Vibriosis is one of the most harmful bacterial diseases that can affect marine organisms. Vibrio sp. namely V. harveyi (V. h), V. parahemolyticus (V. p) and V. alginolyticus (V. a) cause various skin and tissue-related damage in fishes and increase their mortality rate in the aquaculture industry. Phyllanthus amarus, Eclipta prostrata and Acalypha indica plants which demonstrated distinguished antibacterial and anti-inflammatory properties were used for the eco-friendly and cost-effective synthesis of silver nanoparticles (PHNCs). PHNCs were characterized by various physicochemical techniques to confirm their structure and stability. By using UV-Visible spectroscopy the synthesis of PHNCs was confirmed the SPR peak at 420 nm. FTIR analysis confirms the functional groups that are involved in the synthesis process. FESEM images were obtained which specified polymorphic morphology of PHNCs with sizes ranging from 22.56 nm to 48.85 nm. Dynamic light scattering showed an average hydrodynamic diameter of 182.05 nm and a zeta potential of − 17.5 mV, indicating moderate stability in aqueous suspension. The toxicity study conducted in zebrafishes further confirmed its biocompatibility and non-toxic nature when used in a dose-dependent manner. Antimicrobial assays including MIC, MBC and biofilm assays were investigated to check the efficacy of formulated polyherbal nanocolloid. The MIC values were reproducible across triplicate assays and consistently observed at 1.56 µg/mL for V. harveyi, 3.12 µg/mL for V. parahaemolyticus and 6.25 µg/mL for V. alginolyticus. Minimum bactericidal concentration (MBC) assays performed in triplicate showed that all three Vibrio species exhibited an MBC of 6.25 µg/mL. PHNCs effectively inhibited biofilm formation by reducing bacterial adherence and production of extracellular matrix. Mechanistic studies suggested that PHNCs act through multiple pathways, including leakage of proteins and sugars, elevated malondialdehyde (MDA) levels, and decreased activity of antioxidant enzymes namely glutathione reductase (GSH), catalase (CAT), and superoxide dismutase (SOD). PHNCs demonstrated strong antibacterial and antibiofilm effects at low concentrations, biocompatible at lower doses, suggesting that polyherbal nanocolloid could be a promising, eco-friendly alternative to conventional antibiotics for controlling bacterial infections in aquaculture sector.

Synthesis and characterization of polyherbal nanocolloids to combat biofilm causing Vibrio Sp

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发表日期：

2025年12月22日

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J. Nivetha,
S. Ranjani,
S. Hemalatha

摘要

Vibriosis is one of the most harmful bacterial diseases that can affect marine organisms. Vibrio sp. namely V. harveyi (V. h), V. parahemolyticus (V. p) and V. alginolyticus (V. a) cause various skin and tissue-related damage in fishes and increase their mortality rate in the aquaculture industry. Phyllanthus amarus, Eclipta prostrata and Acalypha indica plants which demonstrated distinguished antibacterial and anti-inflammatory properties were used for the eco-friendly and cost-effective synthesis of silver nanoparticles (PHNCs). PHNCs were characterized by various physicochemical techniques to confirm their structure and stability. By using UV-Visible spectroscopy the synthesis of PHNCs was confirmed the SPR peak at 420 nm. FTIR analysis confirms the functional groups that are involved in the synthesis process. FESEM images were obtained which specified polymorphic morphology of PHNCs with sizes ranging from 22.56 nm to 48.85 nm. Dynamic light scattering showed an average hydrodynamic diameter of 182.05 nm and a zeta potential of − 17.5 mV, indicating moderate stability in aqueous suspension. The toxicity study conducted in zebrafishes further confirmed its biocompatibility and non-toxic nature when used in a dose-dependent manner. Antimicrobial assays including MIC, MBC and biofilm assays were investigated to check the efficacy of formulated polyherbal nanocolloid. The MIC values were reproducible across triplicate assays and consistently observed at 1.56 µg/mL for V. harveyi, 3.12 µg/mL for V. parahaemolyticus and 6.25 µg/mL for V. alginolyticus. Minimum bactericidal concentration (MBC) assays performed in triplicate showed that all three Vibrio species exhibited an MBC of 6.25 µg/mL. PHNCs effectively inhibited biofilm formation by reducing bacterial adherence and production of extracellular matrix. Mechanistic studies suggested that PHNCs act through multiple pathways, including leakage of proteins and sugars, elevated malondialdehyde (MDA) levels, and decreased activity of antioxidant enzymes namely glutathione reductase (GSH), catalase (CAT), and superoxide dismutase (SOD). PHNCs demonstrated strong antibacterial and antibiofilm effects at low concentrations, biocompatible at lower doses, suggesting that polyherbal nanocolloid could be a promising, eco-friendly alternative to conventional antibiotics for controlling bacterial infections in aquaculture sector.