Secondary metabolites from the Root of Rhaphiolepis indica var. tashiroi and Their Anti-inflammatory Activity
Rhaphiolepis indica (L.) Lindl. ex Ker var. tashiroi Hay. ex Matsum (Rosaceae) is an evergreen shrub or small tree which distributes from India to southern China, the Ryukyus, Japan, Korea, and Taiwan at low altitudes. The methanolic extract of the root of this species showed anti-inflammatory activity using N-formylmethionylleucylphenylalanine (fMLP)-induced production of superoxide anion, an inflammatory mediator produced by neutrophils in vitro. Previously, we reported seven compounds including four new dibenzofuran derivatives, rhaphiofurans A – D (1-4), two new biphenyl derivatives, rhaphiobiphenyls A – B (5-6) along with 3-hydroxy-5-methoxybiphenyl (7) from the active EtOAc-soluble layer of this plant's root.
Continuing investigation of the active EtOAc-soluble layer of this plant's root led to the isolation of three new triterpenoids, namely 2α,3β-dihydroxy-olean-11,13(18)-dien-28,19-olide (8), 2α, 3β-dihydroxy-olean-13(18)-en-28-oic acid (9) and 3β,5α-dihydroxyglutinanol (10). The structures of these isolates were elucidated by spectral analyses.
Among the isolates, 3, 6, and 7 exhibited potent inhibition against fMLP-induced superoxide production with IC50 values less than 8.36µM.
Acknowledgement: National Science Council of the Republic of China (NSC 97–2320-B-037–010-MY3)