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Abstrak :
Butylated hydroxyanisole (BHA) adalah antioksidan fenolik sintetik yang digunakan sebagai zat aditif pada makanan sebagai pengawet. BHA dan Cr(VI) menghasilkan reactive oxygen species(ROS) yang menyerang DNA, terutama basa guanin, membentuk DNA adduct 8-hidroksi-2'-deoksiguanosin (8-OHdG). Penelitian ini bertujuan untuk menganalisis DNA adduct 8-OHdG sebagai biomarker kerusakan DNA secara in vitro dan in vivo. Studi in vitro dilakukan dengan menyelidiki interaksi 2'-deoxyguanosine (2'-dG) dengan BHA, Cr(VI), H2O2, dan asam askorbat pada waktu inkubasi yang berbeda (24 dan 30 jam), pH (7,4 dan 8,4), dan 37°C. Studi in vivo dilakukan dengan menggunakan tikus yang diberikan paparan BHA dan Cr(VI)  melalui rute ingesti selama 28 hari. Sampel urin dan darah diambil setiap minggu dan dianalisis menggunakan ELISA dan LC-MS/MS. Penelitian ini menunjukkan bahwa peningkatan pH, waktu inkubasi, dan konsentrasi BHA, Cr(VI), H2O2, dan asam askorbat memiliki efek sinergis terhadap pembentukan 8-OHdG. Konsentrasi 8-OHdG tertinggi ditemukan pada sampel yang mengandung 2'-dG, H2O2, BHA, Cr(VI), dan asam askorbat. Rasio 2'-dG terhadap H2O2, BHA, Cr(VI), dan asam askorbat dalam sampel adalah 1:20 pada pH 8,4 selama 24 jam adalah 316,5 ppb pada suhu 37°C. Hasil uji in vivo menunjukkan terbentuknya DNA adduct 8-OHdG pada serum dan urin tikus yang diuji menggunakan ELISA dan LC-MS/MS. ......Butylated hydroxyanisole (BHA) is a synthetic phenolic antioxidant used as a food additive as a preservative. BHA and Cr(VI) produce reactive oxygen species (ROS) which attack DNA, especially the guanine base, forming the DNA adduct 8-hydroxy-2'-deoxyguanosine (8-OHdG). This study aims to analyze DNA adduct 8-OHdG as a biomarker of DNA damage in vitro and in vivo. In H2O2studies were carried out by investigating the interaction of 2'-deoxyguanosine (2'-dG) with BHA, Cr(VI), H2O2, and ascorbic acid at different incubation times (24 and 30 hours), pH (7,4 and 8, 4), and 37°C. In vivo studies were carried out using rats exposed to BHA and Cr(VI) via the ingestion route for 28 days. Urine and blood samples were taken weekly and analyzed using ELISA and LC-MS/MS. This study showed that increasing the pH, incubation time, and concentrations of BHA, Cr(VI), H2O2, and ascorbic acid had a synergistic effect on the formation of 8-OHdG. The highest concentration of 8-OHdG was found in samples containing 2'-dG, H2O2, BHA, Cr(VI), and ascorbic acid. The ratio of 2'-dG to H2O2, BHA, Cr(VI), and ascorbic acid in the sample was 1:20 at pH 8.4 for 24 hours was 316.5 ppb at 37°C. The in vivo test results showed the formation of 8-OHdG DNA adducts in the serum and urine of rats tested using ELISA and LC-MS/MS.

Abstrak :
Pada penelitian ini dilakukan studi mengenai pembentukan DNA adduct 8-hidroksi-2'-deoksiguanosin (8-OHdG) dengan mereaksikan 2'-deoksiguanosin dan H₂O₂ dengan senyawa akrilamida dan TBHQ yang diberikan paparan sinar UVA. Uji pembentukan 8-OHdG dilakukan pada variasi waktu inkubasi (5 dan 7 jam) dan variasi pH (7,4 dan 8,4). Hasil dari pembentukan 8-OHdG dianalisis menggunakan instrumen HPLC fasa terbalik dengan menggunakan larutan penyangga natrium fosfat pH 6,7 dan metanol sebagai eluen dengan komposisi 85:15. Hasil yang diperoleh menunjukkan bahwa dari adanya pencampuran TBHQ dan Akrilamida mengakibatkan pembentukan kadar 8-OHdG dengan menghasilkan efek sinergis dan efek antagonis pada hasil pembentukannya. Efek dari pencampuran senyawa akrilamida dan TBHQ meningkat signifikan ketika diberikan paparan sinar UVA. Sampel yang diinkubasi dengan paparan sinar UVA memiliki kadar 8-OHdG yang lebih banyak dibandingkan sampel tanpa paparan sinar UVA. Semakin lama waktu inkubasi, dihasilkan pula kadar 8-OHdG yang semakin besar. Pada pH 8,4, sebagian besar sampel menghasilkan pembentukan 8-OHdG yang lebih besar bila dibandingkan pada sampel dengan campuran yang sama pada pH 7.4. Sampel dengan hasil pembentukan 8-OHdG tertinggi terdapat pada sampel yang mengandung 2'-deoksiguanosin, akrilamida, TBHQ, dan H₂O₂  pada pH 8,4 dengan penyinaran sinar UVA selama 7 jam.

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In this research, a study was conducted on the formation of DNA adduct 8-hydroxy-2'-deoxyguanosine (8-OHdG) by reacting 2'-deoxyguanosine and H₂O₂ with acrylamide and TBHQ compounds that were exposed to UVA light. The 8-OHdG formation test was carried out at various incubation times (5 and 7 hours) and pH variations (7.4 and 8.4). The results of the formation of 8-OHdG were analyzed using a reverse phase HPLC instrument using a buffer solution of sodium phosphate pH 6.7 and methanol as an eluent with a composition of 85:15. The results showed that the mixing of TBHQ and acrylamide resulted in the formation of 8-OHdG levels by producing a synergistic effect and an antagonistic effect on the formation results. The effect of mixing acrylamide and TBHQ compounds increased significantly when exposed to UVA light. Samples incubated with UVA exposure had higher levels of 8-OHdG than samples without UVA exposure. The longer the incubation time, the greater the 8-OHdG content was produced. At pH 8.4, most of the samples resulted in greater 8-OHdG formation when compared to samples with the same mixture at pH 7.4. Samples with the highest 8-OHdG formation results were found in samples containing 2'-deoxyguanosine, acrylamide, TBHQ, H₂O₂ at pH 8.4 with UVA light irradiation for 7 hours.

Abstrak :
ABSTRAK
Nisin has been extensively used as a safe food preservative: therefore, the occurrence of nisin resistance in various bacteria including nisin exposed Listeria monocytogenes has increased in recent years. This problem could be overcome by using nisin in combination with other antimicrobial agents resulting in synergistic effects. Citric acid is a safe food additive granted GRAS status by the Food and Drug Administration, USA. In the present investigation, the antibacterial activity of nisin and citric acid alone or in combinations against L. monocytogenes 10403S was determined, and their potential as food preservative in food model systems was evaluated. The nisin and citric acid showed minimum inhibitory concentration (MIC) at 250 and 4,000 mg/ml, respectively. Checkerboard microdilution method using both compounds showed synergistic effect at concentration of 62.5mg/ml and 1,000 mg/ml, respectively, with the fractional inhibitory concentration index (FICI) value of 0.5. The potent anti listeria effect of nisin in combination with citric acid on the growth of L. monocytogenes in pork ham (food model) was observed during six days of storage at 4oC. This might be exploited to inhibit foodborne bacteria and minimize the nisin resistant problem of L. monocytogenes in the food industry.

Abstrak :
Bio-oil produced by biomass pyrolysis contains high oxygenates, namely, carboxylic acids, alcohols, and ketones resulting in low calorific fuel, and therefore bio-oil requires upgrading to sequester these oxygenates. By conducting the co-pyrolysis of biomass and plastic feed blend, the donation of hydrogen by plastic free radicals to the oxygen of biomass free radicals may sufficiently reduce oxygenate compounds in the bio-oil and increase its yield. Therefore, the synergetic effects are functional. Currently, co-pyrolysis reactors have high aspect ratios (ratio of height to diameter) of 4 or more and small diameters (maximum 40 mm), in which the heat transfer from the furnace to the feed blend is immaterial even though the plastic material has low thermal conductivity. However, in large-scale reactors, such a design restricts the bio-oil’s capacity due to the heat transfer constraint. To resolve the latter and to improve bio-oil quality, in the present work, the co-pyrolysis of corn cobs and polypropylene (PP) is conducted in a stirred-tank reactor with a low aspect ratio (2). PP composition in the feed blend was varied from 0-100% weight with a 12.5% weight interval, heating rate of 5oC/min, and final temperature of 500oC. The results show that by increasing the PP composition in the feed blend from 37.5% to 87.5%, the bio-oil yield increased from 25.8% to 67.2% feed weight. An analysis of bio-oil quality shows that there was a favorably abrupt increase of non-oxygenate composition in the bio-oil from less than 5% to more than 70% as the PP composition in the feed blend was increased from 37.5% to 50% and more.