Chemotyping of commercially available basil (Ocimum basilicum L.) varieties: Cultivar and morphotype influence phenolic acid composition and antioxidant properties

Basil is an aromatic herb that plays an important role within the culinary traditions of many cultures. Despite basil's prevalence within a variety of food and medicinal products, the phenolic composition and antioxidant properties of many Ocimum basilicum L. subspecies have yet to be determined. Therefore, this study analyzed twenty-two commercially available basil cultivars and classified them into unique chemotypes based on commonalities in phenolic acid profiles among varieties. Hierarchical cluster analysis was used to identify chemotypes, and results showed that basil cultivars with the highest total phenolic content and strongest antioxidant properties were characterized as a caffeic acid rich chemotype. Additionally, cultivar had a significant effect on total phenolic content as well as CUPRAC (cupric ion reducing antioxidant capacity) and ORAC (oxygen radical absorbance capacity) antioxidant capacities. Statistical differences in phenolic acid composition also existed among basil varieties and morphotypes. For example, green Genovese-type basils had high phenolic contents and associated antioxidant capacities while lettuce-leaf basil morphotypes had the lowest.