One of the most dangerous problems that the world faced recently is viral respiratory pathogens. Marine creatures, including Echinodermata, specially Asteroidea class (starfish) have been extensively studied due to their miscellaneous bioactivities, excellent pharmacological properties, and complex secondary metabolites, including steroids, steroidal glycosides, anthraquinones, alkaloids, phospholipids, peptides, and fatty acids. These chemical constituents show antiviral activities against a wide range of viruses, including respiratory viruses. The present study aimed at the identification of potential antiviral compounds from some starfish species. The bioactive compounds from Pentaceraster cumingi, Astropecten polyacanthus, and Pentaceraster mammillatus were extracted using two different solvents (ethyl acetate and methanol). The antiviral activity against influenza A/H1N1 virus showed that ethyl acetate extract from Pentaceraster cumingi has the highest activity, where the selective index was 150.8. The bioactive compounds of this extract were identified by GC/MS analysis. The molecular docking study highlighted the virtual mechanism of binding of the identified compounds towards polymerase basic protein 2 and neuraminidase for H1N1 virus. Interestingly, linoleic acid showed promising binding energy of -10.12 Kcal/mol and -24.20 Kcal/mol for the selected two targets, respectively, and it formed good interactive modes with the key amino acids inside both proteins. The molecular docking analysis showed that linoleic acid was the most active antiviral compound from P. cumingi. Further studies are recommended for in-vitro and in-vivo evaluation of this compound against influenza A/H1N1 virus.

Thirty actinomycete isolates were isolated from soil and tested against Candida albicans in vitro. The active isolate was identified by 16s-rRNA gene sequencing method as Streptomyces toxytricini. The antifungal compound was extracted with ethyl acetate followed by diethyl ether. Both HPLC and GC–MS analysis confirmed presence of one pure compound in the diethyl ether extract. The compound is a yellow liquid has a maximum absorbance at 240 nm in methanol. The chemical structure was elucidated by 1D and 2D-NMR and IR analyses. The elucidated molecular formula was C₃₆H₅₄O₁₄. The compound is a polyacetal tricyclononane derivative, composed of a tricyclononane ring attached from the carbon atom number four with an oligo-acetal chain (six acetal groups in chain) and from the carbon atom number seven with a methoxy carbonyl benzene-1,3-dicarboxylic acid. The purposed name is: 4- {[tricycle(3.2.1.1^1,3)non-8-yl] methoxy carbonyl benzene-1,3-dicarboxylic acid} (2,4,5,6,7,8,9 heptaoxa, 3-ethoxy, 5,6,7,9-tetramethyl unidecane).