In-vitro antibacterial activity of Lantana trifolia flower extracts on bacterial isolates from wounds

Abstract

This study investigated the phytochemical constituents and antibacterial activities of Lantana trifolia flower extracts against bacterial isolates from surgical and diabetic wounds of patients. Phytochemical investigation was done by standard procedure, antimicrobial screening by agar well diffusion method and antibiotics susceptibility of isolates by Kirby-Bauer disc diffusion test. Phytochemicals present include flavonoids, tannins, phenylethanoid glycosides, reducing sugars, terpenoids, saponins, anthraquinones alkaloids and steroids. Bacterial wound isolates were mainly gram +ve and include Staphylococcus aureus, S. epidermidis, Enterococcus faecalis, Corynebacterium sp., Enterobacter aerogenes, Pseudomonas aeruginosa, Mycobacterium sp. and Escherichia coli. Inhibition diameter was  concentration. The range of inhibition diameter was significantly (P<0.05) lower in the aqueous extract (15.2±1.5 to 35.5 ±0.9 mm) than the ethanolic (28.3± 3.4 to 49.1±8.9mm). Antibacterial activity occurred at very low concentrations (18.75mg/ml) for ethanolic extract only. The most L trifolia extract sensitive bacterial isolate was S. aureus (35.5±0.9mm and 49.1±8.9mm for aqueous and ethanolic extracts respectively at 300mg/ml), while the least sensitive were Corynebacterium sp. (15.2±1.5mm) and Mycobacterium sp. (28.3±3.4) at 300mg/ml for aqueous and ethanolic extracts respectively. The minimum inhibitory concentration was lower for ethanolic extract, 18.75/ml to 37.5mg/ml than the aqueous extract (37.5 to 150mg/ml). The minimum bacterial concentration range from 37.5mg/ml to 150mg/ml for ethanolic extract and 75 to 300mg/ml for aqueous extract. S. aureus was the most antibiotic resistant strain (72%), while P. aeruginosa and Mycobacterium sp. were the least resistant (9.1%) strains. L. trifolia was more bacteriostatic than the most effective antibiotics, Ciprofloxacin, Rocephin, Nitrofurantoin, and deserves further investigation.

Keywords: Phytochemical screening, Bacteriostatic activity, Lantana trifolia, Resistance, Wounds