Chemical Review of Gorgostane-Type Steroids Isolated from Marine Organisms and Their 13C-NMR Spectroscopic Data Characteristics.

Gorgostane steroids are isolated from marine organisms and consist of 30 carbon atoms with a characteristic cyclopropane moiety. From the pioneering results to the end of 2021, isolation, biosynthesis, and structural elucidation using 13C-NMR will be used. Overall, 75 compounds are categorized into five major groups: gorgost-5-ene, 5,6-epoxygorgostane, 5,6-dihydroxygorgostane, 9,11-secogorgostane, and 23-demethylgorgostane, in addition to miscellaneous gorgostane. The structural diversity, selectivity for marine organisms, and biological effects of gorgostane steroids have generated considerable interest in the field of drug discovery research.

A Comprehensive In Silico Study of New Metabolites from Heteroxenia fuscescens with SARS-CoV-2 Inhibitory Activity.

Chemical investigation of the total extract of the Egyptian soft coral Heteroxenia fuscescens, led to the isolation of eight compounds, including two new metabolites, sesquiterpene fusceterpene A (1) and a sterol fuscesterol A (4), along with six known compounds. The structures of 1-8 were elucidated via intensive studies of their 1D, 2D-NMR, and HR-MS analyses, as well as a comparison of their spectral data with those mentioned in the literature. Subsequent comprehensive in-silico-based investigations against almost all viral proteins, including those of the new variants, e.g., Omicron, revealed the most probable target for these isolated compounds, which was found to be Mpro. Additionally, the dynamic modes of interaction of the putatively active compounds were highlighted, depending on 50-ns-long MDS. In conclusion, the structural information provided in the current investigation highlights the antiviral potential of H. fuscescens metabolites with 3ß,5α,6ß-trihydroxy steroids with different nuclei against SARS-CoV-2, including newly widespread variants.

Isolation of two new cucurbitane-type triterpenoids from Kedrostis gijef.

Two new cucurbitane-type triterpenoids (2,3), together with two known compounds (1,4), were isolated from the aerial parts of Kedrostis gijef. The structure of all compounds was elucidated based on NMR, HRESIMS analyses, and by comparison with the literature. Additionally, the cytotoxic activity against HeLa, Caco-2, and SH-SY5Y cell lines was determined using MTT colorimetric assay.

Antiviral activity of sulphated specialized metabolites from sea urchin Clypeaster humilis: in vitro and in silico studies.

Chemical investigations of the sea urchin Clypeaster humilis has led to separation of twelve compounds including one new sulfonic acid derivative (7R) tridec-1-en-7-yl hydrogen sulphate (1), first isolated from natural source, pyridine-3-yl methane sulfonate (2), and first isolated from marine organisms, boldine (12), in addition to nine known compounds (3-11), which were isolated for the first time from the genus Clypeaster. Their structures were elucidated based on spectroscopic analyses (1D and 2D NMR), HR-ESI-MS as well as comparison with the previously reported data. The antiviral activity of the crude extract and sulphated compounds were evaluated using MTT colorimetric assay against Coxsackie B4 virus. The crude extract and compound 1 showed very potent antiviral activity with a percentage of inhibition equal to 89.7 ± 0.53% and 86.1 ± 0.92%, respectively. Results of the molecular docking analysis of the isolated compounds within Coxsackie Virus B4 (COX-B4) X-ray crystal structure and quantum chemical calculation for three sulphated compounds are in a consistent adaptation with the in vitro antiviral results. The pharmacokinetic properties (ADME) of isolated compounds were determined.

Diadema setosum: isolation of bioactive secondary metabolites with cytotoxic activity toward human cervical cancer.

In our promising project toward discovery of secondary metabolites with potential anticancer activity against human cervical cancer, seven marine organisms were screened for their cytotoxic activity against HeLa cancer cell line using MTT colorimetric assay. The crude extract of the outer shell of Diadema setosum showed promising activity with 88.02% inhibition at a concentration 250 µg/ml. Chromatographic investigation of the Ethyl acetate fraction, which is the main contributor to the activity (IC50= 43.1 ± 5.94 µg/ml), led to isolation of five compounds. Structures of the isolates (1-5) were elucidated by 1 D and 2 D NMR spectroscopy and HR-ESI-MS analysis. 5α,8α-epidioxycholest-6-en-3ß ol (2) and 5α,8α-epidioxycholest-6,9(11)-en-3ß ol (3) showed the highest cytotoxic activity with IC50 values 12.1 ± 2.74 µg/ml and 21.8 ± 6.32 µg/ml, respectively. Epidioxy steroids with cholestane nucleus could be a prospective candidate for the development of drugs for treatment of human cervical cancer.

Two new polyhydroxylated steroids from Egyptian soft coral Heteroxenia fuscescens (Fam.; Xeniidae).

Two new polyhydroxylated steroids, 3ß-acetoxy-gorgost-5α,6ß,11α-triol (3) and (23 R) methylergosta-20-ene-3ß,5α,6ß,17α-tetrol (4), together with three known gorgosteroid compounds, gorgost-3ß, 5α,6ß,11α- tetrol (1), 11α-acetoxy-gorgost- 3ß,5α, 6ß- triol (2), and gorgost-5 (E) ene-3-ß-ol (5), as well as batyl alcohol (6), were isolated from the Egyptian soft coral Heteroxenia fuscescens. The structures of these compounds were elucidated based on NMR spectroscopic analyses, HR-FAB-MS, and comparisons with published data. The cytotoxic activities of the fractions and compounds were evaluated against MCF-7 cancer cell lines using MTT colorimetric assay. Compounds 2 and 4 showed moderate cytotoxic activity, with IC50 values equal to 33.2 and 25.1 µM, respectively, in comparison with the IC50 of 5-fluorouracil 18.7 µM.