Three new cassane diterpenes from the seeds of Caesalpinia minax Hance

Semisynthesis and Evaluation of Anti-Inflammatory Activity of the Cassane-Type Diterpenoid Taepeenin F and of Some Synthetic Intermediates

A new strategy for the semisynthesis of the aromatic cassane-type diterpene taepeenin F (6) is reported. The introduction of the methyl group at C-14, characteristic of the target compound, was achieved via dienone 13, easily prepared from abietic acid (10), the major compound in renewable rosin. Biological assays of selected compounds are reported. The antiproliferative activity against HT29, B16-F10, and HepG2 tumor cell lines has been investigated. Salicylaldehyde 21 was the most active compound (IC₅₀ = 7.72 μM). Products 16 and 21 displayed apoptotic effects in B16-F10 cells, with total apoptosis rates of 46 and 38.4%, respectively. This apoptotic process involves a significant arrest of the B16-F10 cell cycle, blocking the G0/G1 phase. Dienone 16 did not cause any loss of the mitochondrial membrane potential (MMP), while salicylaldehyde 21 caused a partial loss of the MMP. The anti-inflammatory activity of the selected compounds was investigated with the LPS-stimulated RAW 264.7 macrophages. All compounds showed potent NO inhibition, with percentages between 80 and 99% at subcytotoxic concentrations. Dienone 16 inhibited LPS-induced differentiation of RAW 264.7 cells, by increasing the proportion of cells in the S phase. In addition, salicylaldehyde 21 had effects on the cell cycle, recovering the cells from the G0/G1 full arrest produced in response to LPS action.

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.

Two new cassane-type diterpenoids from the seed kernels of Caesalpinia bonduc (Linn.) Roxb. and their anti-inflammatory activity

In this study, phytochemical investigation on the chloroform soluble fraction of seed kernels of Caesalpinia bonduc led to the isolation of two new cassane-type diterpenoids, norcaesalpinin Q (1) and caesalpinin MR (2), together with seven known compounds (3-9). The structures of the new compounds were elucidated on the basis of extensive NMR spectroscopic and mass spectrometric analyses, and their absolute configurations were determined by electronic circular dichroism (ECD) calculations. All compounds were evaluated for inhibitory effects against NO production of RAW264.7 cells induced by LPS, and compounds 5, 7 and 8 could inhibited the production of NO at the concentration of 50 µM.

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

The seeds of Caesalpinia minax Hance have shown anti-tumor potential, while the chemical principle is still unknown. In a search for anti-tumor compounds, six new cassane-type diterpenoids, 12-demethylcaesalpin G (1), caesalpinolide H (2), 12-demethylcaesalpin H (3), caesalpinolide J (4), 12-O-ethyl neocaesalpin B (5), and 3-deacetyldecapetpene B (6), were isolated from the seeds of C. minax Hance, along with fifteen known analogues. The structures of the new compounds were established by means of spectroscopic techniques (NMR, HRESIMS and IR). The absolute configurations of the new compounds were determined by their ECD spectra. All of the new compounds were tested for their anti-proliferative activity against human lung cancer A549 cells, breast cancer MCF-7 cells, and ovarian cancer HEY cells. The results indicated that only compound 6 displayed moderate cytotoxicity against three cancer cell lines. Thus, the opening of furan ring in cassane-type diterpenoids might enhance the cytotoxic activity.

The Activity Screening of Hmong Herbs Caesalpiniaminax and an Antitumor Effect Study

Aim

To screen active sites from roots, stems, and leaves of Caesalpinia minax and study its antitumor effect.

Methods

Human liver cancer HuH-7 cells were used to screen the active sites of C. minax by MTT assay, and the polar extracts were analyzed by high-performance liquid chromatography (HPLC). The medicated serum prepared from rats was used to investigate the effect on the proliferation of Hepa 1-6 mouse hepatoma cells. The H22 hepatoma-bearing mice model was established and treated with the petroleum ether extract of stems and leaves (HY②) by intraperitoneal injection (20, 60 mg·kg^-1) and intragastric (100, 300 mg·kg^-1) for 12 days.

Results

The petroleum ether extracts were the effective active site. The IC₅₀ value of the petroleum ether extract of stems and leaves (HY②) was 58.9 μg·ml^-1, and that of the roots (HG②) was 46.79 μg·ml^-1. The grey relational analysis cleared that the 11 common peaks of the active extracts had a close correlation with the antitumor activity. The medicated serum prepared by ip. administration had a significant inhibitory effect on the Hepa1-6 cells, but it had no inhibitory effect by intragastric administration. High-dose administration significantly reduced tumor size in H22 hepatoma-bearing mice, and the tumor inhibition rates were 64.47% and 53.41%. Necrosis of tumor cells, infiltration of inflammatory cells, and fibrous tissue proliferation were promoted, and the expression of the proliferating cell nuclear antigen (PCNA) and vascular endothelial growth factor (VEGF) was reduced compared with the control group.

Conclusion

The petroleum ether extract of C. minax had a significant antitumor activity. An immunohistochemical study showed that, through inhibiting the expression of the VEGF and growth of the tumor blood vessel, the proliferation of tumor cell and expression of PCNA can be inhibited.