Chemical variation and antioxidant capacity of sumac (Rhus coriaria L.)

Sumac (Rhus coriaria L.) is a medicinal plant distributed worldwide for its health benefits and its culinary uses as a flavoring agent. The aim of the current study was to detect chemical characterization of Iranian sumac populations. A high degree of variation was found in the chemical characteristics and the results revealed significant differences among the accessions. Titratable acidity varied from 2.01 to 7.84%, while the pH ranged from 2.66 to 3.90. Ascorbic acid ranged from 10.00 to 45.00 mg per g of dry weight, while phenolic content varied from 77.54 to 389.30 mg gallic acid equivalents per g dry weight. In addition, flavonoid content ranged from 2.19 to 7.54 mg quercetin equivalents per g dry weight, while tannin content ranged from 52.00 to 189.80 mg gallic acid equivalents per g dry weight. Free amino acid content ranged from 25.01 to 166.38 mg glycine equivalents per g dry weight, while anthocyanin content varied from 3.57 to 66.14 mg cyanidin-3-glucoside equivalents per g dry weight. Furthermore, antioxidant capacity ranged from 1.55 to 11.09 mg ascorbic acid equivalents per g dry weight. Flavonoid content was positively correlated with pH (r = 0.56) and tannin content (r = 0.28). In addition, antioxidant capacity was positively correlated with flavonoid content (r = 0.45) and tannin content (r = 0.32). Cluster analysis revealed two separate clusters based on the chemical properties. In conclusion, antioxidant activities were found in the sumac fruit extracts, and thus this fruit might be useful as a raw material to generate natural antioxidants. Finally, 15 accessions showed high values in terms of chemical properties and antioxidant capacity and thus may be especially useful for breeding and industrial uses.