The present study was undertaken to provide information about bioactive compounds of the microbial community associated with Ircinia echinata marine sponge collected from the Red Sea. This work investigated the antioxidant and cytotoxicity properties of the tested extracted crude extract. Sponge was taxonomically identified as Ircinia echinata. Moreover, taxonomic and phylogenetic analyses of the bacteria on the basis of 16S rRNA gene sequences showed that dominant phylum was proteobacteria. The results of HPLC analysis revealed that the bacterial crude extracts exhibited highly significant quantities of total phenolic contents in crude extracts of the two tested bacterial isolates. The highest level of total phenolic contents was measured in the extract was shown in extracts HA-MS-41 (3.238±0.03 mg gallic equivalent/ml). Whereas, the lowest value was shown in extract HA-MS-118 (2.946±0.10 mg gallic equivalent/ml).The results of the current study cleared out that extract HA-MS-41[JX484800] contained gallic and tannic acids (1.084 and 1.413 mg/ml), whereas extract HA-MS-118 [JX484801] contained gallic (1.005 mg/ml) but didn't contain tannic acid. The highest level of total flavonoid content was measured in the extract HA-MS-41 extract (5±0.23 mg catechin equivalent / ml). Whereas, much lower value was shown in the HA-MS-118 extract (2.5±0.26 mg catechin equivalent / ml). Carotenoid compounds significantly varied among the two bacterial extracts; the highest total carotenoid concentration was observed in the extract HA-MS-41 (1.165µg/ml). Whereas, lower valuesobserved in the extract HA-MS-118 (0.185 µg/ml). In the meantime, GC/MS profiling for the ethyl acetate extract of the studied sponge-associated bacteria revealed the presence of various phytochemical compounds having different biological activities. Results of FTIR spectroscopic studies have revealed the presence of various chemical constituents in ethyl acetate extract of the HA-MS-41 and HA-MS-118 bacterial isolates.The results of the elemental analysis indicated that the bacterial extracts contained major elements like Na, Mg, Al, Si, S, K, Ca, P and Cl, besides the major elemental constituents in all living organisms; C, N and O. The results showed considerable concentrations of many halides (Fe, Cu, Zn and Br). DPPH scavenging activity in terms of IC50 values was shown to be high in case of the extract HA-MS-41 (1.045 mg/ml) and in case of the extract HA-MS-118 (1. 450 mg/ml). IC50 values of the antioxidant activity of bacterial extracts using NO assay for the tested two extracts were 5.98 and 6.222 %. Moreover, potent antioxidant activity using ABTS+ assay with percentages inhibition of IC50 = 3.404 and 1.64 mg/ml for HA-MS-41and HA-MS-118, respectively. In the present study highly significant total antioxidant capacity values was also obtained by using phosphomolybdenum assay in the bacterial extract suggesting the presence of effective antioxidants in the bacterial extract.The high potency of these isolates is mainly attributed to the presence of vari...

The Red Sea marine sponges have been investigated for isolating novel bacterial strains. The main objective of the present study is to carry out a molecular level identification of the isolated sponge-associated bacteria and examination of their potential to produce biologically active compounds. Sponges were taxonomically identified as Amphimedon Ochracea and as an unidentified species of Amphimedon sp. Taxonomic and phylogenetic analyses on the basis of 16S rRNA gene sequences showed that dominant phylum was Proteobacteria. The results of HPLC analysis revealed that the bacterial exhibited variable patterns of phenolic compounds. Phenolic contents of the examined crude extracts were found to be 2.7491±0.046 and 2.302±0.002 mg gallic equivalent/ml for the HA-MS-52 and HA-MS-11, respectively. Flavonoids contents of the crude extracts of the tested bacterial isolate equivalents of (+catechin) were found to be 12.6±0.634 and 12.5±0.014 for the HA-MS-52 and HA-MS-11 crude extracts. In addition, carotenoid contents tested in the bacterial extracts were Xanthophyll, β-cryptoxanthin and β-carotene. Among these compounds, Xanthophyll significantly showed the highest concentration in both extracts HA-MS-52[JX494759] and HA-MS-11[JX494760] (6.209 & 0.891 µg/ml, respectively); whereas β-carotene exhibited the lowest concentration (0.453 & 0.113 µg/ml, respectively). GC/MS profiling for the ethyl acetate extracts of the studied sponge-associated bacteria revealed the presence of various phytochemical compounds having different biological activities. Results of FTIR spectroscopic studies have revealed the presence of various chemical constituents in the ethyl acetate extract of the HA-MS-52 [JX494759] and HA-MS-11[JX494760] bacterial isolates. Elemental analysis of the ethyl acetate extracts of the HA-MS-52 [JX494759] and HA-MS-11[JX494760] bacterial isolates showed that the bacterial extract indicated the presence of essential elements such as carbon, nitrogen, and oxygen, macro elements such as sodium, potassium and calcium and micro elements such as zinc, The ethyl acetate extract of the HA-MS-52[JX494759] showed un-detectable levels of magnesium, zinc, and bromine.In the meantime, the ethyl acetate extract of the HA-MS-11[JX494760] showed un-detectable levels of Iron. The results of DPPH test indicated that IC50 values of ethyl acetate extracts had high IC50 values of 1.156 and 2.73 mg/ml for the HA-MS-52 [JX494759] and HA-MS-11[JX494760], respectively. This may be due to the presence of some potent antioxidant compounds which are powerful antioxidants and have good radical scavenging activities. This results were confirmed by the nitric oxide assay (IC50: 5.72±0.002 & 8.96±0.001, respectively). The bacterial extracts showed also potent antioxidant activities using ABTS+ assay with percentage inhibition of IC50 = 0.16 & 8.854 mg/ml, respectively. The high potency of the as strong antioxidant capacity may returns to its high phenolic contents as well as high flavonoids compounds. In the present study highly significant to...