Acinetobacter baumannii (AB) is rising as a human pathogen of critical priority worldwide as it is the leading cause of chronic opportunistic infections in healthcare settings and the condition is ineradicable with antibiotic therapy. AB possesses the ability to form biofilm on abiotic as well as biotic surfaces which plays a major role in its pathogenesis and resistance in clinical settings. Hence, the demand for an alternative therapy to combat the biofilm-associated infections is increasing. The present study explored the antibiofilm potential of myrtenol, a bicyclic monoterpene present in various plants against reference and clinical strains of AB. Myrtenol (200 μg/mL) exhibited a strong antibiofilm activity without exerting any harmful effect on growth and metabolic viability of AB strains. Microscopic analyses confirmed the reduction in the biofilm thickness and surface coverage upon myrtenol treatment. Especially, myrtenol was found to be effective in disrupting the mature biofilms of tested AB strains. Furthermore, myrtenol inhibited the biofilm-associated virulence factors of AB strains such as extracellular polysaccharide, cell surface hydrophobicity, oxidant resistance, swarming and twitching motility. Transcriptional analysis unveiled the suppression of the biofilm-associated genes such as bfmR, csuA/B, bap, ompA, pgaA, pgaC, and katE by myrtenol. Notably, myrtenol improved the susceptibility of AB strains towards conventional antibiotics such as amikacin, ciprofloxacin, gentamicin and trimethoprim. Thus, the present study demonstrates the therapeutic potential of myrtenol against biofilm-associated infections of AB.

We report on rapid one-step green synthesis of gold and silver nanoparticles using fruit extract of Averrhoa bilimbi Linn. UV-Vis absorption spectroscopy was used to monitor the quantitative formation of gold and silver nanoparticles. The characteristics of the obtained gold and silver nanoparticles were studied using UV-Vis absorption spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Energy-dispersive spectroscopy (EDX). UV/Vis spectrum showed Surface Plasmon Resonance (SPR) for both gold and silver nanoparticles at 540 and 420 nm. The EDX spectrum of the solution containing gold and silver nanoparticles confirmed the presence of elemental gold and silver signals. The average diameter of the prepared nanoparticles in solution was about 50-150 nm. Synthesized particles were either hexagonal or rhomboidal in shape. This synthesis approach of gold and silver nanoparticles is cost effective and can be widely used in biological systems. The effect of fruit extract and metal ion concentration was also studied.

Silver nanoparticles are applied in nanomedicine from time immemorial and are still used as powerful antibiotic and anti-inflammatory agents. Antibiotics produced by actinomycetes are popular in almost all the therapeutic measures, and this study has proven that these microbes are also helpful in the biosynthesis of silver nanoparticles with good surface and size characteristics. Silver can be synthesized by various chemical methodologies, and most of them have turned to be toxic. This study has been successful in isolating the microbes from polluted environment, and subjecting them to the reduction of silver nanoparticles, characterizing the nanoparticles by UV spectrophotometry and transmission electron microscopy. The nanoparticles produced were tested for their antimicrobial property, and the zone of inhibition was greater than those produced by their chemically synthesized counterparts. Actinomycetes, helpful in bioremediating heavy metals, are useful for the production of metallic nanoparticles. The biosynthesized silver nanoparticles loaded with antibiotics prove to be better in killing the pathogens and have opened up new areas for developing nanobiotechnological research based on microbial applications.

The present study emphasizes to reveal the antivenom activity of Aristolochia bracteolata Lam., Tylophora indica (Burm.f.) Merrill, and Leucas aspera S. which were evaluated against venoms of Daboia russelli russelli (Russell's viper) and Naja naja (Indian cobra). The aqueous extracts of leaves and roots of the above-mentioned plants and their polyherbal (1 : 1 : 1) formulation at a dose of 200 mg/kg showed protection against envenomed mice with LD50 doses of 0.44 mg/kg and 0.28 mg/kg against Russell's viper and cobra venom, respectively. In in vitro antioxidant activities sample extracts showed free radical scavenging effects in dose dependent manner. Computational drug design and docking studies were carried out to predict the neutralizing principles of type I phospholipase A2 (PLA2) from Indian common krait venom. This confirmed that aristolochic acid and leucasin can neutralize type I PLA2 enzyme. Results suggest that these plants could serve as a source of natural antioxidants and common antidote for snake bite. However, further studies are needed to identify the lead molecule responsible for antidote activity.