Terpenoids from Tripterygium hypoglaucum and their inhibition of LPS-induced NO production

Abstract

One new (1) and three known (2–4) sesquiterpenes and four known diterpenes (5–8) were isolated from the root bark of Tripterygium hypoglaucum. Their structures were elucidated on the basis of extensive spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1D-NMR, and 2D-NMR). The inhibitory activity toward LPS-induced NO production of these terpenoids was evaluated, all the compounds showing inhibitory effects.

Key words:

• Tripterygium hypoglaucum
• terpenoid
• NO production

Notes

1. Compound 1: White powder; = +17.2 (c = 0.11, MeOH); IR (KBr) ν_max cm^–1: 3440, 2931, 1722, 1634, 1591, 1281, 1071. ESI-MS m/z 616 [M + H]⁺; HR-ESI-MS m/z 616.2549 [M + H]⁺; calcd. for C₃₅H₃₈NO_6, 616.2547; ¹H-NMR (400 MHz, CDCl₃): 1-furoyloxy group [δ_H 7.80 (1H, s), 7.32 (1H, br. s), 6.50 (1H, br. s)], 6-nicotinoyloxy group [δ_H 9.40 (1H, s), 8.84 (1H, s), 8.56 (1H, d, J = 7.8 Hz), 7.47 (1H, overlapped)], 9-cinnamoyloxy group [δ_H 6.31, 7.48 (each 1H, d, J = 16.0 Hz), 7.41 (2H, overlapped), 7.50 (2H, overlapped), 7.41 (1H, overlapped)], see Table 1 for the other signals; ¹³C-NMR (100 MHz, CDCl₃): 1-furoyloxy group (δ_C 147.5, 119.4, 109.5, 143.5, 162.3), 6-nicotinoyloxy group (δ_C 125.9, 137.9, 123.8, 153.5, 151.3, 164.8), 9-cinnamoyloxy group (δ_C 117.7, 145.5, 134.4, 128.8 × 2, 128.2 × 2, 130.3, 165.9), see Table 1 for the other signals.