In vitro antimicrobial activity of Aloe vera L. extracts against pathogenic bacteria and fungi

The current research aimed to evaluate in vitro antimicrobial activity of crude extract prepared from leaves of Aloe vera L . The extract was prepared in different solvents including methanol and ethanol. The inhibitory potential of extract was determined via agar well diffusion method against diverse range of microbes including Erwinia carotovora, Escherichia coli, Klebsiella pneumoniae , Salmonella typhi, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus and Candida albicans . The extracts were applied at 30 µL and 60 µL concentrations. The zone of inhibition was measured and compared with three standards i.e. Clotrimazole (50 µg mL -1 ) for Candida albicans ; Ciprofloxacin (30 µg mL -1 ) for Gram negative bacteria and Azithromycin (50 µg mL -1 ) for Gram positive bacteria. The antimicrobial susceptibility test showed that leaf and gel extracts inhibited the growth of all the tested microorganisms while the gel has significantly retarded the growth of E. carotovora, E. coli, B. subtilis and S. aureus . Furthermore, the gram positive strains were inhibited up-to larger extent as compared to gram negative one due to absence of lipopolysaccheride layer in cell wall. The higher inhibitory effect was observed for rotary dried gel methanol extract dissolved in water against C. albiacans at both 30 µL and 60 µL (78%, 104%), respectively. Our results suggest that these herbal extracts may be used against bacterial and fungal pathogens which possesses resistant to conventional antibiotics.