• Journal of Plant Biology
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• v.30 no.1
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• pp.11-20
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• 1987

Phenolic compounds, p-coumaric and p-hydroxybenzoic acids, known as inhibitors for development and growth of many pioneer species on early stage of succession were used for the test fo susceptibility in various herbs collected from abandoned agricultural fields in the vicinity of Amherst(U. S. A.). The percent inhibition was generally greater for p-coumaric acid than for p-hydroxybenzoic acid. Concentrations of 5$\times$10-5 and 5$\times$10-4M generally had no significant effects, but at 5$\times$10-3M was inhibitory to germination and growth of tested species. And the percent inhibition caused by the two phenolics was correlated (r=.843, p<.01). Also the indices of resistance for germination and elongation were significant (r=.695, p<.01) in this study. While Cirsium and Lepidium invading species of early stage of succession were sharply susceptible for toxic activity by phenolic acids.

• Journal of Plant Biology
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• v.34 no.2
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• pp.93-100
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• 1991

Walnut (Juglans regia L.) is a common cultivated and wild deciduous tree in the temperate regions of Pakistan and elsewhere. A bare or poor understorey of wild or cultivated species is frequently observed beneath and around it. Soil analysis indicated insignificant differences in nutrient status of soils taken from areas with or without walnut influence. Field investigations revealed that the height, shoot, fresh and dry weight of potato, turnip, corn and bean significantly decreased in the walnut-influenced parts of the field compared to their counter-parts in the same field but without walnut influence. Aqueous extracts from various parts, shoot litter, natural rain leachates and soil collected from beneath walnut significantly reduced the germination, early seedling growth, fresh and dry weight, and moisture contents of corn, turnip and bean in various laboratory experiments. Ferulic, p-coumaric, caffeic, vanillic, jJ-hydroxybenzoic, chlorogenic and gallic acid were identified as the possible allelopathic substances in the aquous extracts and rain leachates of the walnut tree. The findings suggest that the observed poor growth of crops is due to allelopathic effects of walnut.walnut.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.713-720
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• 2006

This study was designed to investigate the possible utilization of Ligustrum japonicum leaves as a source of functional ingredients. Contents of total phenolic compounds and condensed tannin were $0.89{\sim}1.53%$ and $0.10{\sim}0.13%$, respectively. The major flavonoid compounds in the leaves of L. japonicum were luteolin, apigenin and their glycosides. Tyrosol, t-cinnamic acid, p-hydroxybenzoic acid, vanillic acid, shikimic acid and protocatecuic acid were detected in free phenolic acid, while tyrosol, t-cinnamic acid, ferulic acid, esculetin, caffeic acid, p-coumaric acid and hydroxytyrosol were detected in esterified phenolic acid. The insoluble phenolic acid contained tyrosol, t-cinnamic and p-caoumaric acid.

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.169-175
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• 1988

This experiment was conducted to determine the presence of allelopathic substance in Portulaca oleracea L. Water and methanol extract from P. oleracea markedly inhibited the germination of lettuce, rice, raddish etc., indicating the presence of biological substances. The biochemical substances such as ferulic, p-coumaric, salicylic, vanillic, p-hydroxybenzoic acid etc., belonging to phenolic compounds were detected in a large amount, which may be responsible for exhibiting inhibitory effects. Various phenolic compounds were detected from different samples such as freshly, dried plants, seeds and callus. The highest amount of tannic and gallic acids were detected in dried samples of P. oleracea, the highest grantity of salicylic and vanillic acids in fresh samples, the largest amount of ferulic acid in seed sample, the highest amount of p-hydroxybenzoic and p-chlorobenzoic acids in callus. Linolenic acid was presented in amount of 9.203 mg/g in dried plant of P. oleracea as one of the major fatty acids and oxalic acid presented 27.941 mg/g as one of the major organic acids. These compounds seemed to be related to inhibitory effect of P. oleracea which needs further study.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.519-524
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• 1998

Four minor compounds were isolated from fruiting bodies of Polyozellus multiflex by consecutive chromatographic separation. Their structures were identified as ergost-4,6,8,22-tetraen-3-one, 4-methoxy-6-methyl-2H-pyran-2-one, p-anisic acid, and p-hydroxybenzoic acid by spectral analysis. They could not inhibit prolyl endopeptidase nor acetylcholine esterase at the concentration up to 100 ppm.

• YAKHAK HOEJI
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• v.11 no.3_4
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• pp.27-32
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• 1967

유화제또는 현탁화제로 쓰이고 있는 hydrophilic polymer의 일종인 acacia및 sodium alginate와 방부제와의 interaction에 관한 연구로서 Higuchi씨등 solubility mehtod를 실험방법으로 하여 고찰하였다. acacia는 용액중에서 혹종의 interation을 하나 o-hydroxybenzoic acid및 p-hydroxybenzoic acid의 methly, ethly, propyl, butyl ester 와는 그러한 interaction이 없다. sodium alginate는 butyl-p-hydroxybenzoate및 o-hydroxybezoic acid를 제외한 본실험에 사용한 방부제와는 용액내에서 interaction을 나타내었다. 방부제의 초농도와 acacia및 sodium alginate를 가하여 일정시간 반응시켜 평형에 도달했을때의 방부제의 농도와의 비인 K치는 acacia및 sodium alginate의 농도와 함수관계에 있음을 발견하였다.

• Journal of Food Hygiene and Safety
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• v.17 no.3
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• pp.166-172
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• 2002

This study has been carried out to estimate the average daily intakes of preservatives commonly used in Korea. The survey method, which is specific approach that can be applicable for Koreans has been proposed to estimate the daily intakes. The ADIS of sorbates, benzoates, and esters of p-hydroxybenzoic acid were less than 1% and judged to be safe. The EDIs of sorbates, benzoates, and esters of p-hydroxybenzoic acid were 0.39, 0.29, and 0.04 mg/kg bw/day respectively. And these data were compared with existing data. In case with sorbates, the EDI of survey data was higher than that of analytical data but much lower than that of maximum permitted level data. Also, the EDIs of benzoates and esters of p-hydroxybenzoic acid showed to be the same results. In conclusion, the EDIs of survey data lie between maximum Permitted level data and analytical data of Preservatives. The survey method could be considered as the possible alternative of refined method.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.63-67
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• 1987

A laboratory experiment was conducted to find out the concentration of phytotoxin in intensively cultivated hot-pepper, garlic and chinese cabbage, and effects of these phytotoxin to the germination and growth of young hot-pepper plant. Also this experiment presents describes of the bio-assay method and results of phytotoxin application to the toxicity of hot-pepper plant. The results obtained were summarized as follows; 1. A series of non-volatile (aromatic) phenolic compounds such as hydroquinone, benzoic-, p-hydroxybenzoic, and vanillic acid were quantitatively and qualitatively analysed using BSA(N, O-bis(trimethylsilyl)acetamide) by means of gas chromatography method. 2. Phytotoxin as hydroquinone, benzoic-, p-hydroxybenzoic- and vanillic acid were determined in intensively cultivated hot- pepper, garlic and chinese cabbage. Highest concentration of phytotoxin was obtained in hot-pepper cultivated soil. 3. Direct toxic action of the applied phytotoxin to the germination and young hot-pepper plant growth was observed at the levels of 200 ppm. Benzoic acid was obtained the highest toxicity to the young hot-pepper plant growth. 4. Mode of actions of phytotoxins to the young hot-pepper plant growth were observed as stunting of stem elongation, discoloration of leaf and oxygen depletion from consideration as causes of symptom.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.230-238
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• 1998

This study was conducted to compare the regeneration of the seedlings under different vegetation types and to identify the presence of allelopathy in Abies koreana(Ak) natural forest in Banyabong Peak(elevation, 1715m), of Mt. Chiri. Twenty quadrats($10m{\times}10m$) were placed in May, 1996 to classify vegetation structure using TWINSPAN. Water-soluble extracts from leaves and soil humus of different vegetation types were collected to test their effects on both seed germination of Ak and mycelial growth of ectomycorrhizal fungi. Phenolic compounds from soil humus were quantified using HPLC. Among the four vegetation types, Sasa borealis(Sb) was found in both Ak-Quercus mongolica(Qm) and Ak-Rhododendron schlippenbachii(Rs) communities. Natural seeding of Ak was $230,000{\pm}90,000seeds/ha$ in 1995 and their germination rate was 25% in an ideal laboratory condition. Density of Ak seedlings less than 5cm in height was 52,000/ha in 1996, while that of seedlings taller than 5cm in height was only 4,000/ha. In the case of Ak-Qm community, density of Ak seedlings with Sb understory was only 7% of the density of seedlings with Rs understary, suggesting the inhibitory effect of Sb. The germination rate of Ak seeds was significantly reduced by leaf extracts of Sb, and Rhododendron mucronulatum var. ciliatum(Rm) and Ak. Soil humus extract of Ak-Qm-Sb subcommunity reduced germination of Ak seeds by 81% and also reduced by 19% the respiration of mycelia of ectomycorrhizal fumgus, Lactarius sp. Among the seven phenolic compounds identified from the soil humus, extract, Ak-Qm-Sb subcommunity contained significantly high content of p-hydroxybenzoic acid, vanillic acid, and syringic acid. Particularly, p-hydroxybenzoic acid was present at 4.2ppm in the Sb roots and at 16.5ppm in the Sb humus, suggesting that it could be the primary allelopathic compound in Abies koreana forests with Sasa borealis understory.

• Elastomers and Composites
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• v.47 no.3
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• pp.216-222
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• 2012

In this study, p-acryloyloxybenzoic acid(ABA) was synthesized with p-hydroxybenzoic acid(HBA) and acryloyl chloride(AC). The synthesized ABA monomer was grafted onto ethylene-propylene-diene rubber(EPDM) in toluene using benzoyl peroxide(BPO) as an initiator. The structures of ABA and EPDM-g-ABA were characterized by FT-IR, $^1H$-NMR, and $^{13}C$-NMR spectrometer. The graft ratio of EPDM-g-ABA increased with increasing the concentration of the initiator and the monomer. Mechanical properties such as tensile strength and compression set of the EPDM-g-ABA were improved with increasing the graft ratio. The $T_g$ and initial decomposition temperature were also increased with increasing the graft ratio.