author(s)
Senthamil Pandian C, Radhakrishnan L, Karunakaran R, Gopala Krishna Murthy TR, Appa Rao V and Shamsudeen P

abstract
Seven locally available phytobiotics viz., ginger rhizome powder, turmeric rhizome powder, tulsi leaves powder, coriander seeds powder, fenugreek seeds powder, curry leaves powder, moringa leaves powder and its selected combinations were evaluated for in vitro antimicrobial activity of aqueous and ethanol extracts against gram positive and gram negative bacterial strains isolated at Poultry Disease Diagnosis and Surveillance Laboratory, Namakkal. The phytobiotics collected from different parts of Tamil Nadu were cleaned, dried and ground to 1 mm size aseptically for obtaining aqueous and ethonalic extracts. The different levels of extracts prepared from herbs starting from 10 µl or 1.0 mg, 15 µl or 1.5 mg, 20 µl or 2.0 mg and 30 µl or 3.0 mg, were tested against Staphylococcus aureus and Escherischia coli. Antimicrobial activity of selected individual phytobiotics and phytobiotics mixtures were measured as zone of inhibition in mm. Among the phytobiotic extracts, aqueous extracts of the individual herbs did not evince any zone of inhibition at all levels of extracts except at 20 µl or 2.0 mg level. The antimicrobial activity of ethanol extracts of herbs and phytobiotic mixtures gradually increased from lower 10 µl to 20 µl but the activity decreased at 30 µl level. Twenty micro liters of ethanol extracts of ginger rhizome powder, curry leaves powder, turmeric rhizome powder and coriander seeds powder revealed significantly highest antimicrobial activity (P<0.05) against gram positive bacteria over gram negative bacteria. The study also revealed that the aqueous extracts of selected phytobiotic mixtures did not reveal any zone of inhibition. All herbs and herbal mixtures of ethanol extracts possessed antibacterial activity against both gram positive and gram negative bacteria. Among the ethanol extracts of individual herbs, curry leaves powder followed by ginger rhizome powder exerted significantly (P<0.05) highest zone of inhibition at 20 µl level. It could be concluded that ethanol extracts revealed antimicrobial potential in herbs and phytobiotic mixtures compared to aqueous extracts.