• Applied Microscopy
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• v.33 no.3
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• pp.233-241
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• 2003

Patterns of tannin accumulation in leaves of C-4 Euphorbia maculata have been examined using electron microscopy. Tannins, which are secondary metabolite phenolic compounds, were found to be deposited conspicuously in vacuoles of certain tissues regardless of their stage in development. However, patterns of deposit accumulation were distinguishable by their cell type during leaf differentiation. The deposits appeared most concentrated in the concentric bundle sheath cells enclosing veins, while little or no density was detected mostly in the mesophyll cells close to the epidermis. An ultrastructural study revealed that the deposits were restricted to the vacuoles at an early stage of leaf development; during which the vacuoles were almost completely filled with the tanniferous substances. The deposits themselves took different forms ranging from granules to huge globules while expanding leaf blade. As the leaf matured, the deposits accumulated either centripetally adjacent to the inner tangential tonoplast or by penetration into the cytoplasm amongst various cellular organelles, resulting in an extremely dense cytoplasm. Electron micrographs frequently showed the delineation of each organelle by the presence of dense deposits within the cytoplasm. Some large depository vacuoles filled with tannins had a corrugated appearance on the sectioned surface. The pattern and potential role of the deposits have been discussed.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.310-316
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• 1994

The phenolic substances contents of 45 plant foods in Korean diet were determined by different methods. Total phenolics contents by Folin-Denis method were $0.1{\sim}5.8%$ (dry matter basis), in which persimmon leaf, chestnut's inner skin, Chinese quince, walnut, sunflower seed and arrowroot exhibited the higher levels above 2%. Condensed tannin contents by vanillin method were $0{\sim}48%$, in which Chinese quince and chestnut's inner layer gave very high levels. Protein-precipitable phenolic substances ranged from 0.4% to 2.2%, in which chestnut's inner layer, walnut and Chinese quince had the highest content. The ability of phenolics to form precipitate was higher with pepsin and albumin than with trypsin. Among different phenolics content, total phenlolics correlated significantly with protein-precipitable phenolics (r=0.65) and condensed tannin (r=0.56). Chinese quince, chestnut's inner skin and sorghum showed a relatively lower degree of polymerization, as expressed by vanillin/FolinDenis ratio. Processed foods from buckwheat, acorn, mugwort and arrowroot showed a lower content of phenolic substances, suggesting a negligible adverse effect on the bioavailability of food proteins, if any.

• Journal of Adhesion and Interface
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• v.23 no.3
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• pp.70-74
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• 2022

Tannic acid, one of plant-derived polyphenols, has been studied as a molecular adhesive, surface modification, energy storage and generating device, and biomedical application as it can interact with biopolymers. In this study, we synthesized porous silica nanoparticles that are widely used in biomedical engineering fields such as drug delivery and bioimaging, and then analyzed tannic acid mediated surface modification of mesoporous silica nanoparticles.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.417-426
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• 2010

In this study, ten different bio-adsorbents were prepared by immobilization of vegetable tannins such as mimosa(Catechol Tannin) and chestnut(Pyrogallol Tannin) on the collagen matrix which was derived from during leather manufacturing processing. Removal efficiency of Cu(II), Cd(II), Zn(II), Pb(II), Cr(III) by each bio-adsorbent in synthetic wastewater was evaluated by a laboratory-scale batch reactor at different reaction conditions. When mimosa was used as a vegetable tannin, the penetration efficiency of mimosa into the inner bundle of fiber depended on the dose of the naphthalene condensated penetrant; 3% ${\geq}$ 1.5% > 0%. For all bio-adsorbents, removal of heavy metal ions was not observed below pH 3.0 but was rapidly increased between pH 3.0 and 6.0, showing near complete removal of all heavy metal ions except Zn(II) above pH 6.0. Removal of Cr(III) was quite similar for all bio-adsorbents while removal of Cu(II), Zn(II) and Pb(II) was higher by bio-adsorbents immobilized with chestnut than that by mimosa. Adsorption of Pb(II) and Cu(II) by S10 bio-adsorbent was little affected by the presence of monovalent and divalent electrolytes as well as variation of 1000 times ionic concentration with $NaNO_3$.

• Korean Journal of Plant Resources
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• v.27 no.4
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• pp.279-285
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• 2014

Nutritional composition, including total phenolics, tannins and nutrient components, of acorns of Q. actissima, Q. serrata, Q. variabilis and Q. mongolica were analyzed. Acorns were collected from each tree species, which were grown in a seed orchard. Contents of both total phenolics and tannins in acorns of Q. serrata were higher than those of Q. actissima (p<0.05). Interestingly, Q. serrata contained the highest amount of water soluble tannins (71 mg/g dw) and the lowest levels of water insoluble tannins (8.1 mg/g dw) among 4 oak species, resulting that acorns of Q. serrata had the lowest proportion of insoluble tannins. Among 4 oak species tested, Q. mongolicav acorns contained the highest levels of both total dietary fiber (TDF) and ascorbic acid, while the content of beta-carotene in Q. mongolicav was 52-fold lower than that in Q. variabilis ($520{\mu}g/100g$). Our result showed that nutritional composition of acoms was significantly different between oak species, indicating that tastes or nutritional values might be different as well among major oak species in Korea.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.505-510
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• 1999

The seasonal variations of chemical composition of jujuba leaf were studied by analyzing general composition, amino acid composition, fatty acid composition, mineral, phenol, condensed tannin, flavonoid contents. Fresh jujuba leaf contained 4.42~6.31% protein and 4.31~5.71% fat on wet basis. Jujuba leaf was rich in aspartic acid, glutamic acid and leucine, but methionine was a limiting amino acid. Four kinds of free sugar, i.e. glucose, fructose, sucrose and maltose were found in jujuba leaf. The contents of fructose and glucose increased during growth, while the contents of disaccharides, sucrose and maltose, decreased. The main fatty acids of the leaf were palmitic acid, linoleic acid, stearic acid and oleic acid. Jujuba leaf was rich in K, Na and Ca, however, the amounts of Fe, Mn and Cu were low. The contents of Ca and Na increased during growth but the content of Mg decreased. The content of total phenolic compound was 0.83~0.89% and the content of condensed tannin was 0.40~0.45%. Two major flavonoids such as rutin and isoquercitrin were detected and their contents were 103.8~125.2mg/kg and 26.2~40.0mg/kg, respectively.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.945-955
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• 2016

To date, chemical managements of plant bacterial diseases are complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. In this study, thus, we performed screening of eco-friendly farming material (notice no. 2-4-064) containing tannic acid as new antibacterial-activity against 7 plant bacterial pathogens: Pectobacterium carotovorum subsp. carotovorum (Pcc), Ralstonia solanacearum (Rs), Acidovorax avenae subsp. citrulli (Aac), Xanthomonas cirti pv. citri (Xcc), Erwinia pyrifoliae (Ep), Clavibacter michiganensis subsp. michiganensis (Cmm), and Streptomyces scabies (Sc), Initial screening of antibacterial effects of eco-friendly farming material was performed using the paper disk diffusion method and co-cultivation in broth culture. Tannic acid based eco-friendly farming material showed inhibitory effect against Pcc, Rs, Aac, Xcc, Cmm, and Ss, whereas it did not show inhibition zone against Ep. However, when it tested by co-cultivation in broth culture, it showed strong inhibition effect against all pathogens that declined growth curve compared to bacterial pathogen only. Interestingly, when we observed morphological changes on those pathogens by SEM, cell morphologies of 7 pathogens were slightly changed that seem to be malfunction in their cell envelope.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.43-43
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• 2012

본 연구에서는 대량으로 손쉽게 구 할 수 있는 식물염료를 확보하여 새로운 천연색소자원을 탐색하기 위해서 진행되었으며, 시료의 최적 추출 조건을 확립하고 추출된 색소의 실크에 대한 염색 특성을 살펴 최적 염색조건을 설정하고, 염색견뢰도를 평가하여 수수 등겨 추출물의 천연색소로의 활용에 대한 기초 자료를 마련하고자 하였다. 수수 색소 추출 시 생산성과 편리성을 고려하여 추출은 pH 4, 추출온도 $60^{\circ}C$, 추출시간 24시간이 적정조건으로 제시되었으며, 수수 추출물에 함유되어 있는 탄닌의 최대흡수파장은 282nm로 나타났다. 견직물의 pH에 따른 염색 특성은 pH가 증가할수록 K/S값이 증가하여 염착량이 증가하였으며, 염색온도가 높을수록 염색시간이 길어질수록 염착량이 증가하는 경향을 보여주고 있다, 염색온도가 높을수록 염색시간이 경과될수록 색상은 $Y{\rightarrow}YR$로 변화되는 것을 알 수 있었으며 염색온도가 높을수록 채도가 증가하였다. 욕비가 클수록 염착량은 감소하였으나, 채도는 약간 증가하는 것을 알 수 있었다. 매염제 처리에 의한 색상변화에서는 Al, Ni 매염은 색상변화는 적었지만, Cu와 Fe 매염은 명도와 채도를 크게 감소시키고 아울러 색상도 Cu는 적갈색으로 Fe는 진회색으로 변화되었다. Sn과 Ti 매염에 의해서 명도는 약간 감소하고 채도는 약간 상승하여 연한 주황색으로 색상이 변화하였다. 설정된 조건에서 염색된 염색포의 일광견뢰도는 2~3급, 세탁견뢰도 변퇴색은 2~3급, 오염은 4~5급으로 나타났다. Fe로 매염된 염색포의 일광견뢰도는 증가하여 3~4급으로 나타났으며, 매염제 처리에 의한 세탁 견뢰도는 같거나 약간 증가되는 것으로 나타났다.

• Journal of Life Science
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• v.32 no.9
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• pp.734-741
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• 2022

Currently, around 40 million people worldwide are living with human immunodeficiency virus (HIV) infection making HIV a critical global health risk. Present therapies for HIV infection consist of drug cocktails that target different steps of the HIV life cycle to prevent infection, replication, and release of the virus. Due to its mutating nature, drug resistance coupled with side-effects of long-term drug use, novel strategies, and pharmaceuticals to treat and manage HIV infection are constant needs and continuously being studied. Plants allocate a major repertoire of chemical diversity and are therefore regarded as an important source of new bioactive agents that can be utilized against HIV. Since the early 1990s, upon recommendations of the World Health Organization, numerous studies reported phytochemicals from different structural classes such as flavonoids, coumarins, tannins and terpenes with strong inhibitory effects against HIV infection. The present review gathered and presented recent research (2021-present) on plant extracts and phytochemicals that exhibit anti-HIV properties with the aim of providing insights into future studies where ethnomedical and underutilized plant sources may yield important natural products against HIV. Considering the relation and importance of HIV treatment with current viral infection risks such as SARS-CoV-2, screening plants for anti-HIV agents is an important step towards the discovery of novel antivirals.