bioactive ethanol extract of roots of Tephrosia toxicaria Pers., against Aedes aegypti, the main vector of dengue. The absolute configuration of these compounds was determined by circular dichroism (CD) spectra. The LC50 values of the compounds evaluated justify the potential of T. toxicaria as a new natural larvicide.

Unequivocal assignments of flavonoids from Tephrosia sp. (Fabaceae).

1H and 13C NMR chemical shifts of praecansone B, pongaflavone and dehydrorotenone isolated from Tephrosia egregia Sandw and obovatin from T. toxicaria Pers. were unambiguously assigned by 1D and 2D NMR experiments including 1H, 1H COSY, gHMQC and gHMBC, allowing the correction of literature assignments.Copyright

Zanthoxylum articulatum Engler (Rutaceae) Essential Oil: Chemical Composition and Larvicidal Activity

Abstract The leaves of Zanthoxylum articulatum Engler (Rutaceae), collected in Jacobina-Bahia, Northwest of Brazil, was subjected to hydrodistillation and its essential oil was characterized by GC/MS. Twelve compounds were identified representing 90.4% of the oil. Oxygenated sesquiterpenes (65.4%) were the major constituents with viridiforol (35.4%), spathulenol (9.9%), elemol (9.7%) and globulol (6.5%) being the main compounds. The oil was examined with respect to its larvicidal properties against the larvae of a mosquito (Aedes aegypti) and showed LC50 77.62 ± 0.64 ppm.

Constituintes químicos de Sebastiania macrocarpa Muell. Arg. (Euphorbiaceae)

The chemical investigation of the methanolic extract of the aerial part of Sebastiania macrocarpa allowed the isolation of the mixture of steroids β-sitosterol and stigmasterol, gallic acid, and scopoletin. The hexane extract of the roots allowed the isolation of the triterpene lupeol and of the macrociclic diterpene (+)-tonantzitlolone. The structures of all compounds isolated were identified on the basis of their spectral data and by comparison of their spectral data with values described in the literature. This is the first report involving the chemical investigation of this species.

Composition and Larvicidal Activity of the Essential Oil from Tephrosia cinerea Pers.

Abstract The essential oil obtained by hydrodistillation from the leaves of Tephrosia cinerea Pers. (Papilionaceae) was analyzed using GC/FID and GC/MS. Caryophyllene oxide was the major component (63.9%). Furthermore, the oil was examined with respect to its larvicidal properties against the third stage larvae of the mosquito Aedes aegypti and showed LC50 66.07 ± 0.74 ppm.

Constituents of the Essential Oil of Pluchea quitoc DC

Abstract The essential oil obtained from fresh leaves of Pluchea quitoc DC (Compositae) was analyzed by GC and GC/MS. Twenty-four compounds are identifed, of which δ-cadinene (25.3%) and 1,8-cineole (17.3%) were the major constituents.