Protective effect of Corchorus capsularis L. leaves on ethanol-induced acute gastric mucosal lesion in rats.

In Taiwan, Corchorus capsularis L. has long been cultivated and the leaves are consumed as edible vegetable. This study is to investigate the protection effect of extract of C. capsularis leaves (ECC) on ethanol-induced acute gastric mucosal lesion (AGML) in rats. The results of phytochemical determination in ECC for total polyphenol, flavonoid and polysaccharide were 59.88 ± 0.61 mg/g, 86.39 ± 18.0 mg/g and 320.89 ± 6.99 mg/g, respectively. ECC showed significant activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging with IC50 of 0.25 mg/ml. In vivo studies, Sprague-Dawley (SD) rats were randomly divided into five groups: sham, vehicle (control) and low-, medium-, and high-dose ECC (LECC, MECC, HECC; 200, 400, and 1,000 mg/kg/day, respectively). ECC was able to decrease significantly the ulcer index (UI) caused by 80% ethanol in a dose dependent manner. There was no significant effect on growth trend and food intake rate after the administration of ECC in the experimental period. The serum lipid parameters in ECC groups revealed significant increase in glutathione peroxidase (GPx), superoxide dilmutase (SOD) and catalase (CAT), and a decrease in malondialdehyde (MDA). Significant amelioration on pathological lesion score was found in ECC groups compared with the control group (P<0.05). The overall results indicate that ECC has protective effects on ethanol-induced AGML in rats, which could be associated with its antioxidant activity.

Benzyl isothiocyanate (BITC) triggers mitochondria-mediated apoptotic machinery in human cisplatin-resistant oral cancer CAR cells.

Benzyl isothiocyanate (BITC), a component of dietary food, possesses a powerful anticancer activity. Previous studies have shown that BITC produces a large number of intracellular reactive oxygen species (ROS) and increases intracellular Ca2+ release from endoplasmic reticulum (ER), leading to the activation of the apoptotic mechanism in tumor cells. However, there is not much known regarding the inhibitory effect of BITC on cisplatin-resistant oral cancer cells. The purpose of this study was to examine the anticancer effect and molecular mechanism of BITC on human cisplatin-resistant oral cancer CAR cells. Our results demonstrated that BITC significantly reduced cell viability of CAR cells in a concentration- and time-dependent manner. BITC was found to cause apoptotic cell shrinkage and DNA fragmentation by morphologic observation and TUNEL/DAPI staining. Pretreatment of cells with a specific inhibitor of pan-caspase significantly reduced cell death caused by BITC. Colorimetric assay analyses also showed that the activities of caspase-3 and caspase-9 were elevated in BITC-treated CAR cells. An increase in ROS production and loss of mitochondria membrane potential (ΔΨm) occurred due to BITC exposure and was observed via flow cytometric analysis. Western blotting analyses demonstrated that the protein levels of Bax, Bad, cytochrome c, and cleaved caspase-3 were up-regulated, while those of Bcl-2, Bcl-xL and pro-caspase-9 were down-regulated in CAR cells after BITC challenge. In sum, the mitochondria-dependent pathway might contribute to BITC-induced apoptosis in human cisplatin-resistant oral cancer CAR cells.

Inhibitory effect of burdock leaves on elastase and tyrosinase activity.

Burdock (Arctium lappa L.) leaves generate a considerable amount of waste following burdock root harvest in Taiwan. To increase the use of burdock leaves, the present study investigated the optimal methods for producing burdock leaf extract (BLE) with high antioxidant polyphenolic content, including drying methods and solvent extraction concentration. In addition, the elastase and tyrosinase inhibitory activity of BLE was examined. Burdock leaves were dried by four methods: Shadow drying, oven drying, sun drying and freeze-drying. The extract solution was then subjected to total polyphenol content analysis and the method that produced BLE with the highest amount of total antioxidant components was taken forward for further analysis. The 1,1-diphenyl-2-pycrylhydrazyl scavenging, antielastase and antityrosinase activity of the BLE were measured to enable the evaluation of the antioxidant and skin aging-associated enzyme inhibitory activities of BLE. The results indicated that the total polyphenolic content following extraction with ethanol (EtOH) was highest using the freeze-drying method, followed by the oven drying, shadow drying and sun drying methods. BLE yielded a higher polyphenol content and stronger antioxidant activity as the ratio of the aqueous content of the extraction solvent used increased. BLE possesses marked tyrosinase and elastase inhibitory activities, with its antielastase activity notably stronger compared with its antityrosinase activity. These results indicate that the concentration of the extraction solvent was associated with the antioxidant and skin aging-associated enzyme inhibitory activity of BLE. The reactive oxygen species scavenging theory of skin aging may explain the tyrosinase and elastase inhibitory activity of BLE. In conclusion, the optimal method for obtaining BLE with a high antioxidant polyphenolic content was freeze-drying followed by 30-50% EtOH extraction. In addition, the antielastase and antityrosinase activities of the BLE produced may be aid in the development of skincare products with antiwrinkle and skin-evening properties.

Epigallocatechin gallate sensitizes cisplatin-resistant oral cancer CAR cell apoptosis and autophagy through stimulating AKT/STAT3 pathway and suppressing multidrug resistance 1 signaling.

Epigallocatechin gallate (EGCG) is a green tea polyphenol that presents anticancer activities in multiple cancer cells, but no available report was addressed for the underling molecular mechanism of cytotoxic impacts on drug-resistant oral squamous cell carcinoma cells. In the present study, the inhibitory effects of EGCG were experienced on cisplatin-resistant oral cancer CAR cells. EGCG inhibited cell viability in a time- and concentration-dependent manner by a sulforhodamine B (SRB) assay. EGCG induced CAR cell apoptosis and autophagy by 4',6-diamidino-2-phenylindole (DAPI) dye, acridine orange (AO) staining and green fluorescent protein (GFP)-tagged LC3B assay, respectively. EGCG also significantly enhanced caspase-9 and caspase-3 activities by caspase activity assay. EGCG markedly increased the protein levels of Bax, cleaved caspase-9, cleaved caspase-3, Atg5, Atg7, Atg12, Beclin-1, and LC3B-II, as well as significantly decreased the expression of Bcl-2, phosphorylated AKT (Ser473) and phosphorylation of STAT3 on Tyr705 by western blotting in CAR cells. Importantly, the protein and gene expression of multidrug resistance 1 (MDR1) were dose-dependently inhibited by EGCG. Overall, downregulation of MDR1 levels and alterations of AKT/STAT3 signaling contributed to EGCG-induced apoptosis and autophagy in CAR cells. Based on these results, EGCG has the potential for therapeutic effect on oral cancer and may be useful for long-term oral cancer prevention in the future. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 845-855, 2017.

Kaempferol induces ATM/p53-mediated death receptor and mitochondrial apoptosis in human umbilical vein endothelial cells.

Kaempferol is a member of the flavonoid compounds found in vegetables and fruits. It is shown to exhibit biological impact and anticancer activity, but no report exists on the angiogenic effect of kaempferol and induction of cell apoptosis in vitro. In this study, we investigated the role of kaempferol on anti-angiogenic property and the apoptotic mechanism of human umbilical vein endothelial cells (HUVECs). Our results demonstrated that kaempferol decreased HUVEC viability in a time- and concentration-dependent manner. Kaempferol also induced morphological changes and sub-G1 phase cell population (apoptotic cells). Kaempferol triggered apoptosis of HUVECs as detecting by DNA fragmentation, comet assay and immunofluorescent staining for activated caspase-3. The caspase signals, including caspase-8, -9 and -3, were time-dependently activated in HUVECs after kaempferol exposure. Furthermore, pre-treatment with a specific inhibitor of caspase-8 (Z-IETD-FMK) significantly reduced the activity of caspase-8, -9 and -3, indicating that extrinsic pathway is a major signaling pathway in kaempferol-treated HUVECs. Importantly, kaempferol promoted reactive oxygen species (ROS) evaluated using flow cytometric assay in HUVECs. We further investigated the upstream extrinsic pathway and showed that kaempferol stimulated death receptor signals [Fas/CD95, death receptor 4 (DR4) and DR5] through increasing the levels of phosphorylated p53 and phosphorylated ATM pathways in HUVECs, which can be individually confirmed by N-acetylcysteine (NAC), ATM specific inhibitor (caffeine) and p53 siRNA. Based on these results, kaempferol-induced HUVEC apoptosis was involved in an ROS-mediated p53/ATM/death receptor signaling. Kaempferol might possess therapeutic effects on cancer treatment in anti-vascular targeting.

Inhibitory effects of tetrandrine on epidermal growth factor-induced invasion and migration in HT29 human colorectal adenocarcinoma cells.

Tetrandrine has been shown to reduce cancer cell proliferation and to inhibit metastatic effects in multiple cancer models in vitro and in vivo. However, the effects of tetrandrine on the underlying mechanism of HT29 human colorectal adenocarcinoma cell metastasis remain to be fully elucidated. The aim of the present study was focused on tetrandrine­treated HT29 cells following epidermal growth factor (EGF) treatment, and Transwell, gelatin zymography, gene expression and immunoblotting assays were performed to investigate metastatic effects in vitro. Tetrandrine was observed to dose­dependently inhibit EGF­induced HT29 cell invasion and migration, however, no effect on cell viability occurred following exposure to tetradrine between 0.5 and 2 µM. Tetrandrine treatment inhibited the enzymatic activity of matrix metalloprotease (MMP)­2 and MMP­9 in a concentration­dependent manner. The present study also found a reduction in the mRNA expression levels of MMP­2 and MMP­9 in the tetrandrine­treated HT29 cells. Tetrandrine also suppressed the phosphorylation of EGF receptor (EGFR) and its downstream pathway, including phosphoinositide­dependent kinase 1, phosphatidylinositol 3­kinase and phosphorylated AKT, suppressing the gene expression of MMP­2 and MMP­9. Furthermore, tetrandrine triggered mitogen­activated protein kinase signaling through the suppressing the activation of phosphorylated extracellular signal­regulated protein kinase. These data suggested that targeting EGFR signaling and its downstream molecules contributed to the inhibition of EGF­induced HT29 cell metastasis caused by tetrandrine, eventually leading to a reduction in the mRNA and gelatinase activities of MMP-2 and MMP-9, respectively.

The mechanism of honokiol-induced intracellular Ca(2+) rises and apoptosis in human glioblastoma cells.

Honokiol, an active constituent of oriental medicinal herb Magnolia officinalis, caused Ca(2+) mobilization and apoptosis in different cancer cells. In vivo, honokiol crossed the blood-brain or -cerebrospinal fluid barrier, suggesting that it may be an effective drug for the treatment of brain tumors, including glioblastoma. This study examined the effect of honokiol on intracellular Ca(2+) concentration ([Ca(2+)]i) and apoptosis in DBTRG-05MG human glioblastoma cells. Honokiol concentration-dependently induced a [Ca(2+)]i rise. The signal was decreased partially by removal of extracellular Ca(2+). Honokiol-triggered [Ca(2+)]i rise was not suppressed by store-operated Ca(2+) channel blockers (nifedipine, econazole, SK&F96365) and the protein kinase C (PKC) activator phorbol 12-myristate 13 acetate (PMA), but was inhibited by the PKC inhibitor GF109203X. GF109203X-induced inhibition was not altered by removal of extracellular Ca(2+). In Ca(2+)-free medium, pretreatment with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin (TG) or 2,5-di-tert-butylhydroquinone (BHQ) abolished honokiol-induced [Ca(2+)]i rise. Conversely, incubation with honokiol abolished TG or BHQ-induced [Ca(2+)]i rise. Inhibition of phospholipase C (PLC) with U73122 abolished honokiol-induced [Ca(2+)]i rise. Honokiol (20-80µM) reduced the cell viability, which was not reversed by prechelating cytosolic Ca(2+) with BAPTA-AM (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester). Honokiol (20-60µM) enhanced reactive oxygen species (ROS) production, decreased mitochondrial membrane potential, released cytochrome c, and activated caspase-9/caspase-3. Together, honokiol induced a [Ca(2+)]i rise by inducing PLC-dependent Ca(2+) release from the endoplasmic reticulum and Ca(2+) entry via PKC-dependent, non store-operated Ca(2+) channels. Moreover, honokiol activated the mitochondrial pathway of apoptosis in DBTRG-05MG human glioblastoma cells.

Pathways of [Ca²âº]i rise evoked by angiotensin II in MDCK renal tubular cells.

The effect of angiotensin II (Ang II) on cytosolic Ca²âº concentrations ([Ca²âº]i) in MDCK renal tubular cells was explored. The Ca²âº-sensitive fluorescent dye fura-2 was applied to measure [Ca²âº]i. Ang II at concentrations of 5-40 µM induced a [Ca²âº]i rise in a concentration-dependent manner. The response was reduced partly by removing Ca²âº. Ang II evoked store-operated Ca²âº entry that was inhibited by La²âº and Gd³âº. In the absence of extracellular Ca²âº, incubation with the endoplasmic reticulum Ca²âº pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) or thapsigargin abolished Ang II-induced Ca²âº release. Inhibition of phospholipase C with U73122 abolished Ang II-induced [Ca²âº]i rise. Three Ang II analogues [(ASN1,VAL5)-Ang II acetate, (SAR1,THR8)-Ang II acetate, (VAL5)-Ang II acetate] failed to induce a [Ca²âº]i rise. Together, in MDCK cells, Ang II induced a [Ca²âº]i rise via Ca²âº entry through store-operated Ca²âº channels and phospholipase C-dependent Ca²âº release from the endoplasmic reticulum. Moreover, Ang II's amino acid sequence is important in its stimulatory effect on [Ca²âº]i.

Effect of clotrimazole on cytosolic Ca(2+) rise and viability in HA59T human hepatoma cells.

Abstract Clotrimazole is an antimycotic imidazole derivative that interferes with cellular Ca(2+) homeostasis. This study examined the effect of clotrimazole on cytosolic Ca(2+) concentrations ([Ca(2+)](i)) and viability in HA59T human hepatoma cells. The Ca(2+)-sensitive fluorescent dye fura-2 was applied to measure [Ca(2+)](i). Clotrimazole induced [Ca(2+)](i) rises in a concentration-dependent manner. The response was reduced by removing extracellular Ca(2+). Clotrimazole-evoked Ca(2+) entry was suppressed by store-operated channel inhibitors (nifedipine, econazole and SK&F96365) and protein kinase C modulators (GF109203X and phorbol, 12-myristate, 13-acetate). In Ca(2+)-free medium, incubation with the endoplasmic reticulum Ca(2+) pump inhibitor 2,5-di-tert-butylhydroquinone abolished clotrimazole-induced [Ca(2+)](i) rise. Inhibition of phospholipase C with U73122 abolished clotrimazole-induced [Ca(2+)](i) rise. At 10-40 µM, clotrimazole inhibited cell viability, which was not reversed by chelating cytosolic Ca(2+). Clotrimazole at 10 and 30 µM also induced apoptosis. Collectively, in HA59T cells, clotrimazole-induced [Ca(2+)](i) rises by evoking phospholipase C-dependent Ca(2+) release from the endoplasmic reticulum and Ca(2+) entry via store-operated Ca(2+) channels. Clotrimazole also caused apoptosis.