Anti-ulcerogenic activity of dentatin from clausena excavata Burm.f. against ethanol-induced gastric ulcer in rats: Possible role of mucus and anti-oxidant effect.

BACKGROUND: Clausena excavata Burm.f. (Rutaceae) has been used for the treatment of stomach disorders including peptic ulcer. PURPOSE: In this study, we aimed to investigate dentatin isolated from C. excavata Burm.f., for anti-ulcer activity against ethanol ulcer model in rats. METHODS: Gastric acid output, ulcer index, serum profile, histological evaluation using Hematoxylin and eosin (HE), periodic acid Schiff base stainings and immunohistochemical localization for heat shock proteins 70 (HSP70) were all investigated. Possible involvement of reduced glutathione (GSH), lipid peroxidation, prostaglandin E2 (PGE2), superoxide dismutase (SOD) enzymes, radical scavenging, and anti-Helicobacter pylori activity were investigated. RESULTS: Dentatin showed anti-secretory activity against the pylorus ligature model and protected the gastric mucosa from ethanol ulceration, as revealed by the improved macroscopic and histological appearance. Dentatin significantly increased the gastric homogenate content of PGE2 GSH and SOD. Dentatin inhibited the lipid peroxidation as revealed by the reduced gastric content of malondialdehyde (MDA). Moreover, dentatin up-regulated HSP70 expression. However, dentatin showed insignificant anti-H. pylori activity. CONCLUSION: Dentatin possesses gastro-protective activity, which could be attributed to the anti-secretory, mucus production, anti-oxidant, and HSP70 activities.

Dentatin from Clausena excavata Induces Apoptosis in HepG2 Cells via Mitochondrial Mediated Signaling.

Hepatocellular carcinoma (HCC) is a primary liver cancer with high global incidence and mortality rates. Current candidate drugs to treat HCC remain lacking and those in use possess undesirable side effects. In this investigation, the antiproliferative effects of dentatin (DTN), a natural coumarin, were evaluated on HepG2 cells and DTN's probable preliminary molecular mechanisms in apoptosis induction were further investigated. DTN significantly (p<0.05) suppressed proliferation of HepG2 cells with an IC50 value of 12.0 µg/mL, without affecting human normal liver cells, WRL-68 (IC50>50 µg/mL) causing G0/G1 cell cycle arrest via apoptosis induction. Caspase colorimetric assays showed markedly increased levels of caspase-3 and caspase-9 activities throughout the treatment period. Western blotting of treated HepG2 cells revealed inhibition of NF-κB that triggers the mitochondrial-mediated apoptotic signaling pathway by up-regulating cytoplasmic cytochrome c and Bax, and down-regulating Bcl-2 and Bcl-xL. The current findings suggest DTN has the potential to be developed further as an anticancer compound targeting human HCC.

Inclusion Complex of Zerumbone with Hydroxypropyl- ß -Cyclodextrin Induces Apoptosis in Liver Hepatocellular HepG2 Cells via Caspase 8/BID Cleavage Switch and Modulating Bcl2/Bax Ratio.

Zerumbone (ZER) isolated from Zingiber zerumbet was previously encapsulated with hydroxypropyl- ß -cyclodextrin (HP ß CD) to enhance ZER's solubility in water, thus making it highly tolerable in the human body. The anticancer effects of this new ZER-HP ß CD inclusion complex via apoptosis cell death were assessed in this study for the first time in liver hepatocellular cells, HepG2. Apoptosis was ascertained by morphological study, nuclear stain, and sub-G1 cell population accumulation with G2/M arrest. Further investigations showed the release of cytochrome c and loss of mitochondrial membrane potential, proving mitochondrial dysfunction upon the ZER-HP ß CD treatment as well as modulating proapoptotic and anti-apototic Bcl-2 family members. A significant increase in caspase 3/7, caspase 9, and caspase 8 was detected with the depletion of BID cleaved by caspase 8. Collectively, these results prove that a highly soluble inclusion complex of ZER-HP ß CD could be a promising anticancer agent for the treatment of hepatocellular carcinoma in humans.

Dentatin isolated from Clausena excavata induces apoptosis in MCF-7 cells through the intrinsic pathway with involvement of NF-κB signalling and G0/G1 cell cycle arrest: a bioassay-guided approach.

ETHNOPHARMACOLOGICAL RELEVANCE: Clausena excavata Burm. f. has been used in folk medicines in eastern Thailand for the treatment of cancer. MATERIALS AND METHODS: To investigate the apoptosis mechanism, we isolated dentatin (DTN) from this plant using a bioassay-guided approach. DTN-induced cytotoxicity was observed with the MTT assay. Acridine orange/propidium iodide staining was used to detect cells in early apoptosis and high content screening (HCS) to observe nuclear condensation, cell permeability, mitochondrial membrane potential (MMP) and cytochrome c release. Apoptosis was confirmed with a clonogenic assay, DNA laddering and caspase 3/7 and 9 assays. Reactive oxygen species (ROS) formation, Bcl-2 and Bax expression, and cell cycle arrest were also investigated. The involvement of nuclear factor-kappa B (NF-κB) was analysed with the HCS assay. RESULTS: A significant increase in chromatin condensation in the cell nucleus was observed by fluorescence analysis. Apoptosis was confirmed by the reduced number of colonies in the clonogenic assay and the increased number of cellular DNA breaks in treated cells observed as a DNA ladder. Treatment of MCF-7 cells with DTN encouraged apoptosis with cell death-transducing signals that reduced MMP by down-regulation of Bcl-2 and up-regulation of Bax, triggering cytochrome c release from the mitochondria to the cytosol. The released cytochrome c triggered the activation of caspase 9 followed by the executioner caspase 3/7. DTN treatment significantly arrested MCF-7 cells at the G0/G1 phase (p<0.05) and ROS was significantly elevated. Moreover, DTN significantly blocked the induced translocation of NF-κB from cytoplasm to nucleus. CONCLUSION: Together, the results demonstrated that the DTN isolated from Clausena excavata inhibited the proliferation of MCF-7 cells, leading to cell cycle arrest and programmed cell death, which was confirmed to occur through the mitochondrial pathway with involvement of the NF-κB signalling pathway.

Dentatin Induces Apoptosis in Prostate Cancer Cells via Bcl-2, Bcl-xL, Survivin Downregulation, Caspase-9, -3/7 Activation, and NF-κB Inhibition.

This study was set to investigate antiproliferative potential of dentatin (a natural coumarin isolated from Clausena excavata Burm. F) against prostate cancer and to delineate the underlying mechanism of action. Treatment with dentatin dose-dependently inhibited cell growth of PC-3 and LNCaP prostate cancer cell lines, whereas it showed less cytotoxic effects on normal prostate epithelial cell line (RWPE-1). The inhibitory effect of dentatin on prostate cancer cell growth was due to induction of apoptosis as evidenced by Annexin V staining and cell shrinkage. We found that dentatin-mediated accumulation of reactive oxygen species (ROS) and downregulated expression levels of antiapoptotic molecules (Bcl-2, Bcl-xL, and Survivin), leading to disruption of mitochondrial membrane potential (MMP), cell membrane permeability, and release of cytochrome c from the mitochondria into the cytosol. These effects were associated with induction of caspase-9, -3/7 activities, and subsequent DNA fragmentation. In addition, we found that dentatin inhibited TNF-α-induced nuclear translocation of p65, suggesting dentatin as a potential NF-κB inhibitor. Thus, we suggest that dentatin may have therapeutic value in prostate cancer treatment worthy of further development.