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In vitro antibacterial evaluation of ethanolic extract of Thunbergia alata leaves extract against selected microorganisms

Jackie K. Obey, Anthoney Swamy T.*


The aim of this study was to analyse the antibacterial activity of ethanolic extract of Thunbergia alata leaves against laboratory strains of selected microorganisms.  The ethanolic extract of Thunbergia alata leaves are being used in the treatment of aphrodisiac, skin problems, back and joint pains, eye inflammation, piles and rectal cancer.   The mean zones of inhibition of the extract against microorganisms were  29.000 ± 0.577 mm for Staphylococcus epidermidis, 21.750 ± 0.629 mm for Enterobacter aerogenes, 19.000 ± 0.577 mm for Bacillus cereus and 14.250 ± 0.478 mm for Streptococcus α- hemolytic. The microorganism such as E. coli, Serratia marcescens and Streptococcus -γ-hemolytic did not show any zone of inhibitions.  The penicillin positive control showed large zones of inhibition except against Serratia marcescens and the dimethyl sulfoxide negative control did not show any zone of inhibition.  This report suggests that the extract was active against all the other organisms except E. coli, Serratia marcescens and S-γ-hemolytic.  Analysis of variance showed that the zones of inhibition of the extract and antibiotic control against the microorganisms were significantly different (p < 0.0001). The Tukey’s honestly test further showed both significant and non-significant comparisons between the extract and controls for various bacterial organisms.  This study has shown that controlling the growth of microorganisms in vitro can be achieved by the ethanolic extract of Thunbergia alata.


Thunbergia alata; Leaves; Antibacterial; Ethanol; Extract

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