Phytochemical screening and antioxidant activity of Trigonella cariensis seeds

Abstract

The genus Trigonella (Fabaceae) has been widely used for both culinary and clinical purposes since ancient times. The aim of this study was to investigate the chemical composition and in vitro antioxidant activities of Trigonella cariensis seeds for the first time. The seeds were collected in the province of Mersin, Turkey. Chemical analyses were performed using chromatographic methods. Fatty acid, tocopherol and sterol analyses were done on hexane extracts and amino acid and mineral analyses were also carried out on the seeds. The total phenolic and flavonoid contents were measured by using the Folin-Ciocalteu and Al(NO3)3 methods and in vitro antioxidant activity was evaluated via different chemical assays including 1,1-diphenyl-2-picrylhydrazily (DPPH•), cupric reducing antioxidant power (CUPRAC) and 2,2’-azinobis(3-ethylbenzothiazoline)-6-sulphonate (ABTS•+) on its 80% methanolic extract. The seeds were shown to contain mainly linoleic, α-linolenic and oleic acids (43.74±0.24%, 18.38±0.45%, and 10.89±0.71%, respectively). The seeds showed high α-tocopherol content (233.54±2.48 mg/100 g). The main sterols were β-sitosterol, delta-5-avenasterol and campesterol. Na, K, Ca, P, and Mg were the predominant minerals, while glutamic acid, aspartic acid and lysine (5801±0.15, 3629±0.12 and 2062±0.03 mg/100 g, respectively) were determined as the major amino acids in the seeds. The total phenolic and flavonoid contents were 3.34±0.02 mg GAE/g seed and 0.96±0.09 mg QE/g seed, respectively. The results of the ABTS•+, DPPH• and CUPRAC methods were 43.22±3.14%, 31.15±1.79% and 9.67±0.78 mM AAE/g, respectively. In conclusion, T. cariensis seeds provide nutritional value with a good source of polyunsaturated fatty acids, α-tocopherol, β-sitosterol, some amino acids and minerals and medicinal properties with total phenolic and flavonoid contents and antioxidant activities