• Journal of Ginseng Research
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• 제23권2호
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• pp.99-104
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• 1999

인삼과 계피 추출물의 인체 직장암 세포(HT-29), 인체 간암 세포(HepG2)및 인체 결장암 세포(HRT-18)의 증식에 미치는 영향을 in vitro에서 확인하였다. 암세포의 배양액에서 인삼 추출물 또는 계피 추출물의 효과는 농도에 비례하여 암세포의 증식을 억제하였다. 세포증식의 억제 정도는 인삼과 계피 추출물을 단독으로 첨가한 것보다 병용하여 첨가한 경우 현저한 상승 효과를 나타내어, 낮은 인삼 농도에서도 HT-29, HepG2및 HRT-18암세포의 증식을 효과적으로 억제하였으며 심지어는 사멸시켰다. 인삼과 계피의 혼합물은 세포주기 중 G1 단계에서 S단계로의 진행을 지체시킴으로써 암세포의 증식을 억제하는 것으로 나타났다.

• 대한화학회지
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• 제52권3호
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• pp.281-294
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• 2008

Potintiodynamic 분광작용과 임피던스 기술을 이용하여 요드화 이온으로 Azadirachta Indica 엑스가 존재하는 0.5 M HCI용액 속의 Al 에 대한 부식 방지 작용을 상승시켰다. 이는 0.5 M HCI 용액에서 AZI 엑스가 Al의 부식을 방지함을 발견하였다. AZI 엑스 농도가 24% v/v이전에는 농도가 커짐에 따라 방지효율도 따라서 커진다. 하지만 AZI 엑스 농도가 더 커지면 Inh. %는 오히려 작아진다. 요드화 이온의 증가는 방지효율을 상당한 양으로 강화시킨다. 요드화 이온이 혼합적으로 존재할 때 Inh. %값은 증가한다. 이는 낮은 AZI 엑스 농도에서 AZI 엑스는 joint adsorption을 통하여 insoluble complex을 형성한다. 하지만 높은 AZI 엑스 농도에서는 요드화 이온과 형성한 complex사이에 competitive adsorption이 나타나 낮은 Inh. %를 초래한다. At all studied요드화 이온의 농도에서 요드화 이온과 AZI 엑스가 동시에 존재할 때의 Inh. %값은 AZI 엑스만 존재할 때보다 감소된다. Synergism parameter Sq는 표면 Coverage 값으로 계산된다. 이 Parameter는 AZI 엑스경우 unity 보다 더 큼을 알 수 있다. 이는 요드화 이온의 증가로 인하여 방지효율이 강화 되였음을 제시한다.

• Corrosion Science and Technology
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• 제12권2호
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• pp.65-78
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• 2013

The present investigation deals with the corrosion inhibition of mild steel in 1M $H_2SO_4$ with 1, 4-dihydro pyridine and its derivatives prepared using microwave activation method. The synthesis of inhibitor was confirmed by IR spectra. The effect of 1, 4-dihydropyridine derivatives on the corrosion inhibition of mild steel in 1M $H_2SO_4$ was studied using weight loss and electrochemical polarization techniques. Influence of temperature (303-333K) and synergistic effect of halide ions ($I^-$, $Br^-$ and $Cl^-$) on the inhibition behaviour was also studied. Corrosion products on the metal surface were analyzed by scanning electron microscopy (SEM) and a possible mechanism of inhibition by the compounds is suggested. Thermodynamic parameters were calculated using weight loss data in order to elaborate the mechanism of corrosion inhibition. Polarization measurements revealed that the studied compounds acted as mixed type inhibitor but slightly anodic in nature. Electrochemical impedance measurements revealed that the compounds were adsorbed onto the carbon steel surface and the adsorption obeyed the Langmuir adsorption isotherm. The synergistic effect of halide ions on the IE increases with increase in concentration. The IE obtained from atomic absorption spectrophotometric studies was found to be in good agreement with that obtained from the conventional weight loss method. SEM revealed the information of a smooth, dense protective layer in presence of the inhibitors.

• Journal of Electrochemical Science and Technology
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• 제4권2호
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• pp.61-70
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• 2013

Corrosion inhibition of carbon steel in 2M HCl by some benzohydrazide derivatives (I-III) was studied using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques at $30^{\circ}C$. Polarization studies showed that all the investigated compounds are of mixed type inhibitors. Temperature studies revealed a decrease in efficiency with rise in temperature and corrosion activation energies increased in the presence of the hydrazide derivatives, probably implying that physical adsorption of cationic species may be responsible for the observed inhibition behavior. Electrochemical impedance studies showed that the presence of benzohydrazide derivatives decreases the double layer capacitance and increases the charge transfer resistance. The adsorption of these compounds on carbon steel surface was found to obey Temkin's adsorption isotherm. Synergistic effects increased the inhibition efficiency in the presence of halide additives namely KI and KBr. An inhibition mechanism was proposed in terms of strongly adsorption of inhibitor molecules on carbon steel surface.

• Food Science and Biotechnology
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• 제17권2호
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• pp.402-407
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• 2008

The synergistic antimicrobial effect of Achyranthes japonica Nakai (AJN) and Bifidobacterium extracellular factors against Clostridium difficile were measured using a turbidity method. Each broth supernatant of Bifidobacterium infantis ($68.8{\pm}0.02%$) and Bifidobacterium adolescentis ($33.2{\pm}0.2%$) obtained by adding ethyl acetate soluble fractionate from A. japonica Nakai ethanolic extracts (AJNEA, 100 ppm, no inhibition) showed high synergistic antimicrobial activity against C. difficile. In addition, the antimicrobial activity in a laboratory medium and yogurt products against C. difficile were evaluated. In yogurt prepared with a starter 5 (Lactobacillus acidophilus: Streptococcus thermophilus: B. adolescentis =1 : 1 : 1) and a starter 4 (L. acidophilus: S. thermophilus: B. infantis=1 : 1 : 1) and 0.5% AJNEA powder, high antimicrobial effects were recorded that measured 79.0 and 65.2%, respectively. The results indicated the potential of AJN extract for use as an antimicrobial agent. In addition, the efficiency of the antimicrobial activity of the extracts was further improved in combination with lactic acid bacteria, which suggests that they have the potential to be used as a highly effective antibiotic-tolerant microorganism prevention system. Such a strategy can be used for alternative drugs or functional food additives for treatment of antibiotic-associated diarrhea.

• Corrosion Science and Technology
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• 제16권1호
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• pp.31-37
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• 2017

A synergistic effect was observed in the combination of nitrite and ethanolamines. Ethanolamine is one of the representative organic corrosion inhibitors and can be categorized as adsorption type. However, nitrosamines can form when amines mix with sodium nitrite. Since nitrosamine is a carcinogen, the co-addition of nitrite and ethanolamine will be not practical, and thus, a non-toxic combination of inhibitors shall be needed. In order to maximize the effect of monoethanolamine, we focused on the addition of molybdate. Molybdate has been used to alternate the addition of chromate, but it showed insufficient oxidizing power relative to corrosion inhibitors. This work evaluated the synergistic effect of the co-addition of molybdate and monoethanolamine, and its corrosion mechanism was elucidated. A high concentration of molybdate or monoethanolamine was needed to inhibit the corrosion of ductile cast iron in tap water, but in the case of the co-addition of molybdate and monoethanolamine, a synergistic effect was observed. This synergistic effect could be attributed to the molybdate that partly oxidizes the metallic surface and the monoethanolamine that is simultaneously adsorbed on the graphite surface. This adsorbed layer then acts as the barrier layer that mitigates galvanic corrosion between the graphite and the matrix.

• Asian Pacific Journal of Cancer Prevention
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• 제13권9호
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• pp.4531-4536
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• 2012

Objective: To study synergistic effects of nedaplatin and cisplatin on three human carcinoma cell lines (esophageal carcinoma cell line Eca-109, ovarian carcinoma Skov-3 and cervical carcinoma Hela). Methods: Inhibition effects were evaluated by MTT assay and cell apoptosis was detected by flow cytometry. In addition, changes of Ki-67, Bax and Bcl-2 at mRNA and protein levels were quantified by RT-PCR and Western blotting. Results: Growth inhibition in each cell lines was dose-dependent after exposure to nedaplatin or cisplatin alone. The interaction of the two drugs was synergistic at higher concentrations according to the median-effect principle. The inhibition rates with nedaplatin, cisplatin and combined treatment were $41.9{\pm}4.1%$, $47.4{\pm}2.9%$, $52.5{\pm}0.9%$(Eca-109), $39.0{\pm}1.26%$, $45.0{\pm}1.45%$, $56.2{\pm}1.44%$ (Skov-3) and $44.8{\pm}2.11%$, $46.9{\pm}0.99%$, $56.6{\pm}1.83%$ (Hela) respectively, with increase in apoptosis. Compared with the nedaplatin or cisplatin alone treatment group, the combinative treatment group's Ki-67 and bcl-2 mRNA (protein) expression was decreased while that of Bax mRNA (protein) was increased. Conclusion: Compared to the effects of nedaplatin or cisplatin alone at high concentrations, combination of nedaplatin and cisplatin at low concentrations proved to be much more effective for inhibition of proliferation and the induction of apoptosis in the Eca-109, Skov-3 and Hela cell lines.

• Journal of Applied Biological Chemistry
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• 제65권4호
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• pp.337-341
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• 2022

본 연구에서는 항충치 활성을 보이는 지용성의 홍삼박 n-hexane 추출물과 수용성의 arginine의 병용이 S. mutans의 생육에 미치는 영향을 조사하였다. Checkerboard assay로 분석한 결과, 홍삼박 n-hexane 추출물과 arginine은 fractional inhibitory concentration index 0.396으로 S. mutans의 생육 저해에 시너지 효과를 나타내었다. 홍삼박 n-hexane 추출물과 arginine의 병용은 핵산 성분의 유출과 생균수의 감소를 초래하였으며, 이는 모두 홍삼박 n-hexane 추출물의 농도에 비례하였다. 결론적으로 S. mutans의 생육 저해에 대한 홍삼박 n-hexane 추출물과 arginine의 시너지 효과는 주로 홍삼박 n-hexane 추출물이 기여하는 것으로 판단된다.

• 한국식품영양학회지
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• 제25권4호
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• pp.855-862
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• 2012

Resveratrol (RVT) and epigallocatechin gallate (EGCG) individually inhibit adipogenesis in 3T3-L1 adipocytes. The objective was to examine the possibility of interaction between RVT and EGCG, resulting in enhanced inhibition of adipogenesis in 3T3-L1 adipocytes. Preadipocytes were treated with RVT and EGCG individually at 6.25 or $25{\mu}M$ (RVT6.25 or RVT25) and 12.5 or $50{\mu}M$ (EGCG12.5 or EGCG50) and in combination (RVT6.25 + EGCG12.5 and RVT25 + EGCG50). RVT25 as an individual compound decreased lipid accumulation in 3T3-L1 adipocytes by 24%, and RVT25 + EGCG50 further decreased lipid accumulation by 77%. In addition, exposure of 3T3-L1 adipocytes to RVT6.25 + EGCG12.5 and RVT25 + EGCG50 combinations resulted in an enhanced increase of adiponectin release and inhibition of leptin release. Quantitative analysis revealed that the combination of tested materials (RVT6.25 + EGCG12.5 and RVT25 + EGCG50) decreased the expression levels of C/EBP${\alpha}$, PPAR${\gamma}2$, and aP2. These results indicate that the combined treatments with RVT and EGCG produce synergistic effects on inhibiting adipogenesis in 3T3-L1 adipocytes. The overall results suggested that the combining RVT and EGCG might be more capable of exerting antiobesity effects than each individual compound by itself.

• Biomolecules & Therapeutics
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• 제29권4호
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• pp.434-444
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• 2021

BRAF inhibitors are insufficient monotherapies for BRAF-mutated cancer; therefore, we investigated which inhibitory pathway would yield the most effective therapeutic approach when targeted in combination with BRAF inhibition. The oncogenic BRAF inhibitor, PLX4720, increased basal autophagic flux in BRAF-mutated cells compared to wild-type (WT) BRAF cells. Interestingly, early autophagy inhibition improved the effectiveness of PLX4720 regardless of BRAF mutation, whereas late autophagy inhibition did not. Although ATG5 knockout led to PLX4720 resistance in both WT and BRAF-mutated cells, the MEK inhibitor trametinib exhibited a synergistic effect on PLX4720 sensitivity in WT BRAF cells but not in BRAF-mutated cells. Conversely, the prolonged inhibition of endoplasmic reticulum (ER) stress reduced basal autophagy in BRAF-mutated cells, thereby increasing PLX4720 sensitivity. Taken together, our results suggest that the combined inhibition of ER stress and BRAF may simultaneously suppress both pro-survival ER stress and autophagy, and may therefore be suitable for treatment of BRAF-mutated tumors whose autophagy is increased by chronic ER stress. Similarly, for WT BRAF tumors, therapies targeting MEK signaling may be a more effective treatment strategy. Together, this study presents a rational combination treatment strategy to improve the efficacy of BRAF inhibitors depending on BRAF mutation status.