Anti-adipogenic and antioxidant benzophenone dimers from the tea making leaves of cultivated Aquilaria sinensis (Lour.) Spreng

Aquilaria sinensis (Lour.) Gilg leaf has been approved as a new food raw material in China and Japan, and used as tea and other health care products. In the chemical study on the water extract of A. sinensis leaf, a pair of benzophenone atropisomers, named aquidibenzophenonsides A and B (1 and 2), as well as 10 known compounds, were isolated and identified on the basis of a comprehensive interpretation of the MS, CD, and 1D and 2D NMR spectroscopic data. Compounds 1 and 2 are a class of symmetrical benzophenone dimers, representing an unprecedented 10-membered ring system. In the DPPH and ABTS^•+ assays, compounds 1 and 2 exhibited significant antioxidant activity with IC₅₀ values between 12.24 ± 1.08 µg/mL and 30.90 ± 0.40 µg/mL. In the in vivo antioxidant activity assay, compounds 1 and 2 significantly decreased the content of reactive oxygen species (ROS) and improved the survival rate of Caenorhabditis elegans. Furthermore, compounds 1 and 2 could effectively reduce fat deposition in C. elegans. Molecular docking simulations indicated that the anti-adipogenic effects of compounds 1 and 2 may be mediated through their interaction with fatty acid synthase.