Chemical compositions and antioxidant activity of adlay seed (Coixlachryma-jobi L.) oil extracted from four main producing areas in China.

Adlay oil (AO) is an important component of adlay seeds that has many beneficial functions to human health. In this study, the variations in the chemical composition and antioxidant activity of AOs extracted from adlay samples obtained from four main producing areas of China were first investigated. Results revealed that the AO of the adlay samples varied from 7.398 ± 0.486% to 8.464 ± 0.725%. The highest contents of total fatty acid, triolein, total phenolic, and total flavonoid were observed in Xingren AO, whereas coixol content was found to be highest in Pucheng AO. The AO samples were grouped successfully in accordance with the origins by partial least squares-discriminant analysis and hierarchical cluster analysis based on the contents of the chemical components. Furthermore, AOs exhibited considerable levels of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity (IC₅₀ , 0.924 ± 0.113 to 1.116 ± 0.109 mg/mL) radical scavenging activity, ferric-reducing antioxidant power (FRAP) activity (EC₅₀ , 0.019 ± 0.002 to 0.028 ± 0.002 mg/mL) activity, and β-carotene-linoleic acid bleaching activity (IC50, 0.233 ± 0.008 to 0.414 ± 0.012 mg/mL) activity. Total phenolic and total flavonoid both demonstrated highest correlation with ABTS values (r = -0.952 and r = -0.960, respectively). The results derived from above studies suggest that geographic origin has a certain influence on the phytochemical profiles and antioxidant activity of the AOs. PRACTICAL APPLICATION: The chemical composition and antioxidant activity of adlay oils extracted from the adlay samples obtained from four main producing areas of China were evaluated, including total fatty acid, triolein, total phenolic, and total flavonoid, and ABTS radical scavenging activity, FRAP activity, and β-carotene-linoleic acid bleaching activity.