---

Squalene is an unsaturated triterpene hydrocarbon and is a precursor of steroids and cholesterol with antioxidant properties. The aim of this study was to isolate the squalene from the liver of the Persian Gulf spot tail shark Carcharhinus sorrah and to investigate its antimicrobial activity. Extraction was first done by methanol 70% and then, the squalene was separated through column chromatography with silica gel. Identification of the extracted squalene was done by thin layer chromatography (TLC) and gas chromatography coupled with mass spectrometry (GC–MS). Antibacterial properties of the squalene were identified and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were investigated by tubular dilution. Identification of the extracted compounds by GC-MS confirmed the presence of the squalene in the shark liver. Antibacterial studies showed that the squalene inhibited the growth of Gram negative (Escherichia coli, Klebsiella pneumonia and Vibrio harveyi) and Gram positive (Micrococcus roseus and Staphylococcus aureus) bacteria. Therefore, this metabolite has the potential to be more investigated for developing new antimicrobial compounds.

---

The present study aimed to isolate the steroids and fatty acids from the liver of the Persian Gulf spot tail shark Carcharhinus sorrah and to assess their antifungal activity. Extraction was done by methanol 70% and then, the lipids were separated through column chromatography with silica gel. Identification of the extracted lipids was done by thin layer chromatography and gas chromatography coupled with mass spectrometry. Then, antifungal activity of the steroids was investigated through determining the minimum inhibition concentration and minimum fungicidal concentration by tubular dilution method against Aspergillus fumigatus and Candida albicans. Identification of the extracted compounds by GC-MS confirmed the presence of these steroids in the shark liver. The identified steroids included compounds of Y-Sitosterol, Desmosterol and Squalene, which showed different results regarding the growth inhibition and fungicidal effects against the microorganisms at different experimental doses. Desmosterol and Squalene at minimum concentration induced the highest inhibitory effect on the fungus but Y-Sitosterol induced the highest inhibitory effect on the yeast. Squalene showed fungicidal effect only on the fungus and totally, A. fumigatus was more sensitive to the antimicrobial activity of the liver compounds than C.  albicans. In conclusion, promising results were found regarding the antimicrobial activity of the lipid compounds derived from Persian Gulf shark liver, revealing the importance of more comprehensive investigations of these natural compounds for the synthesis of biomedicines from the marine organisms.