Brown Stink Bug Mortality by Seed Extracts of Tephrosia Vogelii Containing Deguelin and Tephrosin

ABSTRACT Extracts of the seeds of Tephrosia vogelii Hook. f. were studied in relation to its chemical composition and toxicity to the brown stink bug Euschistus heros (F.). The extracts were obtained in ethyl acetate and ethanol in the sequence according to the polar nature of the solvents. Extracts were sprayed in concentration of 1.0, 2.5, 5.0, 7.5 and 10% on third-instars nymphs and adults, and mortality was recorded. Presence two rotenoids in ethyl acetate was detected, with analyzed with gas chromatography-mass spectrometry (GC-MS). Crude fraction analyses confirmed the presence of these rotenoids (tephrosin - 2.71% in ethyl acetate and 3.66% in methanol; and deguelin - 10.46% in ethyl acetate and 1.22% in methanol) and three other rotenoids in small amounts. Eight days after applications, ethyl acetate caused more stink bugs mortality and on less time than ethanol extract, because great quantity of rotenoids, as polarity. Concentrations above to 1 and 2.5% of the ethyl acetate extracts caused mortality above 80% of the nymphs and adults of E. heros, respectively. Concentration were considered high, thus chemist analyzes demonstrated high rotenoids presence. In conclusion, seed T. vogelli extracts, rich in deguelin and tephrosin (3:1), cause mortality of E. heros, however, high concentration are necessary.

Antimicrobial activity and chemical investigation of Brazilian Drosera

The antimicrobial activity of three different extracts (hexanic, ethyl acetate, methanol) obtained from Brazilian Drosera species (D. communis, D. montana var. montana, D. brevifolia, D. villosa var. graomogolensis, D. villosa var. villosa, Drosera sp. 1, and Drosera sp. 2 ) were tested against Staphylococcus aureus (ATCC 25923), Enterococcus faecium (ATCC23212), Pseudomonas aeruginosa (ATCC27853), Escherichia coli (ATCC11229), Salmonella choleraesuis (ATCC10708), Klebsiella pneumoniae (ATCC13883), and Candida albicans (a human isolate). Better antimicrobial activity was observed with D. communis and D. montana var. montana ethyl acetate extracts. Phytochemical analyses from D. communis, D. montana var. montana and D. brevifolia yielded 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin); long chain aliphatic hydrocarbons were isolated from D. communis and from D. villosa var. villosa, a mixture of long chain aliphatic alcohols and carboxylic acids, was isolated from D. communis and 3b-O-acetylaleuritolic acid from D. villosa var. villosa.