Elham Hashemi - Master student, School of Biology, Damghan University, Damghan, Iran
Negin Chinjoo - Master student, School of Biology, Damghan University, Damghan, Iran
Sajedeh Kouhnavard Delijan - Master student, School of Biology, Damghan University, Damghan, Iran
Maliheh Safavi - Associate professor, Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
Arezou Rezaei - Assistant professor, School of Biology, Damghan University, Damghan, Iran - Institute of Biological Sciences, Damghan University, Damghan
Zahra Piravi Vanek - Associate professor, Food, Halal and Agricultural Research Department, Food and Agriculture Research Institute, Standard Research Institute, Karaj, Iran

BACKGROUND AND OBJECTIVESPhytosterols (PSs) are plant-originated steroids. Health-promoting effects of PSs include anti-obesity, anti-diabetic, anti-microbial, anti-inflammatory, antioxidant, and immunomodulatory effects. Other studies showed that the ethanolic and hydroalcoholic extracts of different parts (e.g., leaf and fruit) of Pistacia vera L. had antioxidant properties. The consumption of nuts, including pistachio, seems to be useful in improving the intestinal microbial composition. The evaluation of critical sterols such as campesterol, β-sitosterol, stigmasterol, epicoprostanol, etc. against a wide range of bacteria revealed notable antibacterial properties. This is the first report on the antioxidant and antibacterial activities of phytosterol extracted from the green skin of three variants of Damghan’s pistachio.MATERIALS AND METHODSThe Soxhlet method was used to extract total phytosterol from green pistachio skin of Akbari, Khanjari, and Abbasali variants of Damghan’s pistachio, which was obtained from Damghan gardens. The antioxidant activity of the extracted phytosterols was examined using the FRAP method with three repetitions and five different concentrations. Ascorbic acid was used as the control solution. The antibacterial properties of the extracted phytosterols were evaluated against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative) bacteria in duplicate. Statistical analysis of the results of antioxidant activity was done using SPSS software (version ۲۷).RESULTS AND DISCUSSIONThe antioxidant properties of the phytosterols extracted from three pistachios’ skin types were high without any significant difference between them. The highest absorption was observed in concentration of ۲۰ mg/ml in the studied samples. However, the extracted phytosterols showed no antibacterial activities at concentrations of ۱.۶-۱۰۰۰۰ mg/ml.CONCLUSIONAccording to the present outcomes, the phytosterol extracted from the green skin of the studied Damghan’s pistachios had good antioxidant properties. Accordingly, it is worth further studies on the application of phytosterol extracted from the pistachio’s green skin in the pharmaceutical, food, and cosmetic industries. However, contrary to other reports, no antibacterial effect was seen for the extracted phytosterols. We suggest further investigation to find the reason for the seen discrepancy.

Phytosterol, Pistacia vera L., antioxidant, antibacterial, Damghan