Monoterpene Alkaloids from Incarvillea delavayi Bureau et Franchet and Their Inhibition against LPS Induced NO Production in BV2 Cells

Abstract

Three new monoterpene alkaloids, delavatines C -E (1 -3), along with five known ones (4 -8), were separated from the whole plants of Incarvillea delavayi. All compounds were deduced by interpretation of comprehensive NMR spectral data and X-Ray single crystal diffraction, in combination with a quantum chemical calculation of NMR chemical shift coupled with an advanced statistical procedure DP4 + . Compounds 1-8 were assessed NO suppressive effect in LPS-stimulated BV2 microglia cells. Compounds 2, 3, 6, and 8 exhibited significant inhibition against NO production in LPS-induced BV2 cells with IC 50 values of 25.62, 17.29, 19.94 and 23.88 μM, stronger than or comparable to the positive control (AG) with IC 50 value of 26.13 μM.

Exploring the Biomedical Potential of Terpenoid Alkaloids: Sources, Structures, and Activities

“…Delavatines C-E (9)(10)(11), three monoterpene alkaloids with a cyclopentane[c]piperidine skeleton, were isolated from whole plants of Incarvillea delavayi (Bignoniaceae) [18].…”

“…Caryopterisines F-I (4-7) and caryopterisines C-E (16)(17)(18) were subsequently isolated from C. glutinosa Rehder. Caryopterisines F-I (4-7) are four monoterpene alkaloids containing the cyclopentyl[c]pyridine skeleton, while caryopterisines C-E (16-18) represent three novel dimeric monoterpene alkaloids and are believed to be biosynthesized via the Diels-Alder reaction followed by aromatization rearrangement and a series of subsequent reactions [23].…”

“…Caryopterisines F-I (4-7) are four monoterpene alkaloids containing the cyclopentyl[c]pyridine skeleton, while caryopterisines C-E (16-18) represent three novel dimeric monoterpene alkaloids and are believed to be biosynthesized via the Diels-Alder reaction followed by aromatization rearrangement and a series of subsequent reactions [23]. Of these, caryopterisine C ( 16) has an unprecedented 6/5/6/6/5 pentacyclic ring framework, while caryopterisines D (17) and E (18) both have 6/6/6/5 fused ring frameworks.…”

“…[18] Delavatine E (11) In vitro [18] Compounds 286-287 are two C17-labdane DAs isolated from ripe fruits of Forsythia suspensa. The structure of 286 was determined as 3-hydroxyl-4,4,10,13-tetramethyl-1(2),3(4), 5 (10),6(7)-octahydrobenzo[f]quinolin, and 287 was obtained by oxidation of the hydroxyl group at C-3 in 286 [103].…”

“…Delavatines C ( 9) and E (11) showed more significant inhibition of NO production in lipopolysaccharide (LPS)-stimulated BV2 cells compared to aminoguanidine bicarbonate, with IC 50 values of 25.62 and 17.29 µM, respectively, and no cytotoxicity [18]. Stylosine A (157) showed significant inhibitory activity against LPS-induced production of inflammatory cytokines (IL-1β, COX-2, and TNF-α) in RAW264.7 cells at a dose of 0.1 µg/mL without cytotoxicity [74].…”