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Pinguisane Sesquiterpenoids from the Chinese Liverwort Trocholejeunea sandvicensis and Their Anti-Inflammatory Activity

Nine new pinguisane sesquiterpenoid compounds, 1-9, including a highly oxygenated compound (1) and two amides (7 and 8), along with three known compounds (10, 11, and 12), were isolated from the Chinese liverwort Trocholejeunea sandvicensis Mizut (Lejeuneaceae). The structures of these compounds were determined by analysis of IR, UV, HRESIMS, NMR spectroscopic data, electronic circular dichroism calculations, and single-crystal X-ray diffraction analysis. Inhibitory effects against lipopolysaccharide (LPS)-induced NO production in RAW 264.7 murine macrophages indicated that the maximum inhibition rates of NO production of compounds 1, 9, and 10 were 83.15%, 83.54%, and 96.28% under the nontoxic tested concentration, respectively. Compound 9 also displayed moderate anti-inflammatory activity in vivo in a CuSO₄-induced transgenic zebrafish model.

Stereoselective Total Syntheses of Acutifolone A, Bisacutifolone A and B, Pinguisenol, and Isonaviculol

Stereoselective total syntheses of pinguisane type of sesquiterpenoids are described following a unified approach using a chiral building block derived from (R)-pulegone. The functionality embodied in the key intermediate enables their facile elaboration into more complex structures of biological relevance such as acutifolone A (9 steps, 22% overall yield) and bisacutifolone A and B (6 and 8%, respectively) following Furukawa's modified Simmons-Smith cyclopropanation, Luche reduction, Saegusa-Ito oxidation, pyridinium chlorochromate-mediated 1,3-oxidative transposition, and Diels-Alder dimerization as key steps.

Chemosystematics of Porella (Marchantiophyta, Porellaceae)

The taxonomy of the liverwort genus Porella based on plant morphology has been regarded as difficult. Recent DNA-based studies have brought new insights into the systematics of these liverworts and have uncovered some novel relationships that allowed the resolution of controversial treatments based on morphology. One of the outstanding features of these plants, in addition to their form, is their chemical composition, which is characterized by great diversity of secondary metabolites. In this paper the sesqui- and diterpenoids occurring in Porella species are described and their chemosystematic relevance is explored. On the basis of chemical data, the Porella species have been divided into six chemotypes: the drimane- (I), sacculatane- (II), pinguisane-sacculatane- (III), guaiane-germacrane- (IV), pinguisane- (V) and africane- (VI) types. Species belonging to type I are characterized by their hot taste, whereas the other chemotypes are comprised of non-pungent species. Consideration of recent DNA data shows striking correlations between molecular groups and their terpenoid chemistry. The chemical data suggest that the P. vernicosa complex (chemotype I) deserves recognition as a separate section of Porella and that terpenoids are important chemosystematic markers in the family Porellaceae.

Novel Terpenoids from the New Zealand Liverworts Jamesoniella colorata and Bazzania novae-zelandiae

Diethylether extracts of New Zealand liverworts Jamesoniella colorata and Bazzania novae-zelandiae were investigated to reveal novel terpenoids. The former extract afforded a new modified clerodane-type diterpenoid, and the latter gave a degraded clerodane (rearranged drimane) type sesquiterpenoid. The structures of those new compounds were established by 2D NMR spectra.