Antibacterial Screening Activity of Aqueous, Ethanolic and Methanolic Leaf Extracts of Mayana (Coleus Blumei), Oregano (Coleus Aromaticus), Horsetail (Equisetum Hyemale), And Kataka- Taka (Kalanchoe Pinnata)

The ethnobotanical efficacy of four Philippine medicinal plants; Coleus blumei, Coleus aromaticus, Equisetum hyemale, and Kalanchoe pinnata were examined using agar disc diffusion method against clinical gram positive bacteria (Staphylococcus aureus, Bacillus cereus) and clinical gram negative bacteria (Escherichia coli). Leaves were extracted using different solvents such as aqueous, ethanol and methanol. Among treatments, maximum in vitro inhibition was scored in methanol extract of Equisetum hyemale which offered inhibition zone of 1.76 against S. aureus, 2.38 for B. cereus and 0.71 mm for E. coli, seconded by ethanol extract of Coleus blumei with inhibition zone of 1.14, 0.14 and 2.19 mm, respectively, and thirdly followed by methanol extract of Coleus blumei with inhibition zone of 1.14, 1.19 and 1.05 mm, respectively. The standard antibiotics, used as control treatments, were all effective in inhibiting the growth of the test microbes. Penicillin control was able to impede the growth of S. aureus and B. cereus with a maximum Al mean of 2.33 and 3.71 mm, respectively. Streptomycin, used against E. coli, had an Al mean of 4.19 mm. These synthetic antibiotics were found to have more antimicrobial potential than those of the different twelve (12) leaf extracts. A significant inhibition of B. cereus was found in aqueous and in all tested solvent extracts of Kalanchoe pinnata. Whereas, extracts of Coleus aromaticus was found to be ineffective or showed poor inhibition on tested bacteria.