• Natural Product Sciences
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• v.26 no.2
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• pp.144-150
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• 2020

Phytochemical investigation of leaves, barks and roots of Nauclea vanderguchtii led to the isolation of sixteen compounds, which includes one citric acid derivative (2), one alkaloid (16), one peptide derivative (3), and twelve triterpenes (1, 4 - 13). These compounds were identified as rotundanonic acid (1), 2-hydroxy-1,2,3-propanetricarboxylic acid 2-methyl ester (2), asperphenamate (3), lupeol (4), stigmasterol (5), betulin (6), betulenic acid (7), stigmasterol 3-O-β-D-glucopyranoside (8), quinovic acid 3β-O-α-L-rhamnoside (9), α-amyrin (10), 3-oxoquinovic acid (11), ursolic acid (12), hederagenin (13), rotundic acid (14), clethric acid (15), and naucleficine (16) by the analysis of their NMR spectroscopic data including 2D NMR spectra and by comparison of their spectroscopic data reported in the literature. Compounds 1 and 3 were isolated for the first time in the genus Nauclea, and compound 2 was isolated for the first time from the Rubiaceae family. Complete NMR assignations for 1 have been published for the first time.

• Mass Spectrometry Letters
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• v.4 no.4
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• pp.75-78
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• 2013

A gas chromatography/mass spectrometric (GC/MS) method was developed as a candidate reference method for the accurate determination of essential fatty acids (linoleic acid, ${\alpha}$- and ${\gamma}$-linolenic acids) in food supplemental oil products. Samples were spiked with three internal standards (stearic acid-$d_{35}$, $^{13}C_{18}$-linoleic acid, and $^{13}C_{18}$-${\alpha}$-linolenic acid). Samples were then subject to saponification, derivatization for methylation, and extraction by organic solvent. For GC/MS measurement, an Agilent HP-88 column, designed for the separation of fatty acid methyl esters, was selected after comparing with other columns as it provided better separation for target analytes. Target analytes and internal standards were detected by selected ion monitoring of molecular ions of their methyl ester forms. The GC/MS method was applied for the measurement of three botanical oils in NIST SRM 3274 (borage oil, evening primrose oil, and flax oil), and measurement results agreed with the certified values. Measurement results for target analytes which have corresponding isotope-labeled analogues as internal standard were calculated based on isotope dilution mass spectrometry (IDMS) approach, and compared with results calculated by using the other two internal standards. Results from the IDMS approach and the typical internal standard approach were in good agreement within their measurement uncertainties. It proves that the developed GC/MS method can provide similar metrological quality with IDMS methods for the measurement of fatty acids in natural oil samples if a proper fatty acid is used as an internal standard.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.1
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• pp.58-63
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• 2015

The chemical and rheological properties of natural and enzymatically hydrolyzed porphyran isolated from Pyropia yezoensis were investigated. The enzymatic hydrolysate was prepared by hydrolysis of porphyran using ${\beta}$-agarase followed by fractionation based on molecular weight (>300 kDa (Fr-1), 100-300 kDa (Fr-2), 10-100 kDa (Fr-3) and 1-10 kDa (Fr-4) using an ultrafiltration membrane. Each hydrolysate fraction consisted mainly of galactose (42.7-57.5%), 3,6-anhydro galactose (6.5-15.1%) and ester sulfate (8.6-14.1%). The sulfate content of the enzymatically hydrolyzed fractions decreased with an increase in molecular weight, whereas the 3,6-anhydro galactose content increased significantly. The rheological behavior of porphyran and enzymatically hydrolyzed porphyran solutions demonstrated a pseudoplastic behavior, which agrees with the Herschel-Bulkley model. The effect of temperature on the viscosity of the porphyrans and hydolysate fractions were measured and modeled using the Arrhenius equation. The activation energy of the porphyrans and enzymatically hydrolyzed porphyran (Fr-1) increased from 12.30 to 20.29 kJ/mol and 9.06 to 23.84 kJ/mol, respectively with increasing concentrations from 3% to 7%. These data indicate that the extent of the apparent viscosity of porphyran and enzymatically hydrolyzed porphyran are influenced by both temperature and concentration.

• Natural Product Sciences
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• v.23 no.3
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• pp.169-174
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• 2017

The aim of this study was to investigate the effect and action mechanism of quercetin on penile corpus cavernosum smooth muscle (PCCSM). PCCSM precontracted with phenylephrine (Phe) was treated with four different concentrations of quercetin ($10^{-7}$, $10^{-6}$, $10^{-5}$ and $10^{-4}M$). PCCSM were preincubated with N-Nitro-L-arginine methyl ester hydrochloride (L-NAME) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) to block nitric oxide synthase and guanylate cyclase, respectively. The changes in PCCSM tension were recorded, and cyclic nucleotides in the perfusate were measured by radioimmunoassay. The interactions of quercetin with phosphodiesterase type 5 inhibitors (PDE5-Is) such as sildenafil, udenafil and mirodenafil, were also evaluated. PCCSM relaxation induced by quercetin occurred in a concentrationdependent manner. The application of quercetin to PCCSM pre-treated with L-NAME and ODQ significantly inhibited the relaxation. Quercetin significantly increased cGMP in the perfusate. Furthermore, quercetin enhanced PDE5-Is-induced relaxation of PCCSM. Quercetin relaxed the PCCSM by activating the NO-cGMP signaling pathway, and it may be a therapeutic candidate or an alternative treatment for patients with erectile dysfunction who do not completely respond to PDE5-Is.

• Natural Product Sciences
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• v.14 no.1
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• pp.1-11
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• 2008

Peroxynitrite ($(ONOO^-)$ is a cytotoxic species formed from nitric oxide and superoxide anion, which are highly implicated in the pathogenesis of oxidative stress-mediated diseases. The aim of this study was to investigate the scavenging effects of Phellinus linteus on authentic $ONOO^-$, and further phytochemical studies are planned that will attempt to identify the active principles. From the active EtOAc fraction, a mixture of fungisterol and 5-dihydroergosterol (1), a mixture of betulin and 1,2-benzenedicarboxylic acid bis (2-methyl heptyl) ester (2), protocatechualdehyde (3), protocatechuic acid (4), cirsiumaldehyde (5), hispidin (6), caffeic acid (7), phelligridin D (8), uracil (9), gallic acid (10), 2,5-dihydroxybenzoic acid (11), ferulic acid (12), 2,3-dihydroxybenzaldehyde (13), arbutin (14), isoferulic acid (15), guanosine (16), and ellagic acid (17) were isolated, and their structures were characterized based on spectroscopic data. All compounds except 3, 6, 7 and 16 were isolated for the first time from P. linteus. Compounds 3, 4, 6-8, 10-15, and 17 showed potent scavenging activity on $ONOO^-$, with $IC_{50}$ values of $2.06\;{\pm}\;0.10$, $3.45\;{\pm}\;0.57$, $0.71\;{\pm}\;0.05$, $2.78\;{\pm}\;0.36$, $5.42\;{\pm}\;0.26$, $1.13\;{\pm}\;0.02$, $1.82\;{\pm}\;0.17$, $0.91\;{\pm}\;0.19$, $1.59\;{\pm}\;0.09$, $1.88\;{\pm}\;0.07$, $1.22\;{\pm}\;0.37$, and $2.01\;{\pm}\;0.02\;{\mu}M$, respectively, as compared to the positive control, DL-penicillamine, with an $IC_{50}$ value of $5.04\;{\pm}\;0.06\;{\mu}M$.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.902-910
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• 2018

In recent times, development of nanofluid insulation for power transformers is a hot research topic. Many researchers reported the enhancement in dielectric characteristics of nano modified mineral oils. Considering the drawbacks of petroleum based mineral oil, it is necessary to understand the dielectric characteristics of nanofluids developed with natural ester based oils. Palm oil has better insulation characteristics comparable to mineral oil. However very few research reports is available in the area of nanofluids based on palm oil. Partial discharge (PD) is one of the major sources of insulation performance degradation of transformer oil. It is essential to understand the partial discharge(PD) characteristics by collecting huge data base of PD performance of nano modified palm oil which will increase its confidence level for power transformer application. Knowing these facts, in the present work, certain laboratory experiments have been performed on PD characteristics of nano $SiO_2$ modified palm oil at different electrode configurations. Influence of concentration of nano filler material on the PD characteristics is also studied. Partial discharge inception voltage, Phase resolved partial discharge (PRPD) pattern, PD signal time-frequency domain characteristics, PD signal equivalent timelength-bandwidth mapping, Weibull distribution statistical parameters of PRPD pattern, skewness, repetition rate and phase angle variations are evaluated at different test conditions. From the results of the experiments conducted, we came to understand that PD performance of palm oil is considerably enhanced with the addition of $nano-SiO_2$ filler at 0.01%wt and 0.05%wt concentration. Significant reduction in PD inception voltage, repetition rate, Weibull shape parameter and PD magnitude are noticed with addition of $SiO_2$ nanofillers in palm oil. These results will be useful for recommending nano modified palm oil for power transformer applications.

• BMB Reports
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• v.29 no.6
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• pp.500-506
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• 1996

We have isolated a water-extracted novel regulator for blood coagulation from an earthworm, Lumbricus rubellus. As a folk remedy, the earthworm has been known to facilitate blood circulation. After complete heat inactivation of endogenous proteases in the earthworm, an anticoagulant(s) was purified through ammonium sulfate fractionation and three consecutive gel permeation chromatography of Sephacryl S-300, Sephadex G-75, and G-150 by measuring activated partial thromboplastin time (APTT) The anticoagulant was further purified to 2,800 fold with a C4 reversed-phase HPLC This activity was stable under heat ($100^{\circ}C$ for 30 min) and acidic conditions (0.4 N HCl). The effects of this partially purified anticoagulant on thrombin were observed with various substrates such as N${\alpha}$-benzoyl-DL-arginine-p-nitroanilide (BApNA), H-D-phenylalanyl-L-pipecoyl-L-arginine-p-nitroanilide (S-2238), N${\alpha}$-p-tosyl-L-arginine methyl ester (TAME), and fibrinogen as a natural substrate. Only TAME hydrolysis, due to an esterase activity of the enzyme, was inhibited among the chromogenic substrates. In addition, the anticoagulant not only inhibited the conversion of fibrinogen to fibrin but also prolonged the fibrin clot formation monitored with the in vitro coagulation test. Based on these observations, we suggest the significance of measuring the ability of antithrombotic drugs to inhibit the esterase activity of thrombin. In this report, it was also shown that the earthworm indeed contained a water-extractable, heat- and acid-stable anticoagulant which could be used as a novel antithrombotic agent.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.2
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• pp.234-241
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• 2011

Mantidis Vagina Ovorum was formulated to contain various natural products known to cure erectile dysfunction. This study was aimed to investigate the effects of Mantidis Vagina Ovorum on the nitric oxide synthase (NOS) activity, nitrite level, antioxidation and erectile responses in rat's corpus cavernosum penis. The crushed Mantidis Vagina Ovorum was extracted 3 times, each time with 3 volumes of methyl alcohol at $60^{\circ}C$ for 24 h. The extract was filtered and evaporated under a reduced pressure using a rotary evaporator to yield 16.6 g. Mantidis Vagina Ovorum extract oral-administered 75 mg per 1 kg of body weight for 30 days. First, samples were treated with Mantidis Vagina Ovorum, and then cimetidine-treated rats and L-N-Nitroarginine methyl ester (L-NAME) treated rats were put with the samples. The level of urethral lipid peroxide in the cimetidine-Mantidis Vagina Ovorum double administered rats was decreased as low as in the normal group, while the one in the cimetidine-treated group was increased. The urethral NOS activity, the level of urethral nitrite, the level of testosterone and the electile response to cavernous nerve stimulation in the cimetidine-Mantidis Vagina Ovorum double administered rats were increased as high as in the normal group while the one in the cimetidine-treated group was decreased. The electile response to cavernous nerve stimulation and the level of nitrite in L-NAME ($10^{-4}$)-treated rats was restored by the administration of Mantidis Vagina Ovorum as high as in the normal group. Mantidis Vagina Ovorum was effective in restoring the cimetidine-induced or L-NAME-induced erectile dysfunction in rats.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.317-334
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• 2002

Ginsenosides are metabolized (deglycosylated) by intestinal bacteria to active forms after oral administration. 20(S)-Protopanaxadiol $20-O-{\beta}-D-glucopyranoside$ (M1) and 20(S)-protopanaxatriol (M4) are the main intestinal bacterial metabolites (IBMs) of protopanaxadiol- and protopanaxatriol-type glycosides. M1 was selectively accumulated into the liver soon after its intravenous (i.v.) administration to mice, and mostly excreted as bile; however, some M1 was transformed to fatty acid ester (EMl) in the liver. EM1 was isolated from rats in a recovery dose of approximately $24mol\%.$ Structural analysis indicated that EM1 comprised a family of fatty acid mono-esters of M1. Because EM1 was not excreted as bile as Ml was, it was accumulated in the liver longer than M1. The in vitro cytotoxicity of M1 was attenuated by fatty acid esterification, implying that esterification is a detoxification reaction. However, esterified M1 (EM1) inhibited the growth of B16 melanoma more than Ml in vivo. The in vivo antitumor activity paralleled with the pharmacokinetic behavior. In the case of M4, orally administered M4 was absorbed from the small intestine into the mesenteric lymphatics followed by the rapid esterification of M4 with fatty acids and its spreading to other organs in the body and excretion as bile. The administration of M4 prior to tumor injection abrogated the enhanced lung metastasis in the mice pretreated with 2-chloroadenosine more effectively than in those pretreated with anti-asialo GMl. Both EM1 and EM4 did not directly affect tumor growth in vitro, whereas EM1 promoted tumor cell lysis by lymphocytes, particularly non-adherent splenocytes, and EM4 stimulated splenic NK cells to become cytotoxic to tumor cells. Thus, the esterification of IBM with fatty acids potentiated the antitumor activity of parental IBM through delay of the clearance and through immunostimulation. These results suggest that the fatty acid conjugates of IBMs may be the real active principles of ginsenosides in the body.

• Microbiology and Biotechnology Letters
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• v.46 no.4
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• pp.377-389
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• 2018

In this study, a novel microalgal strain, Desmodesmus sp. KAERI-NJ5, was isolated, identified, and evaluated as a candidate for biodiesel feedstock. In a preliminary study, the effects of four general microalgal growth factors, including temperature, pH, light intensity, and concentration of nitrogen source ($KNO_3$), on the microalgal photoautotrophic growth were evaluated. With the exception of light intensity, the growth factors needed to be optimized for the microalgal biomass production. Optimization was done using response surface methodology. The optimal conditions for biomass production were pH 6.54, $27.66^{\circ}C$, and 0.52 g/l $KNO_3$. The biomass production at the optimal conditions was 1.55 g/l, which correlated well with the predicted value of 1.5 g/l. The total lipid and fatty acid methyl ester contents of the cells grown at the optimal conditions were 49% and 21.2% of cell dry weight, respectively. To increase the lipid content of the biomass, microalgae were challenged by nitrogen starvation. Enhancement of total lipid and fatty acid content up to 52.02% and 49%, respectively, were observed. Lipid analysis of the nitrogen-starved cells revealed that C16 and C18 species accounted for 95.9% of the total fatty acids. Among them, palmitic acid (46.17%) and oleic acid (39.43%) dominantly constituted the algal fatty acids. These results suggest Desmodesmus sp. KAERI-NJ5 as a promising feedstock for biodiesel production.