Nagarajan Balachandran Dhayanithi

Dietary supplementation of Avicennia marina extract on immune protection and disease resistance in Amphiprion sebae against Vibrio alginolyticus

The effect of Avicennia marina aqueous leaf extract on innate immune mechanisms such as total white blood cell counts (WBC), serum lysozyme activity, respiratory burst assay, alternative complement (ACH50) assay, phagocytic activity assay, disease resistance, gut bacteria, and survival rate of clownfish (Amphiprion sebae) against Vibrio alginolyticus is reported. Healthy fish challenged with V. alginolyticus (1 × 10(7) cells ml(-1)) were fed with diets supplemented (0, 1, 2, and 4%) with A. marina extract. The survival rate was 85% and 80% in infected fish fed with 4% and 8% supplementation diet; with 1% diet it was 70% while in the infected untreated group it was only 10%. The total gut bacteria flora was high in 8% and 4% supplementation diet groups with 2.8 × 10(5) and 4.7 × 10(4) cfu/g while it was 8.9 × 10(3) cfu/g in 1% diet group. The immunological parameters significantly increased on weeks 6 and 8 when infected fish were fed with 1% or 4% supplementation diet. This study reports that in clownfish challenged with V. alginolyticus, dietary administration of the 1% or 4% of A. marina extract improved the immune status and survival rate.

Isolation of antibacterials from the mangrove, Avicennia marina and their activity against multi drug resistant Staphylococcus aureus

Abstract Objective leaf extract of A. marina was tested on the growth of clinically isolated multi-drug resistant Staphylococcus aureus and its bioactive compounds were attempted. Method Clinical strain of Staphylococcus aureus, were isolated from sputum, pus and blood of different patients and 22 strains were screened for antibiotic susceptibility. Avicennia marina was extracted in different solvents and antibacterial assay was carried out using Kirby-Bauers disk diffusion method. Crude methanol extract of the mangrove was loaded on a silica gel column and eluted with chloroform and methanol (9:1 to 1:9) followed by ethyl acetate and methanol (9:1 to 1:9). Based on in vitro assay, the 12th fraction was subjected for minimum inhibitory concentration (MIC). The active fraction was analysed by using a Clarus 500 Perkin Elmer gas chromatography. Result Based on the antibiotic susceptibility test, six strains (RMSA 6, RMSA12, RMSA16, RMSA18, RMSA19 and RMSA21) were resistance against methicillin, vancomycin and ciprofloxacin. The results indicated that the methanolic leaf extract showed the highest antibacterial activity against all the tested strains RMSA 6 (16mm), RMSA12 (15 mm), RMSA16 (13 mm), RMSA18 (10 mm), RMSA19 (17 mm) and RMSA21 (16 mm). The MIC of the partially purified extract showed potential results against all the multidrug resistant strains however, the lowest concentration was recorded against RMSA 6, RMSA19 and RMSA21 strain. In the GC-MS results, 5 bioactive compounds were identified from the partially purified extract of A. marina. Conclusion The methanolic extract of A. marina has the more potential candidate to inhibit against multidrug resistant S. aureus.

Anti-dermatophytic activity of marine sponge, Sigmadocia carnosa (Dendy) on clinically isolated fungi

OBJECTIVE To screen the anti-fungal effects and find out the active metabolites from sponge, Sigmadocia carnosa (S. carnosa) against four dermatophytic fungi. METHODS The methanol, ethyl acetate and acetone extract of marine sponge, S. carnosa was examined against Trichophyton mentagrophytes (T. mentagrophytes), Trichophyton rubrum (T. rubrum), Epidermophyton floccosum (E. floccosum) and Microsporum gypseum (M. gypseum) and qualitative analysed to find out the active molecules. RESULTS The methanol extract of sponge was expressed significant activity than ethyl acetate and acetone. The minimum inhibitory concentration (MIC) of methanol extract of sponge that resulted in complete growth inhibition of T. mentagrophytes, T. rubrum, E. floccosum and M. gypseum were found to 125, 250, 250 and 250 µg/mL respectively. But, 100 % inhibition of fungal spore germination was observed in T. mentagrophytes at 500 µg/mL concentration followed by T. rubrum, E. floccosum and M. gypseum at 1 000 µg/mL concentration. Other two extracts showed weak anti spore germination activity against the tested dermatophytic fungi. Methanol extracts showed presence of terpenoids, steroids, alkaloids, saponins and glycosides. CONCLUSION Based on the literature, this is the first study which has conducted to inhibit the growth and spore germination of dermatophytic fungi with S. carnosa. Further research also needs to purify and characterize the secondary metabolites from the sponge, S. carnosa for the valuable source of novel substances for future drug discovery.

Isolation of pigments from sea-anemones, Heteractis magnifica (Quoy and Gaimard, 1833) and Stichodactyla haddoni (Kent, 1893) and their effects against aquatic and human bacterial pathogens

Abstract Objective To screen inhibitory activity of pigments extracted from two sea-anemones, Heteractis magnifica (H. magnifica) and Stichodactyla haddoni (S. haddoni) against 10 aquatic and 10 human bacterial pathogens. Methods Crude pigment were extracted by using acetone solvent and the pigment extracts were fractionated into 7 for H. magnifica and 5 for S. haddoni by using silica gel column chromatography and also tested for the antibacterial activity using Agar welldiffusion method. Results The 3rd fraction of H. magnifica and 2nd fraction of S. haddoni displayed higher activity against eight aquatic bacterial pathogens and seven human bacterial pathogens. Conclusions The 3rd fraction of H. magnifica showed higher antibacterial activity than the crude pigment extracts and other fractions of H. magnifica and S. haddoni. Thus the sea-anemone Heteractis magnifica is promising for further exploration of antibacterial drugs.