Biological activities and phenolic contents of Argania spinosa L (Sapotaceae) leaf extract

Purpose: To investigate the phenolic profile and biological activities of Argania spinosa L. leaves.Methods: The crude methanol extract of leaves of A. spinosa L. Skeels was obtained by ultrasonic extraction, and the total polyphenolic and flavonoid contents were determined by ultra-high performance liquid chromatography-electrospray ionization-quadrupole time-of-flight-mass spectrometry (UPLC-ESIQTOF- MS). In vitro antioxidant activity was determined by 2,2-di-phenyl-1-picryl-hydrazil (DPPH) radical assay and antimicrobial activity evaluated using agar disk diffusion method against reference pathogenic strains (Bacillus subtilis ATCC 6633, Bacillus cereus ATCC 14579, Yersinia enterocolitica ATCC 23715, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922). Cytotoxic activity was evaluated by methyl-thiazolyldiphenyl-tetrazolium bromide (MTT) assay.Results: The results revealed abundant polyphenols and flavonoids (221.39 ± 5.70 μg GAEq/1 g and 66.86 ± 3.36 μg CAEq/1 g, respectively) in the leaf extract. UPLC-DAD-ESI-QTOF-MS profiling showed the presence of myrecitin-3-galactoside, myrecitin-3-gluctoside, myrecitin-3-xyloside, quercetin-3- galactoside, quercetin-3-glucoside, quercetin-3-arabinofuranoside, and quercetin-3-rhamnoside. DPPH assay of the leaf extract yielded a half-maximal effective concentration (EC50) value of 125.60 ± 1.87 μg. A. spinosa L. leaves exhibited antibacterial activity against Gram (+) and Gram (-) bacteria, with particularly marked activity against B. subtilis (inhibition zone, 16 mm). Cytotoxicity data showed that the extract inhibited the proliferation of PC3 cells (IC50 ~ 600 μg).Conclusion: A. spinosa L. leaf extract is rich in valuable biologically active compounds and could represent a new resource for natural and preventive therapies.Keywords: Argania spinosa, Polyphenols, Flavonoids, Antioxidant, Antibacterial, Cytotoxic