Atlas pistachio (Pistacia atlantica) unripe fruit extract as a source of phytochemicals with anti-tyrosinase, antioxidant, and antibacterial properties

The current need for biologically active substances that are sustainable, allegedly beneficial to health, and may be employed as ingredients in cosmetic products has encouraged numerous researchers. Pistacia atlantica is known to contain compounds that possess strong biological effects beneficial to health. The objective of this study was the quantification of the polyphenols in unripe Atlas pistachio (AP) fruit extract and the evaluation of hydro-methanolic extract and anthocyanins for their antioxidant, anti-tyrosinase, and antimicrobial effects. The results revealed that the yield of the hydro-methanolic extract was 22.15%, characterized by 75.12 mg GAE/g DM for total phenolics and strong content of hydrolysable tannins (400.16 mg GAE/g DM). 1,1-dimethyl-allyl caffeate, hydroxytyrosol, ellagic acid, rutin, and kaempferol-3-O-glucoside were the most abundant components quantified by HPLC-DAD. The tyrosinase enzyme was significantly inhibited by AP extract (EC50 = 0.70 mg/mL). For the antioxidant properties, the hydrolyzed anthocyanin extract exhibited the best action against reducing power and β-carotene, compared to anthocyanins crude extract and fruits. This extract showed its stronger antibacterial activity. In conclusion, unripe AP fruit is a promising source of diverse phytochemicals that can be applied in medicinal, nutraceutical, and cosmetic applications as antioxidants and antimicrobials.