Identification of Phenolic Compounds from Vietnamese Artichoke (Cynara scolymus L.) Leaf and Their Antioxidant Activities
Anh Nguyet Thi Nguyen, Thanh Tuyen Thi Vu, Hong Tuoi Thi, Thien Hai Nguyen, Huan Van Le, Hong Khuyen Thi Pham, Phu Chi Hieu Truong, Dong Phuong Pham, Manh Hung Tran
Abstract
Artichoke (Cynara scolymus L.) is a perennial plant belonging to the Asteraceae family originating from the Mediterranean region. In Vietnam, there are some varieties of artichoke which are extensively cultivated and propagated in highland areas, however, there have been limited detailed scientific publications on the chemical composition and biological activity of artichoke grown in Vietnam. Therefore, this study provides a detailed description of the extraction, isolation, and structural determination of 20 natural secondary metabolites present in harvested artichoke. The antioxidant activity of the extract and the 9 isolated compounds are tested in 1,1-diphenyl-2-picrylhydrazyl radical scavenging and ex vivo malondialdehyde model. Among the selected compounds, 1-caffeoylquinic acid, 3-caffeoylquinic acid, chlorogenic acid, 4-caffeoylquinic acid, cynarin, 1,5-di-caffeoylquinic acid, 4,5-di-caffeoylquinic acid, cynaroside, and scolymoside exhibited strong radical scavenging activity with IC<SUB>50</SUB> values ranging from 5.7 to 61.6 μM. In the malondialdehyde assay, 1,3-dicaffeoylquinic acid (or cynarin) showed the strongest activity with an IC<SUB>50</SUB> value of 24.7 μM, followed by 1,5-di-caffeoylquinic acid (66.8 μM), and 4,5-di-caffeoylquinic acid (127.3 μM). This outcome contributes to establishing a database on the phytochemical and antioxidant activity of the Vietnamese artichoke.