The discovery of potentially active diterpenoids to inhibit the pyroptosis from Callicarpa arborea

Two New Prostaglandin-Like Compounds from Callicarpa arborea Roxb and Their NLRP3 Inflammasome Activation Inhibitory Activity

Two new prostaglandin-like compounds callicarboric acids A-B (1-2), along with six known compounds (3-8) were isolated from the stems of Callicarpa arborea Roxb. Their structures were determined with the help of modern spectroscopic techniques such as NMR, UV, IR, HR-ESI-MS, ECD, and ORD with the assistance of quantum chemical calculations. Compound 1 exhibited remarkable anti-NLRP3 inflammasome activation potential, demonstrating an IC50 value of 0.74 μM. Additionally, by reducing GSDMD-NT production, inhibiting caspase-1 activation, and suppressing IL-1β secretion, it effectively mitigated NLRP3 inflammasome-induced pyroptosis in J774A.1 cells. These findings indicate that compound 1 possesses the capability to be a valuable candidate for further research and development as an NLRP3 inflammasome inhibitor.

Three New Clerodane Diterpenoids and Their NLRP3 Inflammasome Activation Inhibitory Activity from Callicarpa arborea Roxb

Three new compounds callicarpenoids A-C (1-3), were isolated from the stems of Callicarpa arborea Roxb together with fifteen known compounds (4-18). The structures of these compounds were elucidated using advanced spectroscopic techniques, including 1D and 2D NMR, UV, IR, HR-ESI-MS, ECD, ORD, and quantum chemical calculations. Compound 3, a rare rearranged diterpenoid with a fused 5/6-ring system demonstrated strong potential as an inhibitor of the NLRP3 inflammasome activation with an IC50 value of 3.153 μM. It effectively reduced GSDMD-NT production, inhibited caspase-1 activation, and suppressed IL-1β secretion, thereby mitigating NLRP3 inflammasome-induced pyroptosis in J774A.1 cells. These findings suggest that compound 3 warrants further research and development as a promising NLRP3 inflammasome inhibitor.

Challenges and opportunities for improving the druggability of natural product: Why need drug delivery system?

Bioactive natural products (BNPs) are the marrow of medicinal plants, which are the secondary metabolites of organisms and have been the most famous drug discovery database. Bioactive natural products are famous for their enormous number and great safety in medical applications. However, BNPs are troubled by their poor druggability compared with synthesis drugs and are challenged as medicine (only a few BNPs are applied in clinical settings). In order to find a reasonable solution to improving the druggability of BNPs, this review summarizes their bioactive nature based on the enormous pharmacological research and tries to explain the reasons for the poor druggability of BNPs. And then focused on the boosting research on BNPs loaded drug delivery systems, this review further concludes the advantages of drug delivery systems on the druggability improvement of BNPs from the perspective of their bioactive nature, discusses why BNPs need drug delivery systems, and predicts the next direction.

Nudifloids A-N, structurally diverse 3,4-seco-labdane diterpenoids from Callicarpa nudiflora with inflammatory inhibitory activity

Fourteen undescribed seco-type diterpenoids, named nudifloids A-N, together with ten known analogs, were isolated from the leaves of Callicarpa nudiflora. Nudifloids A-N had a characteristic 3,4-seco-labdane-type diterpenoid skeleton, whereas nudifloids A-C and K-N were 3,4-seco-norditerpenoids. Nudifloid A was the first example of a 3,4-seco-12,13,14,15,16-quartnor-labdane diterpenoid, with a seven-membered lactone ring formed through esterification between C-3 and C-11. Nudifloids B and C were a pair of highly modified 3,4-seco-labdane nor-diterpenoid epimers, of which C-2 and C-18 were cyclized together to form a cyclohexene fragment. The structures of these undescribed diterpenoids were established by spectroscopic analysis and reference data. The anti-inflammatory activity of diterpenoids in rich yield was evaluated by analyzing the inhibition of lipopolysaccharide plus nigericin-induced pyroptosis in J774A.1 cells. Nudifloids D and E exhibited prominent anti-NLRP3 inflammasome activity, with IC₅₀ values of 1.80 and 1.59 μM, respectively. Cell permeability assays revealed that nudifloid D inhibited pyroptosis, which could ameliorate inflammation by blocking the activation of the NLRP3 inflammasome.