Strophiofimbrins A and B: Two Rearranged Norditerpenoids with Novel Tricyclic Carbon Skeletons from Strophioblachia fimbricalyx

Naturally Occurring Cleistanthane Diterpenoids and Their Biological Activities

Cleistanthane diterpenoids, an important class of active natural products, are characterized by a 6/6/6 tricycle system and contain a variety of functional groups. Studies have shown that cleistanthane diterpenoids are widespread in various higher plants and endophytic fungi and exhibit a wide range of biological activities. This review provides extensive coverage of naturally occurring cleistanthane diterpenoids discovered from 1973 to 2024 and sheds light on the sources, structures, biological effects, and primary molecular mechanisms of them and provides a useful reference for the further study and development of these compounds.

Podocarpane and cleistanthane diterpenoids from Strophioblachia glandulosa: structural elucidation, anti-hypertrophy activity and network pharmacology

In the present investigation, fourteen unprecedented podocarpane diterpenoids strophiolosas A-J, L-N and P (1-10, 12-14, 16), two new cleistanthane derivatives strophiolosas Q-R (17-18), two new dibenzopyroan-ones and one new tetralone strophiolosas S-U (19-21), were isolated from the whole plant of Strophioblachia glandulosa. The structures were elucidated via various spectroscopic analysis, quantum chemistry calculations, and X-ray diffraction. Bioactivity test indicated that compounds 5 and 17 possessed promising anti-cardiac hypertrophy effect in vitro (IC50 values of 16.50 and 9.67 μM). Additionally, through network pharmacology prediction, PARP1 may be a potential target of compound 17, mediating its anti-hypertrophic effects through multiple pathways.

Survey of natural products reported by Asian research groups in 2023

The new natural products reported in 2023 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 2023 were summarized. Compounds with unique structural features and/or promising bioactivities originating from Asian natural sources were discussed based on their structural classification.

Structurally diverse diterpenoids and phenanthrene derivatives from the roots of Baliospermumsolanifolium

Ten undescribed diterpenoids (1-10) and three undescribed phenanthrene derivatives (11-13), together with seven known compounds, were isolated from the roots of Baliospermum solanifolium. Their structures were determined by a combination of spectroscopic data analysis, electronic circular dichroism calculations and single-crystal X-ray diffraction studies. Compounds 1-7 (baliosperoids A-G) represent the examples of 20-nor-ent-podocarpane class first discovered in nature. In particular, compound 7 possesses a unique 2,3-seco ring system incorporating γ-butanolide moiety. All isolates were assessed for their cytotoxic activities against HT-29, HCT-116, HCT-15, MCF-7, and A549 cell lines as well as their inhibitory effects on lipopolysaccharide-induced NO production in RAW264.7 cells. Compound 1, a 20-nor-ent-podocarpane-type diterpenoid possessing a Δ1,2 double bond, not only exhibited considerable proliferation inhibition against five human cancer cell lines, with IC50 values ranging from 4.13 to 23.45 μM, but also displayed the most potent inhibitory activity on NO production with IC50 value at the nanomolar level (0.63 ± 0.21 μM).

Structurally diverse deformed phenanthrenes from Strophioblachia fimbricalyx with cytotoxic activities by inducing cell apoptosis

A group of phenanthrene derivatives with different deformed types, including four previously undescribed derivatives (1-4), an undescribed natural product (5) and five known compounds (6-10), were isolated from the leaves and stems of Strophioblachia fimbricalyx by molecular networking based on UPLC-MS/MS method. Their structures were established by 1D/2D NMR spectroscopy, HRESIMS, quantum chemistry calculation, and single crystal X-ray diffraction. In biogenic pathways, series of deformed phenanthrenes were all suspected to be derived from 6/6/6 tricyclic phenanthrenes with a gem-dimethyl unit in one ring as characteristic components of Strophioblachia. Fimbricalyxone (1) and trigoxyphin M (6) with a 6/6/5 tricyclic carbon skeleton were reported for the first time from the genus and fimbricalyxanhydride C (2) is the first example of anhydride type bearing a rare 8,9-oxycycle. All the isolates were evaluated for their cytotoxic activity against three tumor cell lines, and compounds 8 and 10 exhibited significant activity with IC50 values of 4.65-9.02 μM, and the structure-activity relationship of the deformed phenanthrenes was discussed. In addition, the X-ray structure of 8 and 10 and the antineoplastic activity of 10 are reported herein for the first time. Trigohowilol G (10) inhibiting the proliferation of A549 cells might be related to cell cycle distribution and the induction of S phase arrest, and it induced cell apoptosis through Bad/Bax/Cleaved PARP1 pathway.