Smilaxsieboldiol A, a new stilbenoid from the whole plants of Smilax sieboldii Miq. (Smilacaceae).

As part of an ongoing search for new anti-adipogenic agents from medicinal plants, a new stilbenoid (6), together with eight known compounds (1-5 and 7-9), was isolated from the whole plants of Smilax sieboldii Miq. (Smilacaceae). The structure of smilaxsieboldiol A (6) was elucidated using spectroscopic and spectrometric techniques, including 1D and 2D-NMR (COSY, HSQC, and HMBC) and HRESIMS. All isolated compounds were evaluated for metabolic disorder-related activities using an adipocyte differentiation (adipogenesis) inhibition model in 3T3-L1 cells at a concentration of 100 μM. Among them, compounds 1, 3, and 7-9 significantly suppressed lipid accumulation, with ethyl ferulate (1), decursin (7), and decursinol angelate (8) showing particularly strong activity, reducing intracellular lipid content to 14.1 ± 0.63%, 13.2 ± 0.64%, and 13.8 ± 1.00%, respectively. These results suggest that constituents of S. sieboldii possess notable anti-adipogenic properties and may serve as potential natural agents for regulating adipocyte differentiation.