Activity test of crude extracts of invasive plants Ageratina adenophora and Ipomoea carnea ssp. fistulosa against human pathogenic bacteria

Abstract

The aqueous (distilled water) and alcoholic (methanol) crude extract from the leaves of invasive alien plant species Ageratina adenophora and Ipomoea carnea ssp. fistulosa were evaluated against six human pathogenic bacteria, three Gram negative: Escherichia coli (ATCC 25922), Klebsiella pneumoniaea (ATCC 15380) and Proteus mirabilis (ATCC 49132) and three Gram positive: Enterococcus faecalis (ATCC 29212) Bacillus subtilis (ATCC 6633) and Staphylococcus aureus (ATCC 25923) using disc diffusion method. Different concentrations of plant extracts (50 mg/ml, 100 mg/ml, 150 mg/ml, 200 mg/ml and 250 mg/ml) were applied and diameter of zone of inhibition (ZOI) of bacterial growth were recorded. Both plant extracts showed antibacterial activity against Gram positive and Gram-negative bacteria. Methanolic extract of plant extracts exhibited good activity against tested bacteria when compared to aqueous extract. Among tested plants I. carnea ssp. fistula was more active than A. adenophora. The zone of inhibition of bacterial growth increased with increasing concentrations. The demonstration of activity against all these organisms had shown that both alien invasive species; Ageratina adenophora and Ipomoea carnea ssp. fistulosa. can be used to produce raw materials/substances for further development of diverse antibiotics with broad spectrum of activity.