Analysis of secondary metabolites, antibacterial, brine shrimp lethality & larvicidal potentiality of Microcos paniculata fruits

Microcos paniculata traditionally known as ‘Kathgua or Fattashi’ in Bangladesh is widely used for the treatment of various ailments including colds ,diarrhea, hepatitis, heat stroke, dyspepsia, wound healing, fever and as an insecticide. Hence, the present study was designed to investigate the antibacterial, toxicity & 4 th instar Culex quinquefasciatus mosquito larvicidal activities of fruit extracts of M. paniculata using a range of organic & inorganic solvents (methanol, chloroform and water). Antibacterial, toxicity & larvicidal effects were studied by means of agar disc diffusion, brine shrimp lethality bioassay (BSLB) & standard WHO protocol with slight modification. The susceptibility of the microorganisms to the plant extracts was compared with standard antibiotic flucloxacilin. Fruit methanol extract (FME) revealed a broad spectrum of antibacterial activity in contrast to other extracts (Fruit chloroform extract-FCE & Fruit water extract-FWE) , particularly significant against gram negative bacteria, Proteus mirabilis being the most (zone of inhibition 28 mm). Moreover, the FME was found to be the most toxic to brine shrimp nauplii, with LC50 of 52.7 μg/ml, indicating the possibility of finding potential toxic compounds in this plant. 4 th instar Culex quinquefasciatus larval mortality was observed and recorded after 24 h exposure period. Both FME & FCE exhibited considerable larvicidal effects with LC50 of 342.1 μg/ml &441.7 μg/ml respectively. Altogether, these results propose that the organic fractions, FME & FCE could be used as a potential sources of antibacterial agents along with their toxic & larvicidal potentiality.