Chemical constituents and their anti-neuroinflammatory activities from the bark of Taiwan incense cedar, Calocedrus formosana

One undescribed C-40 terpenoid, calomacroquinoic acid; four undescribed diterpenes, 5 alpha,6 alpha-epoxy-7 alpha-hydroxyferruginol, 15-ethoxysugiol, 7-methoxy-6,7-secoabieta-8,11,13-triene-6,12-diol, and ethyl 7,8-secoabieta-11,14-dioxo-7-ate; two compounds isolated from Nature for the first time, 6 beta,7 alpha-dihydroxyferruginol and 12-O-methyltaxochinon; and six known compounds were successfully identified from the bark of Taiwan incense cedar Calocedrus formosana. Structures of all isolates were elucidated by physical data (appearance, ultraviolet, infrared, specific rotation, and X-ray) and spectroscopic data (1D and 2D nuclear magnetic resonance, and high-resolution electron ionization mass spectrometry). The biosynthetic pathway of calomacroquinoic acid is also described in the current study. Nitric oxide production in lipopolysaccharide (LPS)-stimulated BV-2 microglia cells was inhibited by 6,7-dehydroferruginol, 7 alpha,11-dihydroxy-12-methoxy-8,11,13-abietriene, and trans-communic acid. Altogether, the bark of C. formosana possessed several potential natural therapeutics against inflammation-related neuronal diseases.