Objective: To evaluate the antibacterial efficacy of chloroform, petroleum ether, ethyl acetate, methanol, ethanol and aqueous extracts of leaf and leaf derived callus of Orthosiphon aristatus against Bacillus cereus, Bacillus subtiltis, Staphylococcus aureus, Streptococcus pyogenes, Enterobater aerogenes, Escherichia coli, Proteus mirabilis, and Klebseilla pneumoniae. Methods: The leaf segments were cut into small pieces of size 1-2 sq. cm and were cultured on Murashige and Skoog solid medium supplemented with different auxins alone and in combination. Antibacterial efficacy was performed by disc diffusion method followed my MIC determination by two fold serial dilution method. Leaf and leaf callus extracts were subjected to the qualitative phytochemical analysis. Results: Maximum callus formation percentage was obtained from the leaf segments cultured on MS medium supplemented with 2, 4-D (2 mg/l). Ethanolic leaf extract showed maximum inhibition activity with 28 mm zone of inhibition against P. mirabilis with MIC value of 0.32 mg/ml. Out of the callus extracts, ethanolic callus extract showed the maximum bio-efficacy against S. aureus with 26 mm zone of inhibition and MIC value of 0.64 mg/ml. Results revealed that both leaf and leaf derived callus are effective against Gram positive and Gram negative test bacteria.Conclusion: The bioefficacy study confirms the strong antibacterial potential of leaf and leaf derived callus of O. aristatus.Keywords: Leaf, Leaf callus, Antibacterial efficacy, Orthosiphon aristatus.

Aim: The study was carried out to evaluate the in vitro hepatoprotective activity of leaf and leaf callus extracts of Orthosiphon aristatus against alcohol induced toxicity using HepG2 cell line. Materials and Methods: Leaf segments were cultured on Murashige and Skoog solid medium fortified with different auxins alone and in combination. Prior to the determination of hepatoprotective property leaf and leaf callus extracts were subjected to the toxic dose study. The degree of hepatoprotection of extracts was determined by measuring cell viability percentage by MTT assay. Leaf and leaf callus extracts were subjected to the preliminary phytochemical analysis. Results: Maximum percentage of callus formation (94%) was obtained in MS medium augmented with 2 mg/L of 2,4-D. HepG2 cells were pretreated with the different concentrations (below toxic dose) of leaf and leaf callus extracts for 72 hrs. followed by alcohol intoxication. Results revealed that aqueous leaf extract pretreated HepG2 cells show 90% cell viability compared to the standard silymarin pretreated HepG2 cells which showed 81% cell viability. Leaf callus extracts also showed significant hepatoprotective activity where ethanolic callus extract pretreated HepG2 cells showed Original Research Article