Analysis of the components of Cassia nomame and their antioxidant activity.

Cassia nomame, an annual herb belonging to the Leguminosae family, is traditionally consumed as tea in the form of dried whole herbs or beans. To deepen our understanding of the chemical constituents of C. nomame, we isolated 16 compounds, categorised as flavone derivatives (1-4), including a novel compound nomameflavone A (4), a chalcone derivative (5), an aurone derivative (6), a chromone derivative (7), a juglone derivative (8), anthraquinone derivatives (9-11), phenolic compounds (12-14), and sterol derivatives (15, 16). The structure of each compound was elucidated using NMR and MS. Compounds 2, 6, 7, 8, 12, 13, and 14 were successfully isolated from C. nomame for the first time. Furthermore, compounds 1, 3, 5, and 6 exhibited DPPH radical scavenging activities, and the bioactivity of 3 was discovered. The elucidation of the diverse chemical constituents of C. nomame underscores its potential functional ingredients.