Potential in vitro antimicrobial efficacy of Holigarna arnottiana(Hook F)

Objective:To explore the in vitro antimicrobial potential of Holigarna arnottiana(H.arnottiana)against human and shrimp pathogenic bacteria and use GC-MS analysis to elucidate its antimicrobial principles.Methods:In the present study,organic extract of H.arnottiana was examined for in vitro antimicrobial potency against five clinical human pathogens,seven species of human type culture pathogens,six pathogenic Vibrio strains isolated from moribund tiger shrimp(Penaeus monodon)and seven type cultures(Microbial Type Culture Collection,MTCC)of prominent shrimp pathogens.Results:The extraction of H.arnottiana with ethyl acetate yielded bioactive crude extract that efficiently repressed the growth of all tested pathogens.Among the pathogens tested,shrimp pathogens were the most susceptible organisms while clinical pathogens were found to be a little resistant.The chemical constituents of the H.arnottiana were analysed by GC-MS which revealed the presence of major compounds such as 3,7.1 l,15-tetramethyl-2-hexadecen-l-ol(42.1%),l-lodo-2-methylundecane(34.4%)and squalene(11.1%)which might have a functional role in the chemical defence against microbial invasion.Conclusions:Based on the finding it could be inferred that H.arnottiana would be a reliable source for developing shrimp and human bio-therapeutics in future.

An in vivo efficacy validation and immune-modulatory potential of Streptomyces sp.

Objective:To investigate the in vivo efficacy and immune-modulatory potential of antagonistic strain,Streptomyces sp.MAPS15 isolated from marine sponge in Penaeus monodon(P.monodon).Methods:In this study,culture of Streptomyces sp.was incorporated into a commercial feed.P.monodon was orally administered with MAPS15 diet for a period of 21 days followed by a challenge experiment and survival rate was calculated.In addition,the effect of MAPS15 diet on immunological parameters of the haemolymph of P.monodon was also assessed.Results:The overall results of the study showed that survival performance was prominent in MAPS15 treated group when compared with un-treated control groups.That could pertain to the ability of MAPS15 to produce antibiotic compounds to suppress the growth of invading pathogens and thereby increase the disease resistance potency and survival rate.From the results of the immunological studies,it can be envisaged that the immune responses were generally more pronounced with MAPS15 diet treated group.Conclusions:Based on the overall findings,it could be inferred that the health of P.monodon is improved when they are fed with MAPS15 diet for a period of 21 days.

An in vitro efficacy validation of mangrove associates

Objective:To investigate the in vitro antimicrobial potential of mangrove associates against a battery of human and shrimp pathogenic bacteria and to elucidate its antimicrobial principles.Methods:In the present study,12 species of mangrove associates collected from the Kollam(southwest coast of India)vicinity were extracted in different organic solvents of increasing polarity.The resultant extracts obtained from the respective species were examined for the antimicrobial activity against a panel of shrimp and human pathogens by agar diffusion assay.Results:Of the 12 species evaluated,three species of mangrove associates[Calophyllum inophyllum(C.inophyllum),Cerbera odollam and Dalbergia candenatensis]were found to be active.The broadest and highest rank of activity was observed in the crude extract of C.inophyllum.Amongst the pathogens tested,shrimp pathogenic Vibrios were the most sensitive organisms while human pathogens were found to be a bit resistant.In the present study,ethyl acetate was found to be the best solvent for extracting antimicrobial metabolites.The bioactive principles present in the crude extract of C.inophyllum were chemically elucidated by gas chromatography-mass spectrometer.The gas chromatography-mass spectrometer studies revealed the presence of two principal compounds such as 1-Dimethyl(phenyl)silyloxyhexadecane(24.73%)and β-d-Mannofuranoside,O-geranyl(50%)which might play functional role in the chemical defense against microbial invasion.Conclusions:Based on the overall findings,it could be inferred that the mangrove associate C.inophyllum is a promising candidate for the development of plant-based human and veterinary grade antibiotics in future.