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

Figure 3

Effect of HF on P. aeruginosa growth, pigment production, antibiotic susceptibility, and biofilm. (a) Effect of HF on growth and QS-regulated pigment production in P. aeruginosa: bacterial growth was measured as OD₇₆₄, OD of pyoverdine was measured at 405 nm, and OD of pyocyanin was measured at 520 nm. Pyoverdine unit was calculated as the ratio OD₄₀₅/OD₇₆₄ (an indication of pyoverdine production per unit of growth). Pyocyanin unit was calculated as the ratio OD₅₂₀/OD₇₆₄ (an indication of pyocyanin production per unit of growth). Catechin (50 µg/mL) inhibited pyoverdine 17.13% ± 0.06 and pyocyanin 23.65% ± 0.04 production without affecting the bacterial growth. (b) HF acts as a signal-response inhibitor against P. aeruginosa. (c) HF treatment made P. aeruginosa more susceptible to gentamicin and cephalexin. (d) HF reduced P. aeruginosa biofilm formation but did not eradicate preformed biofilm nor had any effect on biofilm viability: the crystal violet assay was performed to measure biofilm formation and biofilm eradication, followed by the measurement of OD at 580 nm. Cell viability in biofilm was estimated through the MTT assay, wherein OD was measured at 560 nm. ; ; ; AS: antibiotic susceptibility; QS: quorum sensing; HF: Herboheal formulation.

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