Antipathogenic Potential of a Polyherbal Wound-Care Formulation (Herboheal) against Certain Wound-Infective Gram-Negative Bacteria

Figure 2

Effect of HF on S. marcescens. (a) Effect of HF on growth and QS-regulated prodigiosin production in S. marcescens: bacterial growth was measured as OD₇₆₄, OD of prodigiosin was measured at 535 nm, and prodigiosin unit was calculated as the ratio OD₅₃₅/OD₇₆₄ (an indication of prodigiosin production per unit of growth). Catechin (50 µg/mL) inhibited prodigiosin production by 10% ± 0.05 without affecting bacterial growth. (b) HF acts as a signal-supply inhibitor against S. marcescens. (c) HF pretreatment reduces susceptibility of S. marcescens to different antibiotics. (d) HF enhances catalase activity and inhibits haemolytic activity of S marcescens: the catalase assay was done by monitoring disappearance of H₂O₂ at 240 nm. Chloramphenicol (5 μg/mL) enhanced catalase activity of this bacterium by 13.40% ± 0.02. Hemoglobin concentration was measured at OD₅₄₀. (e) HF treatment reduces virulence of S. marcescens towards C. elegans: catechin (50 μg/mL) and ofloxacin (0.1 μg/mL) employed as positive controls conferred 100% and 80% protection, respectively, on worm population. Pretreatment of bacteria with HF at 0.025%, 0.05%, 0.1%, and 0.125% conferred 7.5%, 15%, 30%, and 37.5% survival benefit, respectively. Survival benefit refers to the difference between the number of worms surviving in experimental and control wells. HF at tested concentrations showed no toxicity towards C. elegans. ; ; ; AS: antibiotic susceptibility; QS: quorum sensing; HF: Herboheal formulation.

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