Title: Phytochemical Screening and <i>in vitro</i> Antimicrobial Activity of <i>Waltheria indica Linn</i> Root Extracts
Abstract: The aim of this study was to examine the phytochemical constituents and evaluate the antimicrobial activity of <i>Waltherica indica Linn</i> root extracts in solvents of different polarities (ethyl acetate, chloroform and chloroform: methanol (1:1). The experiment was conducted at the Chemistry Advanced Research Centre of Sheda Science and Technology Complex, Abuja, Nigeria between November 2016 and January 2017. Clinical strains of five bacteria and three fungi isolates were utilized. Chloroform, ethyl acetate and chloroform: methanol (1:1) root extracts were tested at 12.5, 25.0 and 50.0 μg/ml using the Agar well diffusion technique. The minimum inhibitory, minimum bactericidal and minimum fungicidal concentrations of each solvent extract were assessed. Phytochemical analysis was also performed using ethanol as the extraction solvent. The phytochemical compounds obtained in the methanol extracts where alkaloids, cardiac glycosides, flavanoids, phenolic acids, saponins, steroids, tannins and terpenoids. Agar well diffusion used for sensitivity study of <i>S. aureus, S. pneumonia, S. pyrogens, K. pneumonia, C. ulcerans, C. albicans, C. krusei</i> and <i>C. tropicalis</i> with 10μg/ml ciprofloxacin and 30μg/ml fluconazole revealed that the ethyl acetate extract of <i>Waltheria indica Linn</i> gave 27±0.20 to 31±0.95mm zones of inhibition, whereas the chloroform extract gave an inhibitory range of 26±0.15 to 30±0.25mm while the chloroform: methanol extracts gave a 26±0.35 to 29±0.85mm zones of inhibition respectively in comparison to the 31±0.65 to 36±0.35mm obtained from the control. The minimal inhibitory content (MIC) of the ethyl acetate extracts was recorded at 0.25 mg/ml, while the MIC values for the chloroform and chloroform: methanol extracts were between 0.25 and 0.50 mg/ml respectively. The results obtained suggested that the studied plants possess anti-microbial spectrum aligned to the phyto-constituents.