An unprecedented spiro-C-glycoside adduct, heteryunine A ( 1 ), along with two uncommon alkaloids featuring a 2,3-diketopiperazine skeleton, heterpyrazines A ( 2 ) and B ( 3 ), were discovered in the roots of Heterosmilax yunnanensis . The detailed spectroscopic analysis helped to clarify the planar structures of these compounds. Compound 1 , containing 7 chiral centers, features a catechin fused with a spiroketal and connects with a tryptophan derivative by a C - C bond. Its complex absolute configuration was elucidated by rotating frame overhauser enhancement spectroscopy (ROESY), specific rotation, and the 13 C nuclear magnetic resonance (NMR) and electronic circular dichroism (ECD) calculation. The possible biosynthetic routes for 1 were deduced. Compounds 1 and 2 showed significant antifibrotic effects and further research revealed that they inhibited the activation, migration and proliferation of hepatic stellate cells (HSCs) through suppressing the activity of Ras homolog family member A (RhoA).