The objective of this study was to determine the ultrasonication-assisted extraction conditions that maximize the DPPH radical scavenging activity of extracts obtained from the stems of Lespedeza bicolor Turcz through the application of the Response Surface Methodology (RSM). Before delving into the analysis of extraction conditions using the RSM model, we conducted efficiency validation of ultrasonication-assisted extraction and executed single-factor experiments for ethanol concentration, extraction time, and extraction temperature. The data obtained from these single-factor experiments were employed to construct the Box-Behnken Design (BBD). In these results, in the single-factor experiments, it was evident that the parameters for ethanol concentration, extraction time, and extraction temperature exhibited quadratic trends. The single-factor experiments allowed us to discern the trends for each parameter leading to the maximum antioxidant capacity, and this data was subsequently applied to the BBD. Following the completion of initial experiments, a Response Surface Methodology (RSM) model was constructed based on Box-Behnken Design (BBD). According to the predictive model developed in this study, it was anticipated that performing ultrasonic-assisted extraction for 85.0412 minutes at an ethanol concentration of 32.573% and an extraction temperature of 51.5608°C will result in a DPPH radical scavenging activity of 79.7146%. The predictive results were statistically verified through a comparative analysis with actual measurements and ANOVA analysis, confirming the statistical significance of the model. The finding of this study underscore the significance of optimizing extraction conditions in the precise quantification of the antioxidant potential for economic advantages in both experimental and industrial contexts.

양파의 이용 다변화를 위하여 껍질과 육질을 각각 100∼300℃의 조건에서 아임계수로 추출하여 그 특성을 조사하였다. 양파 껍질과 육질 모두 추출 온도가 상승함에 따라 아임계수 추출물의 페놀 함량이 증가하였다. 양파 껍질 추출물은 250℃에서 quercetin, quercetin 3,4'-diglycoside, quercetin-3- glucoside의 함량이 가장 높았고, 육질 추출물은 quercetin 3,4'-diglycoside 의 함량이 200℃에서 가 장 높았으나 quercetin 및 quercetin-3-glucoside의 함량은 상대적으로 미미하였다. 양파 껍질과 육질 추출물의 quercetin및 그 배당체 함량은 300℃에서 급격히 감소하였다. 양파 껍질과 육질 모두 추출 온도가 증가할수록 아임계수 추출물들의 DPPH 라디칼 소거능과 alcohol dehydrogenase 활성을 향상시 켰다. 이상의 결과는 적절한 아임계수 조건이 양파 추출물의 생리활성을 향상시킬 수 있음을 시사한다.

This study was conducted to investigate the total phenol contents, antioxidative activities and antibacterial activities of twenty species of entomopathogenic fungi. The total phenol content was highest in Aspergillus flavus (553.0±52.15 ㎍/g) and A. parasiticus (529.9±60.10 ㎍/g). On the other hand those in other strains were within the range of 26.6～121.9 ㎍/g. The antioxdative activity was shown in the most of strains and the highest DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical scavenging activity was observed in A. flavus (90.9±2.90%) and A. parasiticus (77.9±4.13%). This result indicated that the antioxidative activities were very correlated with the total phenol contents. The antibacterial activitiy was found in the every tested pathogenic bacteria. Especially, the antibacterial activity was strongest against Listeria monocytogenes and Escherchia coli.

Lactic Acid Bacteria (LAB) are among the representative probiotics that have been used for a long time in fermented food. Although there are many studies on detecting the radical scavenging activity of LAB, few studies have been conducted on the environmental factors that improve scavenging activity. This study investigated the environmental factors affecting the DPPH radical scavenging and various antioxidant activities of Kimchi-derived Lactobacillus plantarum K-21 with antihypertensive and radical scavenging activities. The optimal conditions for scavenging DPPH radicals were glucose 2%, bactopeptone 0.5%, Tween 80 0.05%, L-cysteine 0.05%, and an initial pH 6.5 at 35℃. Under optimal conditions, the DPPH radical scavenging activity was 94.8±2.2%, which was 1.5 times higher than that of the basic medium. In addition, L. plantarum K-21 had other antioxidant activities; ABTS radical scavenging (93.6±1.5%), hydroxyl radical scavenging (8.5±0.9%), metal chelating (65.9±0.5%), NO scavenging (53.1±19%), SOD-like (25.1±1.5%), and reducing power (11.7±1.4%) activities were detected. Therefore, L. plantarum K-21 may act not only as a starter for lactic acid-fermented foods with improved functionality but also as a drug for various diseases caused by oxidative stress.

This study is conducted to investigate the effects of growth characteristics (GC) and DPPH radical scavenging activity (DRSA) of the heading lettuce ‘Fidel’ depending on four concentrations of activated mineral groups (AMG: 1.6% active minerals and 0.03% CaO) added to basic nutrient solutions (diluted by 0, 0.05, 0.1, and 0.2%) and on four different light-emitting diodes (LED; B:R:W ratio = 0:1:12, 0:1:9, 0:5:5, and 2:3:5). Both 0.1 and 0.2% AMG showed better GC of lettuce in plant width, plant length, leaf width, leaf length, and the number of leaves than those of other AMG, while leaf thickness and chlorophyll value did not show significant difference among all AMG. Moreover, 0.1 and 0.2% AMG showed heavier shoot fresh weights than those of other AMG. As for the combinations of AMG and LED, B0:R5:W5 showed the best lettuce GC regardless of AMG compared to other AMG and LED combinations. As shown in the above results of LED, although there was a difference in lettuce growth by LED, the differences of lettuce growth by AMG were statistically significant. The DRSA was the highest at 82.8% in B2:R3:W5, followed by B0:R5:W5 at 77.8%. LED showed differences but AMG did not affect DRSA. Therefore, the optimal conditions in plant factory for GC and DRSA of the lettuce were 0.1% AMG and B0:R5:W5.

This study was executed to evaluate the phenolic content, DPPH radical scavenging rate, and the cytotoxic effect in human cancer cell, 3T3-L1 cell from C. lanceolata extracts at various ethanol concentration. Total polyphenol and flavonoid content of the C. lanceolata at various ethanol concentration showed the high amount in 70%, 100% ethanol extract. The DPPH radical scavenging activity progressively increased in a dose-dependent manner, and showed the highest in 100% ethanol extract. The cytotoxic effect against human cancer cell of the C. lanceolata was higher in 50% and 70% ethanol extracts. In particular, the cytotoxic effect in MCF-7 cell was relatively higher than in other cells. The IC50 (concentration causing 50% cell death) value showed the highest on MCF-7 cell (538.39 ㎍/㎖) in 70% ethanol extract, and exhibited significant activity against Hela cell (637.87 ㎍/㎖), Calu-6 cell (728.64 ㎍/㎖). The extract of 70% ethanol at 1,000 ㎍/㎖ exhibited a pronounced cytotoxic effect on 3T3-L1 cell comparable to that of the other extracts, and reduced in a concentration-dependent manner.

항산화 및 항균활성을 가진 천연물을 활용해 합성보존료를 대체하고자 하는 연구가 활발한 가운데 국내 자생 식물 중 135종을 대상으로 DPPH radical 소거활성을 측정하였다. 이중 항산화 활성이 10%대로 낮게 나타난 식물 8종에 대해 항균효과를 조사하였다. 식물 추출물의 DPPH radical 소거활성은 0.41~94.84%로 다양하였으며, 가장 효과가 좋은 식물은 꽃향유와 우엉으로 각각 94.84, 80.55%를 나타내었다. 우엉은 잎의 경우 26.87, 뿌리 19.29%의 활성을 나타내 동일 식물이라도 추출부위에 따라 활성의 차이가 있을 것으로 보인다. 선이질풀과 비쭈기나무는 각각 그람양성균인 B. subtilis, 그람음성균인 E. coli 및 Candida속인 C. albicans에 대해 2.2~10.8 mm 수준의 항균활성을 나타내었다. 각 식물에 대한 다양한 추출법을 적용하여 기능성을 확인하고 이들 항산화성 물질에 대한 추가 연구가 진행되어야 할 것으로 사료된다.

본 연구는 녹두나물 재배온도(15~30±1℃ )에 따른 나물의 생육과 수율, 페놀화합물 함량, DPPH와 ADH 및 ALDH활성에 미치는 영향을 분석하였다. 1. 녹두나물 재배온도가 높을수록 나물 생산수율은 높고, 경실비율은 낮았으나 25±1℃ 와 30±1℃ 는 큰 차이가 없었다. 2. 녹두나물의 ethanol 추출물의 총페놀 함량은 재배온도 15±1 , 20±1 , 25±1℃ , 총플라보노이드 함량은 재배온도 15±1 , 20±1℃ 에서 많았다. 3. 녹두나물 ethanol 추출물의 DPPH 라디칼 소거활성은 재배온도가 낮을수록 높았고, ADH와 ALDH활성은 재배온도 간 일정한 경향을 보이지 않았다. 4. 이상의 녹두나물 생산수율, 페놀화합물 함량, 생리활성 등을 고려해볼 때 녹두나물 재배 최적온도는 20~25℃ 로 보아진다.

Changes in the contents of total phenolic compounds in as Agrimonia pilosa well as their antioxidant capacity according to the havest time and positions were examined. The contents of the total phenolic compounds were determined by extraction with MeOH. Among havest times harvestry in July showed highest contents of the total phenolic compounds and harvestry in May showed lowest contents of the phenolic compounds. Among the 4 positions (root, branch, leaf, flower) of Agrimonia pilosa the root contained highest contents of the phenolic compounds. The antioxidant capacities of Agrimonia pilosa were increased roughly with increasing level of contents of phenolic compounds according to positions.

A series of methanol extracts from leaf and root parts in spring- and winter-barley plants were assayed to determine their allelopathy and antioxidant activity. The methanol extracts applied on filter paper in a Petri-dish significantly inhibited root growth of Chinese milkvetch (Astragalus sinicus L.) seedlings. Leaf extracts at 25 and 50 g L-1 inhibited root growth of Chinese milkvetch seedlings more than root extracts. No difference in phytotoxic effects of spring- and winter-barley seedlings extracts on root growth of Chinese milkvetch was observed. Methanol extracts dose-dependently increased DPPH free radical scavenging activity in vitro. DPPH free radical scavenging activity was higher in the methanol extracts from winter-barley seedlings than in those from spring-barley seedlings, and from leaf extracts than from root extracts. The antioxidant potential of the individual fraction from the methanol extracts of spring-barley seedlings was in order of n-butanol>ethyl acetate>water>chloroform>n-hexane fraction. By means of HPLC analysis, spring-barley (200.62 mg 100g-1 ) had more amount of total phenol acid than winter-barley (114.08 mg 100g-1 ). Especially, ferulic acid was detected in spring-barley extract (183.46 mg 100g-1 ) as the greatest amount. These results suggest that early seedlings of barley plants had potent allelopathy and antioxidant activity, and their activities were differently exhibited depending on plant parts and growing condition.

A series of aqueous or methanol extracts from four different Korean salad plants were assayed to determine their allelopathy and antioxidant activity. The extracts applied on filter paper in a Petri-dish bioassay significantly inhibited root growth of against alfalfa (Medicago sativa) seedlings. Leaf extracts from 40 g dry tissue L-1 of Aster yomena was most phytotoxic to alfalfa root growth, and followed by that of Cirsium japonicum, Taraxacum officinale, and Ixeris dentate. Methanol extracts of plants dose-dependently increased DPPH free radical scavenging activity in vitro. Antioxidant activity of methanol extracts from the same plant species was investigated, and the result showed high DPPH free radical scavenging activity in Cirsium japonicum, Aster yomena, and Ixeris dentate, however, in Taraxacum officinale was least activity. By means of HPLC analysis, chlorogenic acid, p-coumaric acid, and total phenolics with 7.68, 17.47 and 18.64 mg, 100g-1, respectively, showed the highest amounts in methanol extracts from Cirsium japonicum leaves. These results suggest that Compositae salad plants contain water-soluble substances with allelopathic potential as well as antioxidant activity.

Phytochemical study on the EtOAc fraction from a MeOH extract of the leaves of Alnus hirsuta Rupr. led to the isolation of nine compounds betulin (1), betulinic acid (2), hirsutanonol (3), hirsutenone (4), quercetin (5), avicularin (6), gallic acid (7), hyperin (8), and daucosterol (9). Among them, six compounds 1, 2, 57, and 9 are report from this plant for the first time. All isolated compounds were evaluated for their antioxidant activity using DPPH radical scavenging capacity and inhibition effect on mitochondrial lipid peroxidation. Six phenolic compounds 3-8 were found to have potent antioxidant activity. Of which, compounds 3, 4 and 5 showed significant free radical scavenging activity with the IC50 values of 18.3 ± 2.5, 15.7 ± 3.8 and 23.5 ± 3.1 μm, respectively. In addition, the compounds 3-8 exhibited inhibition effect on the mitochondrial lipid peroxidation with the IC50 values of 88.0 ± 6.5, 12.6 ± 1.2, 8.0 ± 1.1, 58.5 ± 4.3, 173.6 ± 15.2, and 75.0 ± 6.7 μm, respectively.

This study was to investigate antioxidative activity of rice grain using 1, 1-Diphenyl-2-picrylhydrazyl(DPPH) and thiobarbituric acid (TBA) method and germination ability for screening rice varieties with high antioxidative activities on korean native and foreign rice varieties harvested in 1998 and 1999. The average antioxidative activity of foreign rice varieties (DPPH 63.5% and TBA 55.2%) was significantly higher than that of native rice varieties (DPPH 47.2% and TBA 45.6%) on varieties harvested in 1999. The promptness index (PI) of native rice varieties was higher in stored rices for three months (mean PI=160.7) than that of stored rices for a year (mean PI=141.6). On the other hand, the PI of foreign rice varieties was higher in stored rices stored for a year (mean PI=176.7) than that of stored rices for three months (mean PI=157.5). Varieties with high redness of hulled rice (a-value) showed significant lipid peroxidation inhibitory activity to DPPH in a stored rices for a year (r=0.5744** ) and stored rices for three months (r=0.5630** ) . These results indicate that the pigments of hulled rice varieties may play important antioxidative roles and colored rice varieties with higher antioxidative potentials can be developed and also may provide information with rice breeder to breed rice variety with a high antioxidative activity for a rapid screening of a small amounts of a large number of samples using color value.