• Journal of the Korean Wood Science and Technology
• /
• v.34 no.2
• /
• pp.95-100
• /
• 2006

This study is to isolate bio-active compounds from Alnus firma and evaluate their antioxidant activity. Dried wood powder of A. firma was extracted by organic solvents and fractionated in the sequential extraction steps. The isolated compounds were characterized by EI-MS, $^{13}C-$ and $^1H-NMR$ including COSY, DEFT, HMQC, and HMBC. Antioxidant activities of the isolated compounds were evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging effect. From the wood of A. firma, three kinds of diarylheptanoids, alnusodiol (1), alnusonol (2) and alnusone (3), and gallic acid (4) were isolated. Among these four compounds, compound 1, 2, and 3 are isolated from A. firma for the first time. The antioxidant activity of gallic acid was 93.5% at the concentration of 100 ppm. This compound showed stronger antioxidant activity than those of other isolated compounds and the reference BHT (butylated hydroxytoluene).

• Microbiology and Biotechnology Letters
• /
• v.19 no.6
• /
• pp.598-603
• /
• 1991

An antifungal mixture of six members (component A to F), KRF-001 produced by Bacillzts subtilis subsp. krictiensis was isolated from the fermentation broth. Molecular weight of component A to F was determined by FAB-MS to be 1042, 1056, 1056, 1070, 1070 and 1084 respectively. Various instrumental analyses (amino acid analysis, GC-MS, $^1H-NMR, ^1HH$ COSY NMR) revealed that the mixture was a homologous cyclic peptide composed of each one mole of glutamine, proline, tyrosine, serine, unusual $\beta$-amino acid and three moles of asparagine. The structural differences of component A to F were found in carbon number and terminal structure of the unusual $\beta$-amino acid. After determination of the sequence and stereochemistry of those amino acids, the tentative structure of KRF-001 was determined.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.4
• /
• pp.456-461
• /
• 2012

The leaves of $Stevia$ $rebaudiana$ are well-known in Japan, Korea, and China as a natural sweetener. Medicinal uses of this plant originated in Paraguay and Brazil in the form of aqueous decoctions of the leaves used as a contraceptive agent and for the treatment of hyperglycemia. In the present study, the antioxidant, anti-hypertension, and anti-inflammatory activities of $S.$ $rebaudiana$ extracts are investigated for their use in food. The biologically-active compound was isolated and purified from $S.$ $rebaudiana$. The isolated compound was identified as austroinulin ($C_{20}H_{34}O_3$; molecular weight 322) by mass, IR spectrophotometry, 1D, and 2D-NMR. Austroinulin was characterized as a diterpenoid possessing a 3-methylpenta-2,4-dienyl at C-9. When subjected to an inflammatory mediator inhibitory assay from lipopolysaccharide (LPS)-activated macrophages, the austroinulin inhibited the enhanced production of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) expression (10 ${\mu}g$/mL＝67.9 and 45.1%, respectively). This was significant and dose-dependent. The results suggest that austroinulin from $S.$ $rebaudiana$ inhibited the NO and iNOS in RAW 264.7 cells.

• Journal of Life Science
• /
• v.20 no.8
• /
• pp.1254-1260
• /
• 2010

Microorganisms near the plant rhizosphere usually inhabit the surface or the inside of the plant roots and have a direct effect on plant growth by secreting plant growth promoters or antagonistic materials which protect the root zone system from various pathogens. This study was carried out to identify and isolate the antagonistic materials after isolation of microorganisms showing high antagonistic activities, in hopes of contributing to the development of sustainable agriculture and the preservation of agricultural environments. A number of antagonistic bacteria were isolated from paddy soil. Among isolates, RRj 228 showed plant growth promotion and antagonistic activity. RRj 228 was identified as Pseudomonas sp. according to the results of physiological properties and genetic methods. On the basis of the results of anti-fungal spectrum against several pathogens by RRj 228, the antagonistic effect of the isolate against Botrytis cinerea, Pythium ultimum, Phytopthola capsici, and Rhizoctonia solani, especially against red-pepper anthracnose caused by Colletotrichum acutatum, was remarkable. The experiment evaluating the biological control effect by RRj 228 revealed that the $ED_{50}$ value by the RRj 228 culture against C. acutatum, R. solani and P. ultimum were 0.14 mg/ml, 0.16 mg/ml and 0.29 mg/ml, respectively. An antagonistic substance was isolated and purified by several chromatographies from the RRj 228 culture. The $^1H$ and $^{13}C$ assignment of the antagonistic substance was achieved from two-dimensional $^1H-^1H$ COSY, HMQC, and HMBC. Finally, the antagonistic substance was identified as Phenazine-1-carboxylic acid ($C_{13}H_8N_2O_2$, M.W.=224).