Search

Genus Salsola (family Amaranthaceae) is one of the most prevailing genera in Saudi Arabia. Although several species were reported for their traditional uses, the majority of Salsola species still need to be phytochemically and biologically explored. The current study presents the GC-MS profiling as well as an in vitro investigation of the bioactivities of the n-hexane extracts from the five Salsola species: Salsola arabica, S. cyclophylla, S. imbricata, S. incanescens and S. villosa. Additionally, the compounds identified in the most active extracts were screened for their interaction with the active sites of cyclooxygenase enzyme isoforms (COX-1 and COX-2). GC-MS analysis of the n-hexane extracts from the five species resulted in the identification of 67 constituents. Oleic acid (75.57%), 1-octadecene (14.46%), cinnamaldehyde α-hexyl (57.15%), octacosyl heptafluorobutyrate (25.36%) and hexadecanoic acid methyl ester (26.15%) represent the major constituents in S. arabica, S. cyclophylla, S. imbricata, S. inscanescence and S. villosa, respectively. Results of bioactivity testing highlighted S. villosa as having the highest anti-oxidant activity (IC50 0.99 ± 0.05 mg/mL), which was closely followed by S. cyclophylla (IC50 1.36 ± 0.06 mg/mL) compared to the IC50 of 0.16 ± 0.01 mg/mL recorded by ascorbic acid. S. villosa was further noted for having the strongest COX-2 inhibitory activity (IC50 4.6 ± 0.13 µg/mL) among the tested extracts followed by S. arabica (IC50 13.1 ± 0.37 µg/mL) and S. cyclophylla (IC50 20.1 ± 0.57 µg/mL). On the other hand, S. imbricata extract displayed the most characteristic inhibition activity against COX-1 (IC50 10.2 ± 0.52 µg/mL), which was non-significant from the standard drug celecoxib. Based upon bioactivity results, the phytoconstituents identified in S. villosa and S. imbricata extracts were investigated for their capability to interact with the active sites of both cyclooxygenase enzyme isoforms adopting molecular docking. Results indicated the possibility to incorporate the compounds to active sites of the enzymes where some of them bind with their polar end into the cavity beyond Arg120 and their aliphatic chain oriented to the catalytically important Tyr385 similar to the natural substrate arachidonic acid, indicating that they could be promising candidates for the future development of selective COX inhibitors. [ABSTRACT FROM AUTHOR]

Suaeda aegyptiaca is a halophytic plant widely growing in northeast Africa and Asia. The current study reports on the GC-MS analysis of S. aegyptiaca essential oil. The essential oil was prepared using three different methods: cold n-hexane extraction (CHE), hot n-hexane extraction (HHE), and hydro-distillation extraction (HDE). The GC-MS analysis detected twenty-eight compounds in both CHE (97.28%) and HHE (97.35%) and twenty compounds in HDE (98.65%). 2-methyloctacosane (48.72%); 11-decyldocosane (29.20%); and 1, 2-benzenedicarboxylic acid diisooctyl ester (57.87%) were the main constituents in CHE, HHE, and HDE, respectively. Free radical scavenging activity testing using 2,2-diphenyl-1-picrylhydrazyl (DPPH) revealed the notable anti-oxidant potential of HDE (IC50 0.358 mg/mL) compared to ascorbic acid (IC50 0.264 mg/mL). Moreover, in vitro anti-inflammatory activity testing using COX-1 and COX-2 showed the notable activity of HDE (IC50 5.50 µg/mL and 2.59 µg/mL, respectively). The observed anti-inflammatory activity of HDE was further confirmed by the characteristic decrease in TNF-α levels in RAW264.7 to 572.20 Pg/mL compared to the decrease of 442.80 Pg/mL caused by the positive control (Celecoxib®). On the other hand, a cytotoxic activity investigation indicated that CHE was the most potent against the Caco-2 and HCT-116 cell lines (IC50 8.11 and 11.18 µg/mL, respectively), and it was closely followed by HHE (IC50 12.42 µg/mL) against the Caco-2 cell line. Collectively, S. aegyptiaca essential oil prepared by the hydro-distillation method exhibited notable anti-oxidant and anti-inflammatory activities, while the same essential oil prepared by solvent extraction methods displayed a characteristic cytotoxic activity against the Caco-2 and HCT-116 cell lines. These results confirmed that different extraction methods greatly influence the biological potential of an essential oil, which, in turn, is attributable to the different constituents in each extract Moreover, S. aegyptiaca was noted as a promising halophytic plant for more phytochemical and biological investigations. [ABSTRACT FROM AUTHOR]