• Archives of Pharmacal Research
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• 제29권4호
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• pp.287-292
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• 2006

In this study, we isolated two new isorhamnetin glycosides, designated as nelumboroside A (3) and nelumboroside B (4), as well as the previously-characterized isorhamnetin glucoside (1) and isorhamnetin rutinoside (2), from the n-BuOH fraction of Nelumbo nucifera stamens. The structures of the two new compounds were then determined, using chemical and spectroscopic techniques. All isolated isorhamnetin glycosides 1-4 showed marked antioxidant activities in the DPPH, and $ONOO^-$ assays.

• 대한화학회지
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• 제63권2호
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• pp.78-84
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• 2019

High-resolution $^1H$ NMR spectroscopic technique has been widely used as one of the most powerful analytical tools in food chemistry as well as to define molecular structure. The $^1H$ NMR spectra-based metabolomics has focused on classification and chemometric analysis of complex mixtures. The principal component analysis (PCA), an unsupervised clustering method and used to reduce the dimensionality of multivariate data, facilitates direct peak quantitation and pattern recognition. Using a combination of these techniques, the various green teas and black teas brewed were investigated via metabolite profiling. These teas were characterized based on the leaf size and country of cultivation, respectively.

• Natural Product Sciences
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• 제27권2호
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• pp.122-127
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• 2021

A new steroidal saponin, (23S,24S)-spirosta-5,25(27)-diene-1𝛽,3𝛽,23,24-tetrol 1-O-((2,3-diacetyl-α-L-rhamnopyranosyl)-(1→2)-[𝛽-D-xylopyranosyl-(1→3)]-α-L-arabinopyranoside)-24-O-𝛽-D-glucopyranoside (humilisoside) together with the known 𝛽-sitosterol 3-O-glucopyranoside, adenosine, dioscin, and methylprotodioscin were isolated from the leaves of Dracaena humilis. Their structures were elucidated by spectral techniques including mass spectrometry (ESIMS, HRESIMS, tandem MS-MS), 1D NMR (¹H, ¹³C NMR), 2D NMR (HSQC, ¹H-¹H COSY, HMBC, NOESY), chemical method as well as by comparison with spectroscopic data reported in the literature. The chemotaxonomic significance of the isolation of these compounds is discussed. This is the first report on the phytochemical investigation of D. humilis.

• Natural Product Sciences
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• 제26권4호
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• pp.283-288
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• 2020

Microbial transformation of a potent progestin, norethisterone (17��-hydroxy-19-nor-17α-pregn-4-en-20-yn-3-one) (1) was carried out by using two filamentous fungi Aspergillus niger and Penicillium citrinum. Biotransformation of 1 with A. niger yielded a hydroxylated transformed product 10��,17��-diydroxy-19-nor-17α-pregn-4-en-20-yn-3-one (2) whereas 11��,17��-diydroxy-19-nor-17α-pregn-4-en-20-yn-3-one (3) was obtained through microbial transformation of 1 by P. citrinum. It is the first report of their production from 1 by using A. niger and P. citrinum with complete 1H- and 13C-NMR assignment. The structures of both metabolites were characterized by various spectroscopic techniques and reported data.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.202.3-202.3
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• 2003

Two Known compounds, syringaresinol monoglucoside(8), chimaphilin(14), together with three new compounds, (9)[mp. $106{\sim} 111^{\circ}C$, C_{29}H_{44}O_{13}$], (10)[mp. $180{\sim}182^{\circ}C$, $C_{15}H_{20}O_{9}$] and (11)[mp. $100{\sim}105^{\circ}C$, $C_{18}H_{28}O_{8}$] were isolated from the BuOH fractionof Pyrola japonics(Pyrolaceae). The structures of the known compounds were determined by chemical and spectorscopic methods. The assignments of the $^{1}H-$ and $^{13}C-NMP$ spectra of these compounds were carried out by two-dimensional $^1H-^1H-COSY$, NOESY and $^1H-^{13}C$ multiple-bond, multiplequantum spectroscopic correlation techniques. The characterization of the three new compounds is now in progress.

• 한국염색가공학회지
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• 제34권2호
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• pp.77-92
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• 2022

Natural colorants are regarded as substitutes for synthetic colorants in the fields of fiber dyeing, hair dyeing, cosmetic, and food industries. The use of natural colorants has been increased in view of global environment and sustainability. However, scientific approach to the production is required because the supply of natural colorants depends on the climate, soil, and cultivation methods. This brief review contains the advances in science and technology related to natural colorants including characterization, analysis, CIEL^*a^*b^* and Munsell color systems, and future prospects. For the characterization and the analysis of natural colorants, chromatography, some spectroscopic techniques (UV-Vis, FT-IR, NMR), mass spectrometry, and X-ray diffraction are generally used.

• 대한화학회지
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• 제68권3호
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• pp.146-150
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• 2024

Precise molecular configuration elucidation of poly(3-hexylthiophene) (P3HT) through advanced spectroscopic techniques is pivotal for enhancing P3HT-based photovoltaic device efficiencies since its high charge-carrier mobility is directly correlated to its well-ordered structure. In this study, we examine Raman depolarization ratios of annealed and non-annealed P3HT films to elucidate their intermolecular π-π configurations. Our findings suggest that the backbone of the annealed film possesses stronger π-π conjugation overlaps than that of the non-annealed film owing to the greater depolarization ratio of the annealed film. In addition, the depolarization ratios are also supported by theoretical calculations, where parallel-stacked thiophene structures display a higher depolarization ratio compared with that of twisted-stacked structures, as calculated by the Møller-Plesset perturbation theory. This study highlights the utility of polarized Raman spectroscopy as a versatile tool for assessing the degree of molecular order in highly conjugated polymer films.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1133-1133
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• 2001

Fruit sweetness, as indexed by total soluble solids (TSS), and fruit acidity are key factors in the description of the fruit eating quality. Our group has been using short wave NIR spectroscopy (SW-NIR; 700-1100 nm) in combination with chemometric methods (PLS and MLR) for the non-invasive determination of the fruit eating quality (1,2). In order to further improve calibration performance, we have investigated SW-NIR spectra of sucrose and D-glucose. In previous reports on the band assignment for these sugars in the 1100-2500 nm spectral region (3-7), it has been established that change in concentration, temperature and physical state of sugars reflects on the shape and position of the spectral bands in the whole NIR region(5-7). The effect of change in concentration and temperature of individual sugar solutions and sugar spiked Juice samples was analysed using combined spectroscopic (derivative, difference, 2D spectroscopy) and linear regression chemometric (PLS, MLR) techniques. The results have been compared with the spectral data of a range of fruit types, varying in TSS content and temperature. In the 800-950 nm spectral region, the B-coefficients for apples, peaches and nectarines resemble those generated in a calibration of pure sucrose in water (Fig. 1). As expected, these fruits exhibit better calibration and prediction results than those in which the B-coefficients were poorly related to those for sugar.(Figure omitted).

• 천문학회보
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• 제41권1호
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• pp.68.2-68.2
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• 2016

We present the variability and time lag measurements of PG 0934+013 based on the photometric and spectroscopic monitoring campaign over two years. We obtained 46 epochs of data from the spectroscopic campaign, which was carried out using the South African Large Telescope with 1 week cadence over two sets of 4 month-long observing period, while we obtained 80 epochs of B band data from the campaign. Due to the six month gap between two campaigns, we separately measured the time lag of the $H{\beta}$ emission line by comparing the emission line light curve with the B band continuum light curve using the cross-correlation function techniques. We determined the time lags and black hole mass.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1253-1258
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• 2012

Two phenolic allopyranosides and two phenolic amide allopyranosides, along with eight known phenolic compounds, including cimicifugic acids, shomaside B, fukiic acid, isoferulic acid, and piscidic acid, were isolated from the n-butanolic extract of rhizomes of Cimicifuga heracleifolia. On-line spectroscopic data for UV, NMR, and MS from a combination of LC-NMR and LC-MS techniques directly and rapidly provided sufficient structural information to identify and confirm all the structures of major phenolic compounds in the extract, in addition to their HPLC profiles. This combined analytic information was then used as a dereplication tool for structure-guided screening in order to isolate unknown phenolic compounds in the extract. Successive fractionation and purification using semi-preparative HPLC acquired four unknown allopyranosides, and their structures were identified as cis-ferulic acid 4-O-${\beta}$-D-allopyranoside, trans-ferulic acid 4-O-${\beta}$-D-allopyranoside, trans-feruloyltyramine 4-O-${\beta}$-D-allopyranoside, and trans-feruloyl-(3-O-methyl)dopamine 4-O-${\beta}$-D-allopyranoside, based on a subsequent spectroscopic interpretation.