Callicarpnoids A-C, structurally intriguing ent-Clerodane diterpenoid dimers with cytotoxicity against MCF-7 and HCT-116 cell lines from Callicarpa arborea Roxb.

Callicarpnoids A-C (1-3), three new ent-clerodane diterpenoid dimers formed via a [4 + 2] hetero Diels-Alder cycloaddition, appeared as a third example of this type of dimers, were isolated from the stems of Callicarpa arborea Roxb.. Their structures were elucidated by comprehensive spectroscopic analysis, and the absolute configurations were confirmed by single-crystal X-ray diffraction and electronic circular dichroism (ECD) calculations, as well as DP4 + analysis. Cytotoxicity test in two cell lines indicated that compounds 2 and 3 had significant cytotoxic effect against breast cancer cell (MCF-7) and colorectal cancer cell (HCT-116) with IC50 ranging from 5.2 to 7.2 µM, comparable to those of the positive control. Furthermore, the western blot analysis revealed that the protein expression levels of Bax were increased following compounds 2 and 3 treatment, whereas the expression levels of caspase 8, caspase 3, caspase 9 and Bcl2 were decreased in a dose-dependent manner, indicating that compounds 2 and 3 may induce apoptosis via both intrinsic and extrinsic pathways in MCF-7 and HCT-116 cells.

Asiaticasics A-O, structurally intriguing coumarins from Toddalia asiatica with potential inflammatory inhibitory activity.

Ethyl acetate fraction of Toddalia asiatica was fractionated to yield fifteen previously undescribed prenylated coumarins, asiaticasics A-O (1-15) along with nine (16-24) known derivatives. The structures of these undescribed coumarins were established by spectroscopic analysis and reference data. Biological activity evaluation showed that compound 3 with the IC50 value of 2.830 µM and compound 12 with the IC50 value of 0.682 µM owned anti-inflammatory activity by detecting the rate of lactate dehydrogenase release in pyroptosis J774A.1 cells. The results showed that the expression of Caspase-1 and IL-1ß was decreased in a dose-dependent manner in the compound 12 treatment group, suggesting that compound 12 may reduce pyroptosis by inhibiting NLRP3 inflammasome. To further determine that compound 12 treatment can inhibit macrophage pyroptosis, morphological observation was performed and the results were consistent with the bioactivity evaluation.

Diverse diterpenoids from Callicarpa rubella Lindl. as natural inhibitors of macrophage foam cell formation.

Ten undescribed diterpenoids namely rubellawus E-N of structural types pimarane (1, 3-4), nor-abietane (2), nor-pimarane (5-6), isopimarane (7-9), and nor-isopimarane (10), along with eleven known compounds, were isolated and identified from the aerial parts of Callicarpa rubella Lindl. The structures of the isolated compounds were confirmed by comprehensive spectroscopic analyses and quantum chemical computations. Pharmacologically, almost all the compounds exhibited a potential inhibitory effect on oxidized low-density lipoprotein-induced macrophage foam cell formation, which suggests that these compounds may be promising candidates in the treatment of atherosclerosis.