Anti-Adipogenic Activity of Secondary Metabolites Isolated from Smilax sieboldii Miq. on 3T3-L1 Adipocytes

Smilax sieboldii, a climbing tree belonging to Smilacaceae, has been used in traditional oriental medicine for treating arthritis, tumors, leprosy, psoriasis, and lumbago. To evaluate the antiobesity effects of S. sieboldii (Smilacaceae), we screened methylene chloride (CH2Cl2), ethyl acetate (EtOAc), aqueous-saturated n-butanol, and ethanol (EtOH) extracts of the whole plant at various concentrations to inhibit adipogenesis in adipocytes. The 3T3-L1 cell line with Oil red O staining with the help of fluorometry was used as an indicator of anti-obesity activity. Bioactivity-guided fractionation of the EtOH extract and subsequent phytochemical investigation of the active CH2Cl2 and EtOAc-soluble fractions resulted in the isolation of 19 secondary metabolites (1-19), including a new alpha-hydroxy acid derivative (16) and two new lanostane-type triterpenoids (17 and 18). The structures of these compounds were characterized using various spectroscopic methods. All the isolated compounds were screened for adipogenesis inhibition at a concentration of 100 mu M. Of these, compounds 1, 2, 4-9, 15, and 19 significantly reduced fat accumulation in 3T3-L1 adipocytes, especially compounds 4, 7, 9, and 19, showing 37.05 +/- 0.95, 8.60 +/- 0.41 15.82 +/- 1.23, and 17.73 +/- 1.28% lipid content, respectively, at a concentration of 100 mu M. These findings provide experimental evidence that isolates from S. sieboldii extracts exert beneficial effects regarding the regulation of adipocyte differentiation.

Automated summary

This study extracted 19 secondary metabolites, including a new alpha-hydroxy acid derivative and two new lanostane-type triterpenoids, from the Smilacaceae plant. These compounds showed inhibitory effects on fat accumulation, with compounds 4, 7, 9, and 19 reducing lipid content by 37.05%, 8.60%, 15.82%, and 17.73%, respectively, at a concentration of 100 μM.