(4-Hy-droxy-3-methyl-phen-yl)(phen-yl)methanone.

In the title compound, C14H12O2, the benzene rings make a dihedral angle of 58.84 (12)°. In the crystal, mol-ecules are linked into chains along the b-axis direction by O-H⋯O hydrogen bonds. These chains are further linked by C-H⋯O hydrogen bonds, forming layers parallel to the bc plane.

Bioactivity guided isolation of mosquito larvicide from Piper longum.

OBJECTIVE: To isolate the larvicidal component from the fruits of Piper longum (P. longum) against the filariasis vector, Culex quinquefasciatus (C. quinquefasciatus). METHODS: Pulverized fruits of P. longum were subjected to soxhlet extraction using series of organic solvents of increasing polarity. All the solvent extracts were verified for their larvicidal efficacy against 4th instar larvae of C. quinquefasciatus employing standard WHO procedure. Bioassay-guided fractionation through column chromatography lead to the isolation of a bioactive amide, pipyahyine from the petroleum ether extract. RESULTS: Petroleum ether extract was found to be the most active fraction among all the extracts tested with LC(50) and LC(90) being 1.03 and 2.04 ppm respectively. Whereas, pipyahyine, an isolated component of the same fraction was found to be even more effective than the parent extract in terms of LC(50) being 0.58 and 1.88 ppm respectively. CONCLUSIONS: From the results, it is evident that P. longum can be considered as a powerful arsenal for the control of mosquito population.

Efficacy of bioactive compounds from Curcuma aromatica against mosquito larvae.

With the development of resistance to conventionally used synthetic insecticides, vector management has become acutely problematic. Hence more attention has been focused on botanicals. Therefore our present study was aimed to evaluate the efficacy of extracts from rhizomes of Curcuma aromatica against the larvae of filariasis vector mosquitoes, Culex quinquefasciatus employing standard WHO procedure at Mysore. The soxhlet extraction was carried out using non-polar organic solvent, petroleum ether. The efficacy of petroleum ether extract seemed to be effective with LC(50) and LC(90) values of 11.42 and 18.00 ppm respectively. Bioassay-guided fractionation through flash chromatography lead to the isolation of two larvicidal compounds namely 9-oxoneoprocurcumenol and neoprocurcumenol. Between the two, 9-oxoneoprocurcumenol exerted significant toxicity (P<0.01) on mosquito larvae with LC(50) value of 5.81 ppm and LC(90) being 9.99 ppm compared to neoprocurcumenol with 13.69 and 23.92 ppm of LC(50) and LC(90) values respectively. From the results, C. aromatica could be considered as one of the powerful candidate to bring about useful botanicals so as to prevent the resurgence of mosquito vectors.