New jatropholane-type diterpenes from Jatropha curcas cv. Multiflorum CY Yang

Naturally Occurring Norsteroids and Their Design and Pharmaceutical Application

The main focus of this review is to introduce readers to the fascinating class of lipid molecules known as norsteroids, exploring their distribution across various biotopes and their biological activities. The review provides an in-depth analysis of various modified steroids, including A, B, C, and D-norsteroids, each characterized by distinct structural alterations. These modifications, which range from the removal of specific methyl groups to changes in the steroid core, result in unique molecular architectures that significantly impact their biological activity and therapeutic potential. The discussion on A, B, C, and D-norsteroids sheds light on their unique configurations and how these structural modifications influence their pharmacological properties. The review also presents examples from natural sources that produce a diverse array of steroids with distinct structures, including the aforementioned A, B, C, and D-nor variants. These compounds are sourced from marine organisms like sponges, soft corals, and starfish, as well as terrestrial entities such as plants, fungi, and bacteria. The exploration of these steroids encompasses their biosynthesis, ecological significance, and potential medical applications, highlighting a crucial area of interest in pharmacology and natural product chemistry. The review emphasizes the importance of researching these steroids for drug development, particularly in addressing diseases where conventional medications are inadequate or for conditions lacking sufficient therapeutic options. Examples of norsteroid synthesis are provided to illustrate the practical applications of this research.

Structurally Diverse Diterpenoids from Sandwithia guyanensis

Bioassay-guided fractionation of an EtOAc extract of the trunk bark of Sandwithia guyanensis, using a chikungunya virus (CHIKV)-cell-based assay, afforded 17 new diterpenoids 1-17 and the known jatrointelones A and C (18 and 19). The new compounds included two tetranorditerpenoids 1 and 2, a trinorditerpenoid 3, euphoractines P-W (4-11), and euphactine G (13) possessing the rare 5/6/7/3 (4-7), 5/6/6/4 (8-11), and 5/6/8 (13) fused ring skeletons, sikkimenoid E (12), and jatrointelones J-M (14-17) possessing jatropholane and lathyrane carbon skeletons, respectively. Jatrointelones J (14) and M (17) represent the first naturally occurring examples of C-15 nonoxidized lathyrane-type diterpenoids. The structures of the new compounds were elucidated by NMR spectroscopic data analysis. The relative configuration of compound 16 and the absolute configurations of compounds 3-6 and 14 were determined by single-crystal X-ray diffraction analysis. In addition, jatrointelone K (15) was chemically transformed to euphoractine T (8) supporting the biosynthetic relationships between the two types of diterpenoids. Only compound 15 showed a moderate anti-CHIKV activity with an EC₅₀ value of 14 μM. Finally, using a molecular networking-based dereplication strategy, several close analogues of 12- O-tetradecanoylphorbol-13-acetate (TPA), one of the most potent inhibitors of CHIKV replication, were dereplicated.

Abietane Diterpernoids from the Roots of Euphorbia ebracteolata

A new ent-abietane diterpernoid, named ebracteolata D (1), along with 11 known analogues, was isolated from the roots of Euphorbia ebracteolata Hayata. The structure of 1 was elucidated on the basis of spectroscopic analysis and molecular modeling. Cytotoxicity of compounds 1-12 was evaluated as well as the effect on the NF-κB pathway. Among them, compound 12, jolkinolide B, displayed broad inhibitory effects against proliferation of tumor cell lines. Mechanistic studies indicated that the compound 12 can inhibit TNF-α induced NF-κB activation, thereby inducing tumor cell apoptosis.

Dimericursones A and B: two unprecedented hexacyclic dimeric diterpenoids from the root barks of Jatropha curcas

Two unprecedented hexacyclic dimeric diterpenoids from Jatropha curcas and 2 showed significant NO inhibitory activity with IC₅₀ values of 5.65 μM.

Natural thioredoxin reductase inhibitors from Jatropha integerrima

Nine new diterpenoids were isolated from Jatropha integerrima. The active diterpenoids represent the rare examples of non-aromatic TrxR inhibitors from nature.

Biologically active diterpenes containing a gem-dimethylcyclopropane subunit: an intriguing source of PKC modulators

This review describes diterpenes containing thegem-dimethylcyclopropane subunit isolated from natural sources with a special emphasis on their intriguing biological activities as a source of PKC modulators.