Two Novel Acyclic Monoterpenoids from Patrinia villosa (Thunb.) Juss. and Their Anti-Inflammatory Evaluation
The n-butanol fraction of the ethanol extract of Patrinia villosa (Thunb.) Juss. was subjected to systematic phytochemical investigation using silica gel, ODS, Sephadex LH-20, and semi-preparative HPLC. Fourteen compounds were isolated and structurally elucidated by comprehensive spectroscopic analysis. Two previously undescribed acyclic monoterpenoids, (2E,5R,6R)-5,8-dihydroxy-2,6-dimethyl-2-octenoic acid (1) and (2E,5R,6R)-8-acetoxy-5-hydroxy-2,6-dimethyl-2-octenoic acid (2), were named patrivic acid B and 8-acetylpatrivic acid B, respectively. The remaining twelve known compounds were identified as (2E,6R)-8-hydroxy-2,6-dimethyl-2-octenoic acid (3), (6R,7E,9R)-9-hydroxy-4,7-megastigmadien-3-one (4), ethyl chlorogenate (5), ethyl caffeate (6), dihydrosyringenin (7), 7S,8S-threo-4,7,9,9'-tetrahydroxy-3,3'-dimethoxy-8-O-4'-neolignan (8), (+)-isolariciresinol (9), (7S,8R)-dihydrodehydrodiconiferyl alcohol (10), ceplignan (11), (+)-syringaresinol (12), salicifoliol (13), and 5-hydroxy-4-(4-hydroxyphenyl)-2(5H)-furanone hydroxybutenolide (14). Compounds 3, 4, 10, 11, and 14 were isolated from P. villosa for the first time. Anti-inflammatory activity was assessed by measuring nitric oxide (NO) inhibition in lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophages. At 50 μmol/L, compounds 1 and 2 exhibited NO inhibition rates of (6.16 ± 1.41)% and (11.11 ± 2.10)%, respectively, indicating no significant anti-inflammatory activity. This study expands the chemical diversity of P. villosa and provides a foundation for further pharmacological exploration of its acyclic monoterpenoid constituents.