Effect of Treatment with Selected Plant Extracts on the Physiological and Biochemical Parameters of Rice Plants under Salt Stress

박현화,Pyae Pyae Win,국용인 한국작물학회 2024 한국작물학회지 Vol.69 No.1

ABSTRACT High soil salinity is the most severe threat to global rice production as it causes a significant decline in rice yield. Here, we investigated the effects of various plant extracts on rice plant stress associated with high salinity. Additionally, we examined various physiological and biochemical parameters such as growth, photosynthetic activity, chlorophyll content, and lipid peroxidation – in rice plants after treatment with selected plant extracts under salt stress conditions. Of the 11 extracts tested, four – soybean leaf, soybean stem, moringa (Moringa oleifera), and Undaria pinnatifida extracts – were found to effectively reduce salt stress. A reduction of only 3–23% in shoot fresh weight was observed in rice plants under salt stress that were treated with these extracts, compared to the 43% reduction observed in plants that were exposed to stress but not given plant extract treatments (control plants). The effectiveness varied with the concentration of the plant extracts. Water content was higher in rice plants treated with the extracts than in the control plants after 6 d of salt stress, but not after 4 d of salt stress. Although photosynthetic efficiency (Fv/Fm), electron transport rate (ETR), and the content of pigments (chlorophyll and carotenoid) varied based on the types and levels of stress and the extracts that the rice plants were treated with, generally, photosynthetic efficiency and pigment content were higher in the treated rice compared to control plants. Reactive oxygen species (ROS), such as superoxide radicals, hydrogen peroxide (H2O2), and malondialdehyde (MDA), increased as the duration of stress increased. ROS and MDA levels were lower in the treated rice than in the control plants. Proline and soluble sugar accumulation also increased with the duration of the stress period. However, proline and soluble sugar accumulation were lower in the treated rice than in the control plants. Generally, the values of all the parameters investigated in this study were similar, regardless of the plant extract used to treat the rice plants. Thus, the extracts found to be effective can be used to alleviate the adverse effects of stress on rice crops associated with high-salinity soils.

약용식물 추출물의 숙취 해소 효과에 관한 연구

현창수,박가령,오영미,이영재,한창훈,Hyun, Chang-Su,Park, Garyoung,Oh, Young Mi,Lee, Youngjae,Han, Chang-Hoon 대한수의학회 2014 大韓獸醫學會誌 Vol.54 No.4

The present study was performed to evaluate the effect of medicinal plant extract on relieving hangovers in mice administered alcohol. The animals were divided into three groups. Each group was treated with fermented plant extract, non-fermented plant extract, or water 30 min after consuming ethanol (2 mL/kg). A locomotor activity test showed that all groups had decreased motor activity until 40 min after plant extract administration. The mice treated with water had lower motor activity until 100 min post-administration. However, the group treated with non-fermented plant extract showed increased motor activity 40 min post-administration, and the higher activity level was maintained until 120 min post-administration. The animals treated with fermented plant extract had a level of motor activity between those of the groups treated with water or non-fermented plant extract. Blood was collected from each mouse 120 min post-administration and aldehyde concentration was measured. The group treated with non-fermented plant extract had a significantly higher (p < 0.05) aldehyde concentration than the other groups. These results demonstrate that the non-fermented medicinal plant extract helped alleviate hangovers 40 min after administration by reducing aldehyde concentrations in the blood.

몇 가지 식물추출물이 배양 NIH3T3 섬유모세포의 세포생존율과 세포부착률에 미치는 세포독성에 관한 연구

임요섭 ( Yo-sup Rim ),송원섭 ( Won-seob Song ),서영미 ( Young-mi Seo ),박승택 ( Seung-taeck Park ),김신무 ( Shin-moo Kim ) 대한임상검사과학회 2010 대한임상검사과학회지(KJCLS) Vol.42 No.3

This study was aimed to clerify the cytotoxicity of some plant extracts such as Hosta longissima HONDA (HL), Hemerocallis fulva var. Kwanso REGL (HFVK), Hemerocallis fulva L (HF), Macrocapium officinale NAKAI (MO) and Mentha canadensis var. piperascens HARA (MCVP), the cultured NIH3T3 fibroblasts were treated with 25, 50, 100, 150 and 200 μg/mL of five kinds of plant extracts for 48 hours, respectively. The cytotoxicity of plant extracts was measured by MTT and NR assays for the cell viability, and XTT assay for the cell adhesion activity. In this study, HL, MO and FHVK extracts showed the range of midtoxic-non toxic by the criteria of chemical cytotoxicity. While, the HF and MCVP extracts showed midtoxic. In the extract cytotoxicity, HL, MO and FHVK extracts showed non-toxic by the criteria of extract cytotoxicity. While, HF extract was determined as lower-toxic. In the responsive sensitivity of each plant extract on colorimetric assays, HF extract was sensitive to mitochondrial enzyme by MTT assay, lysosomal enzyme by NR assay and mitochondrial nucleus by XTT assay. While, MCVP extract was sensitive to mitochondrial enzyme by MTT assay and lysosomal enzyme by NR assay than other assays. While, HL, HFVK and MO extracts were most sensitive to NR assay. Cell culture is one of useful materials in the screening of cytotoxic and recovary effect on the putative chemical agents or plant extract. And also, colorimetric assay is regarded as very useful tools for quantitative measurement of cytotoxic effect on plant extracts in vitro.

맞춤형화장품 소재 개발을 위한 제주 식물 탐색

윤경섭,김미진,김무한 한국응용과학기술학회 2018 한국응용과학기술학회지 Vol.35 No.4

In this study, we investigated collagen production and hyaluronic acid production effects for wrinkle improvement test on 50 kinds of land plants and 10 kinds of marine plants native to Jeju Island as a part of developing customized cosmetic materials. Collagen and hyaluronic acid are recognized as major factors affecting skin aging. Cerastium holosteoides var. hallaisanense Mizushima extract (100 μg /mL) produced more than 190% of collagen in the extracts of 50 kinds of land plants. Vicia angustifolia var. segetilis K. Koch. extract (100 μg/mL) produced more than 160% of collagen. Ftsia japonica Decne. et Planch. extract (100 μg/mL), Euonymus japonica Thunb. extract (100 μg/mL), Suaeda malacosperma H.Hara extract (100 μg/mL), Elaeagnus umbelellata Thunb. extract (100 μg/mL), Sedum oryzifolium Makino extract (100 μg/mL), Vicia unijuga A. Br. extract (100 μg/mL), and Brassica juncea var. integrifolia Sinsk. extract (100 μg/mL) showed more than 140% collagen production effect. Among the 10 species of marine plants, Sargassum macrocarpum C. Agardh extract (50 μg/mL) produced more than 190% of collagen, and Carpopeltis angusta (Harvey) Okamura extract (100 μg/mL), Codiumcoactum Okamura extract (100 μg/mL), and Codium tenuifolium S. Shimada, T. Tadano & J. Tanaka extract (100 μg/mL) showed more than 140% collagen production. Suaeda malacosperma H.Hara extract (100 μg /mL) showed the effect of producing hyaluronic acid more than 140%, and Ftsia japonica Decne. et Planch. extract (20 μg/mL) and Wistaria floribunda A.P. DC extract (100 μg/mL) showed more than 130% hyalunonic acid production effect. Among the 10 species of marine plants, Peyssonnelia capensis Montagne extract (100 μg/mL) was the most effective. Carpopeltis angusta (Harvey) Okamura extract (100 μg/mL), Codiumcoactum Okamura extract (100 μg/mL), and Codium tenuifolium S. Shimada, T. Tadano & J. Tanaka extract (100 μ g/mL) showed more than 120% hyalunonic acid production. Jeju resources, which have good collagen and hyaluronic acid production, showed the potential to be applied to solve the skin troubles of customized cosmetics in the future. 본 연구에서 최근 한국 제주 지역에서 큰 관심을 보이고 있는 맞춤형화장품 소재 개발 일환으로서 제주도에서 자생하는 육상식물 50종과 해상식물 10종에 대해 주름개선 검증을 위한 콜라겐 생성 효과와 히알루론산 생성 효과를 조사하였다. 콜라겐과 히알루론산은 피부 노화에 영향을 주는 주요 요인으로 인식되고 있다. 실험 결과, 육상식물 50종 추출물 중에서 점나도나물추출물(100 μg/mL)은 190% 이상 콜라겐을 생성 하였으며, 살갈퀴추출물(100 μg/mL)은 160% 이상, 팔손이추출물(10 μg/mL), 금사철추출물(100 μ g/mL), 기수초추출물(100 μg/mL), 보리수나무추출물(100 μg/mL), 땅채송화추출물(100 μg/mL), 나비 나물추출물(100 μg/mL), 갓추출물 (100 μg/mL)은 140% 이상 콜라겐 생성 효과를 보였다. 해상식물 10 종 추출물 중에서는 큰열매모자반추출물(50 μg/mL)이 190% 이상 콜라겐을 생성하였으며, 붉은뼈까막살 추출물(100 μg/mL), 누운청각추출물(100 μg/mL), 우단청각추출물(100 μg/mL)의 경우는 140% 이상 콜라겐 생성 효과를 보였다. 제주 육상식물 50종 추출물 중에서 기수초추출물(100 μg/mL)이 140% 이상 히알루론산 생성 효과를 보였으며, 팔손이추출물(20 μg/mL), 등나무추출물(100 μg/mL)은 130% 이상의 히알루론산이 생성 효과를 나타냈다. 해상식물 10종 추출물 중에서는 자루바다표고추출물(100 μg/mL)이 가장 효과가 좋았 으며, 이 외에도 붉은뼈까막살추출물(100 μg/mL), 누운청각추출물(100 μg/mL), 우단청각추출물(100 μg/mL)에서 120% 이상 히알루론산 생성 효과를 보였다. 이들 콜라겐과 히알루론산 생성 효과가 양호한 제주 자원들은 향후 맞춤형화장품의 피부 고민을 해결 하는 데 적용될 수 있는 가능성을 보여 주었다.

약용식물(오크라, 엉컹퀴, 엄나무, 줄풀) 유래 페놀성 물질의 항산화 활성

최진영,조민경,구영미,김현경,신진원,김동영,김혜진,이은호,김나현,조영제,Choi, Jin-Young,Jo, Min-Kyeong,Goo, Young-Mi,Kim, Hyun-Kyung,Shin, Jin-Won,Kim, Dong-Yeong,Kim, Hye-Jin,Lee, Eun-Ho,Kim, Na-Hyun,Cho, Young-Je 경북대학교 농업과학기술연구소 2015 慶北大農學誌 Vol.33 No.2

안전한 천연물을 이용한 천연항산화제 개발 연구의 일환으로, 오크라, 엉컹퀴, 엄나무 및 줄풀 등 4종의 천연 약용식물 추출물의 항산화 활성을 측정해보았다. 추출물의 총 phenolic compounds 함량은 오크라와 엉컹퀴는 50% ethanol, 엄나무는 40% ethanol, 줄풀은 60% ethanol에서 최대용출을 나타내었으며, water 추출물에서 2.72~34.15 mg/g, ethanol 추출물에서 2.83~34.23 mg/g의 용출율을 나타내었다. 4종류 약용식물 water과 ethanol 추출물의 DPPH radical 소거능은 $50{\mu}g/mL$의 저농도에서 모두 74% 이상의 높은 소거활성을 나타내었다. ABTS radical cation decolorization을 측정한 결과, 4종의 약용식물 water 추출물과 ethanol 추출물 $100{\mu}g/mL$의 농도에서 모두 88% 이상의 높은 저해율을 나타내었다. 지용성 물질에 대한 항산화 효과를 측정하기 위해 antioxidant protection factor(PF)를 측정한 결과, 엉컹퀴 water과 ethanol 추출물 $50{\ddot{I}}g/mL$의 저 농도에서 각각 1.73과 1.76 PF로 다른 약용식물 보다 높은 항산화효과를 나타내었다. TBARs 생성 억제율을 측정한 결과 오크라를 제외한 3종의 약용식물 추출물 $50{\mu}g/mL$ phenolic 농도에서 80% 이상의 생성억제 효과를 나타내었다. 이러한 결과에 따라 다양한 약용식물 추출물이 항산화 및 기능성 식품 소재로 활용이 가능하다고 판단되었다. In this study, the antioxidant activity of water and ethanol extracts from Hibiscus esculentus, Cirsium japonicum, Zizania latifolia and Kalopanax pictus for functional food source were examined. The optimal conditions for phenolic compounds extraction from medicinal plants were at 50% ethanol with Hibiscus esculentus and Cirsium japonicum var. ussuriense, at 40% ethanol with Kalopanax pictus and at 60% ethanol with Zizania latifolia. The total phenolic contents from the extracts of medical plants were determined to be 2.72~34.15 mg/g in the water extracts and 2.83~34.23 mg/g in the ethanol extracts. The electron-donating abilities (EDA) of the water and ethanol extracts were both above 74% at the low concentration of $50{\mu}g/mL$. The ABTS radical-cation decolorization was above 88% at $100{\mu}g/mL$ concentration in all the extracts of various medicinal plants. The antioxidant protection factor (PF) in the water and ethanol extracts of the Cirsium japonicum var. ussuriense extracts was $1.73{\pm}0.02PF$ and $1.76{\pm}0.01PF$ at $50{\mu}g/mL$ concentration respectively, and was higher than those of the other medicinal-plant extracts. The TBARs inhibition rates of all the medicinal-plant extracts, were above 80% at the $50{\mu}g/mL$ concentration except Hibiscus esculentus. These results confirmed that the various oriental medicinal plants (Hibiscus esculentus, Cirsium japonicum var. ussuriense, Kalopanax pictus and Zizania latifolia) that were included in this study are useful anti-oxidant and functional-food resources.

약용식물의 부위별 및 추출용매에 따른 효능효과의 차이

김경동 ( Kyung-dong Kim ),나민균 ( Min-kyun Na ),김상진 ( Sang-jin Kim ) 대한화장품학회 2006 대한화장품학회지 Vol.32 No.2

본 연구는 한방화장품의 원료로써 사용이 되는 약용식물들의 부위별 및 추출용매에 따른 추출물의 효능효과의 차이를 기술하였다. 기존의 단일성분 분석법 보다 실제로 성분의 복합체인 추출물에 대하여 항산화 관련 효능효과 시험법을 적용하였다. 일차적으로 항산화활성을 가지는 약용식물을 선별한 후, 문헌상 부위별로 사용이 가능한 약용식물 11종을 선정하여 DPPH radical 소거활성 및 hydroxyl radical 소거활성과 같이 널리 알려진 시험법을 통하여 차이를 확인하였다. 예를 들자면 Trachelospermum asiaticum 경우 aerial part와 fruit를 비교하면 DPPH radical 소거활성인 경우 값이 각각 25.2 ± 0.2와 62.4 ± 1.6로 fruit가 2.4배의 높은 효과를 보이며, hydroxyl radical 소거 활성의 경우에는 fruit에서는 효과를 보이지만 aerial part에서는 효과를 확인할 수 없었다. 몇 가지 다른 식물들도 같은 형태를 보여주고 있다. 이 결과로 약용식물 또는 유효성분을 가지는 식물을 추출함에 있어서 부위별 추출이 고려되어야 함을 알 수 있었다. 또한 약용과 염료용으로 많이 사용이 되는 Lithospermum erythrorhizon를 선정하여 추출용매를 변경시킴으로써 용매에 따른 효과 차이를 확인하였다. 실제로 superoxide scavenging activity값을 측정한 결과 용매에 따라 효과 차이가 10~80% 발생함을 확인함으로써 약용식물 추출하여 사용 시 부위별 또는 추출 용매별로 차이가 있음을 고려하여 제품에 적용시 발생 가능한 오차를 줄여야 한다는 것을 보여주었다. This study was to describe the differences in efficacy and effect of herbal extracts by the part and solvent extraction from the medical plants used as materials of oriental herbs cosmetics. And, this study was to apply to the test method of efficacy and effect related to the antioxidation as herbal extracts, complex of actual ingredient, not existing analytical methods of single ingredient. After screening the medical plants with the antioxidative activity primarily and selecting 11 sorts of medical plants to be used by the part in the literature, this study was to confirm the differences through the well-known test methods like DPPH radical scavenging activity test and hydroxyl radical scavenging activity test. For examples, in case of Trachelospermum asiaticum, compared with the aerial part and fruit, the value of DPPH radical scavenging activity test had 25.2 ± 0.2 and 62.4 ± 1.6 each. It has shown that the value of fruit had 2.4 times higher effect than the one of aerial part. In case of hydroxyl scavenging activity test, it was effective in the fruit, but it has shown that there was no effect on the aerial part. It showed the same phenomena in some other plants. From the result above, this researcher could understand that it needed to consider extracting the medical plants or plants with the active principle by the part. Also, this study was to confirm the differences in effect according to the solvent as it changed the solvent extraction after selecting a plant (Lithospermum erythrorhizon) widely used for medicine and dye. As a result of measuring the actual value of superoxide scavenging activity test, this study was to consider that there were differences by the part or solvent extraction in extracting and using the medical plants as it has shown that the effect differences produced 10~80% according to the solvent. When it was applied to the products, this study has shown that it needed to decrease the possible errors.

약용식물 추출물의 항산화 활성

박혜진 ( Hye Jin Park ),강선애 ( Sun Ae Kang ),이주영 ( Ju Yeong Lee ),조영제 ( Young Je Cho ) 한국식품저장유통학회(구 한국농산물저장유통학회) 2012 한국식품저장유통학회지 Vol.19 No.5

In this study, the optimal conditions for phenolic-compound extraction from medicinal plants were found to be 24 h and about 50% ethanol. The electron-donating scavenging activities (DPPH), ABTS radical-cation decolorization (ABTS), antioxidant protection factor (PF), and thiobarbituric acid reaction substance (TBAR) were measured to determine the antioxidant activities of the extracts of Sanguisorba officinalis Linn., Citrus unshiu Markovich, Melia azedarach L., Asparagus cochinchinensis Merr., Citrus unshiu S., Polygonum aviculare L., and Leonurus sibiricus L. The total phenolic contents of the extracts of medical plants were determined to be 0.45-3.00 mg/g in the water extracts and 0.33-3.15 mg/g in the 50% ethanol extracts. The electron-donating abilities (EDA) of the water and ethanol extracts were both above 85% at the 50 μg/ml concentration. The ABTS radical-cation decolorization was above 80% at the 100 μg/ml concentration in all the extracts of various medicinal plants. The antioxidant protection factor (PF) of the Melia azedarach L. extracts was found to be 1.65±0.40 PF in the water extracts at the 100 μg/ml concentration, and was higher than those of the other medicinal-plant extracts. The TBAR inhibition rates of all the medicinal-plant extracts, except Asparagus cochinchinensis Merr., were above 85% at the 100 μg/ml concentration. These results confirmed that the various oriental medicinal plants (Sanguisorba officinalis Linn., Citrus unshiu Markovich, Melia azedarach L., Asparagus cochinchinensis Merr., Citrus unshiu S., Polygonum aviculare L., and Leonurus sibiricus L.) that were included in this study are useful functional-food sources.

Synergistic Growth Inhibition of Herbal Plant Extract Combinations against Candida albicans

( Jeemin Yoon ),( Tae-jong Kim ) 한국목재공학회 2023 목재공학 Vol.51 No.2

Many skin diseases are caused by microbial infections. Representative pathogenic fungus and bacterium that cause skin diseases are Candida albicans and Staphylococcus aureus, respectively. Malassezia pachydermatis is a fungus that causes animal skin diseases. In this study, we propose a method for removing pathogenic microorganisms from the skin using relatively safe edible herbal extracts. Herbal extracts were screened for skin health through the removal of pathogenic microorganisms, and combinations for effective utilization of the screened extracts were identified. In this study, among methanol extracts of 240 edible plants, C. albicans, S. aureus, and M. pachydermatis were killed by extracts of 10 plants: Acori Gramineri Rhizoma, Angelicae Tenuissimae Radix, Cinnamomi Cortex, Cinnamomi Ramulus, Impatientis Semen, Magnoliae Cortex, Moutan Cortex Radicis, Phellodendri Cortex, Scutellariae Radix, and Syzygii Flos. By evaluating the synergistic antifungal activities against C. albicans using all 45 possible combinations of these 10 extracts, five new synergistic antifungal combinations, Acori Gramineri Rhizoma with Magnoliae Cortex extracts, Acori Gramineri Rhizoma with Phellodendri Cortex extracts, Angelicae Tenuissimae Radix with Magnoliae Cortex extracts, Magnoliae Cortex with Phellodendri Cortex extracts, and Phellodendri Cortex with Syzygii Flos extracts, were identified. By utilizing the selected extracts and five combinations with synergistic antifungal effects, this work provides materials and methods to develop new and safe methods for treating candidiasis using natural products.

화장품 개발을 위한 전남 지역 자생 식물 추출물의 활성 연구

임도연(Im, Do-Youn) 한국상품학회 2020 商品學硏究 Vol.38 No.6

본 연구에서는 전남 지역에서 재배, 생산되고 있는 약용 작물 중 생산량이 많은 식물 소재 5종의 열수 추출물을 대상으로 화장품 원료로서 활용 가능성을 검토하였다. 폴리페놀 함량을 확인한 결과에서 녹차와 비파엽 열수추출물이 각각 206.15 μg/mL와 106.53 μg/mL의 폴리페놀 함량을 가지는 것으로 확인되었다. 플라보노이드 함량을 측정한 결과에서 녹차와 비파엽 열수추출물이 각각 29.27 μg/mL와 15.54 μg/mL로 상대적으로 높은 함량을 가지는 것으로 나타났다. 항산화 활성 수분을 확인하기 위해 실시한 DPPH radical 소거능 측정 결과에서 녹차 열수추출물과 비파엽 열수추출물의 DPPH 라디칼 소거능이 각각 93.07%와 75.64%로 나타나 항산화 활성이 높은 것으로 확인되었다. 각 식물 추출물의 자외선 흡수 차단 특성을 확인하기 위해 실시한 액체크로마토그래프-자외선검출기 분석에서 비파엽 열수추출물 중에 측정 대상 자외선 파장을 강력하게 흡수하는 성분이 3종 이상 존재함을 확인하였다. 각 추출물들의 세포 독성을 검토하기 위해 실시한 L-929 세포 생존률 측정에서 각 식물 추출물들은 전반적으로 90% 이상의 세포 생존률을 나타냄에 따라 인체의 피부에 적용되는 화장품의 원료로서 사용 가능성이 충분한 것으로 확인되었다. 이상의 결과에서 비파엽 열수추출물의 강력한 자외선-A 흡수 차단 능력과 녹차 열수추출물의 높은 항산화 활성을 결합한 복합 식물 추출물의 화장품 소재 가능성을 확인할 수 있었다. In this study, the possibility of using hot water extracts of five plant materials with high yield among medicinal crops cultivated and produced in Jeonnam region was examined as a cosmetic ingredients. From the results of checking the polyphenol content, it was confirmed that the hot water extract of green tea and loquat leaf had a polyphenol content of 206.15 μg/mL and 106.53 μg/mL. In flavonoid content, the hot water extract of green tea and loquat leaf was found to have relatively high contents, 29.27 μg/mL and 15.54 μg/mL. The DPPH radical scavenging activity of the green tea hot water extract and the loquat leaf hot water extract showed high antioxidant activity as 93.07% and 75.64%, respectively. In a liquid chromatograph-ultraviolet detector analysis conducted to confirm the UV absorption blocking properties of each plant extract, it was confirmed that three or more components strongly absorbing the UV wavelength to be measured were present in the loquat leaf hot water extract. In the L-929 cell viability measurement conducted to examine the cytotoxicity of each extract, it was confirmed that each plant extract exhibited an overall cell viability of 90% or more, and thus its potential to be used as a raw material for cosmetics applied to human skin. From the above results, it was possible to confirm the possibility of a cosmetic material of a complex plant extract combining the strong UV-A absorption blocking ability of the hot water extract of loquat leaf and the high antioxidant activity of hot water extract of green tea.

천연물 성분을 이용한 환경 유해미생물의 biofilm 생성 저해능 비교에 관한 연구

강은진 ( Eun-jin Kang ),박지헌 ( Ji Hun Park ),진슬 ( Seul Jin ),김영록 ( Young-rok Kim ),도형기 ( Hyung-ki Do ),양웅석 ( Woong-suk Yang ),이재용 ( Jae-yong Lee ),황철원 ( Cher-won Hwang ) 한국환경과학회 2019 한국환경과학회지 Vol.28 No.2

In this study, we investigated the in vitro anti-biofilm activities of plant extracts of chives (Allium tuberosum), garlic (Allium sativum), and radish (Raphanus sativus L.) against environment harmful bacteria (gram-positive Staphylococcus aureus and, gram-negative Salmonella typhimurium and Escherichia coli O157:H7). In the paper disc assay, garlic extracts exhibited the highest anti-biofilm activity. The Minimal Inhibitory Concentration (MIC) of all plant extracts was generally higher for gram-negative bacteria than it was for gram-positive bacteria. Gram-negative bacteria were more resistant to plant extracts. The tetrazolium dye (XTT) assay revealed that, each plant extract exhibited a different anti-biofilm activity at the MIC value depending on the pathogen involved. Among the plant extracts tested, garlic extracts (fresh juice and powder) effectively reduced the metabolic activity of the cells of food-poisoning bacteria in biofilms. These anti-biofilm activities were consistent with the results obtained through light microscopic observation. Though the garlic extract reduced biofilm formation for all pathogens tested, to elucidate whether this reduction was due to antimicrobial effects or anti-biofilm effects, we counted the colony forming units of pathogens in the presence of the garlic extract and a control antimicrobial drug. The garlic extract inhibited the E. coli O157:H7 biofilm effectively compared to the control antimicrobial drug ciprofloxacin; however, it did not inhibit S. aureus biofilm significantly compared to ciprofloxacin. In conclusion, garlic extracts could be used as natural food preservatives to prevent the growth of foodborne pathogens and elongater the shelf life of processed foods.