Lirispirolides A-L (1-12), twelve novel sesquiterpene-monoterpene heterodimers featuring distinctive carbon skeletons, were isolated from the branches and leaves of Chinese tulip tree [Liriodendron chinense (L. chinense)], a rare medicinal and ornamental plant endemic to China. The structural elucidation was accomplished through comprehensive spectroscopic analyses, quantum-chemical calculations, and X-ray crystallography. These heterodimers exhibit a characteristic 2-oxaspiro[4.5]decan-1-one structural motif, biosynthetically formed through intermolecular [4 + 2]-cycloaddition between a germacrane-type sesquiterpene and an ocimene-type monoterpene. The majority of the isolated compounds demonstrated significant anti-neuroinflammatory effects in lipopolysaccharide (LPS)-induced BV-2 microglial cells by reducing the production of pro-inflammatory mediators, specifically tumor necrosis factor-α (TNF-α) and nitric oxide (NO). Further investigation revealed that the lirispirolides' inhibition of NO release correlated with decreased messenger ribonucleic acid (mRNA) expression of inducible NO synthase (iNOS).
Sesquiterpenes/isolation & purification* ; Anti-Inflammatory Agents/isolation & purification* ; Animals ; Mice ; Tumor Necrosis Factor-alpha/genetics* ; Nitric Oxide/immunology* ; Microglia/immunology* ; Molecular Structure ; Liriodendron/chemistry* ; Monoterpenes/isolation & purification* ; Plants, Medicinal/chemistry* ; Cell Line ; Lipopolysaccharides ; Nitric Oxide Synthase Type II/immunology* ; Plant Extracts/pharmacology* ; China

The tulip tree (Liriodendron chinense) has been widely cultivated in Korea as a street or garden tree for its large flowers, which have a superficial resemblance to tulips. Occurrence of anthracnose disease on the leaves of tulip trees growing on the campus of Gyeongsang National University, Jinju, Korea, has been observed. Based on mycological characteristics, pathogenicity, and internal transcribed spacer sequence, the causal fungus was identified as Colletotrichum gloeosporioides. This is the first report on anthracnose disease caused by C. gloeosporioides on tulip trees in Korea.
Colletotrichum ; Flowers ; Fungi ; Korea ; Liriodendron ; Trees ; Tulipa