Tan Phat Nguyen - Academia.edu (original) (raw)

Papers by Tan Phat Nguyen

Natural Product Research, Sep 20, 2021

From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10anthraquinone, la... more From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10anthraquinone, lasibidoupin A (1), and one new 6,7-benzocoumarin, lasibidoupin B (2), together with one known compound, 11-O-methyldamnacanthol (3) were isolated using chromatographic method. Their structures were determined by extensive HRMS, and NMR assignments. Compound 3 was reported for the first time from this species. New compounds (1 & 2) were tested for the cytotoxicity against three human cancer cell lines (MCF-7, HeLa, and NCI-H460) by SRB assay. As results, 1 & 2 exhibited significant cytotoxic activity against all cancer cell lines (IC50 ranged from 0.058 ± 0.003 to 0.177 ± 0.014 μM).

Natural Product Research, Sep 20, 2021

From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10anthraquinone, la... more From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10anthraquinone, lasibidoupin A (1), and one new 6,7-benzocoumarin, lasibidoupin B (2), together with one known compound, 11-O-methyldamnacanthol (3) were isolated using chromatographic method. Their structures were determined by extensive HRMS, and NMR assignments. Compound 3 was reported for the first time from this species. New compounds (1 & 2) were tested for the cytotoxicity against three human cancer cell lines (MCF-7, HeLa, and NCI-H460) by SRB assay. As results, 1 & 2 exhibited significant cytotoxic activity against all cancer cell lines (IC50 ranged from 0.058 ± 0.003 to 0.177 ± 0.014 μM).

Phytochemistry Letters, Feb 1, 2021

This paper presents a framework in which many structural credit risk models can be made hybrid by... more This paper presents a framework in which many structural credit risk models can be made hybrid by randomizing the default trigger, while keeping the capital structure intact. This produces random recovery rates negatively correlated with the default probability. The approach is implemented on a …rm-by-…rm basis using maximum likelihood and the unscented Kalman …lter (UKF) on each of the 225 companies of the CDX NA IG and HY indices using weekly CDS data from December 2007 to January 2012. Adding the surprise element and the time-varying distribution of recovery rates has a large impact on credit spreads as it modi…es both the level and shape of the curves. When a bond portfolio is considered, the presence of dependence among …rm leverage ratios and between default probabilities and recovery rates produces clusters of defaults with low recovery rates. It has a major impact on standard risk measures such as Valueat-Risk and conditional tail expectation.

Phytochemistry Letters, Feb 1, 2021

This paper presents a framework in which many structural credit risk models can be made hybrid by... more This paper presents a framework in which many structural credit risk models can be made hybrid by randomizing the default trigger, while keeping the capital structure intact. This produces random recovery rates negatively correlated with the default probability. The approach is implemented on a …rm-by-…rm basis using maximum likelihood and the unscented Kalman …lter (UKF) on each of the 225 companies of the CDX NA IG and HY indices using weekly CDS data from December 2007 to January 2012. Adding the surprise element and the time-varying distribution of recovery rates has a large impact on credit spreads as it modi…es both the level and shape of the curves. When a bond portfolio is considered, the presence of dependence among …rm leverage ratios and between default probabilities and recovery rates produces clusters of defaults with low recovery rates. It has a major impact on standard risk measures such as Valueat-Risk and conditional tail expectation.

Advances in Natural Sciences: Nanoscience and Nanotechnology, Oct 14, 2016

In this work anti-cancer drug curcumin-loaded superparamagnetic iron oxide (Fe 3 O 4) nanoparticl... more In this work anti-cancer drug curcumin-loaded superparamagnetic iron oxide (Fe 3 O 4) nanoparticles was modified by chitosan (CS). The magnetic iron oxide nanoparticles were synthesized by using reverse micro-emulsion (water-in-oil) method. The magnetic nanoparticles without loaded drug and drug-loaded magnetic nanoparticles were characterized by XRD, FTIR, TG-DTA, SEM, TEM, and VSM techniques. These nanoparticles have almost spherical shape and their diameter varies from 8 nm to 17 nm. Measurement of VSM at room temperature showed that iron oxide nanoparticles have superparamagnetic properties. In vitro drug loading and release behavior of curcumin drug-loaded CS-Fe 3 O 4 nanoparticles were studied by using UV-spectrophotometer. In addition, the cytotoxicity of the modified nanoparticles has shown anticancer activity against A549 cell with IC 50 value of 73.03 μg/ml. Therefore, the modified magnetic nanoparticles can be used as drug delivery carriers on target in the treatment of cancer cells.

Advances in Natural Sciences: Nanoscience and Nanotechnology, Oct 14, 2016

In this work anti-cancer drug curcumin-loaded superparamagnetic iron oxide (Fe 3 O 4) nanoparticl... more In this work anti-cancer drug curcumin-loaded superparamagnetic iron oxide (Fe 3 O 4) nanoparticles was modified by chitosan (CS). The magnetic iron oxide nanoparticles were synthesized by using reverse micro-emulsion (water-in-oil) method. The magnetic nanoparticles without loaded drug and drug-loaded magnetic nanoparticles were characterized by XRD, FTIR, TG-DTA, SEM, TEM, and VSM techniques. These nanoparticles have almost spherical shape and their diameter varies from 8 nm to 17 nm. Measurement of VSM at room temperature showed that iron oxide nanoparticles have superparamagnetic properties. In vitro drug loading and release behavior of curcumin drug-loaded CS-Fe 3 O 4 nanoparticles were studied by using UV-spectrophotometer. In addition, the cytotoxicity of the modified nanoparticles has shown anticancer activity against A549 cell with IC 50 value of 73.03 μg/ml. Therefore, the modified magnetic nanoparticles can be used as drug delivery carriers on target in the treatment of cancer cells.

Journal of Asian Natural Products Research, Apr 1, 2021

Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A... more Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A (1), together with four depsidones, including virensic acid (2), protocetraric acid (3), 8'-O-methylprotocetraric acid (4), and furfuric acid (5) were purified. Their structures were chacracterized using extensive HR-ESI-MS and NMR spectroscopic methods. The isolated compounds (2-5) possessed stronger α-glucosidase inhibitory activity (IC50 = 43.7-110.1 μM) than the standard drug acarbose (IC50 = 214.5 μM). Graphical Abstract

Journal of Asian Natural Products Research, Apr 1, 2021

Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A... more Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A (1), together with four depsidones, including virensic acid (2), protocetraric acid (3), 8'-O-methylprotocetraric acid (4), and furfuric acid (5) were purified. Their structures were chacracterized using extensive HR-ESI-MS and NMR spectroscopic methods. The isolated compounds (2-5) possessed stronger α-glucosidase inhibitory activity (IC50 = 43.7-110.1 μM) than the standard drug acarbose (IC50 = 214.5 μM). Graphical Abstract

Natural Product Research, Jul 22, 2019

From the leaves of Sterculia foetida L., one new oleanane-type triterpenoid, named stercufoetin A... more From the leaves of Sterculia foetida L., one new oleanane-type triterpenoid, named stercufoetin A (1) together with four known ones, vergatic acid (2), β-amyrin (3), oleanolic acid (4) and maslinic acid (5) were purified by diversely chromatographic methods. Their structures were proposed by HR-APCI-MS and NMR experiments. Compounds (2-5) were notified for the first time from this species. Compound 1 showed weak cytotoxic effect against three human cancer cell lines (MCF-7, HepG2 and HeLa) using SRB assay.

Natural Product Research, Oct 23, 2020

Article Information Efficacy of herbal mycotoxin binders in ameliorating induced mycotoxicosis wa... more Article Information Efficacy of herbal mycotoxin binders in ameliorating induced mycotoxicosis was evaluated in white leghorn laying hens. Birds were randomly divided into six groups containing 15 birds in each group. Group I was served as control fed with basal diet, group II birds were fed with aflatoxins and ochratoxin A at 100 ppb each. Group III, IV, V and VI birds were fed with aflatoxins and ochratoxin A at 100ppb each and herbal mycotoxin binders Vilocym ® , Toxiroak ® ,Vilocym-Z ® in feed at 1 kg/tonne and AV/LBP/20 ® at 1 ml/litre in drinking water respectively for 10 weeks. The cultured rice and wheat samples were screened for presence of mycotoxins by LC-MS/MS method. Aflatoxins concentration in cultured rice sample was 826 ppb. Ochratoxin A concentration in cultured wheat sample was 8990 ppb. The hematological parametes viz., Hb, TEC, PCV showed signmificant decreased level in (Group II, III, IV, V and VI) compared to their respective control group. Similarly biochemical parameters viz., aspartate aminotransferase, alanine aminotransferase showed significantly decreased level in treatred groups (Group II, III, IV, V and VI) compared to their respective control group. Serum albumin and serum total protein level significantly decreased in treatred groups (Group II, III, IV, V and VI) compared to their respective control group(Group I). Histopathology of Group II birds revealed toxic effects on liver and kidney. Supplementation of herbal mycotoxin binders in mycotoxicated feed showed improvement in all the parameters indicating that herbal mycotoxin binders reduce the severity of toxicity.

Natural Product Research, Mar 19, 2019

Natural Product Research, Feb 22, 2018

One new cycloartane triterpenoid, named Markhacanasin C (1), together with three known triterpeno... more One new cycloartane triterpenoid, named Markhacanasin C (1), together with three known triterpenoids, oleanolic acid (2), ursolic acid (3) and 6β,19α-dihydroxyursolic acid (4) were isolated by various chromatographic methods from the most cytotoxic fraction of the ethyl acetate extract of Markhamia stipulata var. canaense V.S. Dang leaves. Among them, 4 was reported for the first time from the genus Markhamia, while 2 & 3 were found for the first time from this species. Their structures were elucidated by IR, UV, HR-ESI-MS and NMR experiments. The cytotoxicity of isolated compounds (3 & 4) against three human cancer cell lines (HeLa, HepG2, and MCF-7) were evaluated. At the concentration of 100 μg/mL, 3 exhibited significant cytotoxic activity (86.36 ± 3.69 %).

Natural Product Research, 2021

Two new compounds, comprising one dibenzofuran, named usneaceratin A (1), and one phenolic acid, ... more Two new compounds, comprising one dibenzofuran, named usneaceratin A (1), and one phenolic acid, named usneaceratin B (2), together with one known dibenzofuran, isousnic acid (3), and two known phenolics, orsellinic acid (4) and methyl orsellinate (5) were clarified from the lichen Usnea ceratina using variously chromatographic methods. Their structures were testified by comprehensive HR-ESI-MS, and NMR spectroscopic analysis, and comparison with published data. Their α-glucosidase inhibitory activity of all compounds was measured. Usneaceratin B (2) possessed better inhibition against α-glucosidase enzyme (IC50 value of 41.8 μM) than the standard drug acarbose (IC50 value of 214.50 μM).

From the leaves of <i>Ricinus communis</i> Linn., one new alkaloid, named ricicomin A... more From the leaves of <i>Ricinus communis</i> Linn., one new alkaloid, named ricicomin A (<b>1</b>) together with three known ones, ricinine (<b>2</b>), <i>N</i>-demethylricinine (<b>3</b>) and 4-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid (<b>4</b>) were justified by repeated chromatographic methods. Their structures were determined by comprehensive IR, HR-ESI-MS and NMR analyses. Compound <b>4</b> was identified for the first time from the genus <i>Ricinus</i>. DFT-NMR chemical shift calculations and subsequent DP4+ probability methods were applied to confirm the chemical structure of <b>1</b>. Compounds <b>1–3</b> did not display cytotoxic effect against three human cancer cell lines (MCF-7, HepG2 and HeLa) using SRB assay.

From the leaves of <i>Sterculia foetida</i> L., one new oleanane-type triterpenoid, n... more From the leaves of <i>Sterculia foetida</i> L., one new oleanane-type triterpenoid, named stercufoetin A (<b>1</b>) together with four known ones, vergatic acid (<b>2</b>), <i>β</i>-amyrin (<b>3</b>), oleanolic acid (<b>4</b>) and maslinic acid <b>(5)</b> were purified by diversely chromatographic methods. Their structures were proposed by HR-APCI-MS and NMR experiments. Compounds <b>(2–5)</b> were notified for the first time from this species. Compound <b>1</b> showed weak cytotoxic effect against three human cancer cell lines (MCF-7, HepG2 and HeLa) using SRB assay.

Journal of Asian Natural Products Research, 2021

Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A... more Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A (1), together with four depsidones, including virensic acid (2), protocetraric acid (3), 8'-O-methylprotocetraric acid (4), and furfuric acid (5) were purified. Their structures were chacracterized using extensive HR-ESI-MS and NMR spectroscopic methods. The isolated compounds (2-5) possessed stronger α-glucosidase inhibitory activity (IC50 = 43.7-110.1 μM) than the standard drug acarbose (IC50 = 214.5 μM). Graphical Abstract

Natural Product Research, 2020

Three new diphenyl ethers, named praesorethers E, F and G (1, 2 and 3), were isolated from the li... more Three new diphenyl ethers, named praesorethers E, F and G (1, 2 and 3), were isolated from the lichen Parmotrema praesorediosum. Their chemical structures were elucidated on the basis of extensively spectroscopic analysis including HR-ESI-MS and NMR as well as comparison with previously published data. These compounds were evaluated for the cytotoxicity against three human cancer cell lines (HeLa, NCI-H460 and MCF-7) using SRB assay. As results, 1 and 2 exhibited weak cytotoxic activity against three tested cancer cell lines with the inhibitive percentage of 64-79.9% at the concentration of 100 lg/mL while 3 was inactive.

Natural Product Research, 2021

From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10-anthraquinone, l... more From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10-anthraquinone, lasibidoupin A (1), and one new 6,7-benzocoumarin, lasibidoupin B (2), together with one known compound, 11-O-methyldamnacanthol (3) were isolated using chromatographic method. Their structures were determined by extensive HRMS, and NMR assignments. Compound 3 was reported for the first time from this species. New compounds (1 & 2) were tested for the cytotoxicity against three human cancer cell lines (MCF-7, HeLa, and NCI-H460) by SRB assay. As results, 1 & 2 exhibited significant cytotoxic activity against all cancer cell lines (IC50 ranged from 0.058 ± 0.003 to 0.177 ± 0.014 μM).

Natural Product Research, 2019

Markhasphingolipid A, new phytosphingolipid from the leaves of Markhamia stipulata var. canaense ... more Markhasphingolipid A, new phytosphingolipid from the leaves of Markhamia stipulata var. canaense V.S. Dang From the leaves of Markhamia stipulata var. canaense V.S. Dang, one new phytosphingolipid, named markhasphingolipid A (6), together with five known compounds, 4',7-O-dimethylapigenin (1), narigenin (2), tectoquinone (3), mollic acid (4), 1-hexadecanoyl-sn-glycerol (5) were classified by various chromatographic methods. Their structures were designated by IR, UV, HR-ESI-MS, HR-ESI-MS/MS and NMR experiments. All compounds were recognized for the first time from this species. The cytotoxicity of all n-hexane fractions and isolated compounds (5 & 6) against three human cancer cell lines (HeLa, HepG2, and MCF-7) were evaluated by SRB assay. All n-hexane fractions expressed cytotoxic effect on three tested cancer cell lines (at the concentration of 100 μg/mL, percent of cytotoxicity ranged from 55.81 to 95.83%) as well as compound 5 (IC 50 ranged from 48.51 to 63.30 μM) whereas fraction H.I and compound 6 did not show activity.

Natural Product Research, 2020

Article Information Efficacy of herbal mycotoxin binders in ameliorating induced mycotoxicosis wa... more Article Information Efficacy of herbal mycotoxin binders in ameliorating induced mycotoxicosis was evaluated in white leghorn laying hens. Birds were randomly divided into six groups containing 15 birds in each group. Group I was served as control fed with basal diet, group II birds were fed with aflatoxins and ochratoxin A at 100 ppb each. Group III, IV, V and VI birds were fed with aflatoxins and ochratoxin A at 100ppb each and herbal mycotoxin binders Vilocym ® , Toxiroak ® ,Vilocym-Z ® in feed at 1 kg/tonne and AV/LBP/20 ® at 1 ml/litre in drinking water respectively for 10 weeks. The cultured rice and wheat samples were screened for presence of mycotoxins by LC-MS/MS method. Aflatoxins concentration in cultured rice sample was 826 ppb. Ochratoxin A concentration in cultured wheat sample was 8990 ppb. The hematological parametes viz., Hb, TEC, PCV showed signmificant decreased level in (Group II, III, IV, V and VI) compared to their respective control group. Similarly biochemical parameters viz., aspartate aminotransferase, alanine aminotransferase showed significantly decreased level in treatred groups (Group II, III, IV, V and VI) compared to their respective control group. Serum albumin and serum total protein level significantly decreased in treatred groups (Group II, III, IV, V and VI) compared to their respective control group(Group I). Histopathology of Group II birds revealed toxic effects on liver and kidney. Supplementation of herbal mycotoxin binders in mycotoxicated feed showed improvement in all the parameters indicating that herbal mycotoxin binders reduce the severity of toxicity.

Natural Product Research, Sep 20, 2021

From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10anthraquinone, la... more From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10anthraquinone, lasibidoupin A (1), and one new 6,7-benzocoumarin, lasibidoupin B (2), together with one known compound, 11-O-methyldamnacanthol (3) were isolated using chromatographic method. Their structures were determined by extensive HRMS, and NMR assignments. Compound 3 was reported for the first time from this species. New compounds (1 & 2) were tested for the cytotoxicity against three human cancer cell lines (MCF-7, HeLa, and NCI-H460) by SRB assay. As results, 1 & 2 exhibited significant cytotoxic activity against all cancer cell lines (IC50 ranged from 0.058 ± 0.003 to 0.177 ± 0.014 μM).

Natural Product Research, Sep 20, 2021

From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10anthraquinone, la... more From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10anthraquinone, lasibidoupin A (1), and one new 6,7-benzocoumarin, lasibidoupin B (2), together with one known compound, 11-O-methyldamnacanthol (3) were isolated using chromatographic method. Their structures were determined by extensive HRMS, and NMR assignments. Compound 3 was reported for the first time from this species. New compounds (1 & 2) were tested for the cytotoxicity against three human cancer cell lines (MCF-7, HeLa, and NCI-H460) by SRB assay. As results, 1 & 2 exhibited significant cytotoxic activity against all cancer cell lines (IC50 ranged from 0.058 ± 0.003 to 0.177 ± 0.014 μM).

Phytochemistry Letters, Feb 1, 2021

This paper presents a framework in which many structural credit risk models can be made hybrid by... more This paper presents a framework in which many structural credit risk models can be made hybrid by randomizing the default trigger, while keeping the capital structure intact. This produces random recovery rates negatively correlated with the default probability. The approach is implemented on a …rm-by-…rm basis using maximum likelihood and the unscented Kalman …lter (UKF) on each of the 225 companies of the CDX NA IG and HY indices using weekly CDS data from December 2007 to January 2012. Adding the surprise element and the time-varying distribution of recovery rates has a large impact on credit spreads as it modi…es both the level and shape of the curves. When a bond portfolio is considered, the presence of dependence among …rm leverage ratios and between default probabilities and recovery rates produces clusters of defaults with low recovery rates. It has a major impact on standard risk measures such as Valueat-Risk and conditional tail expectation.

Phytochemistry Letters, Feb 1, 2021

This paper presents a framework in which many structural credit risk models can be made hybrid by... more This paper presents a framework in which many structural credit risk models can be made hybrid by randomizing the default trigger, while keeping the capital structure intact. This produces random recovery rates negatively correlated with the default probability. The approach is implemented on a …rm-by-…rm basis using maximum likelihood and the unscented Kalman …lter (UKF) on each of the 225 companies of the CDX NA IG and HY indices using weekly CDS data from December 2007 to January 2012. Adding the surprise element and the time-varying distribution of recovery rates has a large impact on credit spreads as it modi…es both the level and shape of the curves. When a bond portfolio is considered, the presence of dependence among …rm leverage ratios and between default probabilities and recovery rates produces clusters of defaults with low recovery rates. It has a major impact on standard risk measures such as Valueat-Risk and conditional tail expectation.

Advances in Natural Sciences: Nanoscience and Nanotechnology, Oct 14, 2016

In this work anti-cancer drug curcumin-loaded superparamagnetic iron oxide (Fe 3 O 4) nanoparticl... more In this work anti-cancer drug curcumin-loaded superparamagnetic iron oxide (Fe 3 O 4) nanoparticles was modified by chitosan (CS). The magnetic iron oxide nanoparticles were synthesized by using reverse micro-emulsion (water-in-oil) method. The magnetic nanoparticles without loaded drug and drug-loaded magnetic nanoparticles were characterized by XRD, FTIR, TG-DTA, SEM, TEM, and VSM techniques. These nanoparticles have almost spherical shape and their diameter varies from 8 nm to 17 nm. Measurement of VSM at room temperature showed that iron oxide nanoparticles have superparamagnetic properties. In vitro drug loading and release behavior of curcumin drug-loaded CS-Fe 3 O 4 nanoparticles were studied by using UV-spectrophotometer. In addition, the cytotoxicity of the modified nanoparticles has shown anticancer activity against A549 cell with IC 50 value of 73.03 μg/ml. Therefore, the modified magnetic nanoparticles can be used as drug delivery carriers on target in the treatment of cancer cells.

Advances in Natural Sciences: Nanoscience and Nanotechnology, Oct 14, 2016

In this work anti-cancer drug curcumin-loaded superparamagnetic iron oxide (Fe 3 O 4) nanoparticl... more In this work anti-cancer drug curcumin-loaded superparamagnetic iron oxide (Fe 3 O 4) nanoparticles was modified by chitosan (CS). The magnetic iron oxide nanoparticles were synthesized by using reverse micro-emulsion (water-in-oil) method. The magnetic nanoparticles without loaded drug and drug-loaded magnetic nanoparticles were characterized by XRD, FTIR, TG-DTA, SEM, TEM, and VSM techniques. These nanoparticles have almost spherical shape and their diameter varies from 8 nm to 17 nm. Measurement of VSM at room temperature showed that iron oxide nanoparticles have superparamagnetic properties. In vitro drug loading and release behavior of curcumin drug-loaded CS-Fe 3 O 4 nanoparticles were studied by using UV-spectrophotometer. In addition, the cytotoxicity of the modified nanoparticles has shown anticancer activity against A549 cell with IC 50 value of 73.03 μg/ml. Therefore, the modified magnetic nanoparticles can be used as drug delivery carriers on target in the treatment of cancer cells.

Journal of Asian Natural Products Research, Apr 1, 2021

Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A... more Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A (1), together with four depsidones, including virensic acid (2), protocetraric acid (3), 8'-O-methylprotocetraric acid (4), and furfuric acid (5) were purified. Their structures were chacracterized using extensive HR-ESI-MS and NMR spectroscopic methods. The isolated compounds (2-5) possessed stronger α-glucosidase inhibitory activity (IC50 = 43.7-110.1 μM) than the standard drug acarbose (IC50 = 214.5 μM). Graphical Abstract

Journal of Asian Natural Products Research, Apr 1, 2021

Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A... more Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A (1), together with four depsidones, including virensic acid (2), protocetraric acid (3), 8'-O-methylprotocetraric acid (4), and furfuric acid (5) were purified. Their structures were chacracterized using extensive HR-ESI-MS and NMR spectroscopic methods. The isolated compounds (2-5) possessed stronger α-glucosidase inhibitory activity (IC50 = 43.7-110.1 μM) than the standard drug acarbose (IC50 = 214.5 μM). Graphical Abstract

Natural Product Research, Jul 22, 2019

From the leaves of Sterculia foetida L., one new oleanane-type triterpenoid, named stercufoetin A... more From the leaves of Sterculia foetida L., one new oleanane-type triterpenoid, named stercufoetin A (1) together with four known ones, vergatic acid (2), β-amyrin (3), oleanolic acid (4) and maslinic acid (5) were purified by diversely chromatographic methods. Their structures were proposed by HR-APCI-MS and NMR experiments. Compounds (2-5) were notified for the first time from this species. Compound 1 showed weak cytotoxic effect against three human cancer cell lines (MCF-7, HepG2 and HeLa) using SRB assay.

Natural Product Research, Oct 23, 2020

Article Information Efficacy of herbal mycotoxin binders in ameliorating induced mycotoxicosis wa... more Article Information Efficacy of herbal mycotoxin binders in ameliorating induced mycotoxicosis was evaluated in white leghorn laying hens. Birds were randomly divided into six groups containing 15 birds in each group. Group I was served as control fed with basal diet, group II birds were fed with aflatoxins and ochratoxin A at 100 ppb each. Group III, IV, V and VI birds were fed with aflatoxins and ochratoxin A at 100ppb each and herbal mycotoxin binders Vilocym ® , Toxiroak ® ,Vilocym-Z ® in feed at 1 kg/tonne and AV/LBP/20 ® at 1 ml/litre in drinking water respectively for 10 weeks. The cultured rice and wheat samples were screened for presence of mycotoxins by LC-MS/MS method. Aflatoxins concentration in cultured rice sample was 826 ppb. Ochratoxin A concentration in cultured wheat sample was 8990 ppb. The hematological parametes viz., Hb, TEC, PCV showed signmificant decreased level in (Group II, III, IV, V and VI) compared to their respective control group. Similarly biochemical parameters viz., aspartate aminotransferase, alanine aminotransferase showed significantly decreased level in treatred groups (Group II, III, IV, V and VI) compared to their respective control group. Serum albumin and serum total protein level significantly decreased in treatred groups (Group II, III, IV, V and VI) compared to their respective control group(Group I). Histopathology of Group II birds revealed toxic effects on liver and kidney. Supplementation of herbal mycotoxin binders in mycotoxicated feed showed improvement in all the parameters indicating that herbal mycotoxin binders reduce the severity of toxicity.

Natural Product Research, Mar 19, 2019

Natural Product Research, Feb 22, 2018

One new cycloartane triterpenoid, named Markhacanasin C (1), together with three known triterpeno... more One new cycloartane triterpenoid, named Markhacanasin C (1), together with three known triterpenoids, oleanolic acid (2), ursolic acid (3) and 6β,19α-dihydroxyursolic acid (4) were isolated by various chromatographic methods from the most cytotoxic fraction of the ethyl acetate extract of Markhamia stipulata var. canaense V.S. Dang leaves. Among them, 4 was reported for the first time from the genus Markhamia, while 2 & 3 were found for the first time from this species. Their structures were elucidated by IR, UV, HR-ESI-MS and NMR experiments. The cytotoxicity of isolated compounds (3 & 4) against three human cancer cell lines (HeLa, HepG2, and MCF-7) were evaluated. At the concentration of 100 μg/mL, 3 exhibited significant cytotoxic activity (86.36 ± 3.69 %).

Natural Product Research, 2021

Two new compounds, comprising one dibenzofuran, named usneaceratin A (1), and one phenolic acid, ... more Two new compounds, comprising one dibenzofuran, named usneaceratin A (1), and one phenolic acid, named usneaceratin B (2), together with one known dibenzofuran, isousnic acid (3), and two known phenolics, orsellinic acid (4) and methyl orsellinate (5) were clarified from the lichen Usnea ceratina using variously chromatographic methods. Their structures were testified by comprehensive HR-ESI-MS, and NMR spectroscopic analysis, and comparison with published data. Their α-glucosidase inhibitory activity of all compounds was measured. Usneaceratin B (2) possessed better inhibition against α-glucosidase enzyme (IC50 value of 41.8 μM) than the standard drug acarbose (IC50 value of 214.50 μM).

From the leaves of <i>Ricinus communis</i> Linn., one new alkaloid, named ricicomin A... more From the leaves of <i>Ricinus communis</i> Linn., one new alkaloid, named ricicomin A (<b>1</b>) together with three known ones, ricinine (<b>2</b>), <i>N</i>-demethylricinine (<b>3</b>) and 4-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid (<b>4</b>) were justified by repeated chromatographic methods. Their structures were determined by comprehensive IR, HR-ESI-MS and NMR analyses. Compound <b>4</b> was identified for the first time from the genus <i>Ricinus</i>. DFT-NMR chemical shift calculations and subsequent DP4+ probability methods were applied to confirm the chemical structure of <b>1</b>. Compounds <b>1–3</b> did not display cytotoxic effect against three human cancer cell lines (MCF-7, HepG2 and HeLa) using SRB assay.

From the leaves of <i>Sterculia foetida</i> L., one new oleanane-type triterpenoid, n... more From the leaves of <i>Sterculia foetida</i> L., one new oleanane-type triterpenoid, named stercufoetin A (<b>1</b>) together with four known ones, vergatic acid (<b>2</b>), <i>β</i>-amyrin (<b>3</b>), oleanolic acid (<b>4</b>) and maslinic acid <b>(5)</b> were purified by diversely chromatographic methods. Their structures were proposed by HR-APCI-MS and NMR experiments. Compounds <b>(2–5)</b> were notified for the first time from this species. Compound <b>1</b> showed weak cytotoxic effect against three human cancer cell lines (MCF-7, HepG2 and HeLa) using SRB assay.

Journal of Asian Natural Products Research, 2021

Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A... more Abstract From the lichen Parmotrema praesorediosum, one new diphenyl peroxide, named praesordin A (1), together with four depsidones, including virensic acid (2), protocetraric acid (3), 8'-O-methylprotocetraric acid (4), and furfuric acid (5) were purified. Their structures were chacracterized using extensive HR-ESI-MS and NMR spectroscopic methods. The isolated compounds (2-5) possessed stronger α-glucosidase inhibitory activity (IC50 = 43.7-110.1 μM) than the standard drug acarbose (IC50 = 214.5 μM). Graphical Abstract

Natural Product Research, 2020

Three new diphenyl ethers, named praesorethers E, F and G (1, 2 and 3), were isolated from the li... more Three new diphenyl ethers, named praesorethers E, F and G (1, 2 and 3), were isolated from the lichen Parmotrema praesorediosum. Their chemical structures were elucidated on the basis of extensively spectroscopic analysis including HR-ESI-MS and NMR as well as comparison with previously published data. These compounds were evaluated for the cytotoxicity against three human cancer cell lines (HeLa, NCI-H460 and MCF-7) using SRB assay. As results, 1 and 2 exhibited weak cytotoxic activity against three tested cancer cell lines with the inhibitive percentage of 64-79.9% at the concentration of 100 lg/mL while 3 was inactive.

Natural Product Research, 2021

From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10-anthraquinone, l... more From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10-anthraquinone, lasibidoupin A (1), and one new 6,7-benzocoumarin, lasibidoupin B (2), together with one known compound, 11-O-methyldamnacanthol (3) were isolated using chromatographic method. Their structures were determined by extensive HRMS, and NMR assignments. Compound 3 was reported for the first time from this species. New compounds (1 & 2) were tested for the cytotoxicity against three human cancer cell lines (MCF-7, HeLa, and NCI-H460) by SRB assay. As results, 1 & 2 exhibited significant cytotoxic activity against all cancer cell lines (IC50 ranged from 0.058 ± 0.003 to 0.177 ± 0.014 μM).

Natural Product Research, 2019

Markhasphingolipid A, new phytosphingolipid from the leaves of Markhamia stipulata var. canaense ... more Markhasphingolipid A, new phytosphingolipid from the leaves of Markhamia stipulata var. canaense V.S. Dang From the leaves of Markhamia stipulata var. canaense V.S. Dang, one new phytosphingolipid, named markhasphingolipid A (6), together with five known compounds, 4',7-O-dimethylapigenin (1), narigenin (2), tectoquinone (3), mollic acid (4), 1-hexadecanoyl-sn-glycerol (5) were classified by various chromatographic methods. Their structures were designated by IR, UV, HR-ESI-MS, HR-ESI-MS/MS and NMR experiments. All compounds were recognized for the first time from this species. The cytotoxicity of all n-hexane fractions and isolated compounds (5 & 6) against three human cancer cell lines (HeLa, HepG2, and MCF-7) were evaluated by SRB assay. All n-hexane fractions expressed cytotoxic effect on three tested cancer cell lines (at the concentration of 100 μg/mL, percent of cytotoxicity ranged from 55.81 to 95.83%) as well as compound 5 (IC 50 ranged from 48.51 to 63.30 μM) whereas fraction H.I and compound 6 did not show activity.

Natural Product Research, 2020

Article Information Efficacy of herbal mycotoxin binders in ameliorating induced mycotoxicosis wa... more Article Information Efficacy of herbal mycotoxin binders in ameliorating induced mycotoxicosis was evaluated in white leghorn laying hens. Birds were randomly divided into six groups containing 15 birds in each group. Group I was served as control fed with basal diet, group II birds were fed with aflatoxins and ochratoxin A at 100 ppb each. Group III, IV, V and VI birds were fed with aflatoxins and ochratoxin A at 100ppb each and herbal mycotoxin binders Vilocym ® , Toxiroak ® ,Vilocym-Z ® in feed at 1 kg/tonne and AV/LBP/20 ® at 1 ml/litre in drinking water respectively for 10 weeks. The cultured rice and wheat samples were screened for presence of mycotoxins by LC-MS/MS method. Aflatoxins concentration in cultured rice sample was 826 ppb. Ochratoxin A concentration in cultured wheat sample was 8990 ppb. The hematological parametes viz., Hb, TEC, PCV showed signmificant decreased level in (Group II, III, IV, V and VI) compared to their respective control group. Similarly biochemical parameters viz., aspartate aminotransferase, alanine aminotransferase showed significantly decreased level in treatred groups (Group II, III, IV, V and VI) compared to their respective control group. Serum albumin and serum total protein level significantly decreased in treatred groups (Group II, III, IV, V and VI) compared to their respective control group(Group I). Histopathology of Group II birds revealed toxic effects on liver and kidney. Supplementation of herbal mycotoxin binders in mycotoxicated feed showed improvement in all the parameters indicating that herbal mycotoxin binders reduce the severity of toxicity.