Two novel biscembranoids, sarelengans A and B (1 and 2), five new cembranoids, sarelengans C-G (3-7), along with two known cembranoids (8 and 9) were isolated from the South China Sea soft coral Sarcophyton elegans. Their structures were determined by spectroscopic and chemical methods, and those of 1, 4, 5, and 6 were confirmed by single crystal X-ray diffraction. Compounds 1 and 2 represent the first example of biscembranoids featuring a trans-fused A/B-ring conjunction between the two cembranoid units. Their unique structures may shed light on an unusual biosynthetic pathway involving a cembranoid-∆ 8 rather than the normal cembranoid-∆ 1 unit in the endo-Diels-Alder cycloaddition. Compounds 2 and 3 exhibited potential inhibitory effects on nitric oxide production in RAW 264.7 macrophages, with IC 50 values being at 18.2 and 32.5 µM, respectively.

One alkaloid with an unprecedented skeleton and one alkaloid with anti-obesity effect were isolated from the seeds of Clausena lansium.

Ten new cassane‐type diterpenoids were isolated from the seeds of Caesalpinia bonduc (L.) Roxb., including 6α‐hydroxycaesalpinin P (1), 14‐epi‐caesalpinin E1 (2), 6‐deacetylcaesalmin Z (3), 14‐epi‐caesalmin Z (4), caesalpinolides I (5), K (6), L (7), M (9) and N (10), and 14‐epi‐neocaesalpin L (8). Their planar structures and absolute configurations were fully determined by comprehensive spectroscopic methods, including 2D NMR and electronic circular dichroism spectra. Compounds 1–4 are tetracyclic cassane diterpenoids possessing a furan ring, and compounds 5–10 are tetracyclic cassane diterpenoids possessing a fused butenolide moiety. The anti‐inflammatory and cytotoxic activities of the isolates were evaluated, while none of them showed obvious effects. The current study identified ten new cassane‐type diterpenoids from the seeds of C. bonduc (L.) Roxb., which enriched the chemical diversity of the titled herbal medicine.

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Protein-tyrosine phosphatase 1B (PTP1B) has been considered as a promising target for treating insulin resistance. In searching for naturally occurring PTB1B antagonists, two new pimarane diterpenoids, named 2α-hydroxy-7-oxo-pimara-8(9),15-diene (1) and 19-hydroxy-2α-acetoxy-7-oxo-pimara-8(9),15-diene (2), were isolated from the seeds of Caesalpinia minax. Their structures were determined by extensive analysis of NMR and HR-ESIMS data, and their absolute configurations were determined by electronic circular dichroism (ECD) spectra. Compound 1 was disclosed as a competitive inhibitor of PTP1B with an IC50 (the half-maximal inhibitory concentration) value of 19.44 ± 2.39 µM and a Ki (inhibition constant) value of 13.69 ± 2.72 μM. Moreover, compound 1 dose-dependently promoted insulin-stimulated glucose uptake in C2C12 myotubes through activating insulin signaling pathway. Compound 1 might be further developed as an insulin sensitizer.

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