Tagetes erecta Linn. and its mosquitocidal potency against Culex quinquefasciatus

<p><b>OBJECTIVE</b>To investigate mosquitocidal effects of ethanolic extract of flowers of Tagetes erecta (T. erecta) and its chloroform and petroleum ether soluble fractions against the larvae of Culex quinquefasciatus (Cx. quinquefasciatus).</p><p><b>METHODS</b>The fresh flowers of T. erecta were extracted in cold with ethanol (5.0 L) and after concentration, the ethanol extract was fractionated with chloroform and petroleum ether to afford a brownish syrupy suspension of ethanol extract (50.0 g), petroleum ether soluble fraction (18.6 g) and chloroform soluble fraction (23.8 g). The larvicidal effect of ethanol extract and their solvent fractions were determined by the standard procedure of WHO against different instars of Cx. quinquefasciatus.</p><p><b>RESULTS</b>Among the tested samples the chloroform soluble fractions showed the highest toxicity and consequently, the lowest LC50 values (14.14 µg/mL, 17.06 µg/mL, 36.88 µg/mL and 75.48 µg/mL) for all the instars larvae of Cx. quinquefasciatus. The larvae showed comparative tolerance in the course of increasing age and time.</p><p><b>CONCLUSIONS</b>It can be concluded that the flowers of T. erecta are very effective natural larvicide and could be useful against Cx. quinquefasciatus.</p>

Antimicrobial and Cytotoxic Activity of Di-(2-ethylhexyl) Phthalate and Anhydrosophoradiol-3-acetate Isolated from Calotropis gigantea (Linn.) Flower

A phytochemical study on the flowe r of Calotropis gigantea (Linn.) using silica gel column chromatography and preparative thin layer chromatography, led to the first time isolation of Di-(2-ethylhexyl) phthalate (compound 1) and anhydrosophoradiol-3-acetate (compound 2). The structures of these compounds were confirmed by spectroscopic analyses (IR, HRTOFMS and NMR). The antibacterial and antifungal activities of ethyl acetate extract, compound 1 and compound 2 were measured using the disc diffusion method. Ethyl acetate extract and compound 1 presented better results than compound 2. The minimum inhibitory concentrations (MICs) of the extract and compounds were found to be in the range of 16~128 microg/ml. The cytotoxicity (LC50) against brine shrimp nauplii (Artemia salina) were also evaluated and found to be 14.61 microg/ml for ethyl acetate, 9.19 microg/ml for compound 1 and 15.55 microg/ml for compound 2.

Antishigellosis and Cytotoxic Potency of Crude Extracts and Isolated Constituents from Duranta repens

The crude ethanol extracts (stem and fruits), their fractions and two triterpenes, beta-Amyrin and 12-Oleanene 3beta, 21beta-diol, isolated as a mixture from the chloroform soluble fraction of an ethanolic extract of Duranta repens stem, were evaluated for antibacterial, antifungal activities by the disc diffusion method and cytotoxicity by brine shrimp lethality bioassay. The structures of the two compounds were confirmed by IR, 1H-NMR, 13C-NMR and LC-MS spectral data. The chloroform soluble fraction of stem and ethanol extract of fruits possess potent antishigellosis activity and also exhibited moderate activity against some pathogenic bacteria and fungi but the isolated compound 1 (mixture of beta-Amyrin and 12-Oleanene 3beta, 21beta-diol) showed mild to moderate inhibitory activity to microbial growth. The minimum inhibitory concentrations (MICs) of the extracts (stem and fruits), their fractions and compound 1 were found to be in the range of 32~128 microg/ml. The chloroform soluble fractions of stem and ethanol extract of fruit showed significant cytotoxicity with LC50 value of 0.94 microg/ml and 0.49 microg/ml, respectively against brine shrimp larvae.

Antimicrobial Activity of Some Schiff Bases Derived from Benzoin, Salicylaldehyde, Aminophenol and 2,4 Dinitrophenyl Hydrazine

The antibacterial and antifungal activities of three schiff bases were evaluated against some pathogenic bacteria and fungi. Parallel experiments were also carried out with standard drugs (Kanamycin for bacteria and Nystatin for fungi). Two compounds [N-(1-phenyl-2-hydroxy-2phenylethylidine)-2',4' dinitrophenyl hydrazine, abbreviated as PDH and N-(2-hydroxy benzylidine)-2'-hydroxy imine, abbreviated as HHP] showed significant antimicrobial activities. The rest one [N-(1-phenyl 2-hydroxy-2 phenyl ethylidine) 2'-hydroxy phenyl imine, abbreviated as PHP] showed moderate activity. All these three compounds were found to possess pronounced cytotoxic effect. These compounds can be considered as potent antimicrobial agents.