Neuroprotective Dihydroagarofuran Sesquiterpene Derivatives from the Leaves of Tripterygium wilfordii

Abstract

Thirteen dihydroagarofuran derivatives, including 12 new sesquiterpenoid esters and one known sesquiterpenoid alkaloid, were obtained from the leaves of Tripterygium wilfordii. Spectroscopic techniques and the ECD method were used for the structure elucidation of the compounds. The structures of compounds 1 and 8 were confirmed by single-crystal X-ray crystallographic analyses. Compounds 8, 9, 11, 12, and 13 increased cell viability of the okadaic acid treated PC12 cells from 60.4 ± 23.0% to 72.4 ± 14.1, 71.5 ± 11.5, 75.7 ± 15.6, 81.2 ± 13.1, and 86.2 ± 25.5% at 10 μM, respectively.

Characteristic Dihydroagarofuran Sesquiterpenoids with Neuroprotective Effects from the Celastraceae Plant Tripterygium wilfordii

“…A negative Cotton effect at 260 nm (Δ ε = −1.30) and a positive Cotton effect at 217 nm (Δ ε = +1.31) were shown in its ECD spectrum (Figure 89, Supporting Information), which were quite similar to those of triptersinine X. [ 18 ] The absolute configuration (1 S ,4 S ,5 R ,6 R ,7 R ,8 S ,9 S ,10 S ) of triptersinine Z23 ( 9 ) was thus established.…”

“…Comprehensive analysis of its NMR data suggested compound 1 was a sesquiterpenoid with dihydroagarofuran skeleton, attached with substitutions including a trans ‐cinnamoyl, a tigloxyl, and an acetyl group. [ 18 ]…”

“…The NMR data of 4 and 5 resembled those of triptersinine Z6 except for the locations of the acyl groups. [ 18 ] The connections of the ester groups were ascertained through HMBC correlations of H‐1/Fu, H‐5/Ac, H‐7/Nic, H‐8/Fu, and H‐11/Ac in 4 , while H‐1/Ac, H‐5/Fu, H‐7/Nic, H‐8/Fu, and H‐11/Ac in 5 . NOESY correlations from H‐5 to H‐6, H‐11, and H‐12, followed by cross peaks from H‐8 to H‐1, H‐7, and H 3 ‐14 established the relative configurations of 4 and 5 .…”

“…[ 17 ] These characteristic constituents, featured with several ester groups and multiple stereocenters, are of great interest to phytochemical investigators. [ 18–23 ]…”

New 18(4→3)-Abeo-Abietanoids from Tripterygium wilfordii

“…Tripterygium wilfordii, also called “leigongteng”, is a member of the Celastracrae family [ 1 ], and was commonly used in Traditional Chinese Medicines to cure IgA nephropathy cancer, systemic lupus erythematosus, ankylosing spondylitis, psoriasis, and idiopathic diseases [ 2 , 3 , 4 ]. Earlier chemical studies on T. wilfordii have led to the isolation of alkaloids [ 5 , 6 , 7 ], diterpenes [ 8 ], triterpenes [ 9 ], sesquiterpenes [ 10 , 11 , 12 ], and lignans [ 13 ], which showed a wide range of biological activity, including anti-fertility, anti-inflammatory, immunosuppressive, anti-HIV, and anti-tumor [ 14 ]. In order to explore structurally and biologically interesting natural products from T. wilfordii , three new 18(4→3) -abeo -abietanoids ( Figure 1 ), containing a new natural product and two new compounds, named tripordolides A–C ( 1 – 3 ), were isolated.…”