The phytochemical investigation of the leaves of Litsea glutinosa revealed the presence of secondary metabolites like alkaloids, anthraquinones, cardiac glycosides, flavonoids, glycosides, phenols, saponins, steroids, tannins, terpenoids, volatile compounds, amino acids and carbohiydrates. The antimicrobial activity and minimum inhibition concentration values were determined for these phytochemical constituents as crude extracts using the agar well diffusion and two-fold serial dilution methods. The results indicated that Bacillus subtilis was the most susceptible bacterium with high inhibition zones for the methanol and chloroform extracts of 31 mm and 26 mm, respectively. The MIC values indicated that extracts possess good antimicrobial activity with significant MIC value against Enterococcus faecalis, Pseudomonas aeruginosa and Staphylococcus pneumoniae at 31.2 µg/ml concentrations. The extracts showed marked antimicrobial activity against both bacteria and fungi. Among the bacterial strains, gram-positive bacteria were more susceptible than the gram-negative. All the 13 microorganisms tested showed dose dependent susceptibility towards the phytochemicals present in the foliar extracts. The study suggests that Litsea glutinosa leaves possess potent antimicrobial activity and can be a good source for the development of new antibiotics.

Microbial pathogens develop resistance to antibiotics after repeated administration during the treatment of infectious diseases. Therefore, it is necessary to find alternative antimicrobial drugs and the present trend is focused on medicinal plants. The hereby research work was carried out to investigate the antimicrobial activity of solvents as well as aqueous extracts of Rauwolfia serpentina roots. The extracts were tested against Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Micrococcus luteus, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Streptococcus pneumoniae, Aspergillus niger, Candida albicans and Saccharomyces cerevisiae by agar well diffusion method. It was observed that methanol extract showed the highest antimicrobial activity against multi drug resistance S. aureus at 100 mg/ml concentration, while S. aureus was the most susceptible bacterium to all extracts. However, E. faecalis, M. luteus and S. pneumoniae were also susceptible to the experimented solvents and extracts. On the other hand, K. pneumoniae was resistant against the solvent and aqueous extracts. The present study suggested that methanol extracts of R. serpentina roots would be helpful in treating diseases caused by human pathogenic bacteria and fungi. In particular, based on the results obtained in the current experiment, it can be recommended for the control of infectious Gram-positive bacteria.

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Antimicrobial activity of Abitulon indicum roots was studied against seven pathogenic bacteria and three fungal strains by agar well diffusion method. Antimicrobial activity was recorded for hexane, chloroform, methanol, ethanol and aqueous extracts. Alcohol (ethanol and methanol) extracts exhibited the highest degree of antimicrobial activity compared to aqueous, chloroform and hexane extracts. Pseudomonas aeruginosa was turned out to be the most susceptible bacterium to the crude root chemical constituents, using the standard Tetracycline and Clotrimazole. Minimum inhibition concentration values of hexane, chloroform, methanol, ethanol and aqueous extracts were determined by the agar dilution method and ranged between 62.5 and 1,000 µg. The study suggested that the root extracts possess bioactive compounds with antimicrobial activity against the tested bacteria and fungi, revealing a significant scope to develop a novel broad spectrum of antimicrobial drug formulation from Abitulon indicum.