In Guk Hwang

Anti-proliferate and pro-apoptotic effects of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyranone through inactivation of NF-κB in Human Colon Cancer Cells

Many natural compounds have been shown to prevent cancer cell growth through the redox regulation of transcription factors. NF-κB, a redox transcription factor, has been implicated in the apoptotic cell death of several cancer cells. This study examined whether or nor 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyranone (DDMP) isolated from onions can modulate the activity of NF-κB, thereby induce the apoptotic cell death of colon cancer cells. Treatment with different DDMP concentrations (0.5–1.5 mg/mL) for various periods (0–48 h) inhibited the growth of colon cancer cells (SW620 and HCT116) followed by the induction of apoptosis in a dose dependent manner. It was also found that DDMP modulated tumor necrosis factor-α (TNF-α) and tetradeanoyl phorbol acetate (TPA)-induced NF-κB transcriptional and DNA binding activity. Moreover, DDMP suppressed the NF-κB target anti-apoptotic genes (Bcl-2), whereas it induced the expression of the apoptotic genes (Bax, cleaved caspase-3 and cleaved PARP). These results suggest that DDMP from onions inhibit colon cancer cell growth by inducing apoptotic cell death through the inhibition of NF-κB.

Effects of Different Cooking Methods on the Antioxidant Properties of Red Pepper (Capsicum annuum L.)

We investigated the effect of various cooking methods (boiling, steaming, stir-frying, and roasting) and three cooking times (5, 10, and 15 min) on the antioxidant properties of red pepper. Raw and cooked peppers were measured for proximate composition, ascorbic acid (AsA) content, total carotenoid content (TCC), total polyphenol content (TP), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities. Results showed that the proximate composition, AsA content, TCC, TP, and antioxidant activities were significantly (p<0.05) affected by the cooking procedure; the loss rate varied among individual compounds. Boiling and steaming significantly reduced AsA content (24.3~66.5%), TP (13.9~ 54.9%), and antioxidant activity (21.7~60.5%) in red pepper, while stir-frying and roasting slightly reduced AsA content (2.7~25.9%), TP (1.8~4.9%), and antioxidant activity (4.9~17.9%). The highest loss was observed after boiling, followed by steaming, roasting, and stir-frying. Stir-frying and roasting better preserved AsA content, TCC, TP, and antioxidant activity. In conclusion, dry-heat cooking methods such as stir-frying and roasting may be preferred to retain the nutrient compositions and antioxidant properties of red pepper.

Physicochemical Characteristics and Antioxidant Activity of Heated Radish (Raphanus sativus L.) Extracts

무(Raphanus sativus L.)는 십자화과(Cruciferae)에 속하는 식물로 우리나라에서는 김치의 재료로 사용되고 있으며, 국내 생산 과채류 중 배추와 더불어 총 생산량의 60% 이상을 점하는 매우 중요한 채소류이다(1). 무의 이용에 관한 민간요법과 고전문헌에서는 내복근이라 하여 소화 촉진과 어패류 또는 면류의 중독해소에 효과가 있고, 종자는 내복자라 하여 기담, 혈담, 천식 및 늑간 신경통 등에 쓰이며, 이 외에도 이뇨작용, 정장작용, 진해․거담작용, 해열, 소염작용, 혈당저하, 니코틴 제거 작용, 담석증 치료 및 지혈작용 등과 같은 생리활성 효과들이 있는 것으로 알려져 있다(2). 무에는 flavonoid인 kaempferol이 함유되어 있다고 보고되고 있으며(3), 식이섬유와 항산화 vitamin, flavonoid계 색소, phenol계 및 방향족 amine 등 항산화 작용을 나타내는 물질이 다량 함유되어 있어 이들 생리활성성분에 대한 연구들이 진행되고 있다(4,5).식품의 열처리 가공은 식품의 저장수명을 연장시키고 품질을 향상시키기 위하여 사용되어지고 있다. 열처리 가공 중 영양소의 파괴 및 활성물질의 손실 등의 문제점이 있지만, 몇몇 과일류 및 채소류 등을 열처리할 경우 다양한 화학적 변화에 의해 생리활성물질이 증가한다고 보고되어지고 있는데 탈지대두박에 대한 열처리는 페놀성 화합물의 추출을 촉진하며(6), 마늘을 열처리하면 착즙액의 항산화 활성이 증가되고(7), 감초를 열처리할 경우에도 항산화 활성이 증가한다고 보고하였다(8). 그 밖에도 인삼(9), 한국산 배(10), 마늘(11), 멜론, 사과, 토마토, 참외 및 수박 등(12)의 여러 가지의 과일류 및 채소류의 열처리 시 폴리페놀 및 플라보노이드 함량이 증가하여 항산화 활성이 증가한다고 보고하는 등 열처리 관련 연구들이 활발하게 진행되고 있다.무의 추출물의 생리활성에 대한 연구로 Jung 등(13)이 무 에탄올 추출물에 대하여 미백, 숙취해소, 항균, 항산화 활성 등을 조사한 결과 항산화 식품과 기능성 화장품 등으로의 개발 가능성을 시사하고 있으며, Yim 등(14)은 인체 폐암 세포주(A-549)에 대한 무 에탄올 추출물의 세포독성에 대한 연구에서 항암활성을 확인하였고, Kang 등(15)은 콩나물, 미나리, 무의 용매분획 추출물들이 alcohol dehydrogenase의 활성에 대한 효과를 확인하는 등 추출물에 대한 연구가 주를 이루고 있을 뿐 무 자체를 열처리 하였을 경우 변화되는 생리활성에 대한 연구는 찾아보기 어려운 실정이다.

Changes in ginsenoside compositions and antioxidant activities of hydroponic-cultured ginseng roots and leaves with heating temperature

Background This study evaluated changes in ginsenoside compositions and antioxidant activities in hydroponic-cultured ginseng roots (HGR) and leaves (HGL) with heating temperature. Methods Heat treatment was performed at temperatures of 90°C, 110°C, 130°C, and 150°C for 2 hours. Results The ginsenoside content varied significantly with heating temperature. The levels of ginsenosides Rg1 and Re in HGR decreased with increasing heating temperature. Ginsenosides F2, F4, Rk3, Rh4, Rg3 (S form), Rg3 (R form), Rk1, and Rg5, which were absent in the raw ginseng, were formed after heat treatment. The levels of ginsenosides Rg1, Re, Rf, and Rb1 in HGL decreased with increasing heating temperature. Conversely, ginsenosides Rk3, Rh4, Rg3 (R form), Rk1, and Rg5 increased with increasing heating temperature. In addition, ginsenoside contents of heated HGL were slightly higher than those of HGR. The highest extraction yield was 14.39% at 130°C, whereas the lowest value was 10.30% at 150°C. After heating, polyphenol contents of HGR and HGL increased from 0.43 mg gallic acid equivalent/g (mg GAE eq/g) and 0.74 mg GAE eq/g to 6.16 mg GAE eq/g and 2.86 mg GAE eq/g, respectively. Conclusion Antioxidant activities of HGR and HGL, measured by 1,1-diphenyl-2-picrylhydrazyl and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging ability, increased with increasing heating temperature. These results may aid in improving the biological activity and quality of ginseng subjected to heat treatments.

Thermal degradation characteristics and antioxidant activity of fructose solution with heating temperature and time.

This study investigated the thermal degradation characteristics of fructose. A 20% fructose solution was heated to 110-150°C for 1-5 hours. Chromaticity, pH, organic acid, 5-hydroxymethylfurfural (HMF), fructose content, electron-donating ability (EDA) (as a percentage), and ascorbic acid (AA) equivalent antioxidant capacity (AEAC) of heated fructose solutions were evaluated. With increasing heating temperature and time, the L-value decreased, and the a- and b-values increased to 120°C for 4 hours and 2 hours, respectively, and then decreased thereafter; however, total color difference increased. The pH and fructose content decreased. Organic acids, such as formic acid, lactic acid, and levulinic acid, and HMF content increased with increasing heating temperature and time. Antioxidant activity increased with increasing heating temperature and time (no antioxidant activity in 20% fructose solution). The EDAs after heating at 130°C for 3 and 4 hours were 17.21% and 31.73%, respectively, and the highest antioxidant activity was 94.57% (150°C for 4 hours). The AEAC was 1.71 mg of AA eq/g before heating and 24.43 mg of AA eq/g after heating at 150°C for 4 hours. These results suggest that heat treatment may be a useful method for increasing the antioxidant activity of fluid foodstuffs such as fruit juices and fructose-containing foods.

Isolation and Identification of the Antioxidant DDMP from Heated Pear (Pyrus pyrifolia Nakai)

We evaluated antioxidant activities of heated pear juice (HPJ) exposed to 120, 130, and 140°C for 2 hr. HPJ was partitioned using n-hexane, chloroform, ethyl acetate, n-butanol, and water. The ethyl acetate fraction treated at 130°C for 2 hr showed strong antioxidant activity; thus, this extract was isolated and purified using silica gel column chromatography and preparative high performance liquid chromatography. The structure of the purified compound was determined using ultraviolet and mass spectrometry, 1H-nucelar magnetic resonance (NMR), and 13C-NMR. Antioxidant activities of the isolated compound were evaluated and compared with α-tocopherol, ascorbic acid, and butylated hydroxytoluene (BHT) using DPPH and ABTS assays. The isolated compound was identified as 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP). The DPPH radical-scavenging activity (IC50) of DDMP occurred in the following order: ascorbic acid (45.3 μg/mL)> α-tocopherol (69.2 μg/mL)> DDMP (241.6 μg/mL)> BHT (268.0 μg/mL). Furthermore, DDMP showed strong ABTS radical-scavenging activity (569.0 mg AA eq/g).

Isolation and Identification of an Antiproliferative Compound from Fructose–Tryptophan Maillard Reaction Products

This study was performed to isolate and identify a compound with antiproliferative activity against human stomach cancer cell lines, from fructose-tryptophan Maillard reaction products (MRPs). The MRPs, prepared from a fructose-tryptophan solution heated at 130 °C for 2 h, were fractionated into five solvent fractions: n-hexane, chloroform, ethyl acetate, butanol, and water. The highest antiproliferative activity was found in the chloroform fraction (85.93% at 200 μg/mL), and the active compound from this chloroform fraction was purified by silica gel column chromatography, TLC, and preparative HPLC. The antiproliferative activity (IC50) of the active compound was 42.24 μg/mL, and the active compound was identified as perlolyrine (C16H10N2O2) by (1)H/(13)C NMR, DEPT, HMBC, and LC-ESI-MS. Therefore, this research may be useful in developing perlolyrine as a functional therapeutic agent.

Isolation and Identification of an Antioxidant Substance from Heated Onion (Allium cepa L.)

The objectives of this study were to identify antioxidant substance in heated onion. The isolation of active compound was performed in three steps: silica gel column chromatography, preparative TLC, and preparative HPLC. The structure of the purified compound was determined using spectroscopic methods, i.e., ultraviolet, mass spectrometry, H-NMR, C-NMR, and DEPT. The antioxidant activities of isolated compound were evaluated and compared with α-tocopherol, ascorbic acid, and butylated hydroxytoluene (BHT) using DPPH and ABTS assay. The isolated compound was identified as 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP). The DPPH radical-scavenging activity (IC50) of the DDMP was in the following order: ascorbic acid (45.3 μg/mL)>α-tocopherol (69.2 μg/mL)>DDMP (241.6 μg/mL)>BHT (268.0 μg/mL). In addition, DDMP showed strong ABTS radical-scavenging activity of 569.0 mg AA eq/g.

Antioxidant Activity of Ethanol Extraction on Citron Seed by Response Surface Methodology

Extraction characteristics of citron (Citrus junos Sieb. ex Tanaka) seeds and functional properties of corresponding extract were monitored by response surface methodology (RSM). Maximum extraction yield of 20.23% was obtained at extraction temperature of 50.23 o C, extraction time of 3.03 hr, and shaking velocity of 400.06 rpm. At extraction temperature, extraction time, and shaking velocity of 49.88 o C, 2.72 hr, and 400.39 rpm, respectively, maximum polyphenol content was 4.37 mg/g. At extraction temperature, extraction time, and shaking velocity of 50.28 o C, 3.42 hr, and 399.96 rpm, respectively, maximum electron donating ability (EDA) was 49.69%. Maximum nitrite scavenging activity (NSA) was 47.79% at extraction temperature, extraction time, and shaking velocity of 49.19 o C, 0.68 hr, and 602.95 rpm, respectively. Based on superimposition of 3-dimensional RSM with respect to extraction yield, polyphenol, EDA, and NSA, optimum ranges of extraction conditions were extraction temperature of 50 o C, extraction time of about 3 hr, and shaking velocity of 400 rpm.

Antioxidant Contents and Antioxidant Activities of White and Colored Potatoes (Solanum tuberosum L.).

This study was performed to evaluate and compare the antioxidant substance content and antioxidant activities of white (Superior) and colored (Hongyoung, Jayoung, Jasim, Seohong, and Jaseo) potatoes. The potatoes were extracted with 80% ethanol and were evaluated for the total polyphenol, flavonoid, and anthocyanin contents and for 1,1-diphenyl- 2-picrylhydrazyl (DPPH)/2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity, reducing power, and ferrous metal ion chelating effect. The total polyphenol, flavonoid, and anthocyanin contents of Hongyoung and Jayoung were higher than white and other colored potatoes. All colored potato extracts, except for Jaseo and Seohong, showed higher ABTS radical scavenging activities than the general white potato extract. Hongyoung and Jayoung had the highest ABTS and DPPH radical scavenging activities. Optical density values for the reducing power of Jayoung and Jaseo at concentration of 2 mg/mL were 0.148 and 0.090, respectively. All colored potato extracts had lower ferrous metal ion chelating effect than the white potato. A significant (P<0.05) positive correlation was observed between total polyphenol content and total flavonoid content (r=0.919), anthocyanin content (r=0.992), and ABTS radical scavenging activity (r=0.897). Based on these results, this research may be useful in developing the Hongyoung and Jayoung cultivars with high antioxidant activities.