Preliminary Analysis of Insecticidal and Antimicrobial Potential of Andrographis paniculata

Abstract

Bioactive products of plant origin have been in practice to treat various diseases and food protection. The insecticidal and antimicrobial effects of leaf extracts of Andrographis paniculata (Family-Acanthaceae), prepared by the hot-wet extraction method using five solvents, were studied on the storedgrain insect, Tribolium castaneum (Herbst) and four aquatic pathogens. Statistical comparative analyses of the mortality rate of insects were evaluated concerning increasing concentration as well as for the study of antibacterial activity. The iso-propanolic extract showed a maximum lethal effect (57 %) on the insect as compared to other solvent extracts. The LD50 value of propanolic extract after 10 days of treatment was 63.27 mg/ g. On the other hand, the aqueous (82 %) and iso-propanolic extracts exhibited a significant antibiosis effect. The gram-negative pathogens A. hydrophila and V. parahaemolyticus showed selective susceptibility towards different solvent extracts compared to the high susceptibility effect of gram-negative P. fluorescens and grampositive Streptococcus sp. The present findings support the potential of A. paniculata as a natural alternative and suggest the preferred choice of solvents for the extraction of specific phytoactive compounds with insecticidal and antibiotic potential.