Two new prenylflavanones, propolin A (2) and propolin B (3), were isolated and characterized from Taiwanese propolis. Both compounds were found to have cytotoxic properties against three cancer cell lines. DNA content analyses and DNA fragmentation indicated that propolin A (2) efficiently induced apoptosis in cancer cell lines, but had no effect on the cell cycle program. Furthermore, both propolin A (2) and B (3) are potential antioxidant agents and show strong scavenging effects against most types of free radicals.

By using the active metabolite 5 as an initial template, further structural modifications led to the identification of the titled compound 24 (BPR-890) as a highly potent CB1 inverse agonist possessing an excellent CB2/1 selectivity and remarkable in vivo efficacy in diet-induced obese mice with a minimum effective dose as low as 0.03 mg/kg (po qd) at the end of the 30-day chronic study. Current SAR studies along with those of many existing rimonabant-mimicking molecules imply that around the pyrazole C3-position, a rigid and deep binding pocket should exist for CB1 receptor. In addition, relative to the conventional carboxamide carbonyl, serving as a key hydrogen-bond acceptor during ligand-CB1 receptor interaction, the corresponding polarizable thione carbonyl might play a more critical role in stabilizing the Asp366-Lys192 salt bridge in the proposed CB1-receptor homology model and inducing significant selectivity for CB1R over CB2R.

A novel linear dihydrodichromene derivative, metacalypogin, was identified from the Taiwanese liverwort Metacalypogeia alternifolia. Together with data from M. cordifolia, the chemical marker of the genus Metacalypogeia is obvious chroman derivatives, which is far different from that of Calypogeia, the other genus in the same family. In addition, two isomeric diterpenoids of cembrane‐type were identified from the Chinese liverwort Chandonanthus hirtellus. The relative stereostructures of the latter two isomers were proved by X‐ray crystallography. Both compounds were unstable in chloroform solution and further oxidized to the corresponding peroxy hemiacetal derivatives.

Three new (8, 12, 13) and two revised (7, 9) eudesmane alcohols have been identified from the Taiwanese liverwort Lepidoziafauriana, together with a known macrocyclic bisbibenzyl, isoplagiochin D, and other known sesquiterpenoids. Their structures were determined by NMR and X-ray analyses. Three chemo-types of Lepidoziafauriana may be classified according to the skeleton of the major sesquiterpenoids identified in the species.