Anti-proliferative cassane-type diterpenoids from the seeds of Caesalpinia minax

Chemical constituents with antioxidant activity from the branches and leaves of Hultholia mimosoides

Four undescribed homoisoflavanoids (1-4), one homoflavonoid (5), ten dibenzoxocin derivatives (6a-10a and 6b-10b), one dibenzoxocin-derived phenolic compound (11), one diterpenoid (13), three aliphatic dicarboxylic acid derivatives (14-16), together with the known diterpenoid 12-O-ethylneocaesalpin B (12) were obtained from the branches and leaves of Hultholia mimosoides. Their structures were elucidated by extensive spectroscopic techniques. Notably, each of the dibenzoxocins 6-10 existed as a pair of interconvertible atropisomers and the conformation for these compounds was clarified by NMR and ECD analyses. Protosappanin F (11) was a previously undescribed dibenzoxocin-derived compound in which one of the benzene rings was hydrogenated to a polyoxygenated cyclohexane ring and an ether linkage was established between C-6 and C-12a. The isolated polyphenols were tested for induction of quinone reductase and compounds 3 and 8 showed potent QR-inducing activity in Hepa-1c1c7 cells.

A new cassane diterpenoid from the seed of Caesalpinia sappan

In this study, a previously undescribed cassane diterpenoid, named caesalpinin JF (1), along with two known cassane diterpenoids caesanine C (2) and tomocinol B (3), was isolated from 95% EtOH extract of the seeds of Caesalpinia sappan Linn. Additionally, three known compounds including pulcherrin R (4), syringaresinol-4'-O-β-D-glucopyranoside (5) and kaempferol (6) were also identified. The structures of the isolated compounds were elucidated by comprehensive 1D and 2D NMR spectroscopic analyses. Additionally, electronic circular dichroism (ECD) calculation was used to identify the absolute structure of compound 1. Among the isolated compounds, compound 1 displayed a potent anti-neuroinflammation with an IC50 value of 9.87 ± 1.71 μM.

Discovery of plant-derived anti-tumor natural products: Potential leads for anti-tumor drug discovery

Natural products represent a paramount source of novel drugs. Numerous plant-derived natural products have demonstrated potent anti-tumor properties, thereby garnering considerable interest in their potential as anti-tumor drugs. This review compiles an overview of 242 recently discovered natural products, spanning the period from 2018 to the present. These natural products, which include 69 terpenoids, 42 alkaloids, 39 flavonoids, 21 steroids, 14 phenylpropanoids, 5 quinolines and 52 other compounds, are characterized by their respective chemical structures, anti-tumor activities, and mechanisms of action. By providing an essential reference and fresh insights, this review aims to support and inspire researchers engaged in the fields of natural products and anti-tumor drug discovery.

Caesalpinaxin, a cassane-type diterpenoid with a 21-carbon core skeleton from the seeds of Caesalpinia minax possessing pro-angiogenetic property

A novel cassane-type diterpenoid, caesalpinaxin (1), was isolated from the seeds of Caesalpinia minax Hance. The structure of caesalpinaxin was established by means of spectroscopic techniques (NMR, HR-ESIMS, UV and IR). The absolute configuration of caesalpinaxin was determined by quantum chemical calculations of its theoretical electronic circular dichroism (ECD) spectrum. Caesalpinaxin is the first cassane-type diterpenoid with 21 carbons core skeleton, containing an unusual δ-lactone ring. A plausible biosynthetic pathway was proposed for compound 1. Furthermore, caesalpinaxin was tested for the pro-angiogenetic activity on human umbilical vein endothelial cells(HUVECs). The results indicated that this compound significantly stimulated migration and tuber formation through enhancing the level of vascular endothelial growth factor (VEGF). Thus, caesalpinaxin might be applied in accelerating wound healing.

Mechanism of interaction between autophagy and apoptosis in cancer

The mechanisms of two programmed cell death pathways, autophagy, and apoptosis, are extensively focused areas of research in the context of cancer. Both the catabolic pathways play a significant role in maintaining cellular as well as organismal homeostasis. Autophagy facilitates this by degradation and elimination of misfolded proteins and damaged organelles, while apoptosis induces canonical cell death in response to various stimuli. Ideally, both autophagy and apoptosis have a role in tumor suppression, as autophagy helps in eliminating the tumor cells, and apoptosis prevents their survival. However, as cancer proceeds, autophagy exhibits a dual role by enhancing cancer cell survival in response to stress conditions like hypoxia, thereby promoting chemoresistance to the tumor cells. Thus, any inadequacy in either of their levels can lead to tumor progression. A complex array of biomarkers is involved in maintaining coordination between the two by acting as either positive or negative regulators of one or both of these pathways of cell death. The resulting crosstalk between the two and its role in influencing the survival or death of malignant cells makes it quintessential, among other challenges facing chemotherapeutic treatment of cancer. In view of this, the present review aims to highlight some of the factors involved in maintaining their diaphony and stresses the importance of inhibition of cytoprotective autophagy and deletion of the intermediate pathways involved to facilitate tumor cell death. This will pave the way for future prospects in designing drug combinations facilitating the synergistic effect of autophagy and apoptosis in achieving cancer cell death.

Cassane-Type Diterpenoids from the Seeds of Caesalpinia bonduc (L.) Roxb

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.