Biosurfactants have gained a renewed interest in the recent years for their commercial application in diverse research areas. Recent evidences suggest that the antimicrobial activities exhibited by biosurfactants make them promising molecules for the application in the field of therapeutics. Marine microbes are well known for their unique metabolic and functional properties; however, few reports are available till date regarding their biosurfactant production and antimicrobial potential. In an ongoing survey for bioactive microbial metabolites from microbes isolated from diverse ecological niches, a marine Staphylococcus saprophyticus SBPS 15 isolated from the petroleum hydrocarbon contaminated coastal site, Puducherry, India, was identified as a promising biosurfactant producer based on multiple screening methods. This bacterium exhibited growth-dependent biosurfactant production and the recorded yield was 1.345 ± 0.056 g/L (on dry weight basis). The biosurfactant was purified and chemically characterized as a glycolipid with a molecular mass of 606.7 Da, based on TLC, biochemical estimation methods, FT-IR spectrum and MALDI-TOF–MS analysis. Further, the estimated molecular mass was different from the earlier reports on biosurfactants. This new glycolipid biosurfactant exhibited a board range of pH and temperature stability. Furthermore, it revealed a promising antimicrobial activity against many tested human pathogenic bacterial and fungal clinical isolates. Based on these observations, the isolated biosurfactant from the marine S. saprophyticus revealed board physicochemical stabilities and possess excellent antimicrobial activities which proves its significance for possible use in various therapeutic and biomedical applications. To the best of our knowledge, this is the first report of a biosurfactant from the bacterium, S. saprophyticus.

Medicinal plants were used to treat diseases traditionally since ancient times. The present work aims to investigate the bioactive constituents through GC MS analysis of ethanolic leaf extracts of A.marina. Phytochemical screening confirmed the presence of Alkaloids, Flavonoids, Phenols, Reducing sugars, Saponins, Tannin, Glycoside, Triterpenoids and Carbohydrate in A.marina. The characterization of the compounds by Gas Chromatography – Mass Spectrometry (GC-MS) technique has reported the presence of thirty compounds in A.marina leaves. These compounds possess different pharmacological properties like anti-microbial, antioxidant, anti-inflammatory and hepatoprotective properties. Keywords: Avicennia marina, GC-MS, Bioactive compounds, Antibacterial activity.

In recent times, plant-mediated synthesis of nanoparticles has garnered wide interest owing to its inherent features such as rapidity, simplicity, eco-friendliness and cheaper costs. For the first time, silver nanoparticles were successfully synthesized using Phyllanthus niruri leaf extract in the current investigation. The silver nanoparticles were characterized by UV–Vis spectrophotometer and the characteristic surface plasmon resonance peak was identified to be 423 nm. The morphology of the silver nanoparticles was characterized by scanning electron microscopy (SEM). The size of the silver nanoparticles was found to be 10-50 nm, with an average size 15 nm.  FTIR analysis was done to identify the functional groups responsible for the synthesis of the AgNPs. The antibacterial potential of synthesized AgNPs was compared with that of aqueous extracts of P.niruri by well diffusion method. The AgNPs at 50µl concentration significantly inhibited bacterial growth against A.hydrophila (16 ± 0.09 mm). Thus AgNPs showed broad spectrum antibacterial activity at lower concentration and may be a good alternative therapeutic approach in future. Keywords: Phyllanthus niruri, AgNps, Aeromonas hydrophila, Antibacterial Activity.