Hashim A. Hassanean

New antibacterial xanthone from the marine sponge-derived Micrococcus sp. EG45

Microluside A [4 (19-para-hydroxy benzoyloxy-O-β-D-cellobiosyl), 5 (30-para-hydroxy benzoyloxy-O-β-D-glucopyranosyl) xanthone (1)] is a unique O-glycosylated disubstituted xanthone isolated from the broth culture of Micrococcus sp. EG45 cultivated from the Red Sea sponge Spheciospongia vagabunda. The structure of microluside A was determined by 1D- and 2D-NMR techniques as well as high resolution tandem mass spectrometry. The antimicrobial activity evaluation showed that 1 exhibited antibacterial potential against Enterococcus faecalis JH212 and Staphylococcus aureus NCTC 8325 with MIC values of 10 and 13 μM, respectively.

Antiproliferative Scalarane-Based Metabolites from the Red Sea Sponge Hyrtios erectus

Two new sesterterpenes analogs, namely, 12-acetoxy,16-epi-hyrtiolide (1) and 12β-acetoxy,16β-methoxy,20α-hydroxy-17-scalaren-19,20-olide (2), containing a scalarane-based framework along with seven previously reported scalarane-type sesterterpenes (3–9) have been isolated from the sponge Hyrtios erectus (order Dictyoceratida) collected from the Red Sea, Egypt. The structures of the isolated compounds were elucidated on the basis of their spectroscopic data and comparison with reported NMR data. Compounds 1–9 exhibited considerable antiproliferative activity against breast adenocarcinoma (MCF-7), colorectal carcinoma (HCT-116) and hepatocellular carcinoma cells (HepG2). Compounds 3, 5 and 9 were selected for subsequent investigations regarding their mechanism of cell death induction (differential apoptosis/necrosis assessment) and their influence on cell cycle distribution.

A New Bioactive Metabolite Isolated from the Red Sea Marine Sponge Hyrtios erectus

Chemical investigation of the lipophilic fraction of Hyrtios erectus, a Red Sea sponge, yielded a new pentacyclic nitrogen-containing scalarane; 24-methoxypetrosaspongia C (1), together with the previously reported scalaranes sesterstatin 3 (2), 12-deacetyl-12-epi-scalaradial (3) and 12-deacetyl-12,18-di-epi-scalaradial (4). The compounds were identified using HRESIMS, 1D and 2D NMR experiments. The isolated compounds showed growth inhibitory activity against hepatocellular carcinoma (HepG2), colorectal carcinoma (HCT-116) and breast adenocarcinoma cells (MCF-7).

Mechanism of action of antiepileptic ceramide from Red Sea soft coral Sarcophyton auritum.

Chemical investigation of the Red Sea soft coral Sarcophyton auritum led to the isolation and structure elucidation of a new ceramide N-((2S,3R,4E,6E)-1,3-dihydroxyhenicosa-4,6-dien-2-yl)tridecanamide (1). Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. The anticonvulsant activity of the isolated ceramide was measured in vivo using the pentylenetetrazole (PTZ)-induced seizure model, where it successfully antagonized the lethality of pentylenetetrazole in mice. In addition, the isolated ceramide showed good anxiolytic activity when used in the light–dark transition box and the elevated plus maze compared to diazepam. The molecular modeling studies for the antiepileptic and antianxiety mechanism of the isolated ceramide suggested a CNS depressing activity possibly through GABA and serotonin receptors modulation. The pharmacological activity of the ceramide involved agonistic activity on GABA-A receptors but not 5HT3 receptors.

New fatty acids from the Red Sea sponge Mycale euplectellioides

Chemical investigation of the Red Sea sponge Mycale euplectellioides afforded two new compounds; hexacosa-(6Z,10Z)-dienoic acid methyl ester (1) and hexacosa-(6Z,10Z)-dienoic acid (2), along with two known compounds: icosa-(8Z,11Z)-dienoic acid methyl ester (3) and β-sitosterol (4). The structures were elucidated by the interpretation of their spectral data. The total methanol extract (TME) of the sponge exhibited potent antimicrobial activity against the different strains at a concentration of 100 mg/mL. All tested fractions did not exhibit any activity against Serratia marcescens and tested fungal strains. The TME and different fractions displayed anti-inflammatory and antipyretic activities at doses of 100 and 200 mg/kg compared with indomethacin (8 mg). The TME exhibited a remarkable hepato-protective effect in CCl4-induced liver damage compared with silymarin. Furthermore, compounds 1 and 2 displayed weak activity against A549 non-small cell lung cancer, the U373 glioblastoma and the PC-3 prostate cancer cell lines.

Anti-H5N1 virus new diglyceride ester from the Red Sea grass Thallasodendron ciliatum

Some Egyptian plants were screened against highly pathogenic avian influenza strain H5N1 using plaque inhibition assay in Madin–Darby canine kidney. The results indicated that the extracts of Red Sea grass Thallasodendron ciliatum possessed potent antiviral activity (100% inhibition at the concentration of 1 μg mL− 1). The bioactivity-guided fractionations led to the isolation of a new diglyceride ester (1) along with asebotin (2) for the first time from the plant. The two isolates showed reduction of virus titre by 67.26% and 53.81% inhibition at concentration of 1 ng mL− 1, respectively.

Anticancer Activities of Some Organisms from Red Sea , Egypt

Encouraged by new drug developments, the present research was investigated on extracts of Red Sea marine resources all from Egypt. Extracts from three sponges namely Spheciospongia vagabunda (SAA14), Negombata corticata (SAA-8) and Negombata magnifica (SAA-64) in addition to two soft corals Sarcophyton glaucum (SAA-33) and Sarcophyton auritum (SAA-43) were found to display high potential against HepG2 (liver cancer cell line) and MCF-7 (breast cancer cell line). Cytotoxic potential activities of these five extracts were measured by the Sulpho-Rhodamine-B (SRB) assay. The anticancer activity of SAA-8, SAA-14,SAA-33, SAA-43 and SAA-64 was significantly enhanced in the liver cancer cell line with the values ranged from16.3 to 19.3μg/ml and in the breast cancer cell line with concentrations of 24.7, 19.7, 18.7,21.1and 25.8μg/ml, respectively compared to doxorubicin as positive control. Negom batacorticataand Sarcophyton auritum based extracts exhibited promising antifungal activity against fungi of genus Candida, Cryptococcus and Aspergillus, moreover, the five extracts revealed antiprotozoal and antimicrobial activity after in vitro assays. Also Negombata corticata has good antituberculosis, antimalarial and antilieshmanial potentials.