Evaluation of antimicrobial efficacy of flavonoids and alkaloids of Andrographis paniculata nees

Abstract

Context: The persistent increase in the number of antibiotic resistant strains of microorganisms has led to the development of more potent but more expensive antibiotics. Synthetic drugs are mostly associated with side effects and are generally costly, hence are not affordable to economically poor class of the society when long term treatment is required, thus interest has been developed in the use of herbal medicines which have been reported to have either very little or no side effects. Aims: Present work was carried out to assess the antimicrobial activity of A. paniculata against some multidrug resistant pathogenic bacteria. Materials and Methods: Different parts (leaf, stem, root) of A. paniculata were collected and air dried and soxhlet extracted by using standard methods for flavonoid
and alkaloid extraction. These extracts were then tested for antimicrobial activity using disc diffusion method. Minimum inhibitory concentration, Minimum bactericidal concentration and Total activity were also calculated. Statistical Analysis: Mean value and Standard Deviation were calculated for the test bacteria and fungi. Data were analysed by one‑way analysis of variance and P values were considered significant at P < 0.05. Results: C. albicans was found to be the most susceptible organism followed by P. mirabilis, S. aureus, E. coli, P. aeruginosa and A. flavus. A. niger and T. mentegrophyte were observed to be resistant as none of the tested extracts
showed activity against them. Free flavonoid extract of root showed best activity against C. albicans (IZ 14 mm, MIC 0.156), whereas leaf free flavonoid extract showed maximum 21 mm inhibition zone against P. mirabilis.The range of MIC and MBC was found to be 1.25‑0.039 and 2.5‑0.078 respectively. Conclusion: Results of the present study reveal that extracts of A. paniculata are showing great antimicrobial potential against tested microorganisms, and may be exploited for future antimicrobial drugs
Key words: Flavonoids, minimum inhibitory concentration, minimum bactericidal concentration and total activity