Biomedical subjects

Bei Jiang

Publications and source records attributed to Bei Jiang.

14 recordsLinked to original sources

PubMed2006

Actein and a fraction of black cohosh potentiate antiproliferative effects of chemotherapy agents on human breast cancer cells.

The purpose of this study was to determine whether the triterpene glycosides present in black cohosh enhance the growth inhibitory effects of specific breast cancer chemotherapy agents. Black cohosh roots and rhizomes were extracted with methanol (MeOH)/water (H (2)O) and fractionated by solvent-solvent partitioning to yield three fractions: hexane, ethyl acetate (EtOAc) and water. The EtOAc fraction is enriched in triterpene glycosides, including the compound actein. Actein and the EtOAc fraction were then tested, alone and in combination with chemotherapy agents, for growth inhibition of the ER (-) Her2 overexpressing breast cancer cell line MDA-MB-453. We found that actein exerted a synergistic effect on growth inhibition when combined with doxorubicin or 5-flourouracil. Synergy was also obtained when the EtOAc fraction was combined with doxorubicin. Actein increased the percent of cells in the G1 phase of the cell cycle and had a similar effect when combined with 5-flourouracil or doxorubucin. Actein enhanced the induction of apoptosis by paclitaxel, 5-flourouracil or doxorubicin. Our results indicate that relatively low concentrations of actein or the EtOAc fraction of black cohosh can cause synergistic inhibition of human breast cancer cell proliferation when combined with different classes of chemotherapy agents.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2006

Comparative analyses of bioactive Mammea coumarins from seven parts of Mammea americana by HPLC-PDA with LC-MS.

Mammea americana L. is tropical plant in the Clusiaceae family that bears edible fruit. Mammea coumarins are isoprenylated derivatives of the lactones of the 2-hydroxy-Z-cinnamic acids that are bioactive and have limited distribution in three Clusiaceae genera. Qualitative and quantitative analyses were performed to determine the distribution of mammea coumarins in the seed nucleus, seed coat, fruit flesh, fruit skin, leaf, stem, and root of M. americana using high-performance liquid chromatography-photodiode array detector (HPLC-PDA) and liquid chromatography-mass spectrometry (LC-MS). Ten major mammea coumarins, mammea E/BD (1), mammea E/BC (2), mammea E/BA (3), mammea E/BB (4), mammea B/BA hydroxycyclo F (5), mammea B/BD (6), mammea B/BC (7), mammea B/BA (8), mammea B/BB (9), and mammea B/BA cyclo F (10), were isolated and identified from the seed nucleus of M. americana and employed as standards. The HPLC-PDA method was validated with respect to sensitivity, linearity, recovery, accuracy, and precision. The total content (w/w %) of the 10 major mammea coumarins in M. americana was determined to be highest in the root (0.75%), followed by the leaf (0.64%), seed nucleus (0.48%), fruit skin (0.11%), stem (0.08%), seed coat (0.02%), and fruit flesh (<0.01%). The leaf and seed nucleus are rich and sustainable natural sources of mammea coumarins. Additionally, the described HPLC-PDA and LC-MS methods are sensitive and accurate and can be applied to the analysis of mammea coumarins in other samples.

Chromatography, High Pressure Liquid↗

PubMed2006

Evaluation of the botanical authenticity and phytochemical profile of black cohosh products by high-performance liquid chromatography with selected ion monitoring liquid chromatography-mass spectrometry.

Black cohosh (Actaea racemosa L., syn. Cimicifuga racemosa L.) has become increasingly popular as a dietary supplement in the United States for the treatment of symptoms related to menopause, but the botanical authenticity of most products containing black cohosh has not been evaluated, nor is manufacturing highly regulated in the United States. In this study, 11 black cohosh products were analyzed for triterpene glycosides, phenolic constituents, and formononetin by high-performance liquid chromatography-photodiode array detection and a new selected ion monitoring liquid chromatography-mass spectrometry method. Three of the 11 products were found to contain the marker compound cimifugin and not cimiracemoside C, thereby indicating that these plants contain Asian Actaea instead of black cohosh. One product contained both black cohosh and an Asian Actaea species. For the products containing only black cohosh, there was significant product-to-product variability in the amounts of the selected triterpene glycosides and phenolic constituents, and as expected, no formononetin was detected.

Chromatography, High Pressure Liquid↗

PubMed2006

Polyphenolic constituents of Actaea racemosa.

A new lignan, actaealactone (1), and a new phenylpropanoid ester derivative, cimicifugic acid G (2), together with 15 known polyphenols, protocatechuic acid, protocatechualdehyde, p-coumaric acid, caffeic acid, methyl caffeate, ferulic acid, ferulate-1-methyl ester, isoferulic acid, 1-isoferuloyl-beta-d-glucopyranoside, fukinolic acid, and cimicifugic acids A, B, and D-F, were isolated from an extract of the rhizomes and roots of black cohosh (Actaea racemosa). The structures of the new compounds were determined on the basis of NMR spectroscopic analysis. Compounds 1 and 2 displayed antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay with IC(50) values of 26 and 37 microM, respectively. Other antioxidants identified from A. racemosa include cimicifugic acid A (3), cimicifugic acid B (4), and fukinolic acid (5). Compounds 1 and 2 also exhibited a small stimulating effect on the growth of MCF-7 breast cancer cell proliferation 1.24-fold (14 microM) and 1.14-fold (10 microM), respectively, compared to untreated cells.

Biphenyl Compounds↗

PubMed2005

Antioxidant and cytotoxic isoprenylated coumarins from Mammea americana.

Antioxidant-guided fractionation of Mammea americana L. seeds resulted in the identification of three new isoprenylated coumarins, mammea B/BA hydroxycyclo F (1), mammea E/BC (2), and mammea E/BD (3). In addition, twelve known isoprenylated coumarins, mammea A/AA (4), mammea A/AA cyclo D (5), mammea A/AA cyclo F (6), mammea A/AC cyclo D (7), mammea A/AD cyclo D (8), mammea B/BA (9), mammea B/BA cyclo F (10), mammea B/BB (11), mammea B/BC (12), mammea B/BD (13), mammea E/BA (14), and mammea E/BB (15), as well as two known flavanols, (+)-catechin (16) and (-)-epicatechin (17) were identified. The fifteen isoprenylated coumarins were screened for their cytotoxicity in the SW-480, HT-29, and HCT-116 human colon cancer cell lines and antioxidant capacities in the DPPH (1,1-diphenyl-2-picrylhydrazyl) free-radical assay. Compounds 1 - 15 exhibited significant cytotoxic activities in the SW-480, HT-29, and HCT-116 human colon cancer cell lines (IC50 ranges 13.9 - 88.1, 11.2 - 85.3, and 10.7 - 76.7 microM, in the three cell lines, respectively) at concentrations comparable to 5-fluorouracil (IC50 = 53.0, 46.1, and 45.1 microM), a drug frequently used for human colon cancer treatment. Compounds 2 - 4, 9, and 11 - 15 displayed high antioxidant activity in the DPPH assay (IC50 range 86 - 135 microM), compounds 1, 5 - 8, and 10, however, had no antioxidant activity (IC50 > 200 microg/mL) in the DPPH assay. The results of these assays were used to study the structure-activity relationships for this class of compounds. In the SW-480 cell line, the three new coumarins, 1 - 3, also exhibited dose-dependent increases in sub-diploid cells by flow cytometry, indicating that they induce apoptosis.

Antineoplastic Agents, Phytogenic↗

PubMed2005

Three new compounds from Isodon melissoides.

Reinvestigation of the aerial parts of Isodon melissoides has afforded two new ent-diterpenoids, melissoidesins V (1) and W (2), together with five known ones, glabcensin W (3), melissoidesin C (4), melissoidesin A (5), melissoidesin B (6) and melissoidesin D (7), one new ionone derivative 3alpha,4alpha-isopropyliden-beta-ionol (8), as well as three analogues, 3-hydroxy-4-oxo-beta-ionol (9), megastigma-7-en-3,5,6,9-tetraol (10) and blumenol A (11), and three phenolic compounds salicylic acid (12), syringic acid (13) and cirsiliol (14). The new structures were elucidated on the basis of spectroscopic techniques, especially the 2D-NMR spectral analysis.

Chromatography, Gel↗

PubMed2004

Electromechanical properties of fine-grain, 0.7 Pb(Mg(1/3)Nb(2/3))O3-0.3PbTiO3 ceramics.

A fine grain, relaxor-based piezoelectric ceramic 0.7 Pb(Mg(1/3)Nb(2/3))O3-0.3PbTiO3 (PMN-30% PT) has been investigated, which was fabricated using the columbite precursor method. The complete set of electromechanical properties of the piezoceramic at room temperature is determined using a combination of ultrasonic and resonance techniques. This fine-grain ceramic (grain size < or = 2.5 microm) exhibits ultra-high dielectric permittivity (epsilon33(T)/epsilon0 approximately 7000) and a high coupling coefficient k(33) (= 0.78). Ultrasonic spectroscopy was used to measure the dispersion of the phase velocity and attenuation for the longitudinal wave propagating in the poling direction. Lower attenuation and smaller velocity dispersion were observed compared to modified Pb(Zr(x)Ti(1-x)O3 (PZT-5H) ceramics. The measurement results show that this fine-grain PMN-30% PT ceramic is a very good material for making ultrasonic array transducers.

Journal Article↗

PubMed2003

Characterization of piezoelectric materials with large piezoelectric and electromechanical coupling coefficients.

The relaxor based ferroelectric (1-x)Pb(Zn(1/3)Nb(2/3))O(3)-xPbTiO(3) and (1-x)Pb(Mg(1/3)Nb(2/3))O(3)-xPbTiO(3) single crystals provided new challenges in property characterization because their extraordinarily large piezoelectric coefficients and electromechanical coupling coefficients. Large errors may occur in some of the derived material constants using conventional characterization techniques. This paper will analyze the inadequacy of the traditional characterization methods and provide some basic guidelines for properly characterizing piezoelectric materials with extremely high piezoelectric and electromechanical coupling coefficients.

Crystallography↗

PubMed2002

Constituents of Gnetum montanum.

A new stilbene, gnetifolin M (1), was isolated from the lianas of Gnetum montanum, together with seven known compounds, resveratrol (2), gnetol (3), 4', 5,7-trihydroxy-3'-methoxyflavone, beta-sitosterol, daucosterol, ursolic acid, and tetracosanoic acid. The structure of 1 was determined to be 2-(5'-methoxy-3'-hydroxyphenyl)-4-hydroxybenzofuran on the basis of spectroscopic evidence.

Benzofurans↗

PubMed2002

Abietane diterpenoids from Coleus xanthanthus.

Eight new abietane diterpenoids, coleon U 11-acetate (1), 16-acetoxycoleon U 11-acetate (2), and xanthanthusins F-K (3-8), together with five known analogues, coleon U (9), 16-O-acetylcoleon C (10), coleon U-quinone (11), 8alpha,9alpha-epoxycoleon U-quinone (12), and xanthanthusin E (13), were isolated from the aerial parts of Coleus xanthanthus. The structures of 1-8 were elucidated on the basis of spectral methods. Compounds 1, 5, and 11-13 were evaluated for their cytotoxicity against K562 human leukemia cells.

Antineoplastic Agents, Phytogenic↗

PubMed2002

Diterpenoids from Isodon adenantha.

Eleven new diterpenoids, adenanthins B-L (1-11), together with five known analogues, calcicolin B (12), adenanthin (13), weisiensin A (14), nervosanin (15), and forrestin C (16), were isolated from the aerial parts of Isodon adenantha. The structures of 1-11 were elucidated on the basis of spectral methods, as well as the X-ray crystallographic analysis of 11. Compounds 2, 5, and 14 showed significant inhibitory activities against K562 cells, with IC(50) values less than 4.0 microg/mL, respectively.

Diterpenes↗

PubMed2002

Cytotoxic ent-kaurane diterpenoids from Isodon sculponeata.

Four new ent-kaurane diterpenoids, sculponeatins F-I (1-4), together with six known compounds, sculponeatin E (5), epi-nodosin (6), epi-nodosinol (7), enmein (8), and macrocalyxoformins A and B (9 and 10), were isolated from the leaves of Isodon sculponeata. Also obtained were ursolic acid, 2alpha,3beta-dihydroxy-urs-12-en-28-oic acid, 2alpha,3beta,19alpha-trihydroxy-urs-12-en-28-oic acid, beta-sitosterol, daucosterol, quercetin, pedalitin, rosmarinic acid, caffeic acid and ethyl caffeic acid. Their structures were determined by spectral methods (1D-, 2D-NMR and MS). Some diterpenoids were tested for their cytotoxicity to inhibit three kinds of human tumor cells K562, A549 and T24. Compounds 3, 4, 6, 8, and 10 showed significant inhibitory effect toward K562 with IC(50) values ranging from 3.2 microg/ml to 8.2 microg/ml, while 3 and 6 exhibited potent antitumor activity against T24, but none exhibited cytotoxicity toward the cells of A549.

Antineoplastic Agents, Phytogenic↗

PubMed2002

Constituents from the roots of Heracleum rapula Franch.

A new coumarin glucoside, 8-hydroxy-5-O-beta-D-glucosylpsoralen, along with 17 known coumarins and one steroid, was isolated from the roots of Heracleum rapula Franch. Four coumarin glucosides, including the new one, were obtained from the water-soluble fraction. The other coumarins isolated from the ethyl acetate-fraction included 10 furanocoumarins, a simple coumarin and three types of bicoumarins. Their structures were elucidated by means of spectroscopic analysis.

Coumarins↗

PubMed2002

Anisotropy in domain engineered 0.92Pb(Zn1/3 Nb2/3)O3-0.08PbTiO3 single crystal and analysis of its property fluctuations.

The orientation dependence of slowness and electromechanical coupling coefficients of 0.92Pb(Zn1/3 Nb2/3)O3-0.08PbTiO3 (PZN-8%PT) domain engineered single crystal was analyzed based on the measured complete set of elastic, piezoelectric, and dielectric constants. There exist one quasi-longitudinal, one quasi-shear, and one pure shear wave in each of the [100]-[010], [010]-[001], and [001]-[110] planes. The slowness of the quasi-shear wave exhibits strong anisotropy in all three planes, and the coupling coefficient k33 and k31 reach their maximum in [001] and [110] directions of cubic axis, respectively. Because the composition of PMN-8%PT system is very close to the morphotropic phase boundary, the extraordinary large piezoelectric coefficients d31 and d33, and high coupling coefficient k33 are very sensitive to compositional variation. We have performed error analysis and proposed an improved characterization scheme to derive a complete data set with best consistency.

Anisotropy↗