Study of novel ginsenoside metabolites targeting HSP70 as anti-prostate cancer drugs.

Ginsenoside 20 (R)-25-methoxy-dammarane-3 ß, twelve ß, 20 triol (AD-1) is a promising new drug for the treatment of prostate cancer, but its bioavailability is low. This study investigated the effects of the main metabolites PD and M6 of AD-1 on prostate cancer cell PC3. The in vitro experimental results showed that the IC50 values of PC3 cells treated with PD and M6 were 65.61 and 11.72, respectively. Both PD and M6 inhibited the migration of PC3 cells, and the cell cycle was blocked in the G1 phase. The apoptosis rates of cells following M6 treatment at concentrations of 7.5, 15, and 30 µM were 13.4 %, 17.5 %, and 41.4 %, respectively, which stimulated the expression of apoptosis protein and significantly increased intracellular ROS levels. In xenograft models, PD and M6 have been reported to significantly inhibit tumor growth. We used a genome-wide mRNA expression profile to study the effects of PD and M6 on gene expression in PC3 cancer cells. PD and M6 induced downregulation of HSP70 subtypes HSPA1A and HSPA1B. RT-PCR confirmed that the significant down-regulation of HSP70 subtype expressions was consistent with the results of Transcriptome analysis. Moreover, M6 significantly downregulated the expression of AR, which was further proved by Western blot analysis. In summary, our research findings provide a scientific basis for interpreting the significant activity of AD-1 in prostate cancer, and for the research and development of PD and M6 as novel HSP70 inhibitors.

Panaxadiol carbamate derivatives: Synthesis and biological evaluation as potential multifunctional anti-Alzheimer agents.

It is reported that panaxadiol has neuroprotective effects. Previous studies have found that compound with carbamate structure introduced at the 3-OH position of 20 (R) -panaxadiol showed the most effective neuroprotective activity with an EC50 of 13.17 µM. Therefore, we designed and synthesized a series of ginseng diol carbamate derivatives with ginseng diol as the lead compound, and tested their anti-AD activity. It was found that the protective effect of compound Q4 on adrenal pheochromocytoma was 80.6 ±â€¯10.85 % (15 µM), and the EC50 was 4.32 µM. According to the ELISA results, Q4 reduced the expression of Aß25-35 by decreasing ß-secretase production. Molecular docking studies revealed that the binding affinity of Q4 to ß-secretase was -49.67 kcal/mol, indicating a strong binding affinity of Q4 to ß-secretase. Western blotting showed that compound Q4 decreased IL-1ß levels, which may contribute to its anti-inflammatory effect. Furthermore, compound Q4 exhibits anti-AD activities by reducing abnormal phosphorylation of tau protein and activation of the mitogen activated protein kinase pathway. The learning and memory deficits in mice treated with Q4in vivo were significantly alleviated. Therefore, Q4 may be a promising multifunctional drug for the treatment of AD, providing a new way for anti-AD drugs.

Cucurbitacin B inhibits the translational expression of hypoxia-inducible factor-1α.

Cucurbitacin B is a triterpenoid compound isolated from Trichosanthes kirilowii Maximowicz, which has been used in oriental medicine for its antitumor activities. However, the mechanisms by which cucurbitacin B inhibits tumor growth are not fully understood. We here demonstrated the effect of cucurbitacin B on hypoxia-inducible factor-1 (HIF-1) activation. Cucurbitacin B showed the potent inhibitory activity against HIF-1 activation induced by hypoxia in various human cancer cell lines. This compound markedly decreased the hypoxia-induced accumulation of HIF-1α protein dose-dependently, whereas it did not affect the expressions of HIF-1ß. Further analysis revealed that cucurbitacin B inhibited HIF-1α protein synthesis, without affecting the expression level of HIF-1α mRNA or degradation of HIF-1α protein. Rather, we found that suppression of HIF-1α accumulation by cucurbitacin B correlated with strong dephosphorylation of mammalian target of rapamycin (mTOR) and its effectors ribosomal protein S6 kinase (p70S6K) and eukaryotic initiation factor 4E-binding protein-1 (4E-BP1) and extracellular signal-regulated kinase-1/2 (ERK1/2), a pathway known to regulate HIF-1α expression at the translational level. Cucurbitacin B also activated Akt, a mechanistic feature exhibited by established mTOR inhibitors in many tumor cells. Furthermore, cucurbitacin B prevented hypoxia-induced expression of HIF-1 target genes and suppresses the invasiveness of tumor cells. In vivo studies further confirmed the inhibitory effect of cucurbitacin B on the expression of HIF-1α proteins, leading to a decrease growth of HeLa cells in a xenograft tumor model. These results show that cucurbitacin B is an effective inhibitor of HIF-1 and provide new perspectives into the mechanism of its anticancer activity.

Acanthoic acid, a diterpene in Acanthopanax koreanum, protects acetaminophen-induced hepatic toxicity in mice.

The protective effect of a diterpenoid acanthoic acid (AA) isolated from Acanthopanax koreanum Nakai was investigated in acetaminophen (APAP)-induced hepatic toxicity. Drug-induced hepatotoxicity induced by an intraperitoneal (i.p.) injection of 300mg/kg (sub-lethal dose) of APAP. Pretreatment with AA (50 and 100mg/kg) orally 2h before the APAP administration attenuated the APAP-induced acute increase in serum aspartate aminotransferase (AST), and alanine aminotransferase (ALT) activites, replenished the depleted hepatic glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) activities, decreased malondialdehyde (MDA) level and considerably reduced the histopathological alterations in a manner similar to silymarin (Sily). Immunohistochemical analyses also demonstrated that AA could reduce the appearance of necrosis regions as well as caspase-3 and hypoxia inducible factor-1alpha (HIF-1alpha) expression in liver tissue. Our results indicated that AA protected liver tissue from the oxidative stress elicites by APAP-induced liver damage and suggestes that the hepatic protection mechanism of AA would relate to antioxidation and hypoxia factor on APAP-induced hepatotoxicity.