Preparative HPLC-PDA/ESI-MS/MS-Guided Fractionation and Characterization of Phenolic Constituents from Wild Smilax aspera Fruit: Antioxidant and Antimicrobial Activity of Its Extracts

Smilax aspera L. (Smilacaceae), or sarsaparilla, is a wild Mediterranean climbing shrub whose red berries are used in Palestinian folk medicine for inflammatory, rheumatic, and dermatological conditions. Although its leaves, stems, and roots have attracted renewed phytochemical interest, the fruit remains only partly characterized at the compound level. This work determined the phenolic and flavonoid content of wild Palestinian S. aspera fruit extracted with water, 80% ethanol, and 99% ethanol; evaluated antioxidant activity by the DPPH and FRAP assays; screened antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans; fractionated the major UV-active constituents by preparative HPLC-PDA; and characterized them by ESI-MS and MS/MS. Water gave the highest phenolic content (8.21 mg GAE/g), while the FRAP responses of all three extracts were low and below the limit of quantification; 80% ethanol gave the highest flavonoid content (1.22 mg CE/g); and 99% ethanol showed the strongest DPPH activity (5.96 mg TE/g; 78.96% inhibition). Both ethanolic extracts inhibited S. aureus (20 mm) and C. albicans (19–20 mm), but not E. coli, while the aqueous extract inhibited only C. albicans (13 mm). Preparative HPLC-PDA gave eight fractions. Rutin (quercetin-3-O-rutinoside) and a caffeoylquinic acid of the chlorogenic acid type were identified as the main constituents, together with a quercetin-O-hexoside and an isorhamnetin-O-deoxyhexosyl-hexoside accompanied by a minor kaempferol-O-deoxyhexosyl-hexoside. The 80% ethanolic extract caused no visible morphological changes in HT-29 colon cancer cells. Wild Palestinian S. aspera fruit is therefore a source of flavonol glycosides and a caffeoylquinic acid that may contribute to the antioxidant and antimicrobial activity of its extracts, which supports further study of the fruit as a nutraceutical ingredient.