Iridoid Constituents of Viburnum brachybotryum

Ten cyclopentanoid monoterpenes from the whole plant of Rehmannia piasezkii maxim

Ten new cyclopentanoid monoterpenes (1-10) were isolated from the whole plant of Rehmannia piasezkii. The structures of these compounds were elucidated based on spectroscopic data analysis. In in-vitro assays, compounds 3, 7, and 9 exhibited weak hepatoprotective activities against APAP-induced HepG2 cell damage. Compound 9 exhibited protective effect on hapassocin carbon tetrachloride model.

A Survey of Recently Discovered Naturally Occurring Organohalogen Compounds

The discovery of naturally occurring organohalogen compounds has increased astronomically in the 55 years since they were first discovered─from fewer than 50 in 1968 to a combined 7,958 described examples in three comprehensive reviews. The present survey, which covers the period 2021-2023, brings the number of known natural organohalogens to approximately 8,400. The organization is according to species origin, and coverage includes marine and terrestrial plants, fungi, bacteria, marine sponges, corals, cyanobacteria, tunicates, and other marine organisms.

Cyclopentanoid monoterpenes from the whole plant of Rehmannia piasezkii maxim

Twelve undescribed cyclopentanoid monoterpenes, Jiopiasins A-K and 6-epi-rehmaglutin A, and 19 known compounds were isolated from the whole plant of Rehmannia piasezkii Maxim. The structures of these compounds, especially their absolute stereochemistry, were established by extensive spectroscopic analysis, various quantum chemical calculations, and/or X-ray diffraction analyses. Furthermore, in vitro assays, some compounds exhibited moderate hepatoprotective activities against N-acetyl-p-aminophenol (APAP)-induced HepG2 cell damage.

Survey of natural products reported by Asian research groups in 2021

The new natural products reported in 2021 in peer-reviewed articles in journals with good reputations were reviewed and analyzed. The advances made by Asian research groups in the field of natural products chemistry in 2021 were summarized. Compounds with unique structural features and/or promising bioactivities originating from Asian natural sources were discussed based on their structural classification.