Fifty-five compounds were isolated from the fresh stems of Cissus assamica, including 14 benzenoids, 11 triterpenes, nine steroids, five tocopherols, five chlorophylls, four flavonoids, two benzoquinones, two tannins, and three other compounds. Their structures were constructed by 1D and 2D nuclear magnetic resonance (NMR) and mass spectral data, and were also identified by a comparison of their spectral data with those reported in the literature. Among these isolates, 1,2-bis-(5-γ-tocopheryl) ethane (51) was reported for the first time from natural sources. Some purified compounds were examined for their anti-inflammatory and anticancer bioactivities. The results indicated that betulinic acid (16) exhibited strong inhibition of superoxide anion generation with IC50 value of 0.2 ± 0.1 μM, while betulinic acid (16) and pheophytin-a (47) inhibited elastase release with IC50 value of 2.7 ± 0.3 and 5.3 ± 1.0 μM, respectively. In addition, betulinic acid (16) and epi-glut-5(6)-en-ol (18) exhibited potential cytotoxicity to non-small-cell lung carcinoma (NCI-H226) and colon cancer (HCT-116) cell lines with IC50 values in the range of 1.6 to 9.1 μM.
Constitutive androstane receptor (CAR) activation has found to ameliorate diabetes in animal models. However, no CAR agonists are available clinically. Therefore, a safe and effective CAR activator would be an alternative option. In this study, sixty courmarin derivatives either synthesized or purified from Artemisia capillaris were screened for CAR activation activity. Chemical modifications were on position 5,6,7,8 with mono-, di-, tri-, or tetra-substitutions. Among all the compounds subjected for in vitro CAR activation screening, 6,7-diprenoxycoumarin was the most effective and was selected for further preclinical studies. Chemical modification on the 6 position and unsaturated chains were generally beneficial. Electron-withdrawn groups as well as long unsaturated chains were hazardous to the activity. Mechanism of action studies showed that CAR activation of 6,7-diprenoxycoumarin might be through the inhibition of EGFR signaling and upregulating PP2Ac methylation. To sum up, modification mimicking natural occurring coumarins shed light on CAR studies and the established screening system provides a rapid method for the discovery and development of CAR activators. In addition, one CAR activator, scoparone, did showed anti-diabetes effect in db/db mice without elevation of insulin levels.
The whole plant of Anisomeles ovata has been widely used in Taiwan for treating inflammation-related skin and liver diseases, however, the detailed pharmacology mechanisms have yet to be elucidated. In the present study, one of the major components, 5,6,4′-trihydroxy-7,3′-dimethoxyflavone (5-TDMF), was purified from a methanol extract of Anisomeles ovata. A pharmacological study of this compound suggests that 5-TDMF possesses potent free radical scavenging activity both in vitro and ex vivo. Furthermore, 5-TDMF reduces nitric oxide and pro-inflammatory cytokine production in LPC-treated RAW 264.7 cells through the attenuation of nitric oxide synthase and cyclooxygenase-2. Additional experiments suggest that of 5-TDMF interferes with nuclear factor-κB translocation and mitogen-activated protein kinase pathways. These results identify 5-TDMF as an anti-oxidant and anti-inflammatory compound, explain the pharmacologic function of Anisomeles ovata and suggest its great potential as a new anti-inflammatory remedy.
Two new drimane-type compounds, nigrofomins A (1) and B (2), possessing a rare dioxabicyclooctane moiety, were purified from the fruiting bodies of Nigrofomes melanoporus. Their structures were determined using 1D-, 2D-NMR and HR-ESI-MS spectroscopic analyses. In addition, 1 was established by X-ray crystallographic studies. Both nigrofomins A (1) and B (2) exhibited cytotoxicity on acute T-cell leukemia (Jurkat), human nasopharyngeal carcinoma (NPC-TW01), and lung cancer (NCI-H661) cells with IC50 values in the range of 99.44–246.32 µM. Furthermore, the effects of 1 and 2 on cell-cycle progression of Jurkat cells displayed a concentration-dependent accumulation in the G0/G1 phase.