Diterpenoids and lignans from fossil Chinese medicinal succinum and their activity against renal fibrosis

Five previously undescribed diterpenoids, named succipenoids D‒H (1‒5), along with four undescribed lignans, named succignans A‒D (6‒9), were isolated from the dichloromethane extract of Chinese medicinal succinum. Compounds 1‒5 were characterized as nor-abietane diterpenoids, while compounds 6‒9 were identified as lignans polymerized from two groups of phenylpropanoid units. The structures of these new compounds, including their absolute configurations, were confirmed by spectroscopic and computational methods. Biological evaluations against renal fibrosis exhibited that compounds 6 and 7 can reduce the expression of proteins involved in renal fibrosis, such as α-SMA, collagen I, and fibronectin in transforming growth factor-β1 (TGF-β1) induced NRK-52e cells.