• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4599-4602
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• 2013

We intended to study the mechanism of the inhibitory action of curcumin on human non-small cell lung cancer A549 cell. The cell growth was determined by CCK-8 assay, and the results indicated that curcumin inhibited the cell proliferation in a concentration dependent manner. And to further confirm the relative anti-cancer mechanism of curcumin, RT-PCR was carried out to analysis the expression of relative apoptotic proteins Bax, Bcl-2. We found that curcumin could up-regulate the expression of Bax but down-regulate the expression of Bcl-2 in A549 cells. In addition, curcumin affect the mitochondrial apoptosis pathway. These results suggested that curcumin inhibited cancer cell growth through the regulation of Bcl-2/Bax and affect the mitochondrial apoptosis pathway.

• Preventive Nutrition and Food Science
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• 제20권4호
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• pp.221-229
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• 2015

Hesperidin has been shown to possess a potential inhibitory effect on vascular formation in endothelial cells. However, the fundamental mechanism for the anti-angiogenic activity of hesperidin is not fully understood. In the present study, we evaluated whether hesperidin has anti-angiogenic effects in mouse embryonic stem cell (mES)-derived endothelial-like cells, and human umbilical vascular endothelial cells (HUVECs), and evaluated their mechanism via the AKT/mammalian target of rapamycin (mTOR) signaling pathway. The endothelial cells were treated with several doses of hesperidin (12.5, 25, 50, and $100{\mu}M$) for 24 h. Cell viability and vascular formation were analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and tube formation assay, respectively. Alteration of the AKT/mTOR signaling in vascular formation was analyzed by western blot. In addition, a mouse aortic ring assay was used to determine the effect of hesperidin on vascular formation. There were no differences between the viability of mES-derived endothelial-like cells and HUVECs after hesperidin treatment. However, hesperidin significantly inhibited cell migration and tube formation of HUVECs (P<0.05) and suppressed sprouting of microvessels in the mouse aortic ring assay. Moreover, hesperidin suppressed the expression of AKT and mTOR in HUVECs. Taken together, these findings suggest that hesperidin inhibits vascular formation by blocking the AKT/mTOR signaling pathways.

• Journal of Pharmaceutical Investigation
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• 제40권5호
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• pp.269-275
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• 2010

P-gp plays a critical role in drug disposition and represents a mechanism for the development of multidrug resistance. Flavonoids, a major class of natural compounds widely present in foods and herbal products, have been shown to inhibit P-gp. Therefore, the aim of this study was to identify new candidate chemosensitizers by screening various plant extracts. The ability of natural plant extracts to inhibit P-gp activity was assessed by measuring cellular accumulation of calcein AM, daunorubicin and vincristine in P-gp overexpressing MDCKII-MDR1 cells. Among more than 800 plant extracts, eight were found to inhibit P-gp activity. Curcuma aromatica extract produced greatest inhibition, followed by Curcuma longa and Dalbergia odorifera extracts. Extracts of Aloe ferox, Curcuma zedoariae rhizome, Zanthoxylum planispinum, and Ageratum conyzoides showed moderate inhibitory effects. Curcumin and quercetin exhibited similar inhibition of P-gpmediated efflux of daunorubicin and vincristine, and flavones had a lesser effect. When chemosensitizing effect was evaluated by measuring daunorubicin sensitivity to MDCKII-MDR1 cells in the presence of natural plant extracts, Curcuma aromatica showed the most potent chemosensitizing effect based on daunorubicin cytotoxicity. In conclusion, natural plant extracts such as Curcuma aromatica can potently inhibit P-gp activity and may have potential as a novel chemosensitizers.

• 동의생리병리학회지
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• 제24권1호
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• pp.91-95
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• 2010

Alzheimer's disease (AD) is characterized pathologically by the presence of intracellular neurofibrillary tangles and deposition of ${\beta}$-amyloid (A${\beta}$) peptides. It is urgent to develop effective therapies for the treatment of AD, since our society rapidly accelerate aging. A${\beta}$ peptides have been believed to be neurotoxic and now are also considered to have affects on the mechanism of memory formation, which are generated by processing of amyloid precursor protein (APP). In this study, effects of Styrax Liquides (SL) on the metabolism of APP were analyzed. SL inhibited the secretion of A${\beta}$ from the Neuro2a cell line (APPswe cell) expressing a mutation of APPswe. Immunoblotting study showed that it inhibited ${\beta}$-site APP cleaving enzyme (BACE) from the APPswe cells. We suggest that SL inhibits APP metabolism and A${\beta}$ generation by the means of BACE inhibitory mechanism. This is the first report that SL inhibits the secretion of A${\beta}$ peptides from neuroblastoma cells.

• Natural Product Sciences
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• 제10권4호
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• pp.182-189
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• 2004

To find the action mechanism of the MeOH extract (LFS) of Ligularia fischeri var. spiciformis herbs (Compositae) and its active component, 3,4-dicaffeoylquinic acid (DCQA) on antihepatotoxicity, the effect was investigated on hepatic lipid perxodation and drug-metabolizing enzyme activities in acetaminophen-treated rat. Pretreatment with 250 mg/kg LFS (p.o.) and 10 mg/kg DCQA (p.o.) significantly decreased hepatic lipid peroxidation caused by acetaminophen injection. Further, LFS and DCQA inhibited hepatic microsomal enzyme activation such as hepatic P-450 cytochrome $b_5$, aniline hydroxylase and aminopyrine N-demethylase, suggesting that the two substances might effectively prevent the metabolic activation or scavenge electrophilic intermediates capable of causing hepatotoxicity. Both LFS and DCQA increased hepatic glutathione content and glutathione reductase activity, indicating that both resultantly prevented hepatotoxicity via antioxidative mechanism. Therefore, it was found that LFS had antihepatotoxicity based on the antioxidative action of DCQA.

• The Journal of Korean Physical Therapy
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• 제12권1호
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• pp.49-56
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• 2000

The purpose of this study was to investigate the influnce of afferent stimuli, transcutaneous electrical nerve stimulation and ultra sound, on the electrdiagnostic study of normal subjects. Electrodiagnostic study was performed before and after the application of afferent stimulation of the right popliteal fossa on 18 healthy female volunteers. After the transcutaneous electrical nerve stimulation, there is no significantly change of latencies and amplitudes of SEP, H-reflex, peroneal nerve F-wave, and sensory nerve conduction. After the ultra sound, there is no significantly change of latencies and amplitudes of SEP, H-reflex, peroneal nerve F-wave, and sensory nerve conduction. Tibial nope F-wave and motor nerve shows prolonged latency after TENS and US (p<0.01). Ultrasound may have a similar mechanism of action compared to transcutaneous electrical nerve stimulation by having localized inhibitory effects of the peripheral nerve. However, further investigation is needed to assess their mechanism of action and the precise relevance of stimulation modality.

• Archives of Pharmacal Research
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• 제22권3호
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• pp.232-236
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• 1999

In this study, we present evidence that cotreatment of aloesin and arbutin inhibits tyrosinase activity in a synergistic manner by acting through a different action mechanism. Aloesin or arbutin similarly inhibited enzyme activity of human- and mushroom-tyrosinases with an IC50 value of 0.1 or 0.04 mM, respectively. Lineweaver-Burk plots of the enzyme kinetics data showed that aloesin inhibited tyrosinase activity noncompetitively with a Ki value of 5.3 mM, whereas arbutin did it competitively (Maeda, 1996). We then examined whether cotreatment of these agents inhibits the tyrosinase activity in a synergistic manner. The results showed that 0.01 mM aloesin in the presence of 0.03 mM arbutin inhibited activity of mushroom by 80% of the control value and the reverse was also true. The inhibitory effects were calculated to be synergistic according to the B rgi method. Taken together, we suggest that aloesin along with arbutin inhibits in synergy melanin production by combined mechanisms of noncompetitive and competitive inhibitions of tyrosinase activity.

• Archives of Pharmacal Research
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• 제20권6호
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• pp.579-585
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• 1997

To gain further insight into the mechanism of action of antiestrogens, we examined the interaction of antiestrogen with the estrogen receptor system and with estrogen- noncompetable antiestrogen binding sites. In addition to binding directly to the estrogen receptor, antiestrogens can be found associated with binding sites that are distinct from the estrogen receptor. In contrast to the restriction of estrogen receptors to estrogen target cells, such as those of uterus and mammary glands, antiestrogen binding sites are present in equal amounts in estrogen receptor-positive and -negative human breast cancer cell lines, such as MCF-7, T47D, and MDA-MB-231 that differ markedly in their sensitivity to antiestrogens. In order to gain greater insight into the role of these antiestrogen binding sites in the action of antiestrogens, we have examined the biopotency of different antiestrogens for the antiestrogen binding sites and that is CI628 > tamoxifen > trans-hydroxy tamoxifen > CI628M > H1285 > LY117018. This order of affinities does not parallel the affinity of these compounds for the estrogen receptor nor the potency of these compounds as antiestrogens. Indeed, compounds with high affinity for the estrogen receptor and greatest antiestrogenic potency have low affinities for these antiestrogen binding sites. Antiestrogenic potency correlates best with estrogen receptor affinity and not with affinity for antiestrogen binding sites. In summary, our findings suggested that interaction with the estrogen receptor is most likely the mechanism through which antiestrogens evoke their growth inhibitory effects.

• 생약학회지
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• 제52권3호
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• pp.127-133
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• 2021

Platelet activation plays a major role in cardiovascular disorders (CVDs). Thus, disrupting platelet activation represents an attractive therapeutic target on CVDs. Esculetin, a bioactive 6,7-dihydroxy derivative of coumarin, possesses pharmacological activities against obesity, diabetes, renal failure, and CVDs. In other report, the effect of esculetin has been examined in human platelet activation and experimental mouse models, and esculetin inhibited collagen- and arachidonic acid-induced platelet aggregation in washed human platelets. However, it had no effects on other agonists such as thrombin and U46619, and its mechanism is not also clearly known. This study investigated the effect of esculetin on collagen-induced human platelet aggregation, and we clarified the mechanism. Esuletin has effects on the down regulation of PI3K/Akt and MAPK, phosphoproteins that act in the signaling process in platelet aggregation. The effects of esculetin reduced of TXA₂ production and phospholipase A₂ activation, and intracellular granule secretion including ATP and serotonin, leading to inhibit platelet aggregation. These results clearly clarified the effect of esculetin in inhibiting platelet activity and thrombus formation in humans.

• 한국자원식물학회지
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• 제34권3호
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• pp.216-222
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• 2021

Ulcerative colitis (UC) is an inflammatory bowel disease and a chronic gastrointestinal disorder. Rubi Fructus (RF), the fruit of Rubus coreanus Miquel, is known to exert several pharmacological effects including anti-oxidative, anti-obesity and anti-inflammatory properties. However, the improving effect and mechanism of RF on intestinal inflammation is not been fully understood. The purpose of this study was to investigate the regulatory effect of RF on dextran sulfate sodium (DSS)-induced colitis in mice. We evaluated the effects of RF on DSS-induced clinical signs by analyzing weight loss and colon length. The inhibitory effects of RF on inflammatory mediators such as prostaglandin E₂ (PGE₂), cyclooxygenase (COX)-2, as well as the activation of nuclear factor-κB (NF-κB), were determined in colitis tissue. Our data indicated that mice treated with DSS showed clinical symptoms of colitis, including weight loss, colon length decrease and diarrhea. However, we observed that RF treatment significantly improved these clinical symptoms of weight loss, colon length decrease and diarrhea induced by DSS. RF inhibited the enhanced levels of COX-2 and PGE₂ caused by DSS. We also showed that the anti-inflammatory mechanism of RF by suppressing the activation of NF-kB in DSS-treated colon tissues. Collectively, the findings of this study indicate the prospect of developing new drugs from RF for UC treatment.