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To investigate antimicrobial effects of ethanolic extract of Zingiber zerumbet (Z. zerumbet) (L.) Smith and its chloroform and petroleum ether soluble fractions against pathogenic bacteria and fungi.The fresh rhizomes of Zingiber zerumbet were extracted in cold with ethanol (4.0 L) after concentration. The crude ethanol extract was fractionated by petroleum ether and chloroform to form a suspension of ethanol extract (15.0 g), petroleum ether fraction (6.6 g) and chloroform soluble fraction (5.0 g). The crude ethanol extract and its petroleum ether and chloroform fractions were evaluated for antibacterial and antifungal activity against thirteen pathogenic bacteria and three fungi by the disc diffusion method. Commercially available kanamycin (30 µg/disc) was used as standard disc and blank discs impregnated with the respective solvents were used as negative control.At a concentration of 400 µg/disc, all the samples showed mild to moderate antibacterial and antifungal activity and produced the zone of inhibition ranging from 6 mm to 10 mm. Among the tested samples, the crude ethanol extract showed the highest activity against Vibrio parahemolyticus (V. parahemolyticus). The minimum inhibitory concentration (MIC) of the crude ethanol extract and its fractions were within the value of 128-256 µg/mL against two Gram positive and four Gram negative bacteria and all the samples showed the lowest MIC value against V. parahemolyticus (128 µg/mL).It can be concluded that, potent antibacterial and antifungal phytochemicals are present in ethanol extract of Z. zerumbet (L).

Objective To investigate the cytotoxicity of the crude ethanol extract of the rhizome of Zingiber zerumbet ( Z. zerumbet ) (L) Smith. and Curcuma zedoaria ( C. zedoaria ) Rosc. against Artemia salina Leach Methods Fresh rhizomes of Z. zerumbet (L) Smith. and C. zedoaria Rosc. were extracted separately in cold with ethanol (2.5 L) and after concentration a brownish syrupy suspension of ethanol extracts of Z. zerumbet (L) Smith. and C. zedoaria Rosc. was obtained. The cytotoxic effect of the crude ethanol extracts of both plants was determined by brine shrimp lethality bioassay Results Crude ethanol extracts of the rhizome of Z. zerumbet (L) Smith. showed the highest cytotoxicity (LC 50 was 1.24 μg/mL) against brine shrimp nauplii as compared with C. zedoaria Rosc. (LC 50 was 33.593 μg/mL) after 24 h of exposure. Conclusions It can be concluded that the rhizome of Z. zerumbet (L) Smith. and C. zedoaria Rosc. can be used as a source of cytotoxic agent.

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).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.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.It can be concluded that the flowers of T. erecta are very effective natural larvicide and could be useful against Cx. quinquefasciatus.