Three rare anti-inflammatory sesquiterpene lactones from Magnolia grandiflora

Abstract

Four new sesquiterpene lactones (SLs) (1-4), along with a biosynthetically related SL (5), have been isolated from the leaves of Magnolia grandiflora. Magrandate A (1) is notable as the first C18 homogemarane type SL, featuring a unique 1,7-dioxaspiro[4.4]nonan-6-one core. Compounds 2 and 3, representing the first instances of chlorine-substituted gemarane-type SL analogs in natural products, were also identified. The structures of these isolates were elucidated through a combination of spectroscopic data analysis, electronic circular dichroism calculations, and X-ray single-crystal diffraction analysis. All isolates demonstrated anti-inflammatory activity in lipopolysaccharide-stimulated RAW264.7 cells. Notably, 3-5 showed a significant inhibitory effect on nitric oxide production, with IC₅₀ values ranging from 0.79 to 4.73 μmol·L⁻¹. Additionally, 4 and 5 exhibited moderate cytotoxic activities against three cancer cell lines, with IC₅₀ values between 3.09 and 11.23 μmol·L⁻¹.

Keywords

Magnolia grandiflora / Sesquiterpene lactones / Isolation and identification / Anti-inflammatory activity

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Funding

National Natural Science Foundation of China(82060631)

National Natural Science Foundation of China(32270413)

Science and Technology Department of Guizhou Province(QKH JC(2020)1Z076)

Science and Technology Department of Guizhou Province(QKH JC (2020)1Y400)

Cultivation Project of National Natural Science Foundation of Guizhou Medical University(2023-106)

Outstanding Young Scientific and Technological Talents in Guizhou Province(QKH PTRC(2021)5633)

High-level Innovative Talents in Guizhou Province(Thousand Levels of Talent for YUAN Chunmao in 2018)

“Light of the West” Talent Cultivation Program of Chinese Academy of Sciences for YUAN Chunmao [RZ (2020)82], Guizhou Science and Technology Innovation Talent Team(QKHPTRC-CXTD[2022]007)

Natural Science Foundation of Guizhou Province [No. QKHZYD(QKHZYD (2022)4015)