Two new bioactive salsolanol and biphenylsalsinol from the aerial parts of Salsola villosa Delile. ex Schul. (Chenopodiaceae) growing in Saudi Arabia

Abstract

Objective: To isolate and characterize the bioactive secondary metabolites from aerial parts of widespread Chenopodiaceae taxa growing in Saudi Arabia: Salsola villosa Delile. ex Schul. Methods: Antibacterial activities of chloroformic extract, fractions and isolate compounds was evaluated against five bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus and Staphylococcus epidermidis), using a paper disc diffusion method. The purification of compound(s) of chloroform extract was done by chromatographic column of silica gel. The structure elucidation was determined by extensive spectroscopic analysis (1H and 13C nuclear magnetic resonance, correlation spectroscopy, heteronuclear multiple bond correlation, heteronuclear multiple quantum coherence and nuclear overhauser enhancement spectroscopy) and high resolution electrospray ionization mass spectroscopy analysis. Results: Bioactivity guided fractionation of the chloroformic extract led to the isolation of two bioactive compounds: 4-(4′-hydroxy-2′-methylcyclopent-2′-enyloxy)-4-methylcyclopent-2-enol (1) named salsolanol and 4′-[3-(hydroxymethyl)oxiran-2-yl]-3-[(E)-3-hydroxyprop-1-en-1-yl]-6, 2′-dimethoxy [1, 1′-biphenyl]-2-ol (2) named biphenylsalsinol. The antibacterial effects of the chloroform extracts, fractions and isolated compounds 1 and 2 were also evaluated in this work. Results showed that the compounds 1 and 2 exhibited antibacterial activities against four strains: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa with diameter of zone of inhibition ranging between (9.33 ± 0.94) to (26.33 ± 0.94) mm. Conclusions: Based on data presented here, two new natural compounds secondary cyclic alcohol 1 and biphenylpropanoid 2 isolated from bioactive chloroformic extract from aerial parts of Salsola villosa can be responsible for its antibacterial activities.

Keywords

• Salsola villosa
• Salsolanol
• Biphenylsalsinol
• Spectroscopic analysis
• Antimicrobial activities