Wendy L. Zhang
Hong Kong University of Science and Technology
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Publication
Featured researches published by Wendy L. Zhang.
Journal of Agricultural and Food Chemistry | 2011
Ken Y.Z. Zheng; Roy Chi Yan Choi; Anna Wing Han Cheung; Ava J. Y. Guo; Cathy W. C. Bi; Kevin Y. Zhu; Qiang Fu; Yingqing Du; Wendy L. Zhang; Janis Ya-Xian Zhan; Ran Duan; David Tai Wai Lau; Tina Ting Xia Dong; Karl Wah Keung Tsim
Radix Astragali (RA) is commonly used as a health food supplement to reinforce the body vital energy. Flavonoids, including formononetin, ononin, calycosin, and calycosin-7-O-β-d-glucoside, are considered to be the major active ingredients within RA. Here, we provided different lines of evidence that the RA flavonoids stimulated the expression of erythropoietin (EPO), the central regulator of red blood cell mass, in cultured human embryonic kidney fibroblasts (HEK293T). A plasmid containing hypoxia response element (HRE), a critical regulator for EPO transcription, was tagged upstream of a firefly luciferase gene, namely, pHRE-Luc, which was being transfected into fibroblasts. The application of RA flavonoids onto the transfected cells induced the transcriptional activity of HRE. To account for the transcriptional activation after the treatment of flavonoids, the expression of hypoxia-inducible factor-1α (HIF-1α) was markedly increased: The increase was in both mRNA and protein levels. In addition, the degradation of HIF-1α was reduced under the effect of flavonoids. The regulation of HIF-1α therefore could account for the activation of EPO expression mediated by the RA flavonoids. The current results therefore reveal the function of this herb in enhancing hematopoietic functions.
Journal of Agricultural and Food Chemistry | 2013
Jianping Chen; Zhonggui Li; Maitinuer Maiwulanjiang; Wendy L. Zhang; Janis Ya-Xian Zhan; Candy Ting Wai Lam; Kevin Y. Zhu; Ping Yao; Roy Chi Yan Choi; David Tai Wai Lau; Tina Ting Xia Dong; Karl Wah Keung Tsim
Chinese date, the fruit of Ziziphus jujuba Mill., has thousands of years cultivation history, and about 700 cultivars of dates in China. Two types of dates are commonly found in the market: (i) fresh immature dates consumed as fruits, and (ii) dried mature dates used as Chinese medicines. Here, chemical and biological properties of these dates were revealed. Different sources of dates showed similar chemical profiles; however, the amounts of identified chemicals showed a great variation. The amount of nucleotides, flavonoids and polysaccharides in dates could be affected by its maturity and drying process. In parallel, the antioxidative functions of their extracts were compared. The date extracts protected PC12 cells against tBHP-induced cytotoxicity, and which also stimulated the transcriptional activity of antioxidant response element. The antioxidative effects were varied among different dates. The current results suggested the optimization of sources and specific usage of different maturity dates.
Journal of Agricultural and Food Chemistry | 2011
Janis Ya-Xian Zhan; Ken Yu Zhong Zheng; Kevin Y. Zhu; Cathy W. C. Bi; Wendy L. Zhang; Crystal Ying Qing Du; Qiang Fu; Tina Ting Xia Dong; Roy Chi Yan Choi; Karl Wah Keung Tsim; David Tai Wai Lau
The roots of Angelica sinensis [Angelica Sinensis Radix (ASR)] have been used as a common health food supplement for womens care for thousands of years in China. According to Asian tradition, ASR could be processed with the treatment of wine, which subsequently promoted the biological functions of ASR. By chemical and biological assessments, an orthogonal array design was employed here to determine the roles of three variable parameters in the processing of ASR, including oven temperature, baking time, and flipping frequency. The results suggested that oven temperature and baking time were two significant factors, while flipping frequency was a subordinate factor. The optimized condition of processing with wine therefore was considered to be heating in an oven at 80 °C for 90 min with flipping twice per hour. Under the optimized processing conditions, the solubilities of ferulic acid and Z-ligustilide from ASR were markedly increased and decreased, respectively. In parallel, the biological functions of processed ASR were enhanced in both anti-platelet aggregation and estrogenic activation; these increased functions could be a result of the altered levels of ferulic acid and Z-ligustilide in wine-processed ASR. Thus, the chemical and biological assessment of the processed ASR was in full accordance with the Chinese old tradition.
Phytotherapy Research | 2014
Jianping Chen; Crystal Ying Qing Du; Kelly Yin Ching Lam; Wendy L. Zhang; Candy Ting Wai Lam; Artemis Lu Yan; Ping Yao; David Tai Wai Lau; Tina Ting Xia Dong; Karl Wah Keung Tsim
The fruit of Ziziphus jujuba Mill., known as jujube or Chinese date, is commonly consumed as a health supplement or herbal medicine worldwide. To study the beneficial role of jujube in regulating immune response, we investigated its roles on the expressions of pro‐inflammatory cytokines in cultured macrophages. Application of chemically standardized jujube water extract for 24 h stimulated the transcriptional expression of interleukin (IL)‐1β, IL‐6, and tumor necrosis factor (TNF)‐α in cultured RAW 264.7 macrophages. In contrast, the pretreatment with jujube water extract suppressed the expression of IL‐1β and IL‐6, but not for TNF‐α in lipopolysaccharide (LPS)‐stimulated macrophages. The IL‐1β and IL‐6 cytokines in LPS‐induced macrophages were suppressed by jujube water extract in both mRNA and protein levels. In parallel, the inhibition of jujube water extract on the transcriptional activity of nuclear factor‐kappa B was revealed in LPS‐induced macrophages. These results verified the bidirectional immune‐modulatory roles of jujube by regulating the expressions of pro‐inflammatory cytokines in macrophages. Copyright
Journal of Agricultural and Food Chemistry | 2014
Jianping Chen; Maitinuer Maiwulanjiang; Kelly Yin Ching Lam; Wendy L. Zhang; Janis Ya-Xian Zhan; Candy Ting Wai Lam; Sherry L. Xu; Kevin Y. Zhu; Ping Yao; David Tai Wai Lau; Tina Ting Xia Dong; Karl Wah Keung Tsim
The fruit of Ziziphus jujuba Mill., known as Chinese date or jujube, is consumed as a health supplement worldwide. To study the role of jujube in brain benefits, its effects on neuronal differentiation of PC12 cells were studied. Application of jujube water extract induced neurite outgrowth of PC12 cells, >25% of which were differentiated; this effect was similar to that of nerve growth factor. In parallel, the expressions of neurofilaments (NFs) in jujube-treated cultures showed a dose-dependent increase, with the highest inductions by ∼150% for NF68 and NF160 and by ∼100% for NF200. Application of H89, a protein kinase A inhibitor, attenuated jujube-induced neurite outgrowth of the cultures. Besides, using jujube extract induced the phosphorylation of cAMP responsive element binding protein on PC12 cells, which was blocked by H89. These results support the use of jujube as a food supplement for the prevention of neurodegenerative diseases in which neurotrophin deficiency is involved.
Evidence-based Complementary and Alternative Medicine | 2013
Hui Yu; Wendy L. Zhang; Xianting Ding; Ken Yu Zhong Zheng; Chih-Ming Ho; Karl Wah Keung Tsim; Yi-Kuen Lee
Identifying potent drug combination from a herbal mixture is usually quite challenging, due to a large number of possible trials. Using an engineering approach of the feedback system control (FSC) scheme, we identified the potential best combinations of four flavonoids, including formononetin, ononin, calycosin, and calycosin-7-O-β-D-glucoside deriving from Astragali Radix (AR; Huangqi), which provided the best biological action at minimal doses. Out of more than one thousand possible combinations, only tens of trials were required to optimize the flavonoid combinations that stimulated a maximal transcriptional activity of hypoxia response element (HRE), a critical regulator for erythropoietin (EPO) transcription, in cultured human embryonic kidney fibroblast (HEK293T). By using FSC scheme, 90% of the work and time can be saved, and the optimized flavonoid combinations increased the HRE mediated transcriptional activity by ~3-fold as compared with individual flavonoid, while the amount of flavonoids was reduced by ~10-fold. Our study suggests that the optimized combination of flavonoids may have strong effect in activating the regulatory element of erythropoietin at very low dosage, which may be used as new source of natural hematopoietic agent. The present work also indicates that the FSC scheme is able to serve as an efficient and model-free approach to optimize the drug combination of different ingredients within a herbal decoction.
Planta Medica | 2014
Jianping Chen; Candy Ting Wai Lam; Ava Y.Y. Kong; Wendy L. Zhang; Janis Ya-Xian Zhan; Cathy W. C. Bi; Gallant K. L. Chan; Kelly Yin Ching Lam; Ping Yao; Tina Ting Xia Dong; Karl Wah Keung Tsim
The fruit of Ziziphus jujuba Mill., known as jujube or Chinese date, is commonly consumed as health supplement or herbal medicine worldwide. To study the beneficial role of jujube in enhancing hematopoietic function, we investigated its roles on the expression of erythropoietin in cultured Hep3B human hepatocellular carcinoma cells. Application of chemically standardized jujube water extract stimulated erythropoietin expression in a dose-dependent manner, with the highest response by ~ 100 % of increase. A plasmid containing hypoxia response element, a critical regulator for erythropoietin transcription, was transfected into Hep3B cells. Application of jujube water extract onto the transfected cells induced the transcriptional activity of the hypoxia response element. To account for its transcriptional activation, the expression of hypoxia-inducible factor-1α was increased after treatment with jujube water extract: the increase was in both mRNA and protein levels. These results confirmed the hematopoietic function of jujube in the regulation of erythropoietin expression in liver cells.
Phytomedicine | 2014
Janis Ya-Xian Zhan; Ping Yao; Cathy Wenchuan Bi; Ken Yuzhong Zheng; Wendy L. Zhang; Jianping Chen; Tina Ting Xia Dong; Zi-Ren Su; Karl Wah Keung Tsim
Angelica Sinensis Radix (roots of Angelica sinensis; ASR) is a popular herbal supplement in China for promoting blood circulation. Today, sulfur-fumigation is commonly used to treat ASR as a means of pest control; however, the studies of sulfur-fumigation on the safety and efficacy of ASR are very limited. Here, we elucidated the destructive roles of sulfur-fumigation on ASR by chemical and biological assessments. After sulfur-fumigation, the chemicals in ASR were significantly lost. The biological activities of anti-platelet aggregation, induction of NO production and estrogenic properties were compared between the water extracts of non-fumigated and sulfur-fumigated ASR. In all cases, the sulfur-fumigation significantly reduced the biological properties of ASR. In addition, application of water extract deriving from sulfur-fumigated ASR showed toxicity to cultured MCF-7 cells. In order to ensure the safety and to achieve the best therapeutic effect, it is recommended that sulfur-fumigation is an unacceptable approach for processing herbal materials.
Evidence-based Complementary and Alternative Medicine | 2013
Wendy L. Zhang; Ken Y.Z. Zheng; Kevin Y. Zhu; Janis Ya-Xian Zhan; Cathy W. C. Bi; Jian-Nan Chen; Tina Ting Xia Dong; Roy Chi Yan Choi; David Tai Wai Lau; Karl Wah Keung Tsim
Roots of Angelica sinensis (Danggui) have been used in promoting blood circulation as herbal medicine for over 2000 years in China. Another species of Angelica roots called A. gigas is being used in Korea. To reveal the efficiency of different Angelica roots, the chemical and biological properties of Angelica roots from different cultivated regions were compared. Roots of A. sinensis contained higher levels of ferulic acid, Z-ligustilide, and senkyunolide A, while high amounts of butylphthalide and Z-butylenephthalide were found in A. gigas roots. The extracts deriving from A. gigas roots showed better effects in osteogenic and estrogenic properties than that of A. sinensis from China. However, this difference was markedly reduced when the Angelica roots were being prepared in a Chinese herbal decoction together with Astragali Radix as Danggui Buxue Tang. In contrast, the herbal decoction prepared from A. sinensis roots showed better responses in cell cultures. In addition, the extracts of A. gigas roots showed strong cell toxicity both as single herb and as Danggui Buxue Tang. This result revealed the distinct properties of Angelica roots from China and Korea suggesting the specific usage of herb in preparing a unique herbal decoction.
Molecules | 2014
Pui Hei Nicholas Chan; Wendy L. Zhang; Chung-Ho Lau; Chi Yuen Cheung; Hector C. Keun; Karl Wah Keung Tsim; Henry H N Lam
Angelica Radix, the roots of the genus Angelica, has been used for more than 2,000 years as a traditional medicine in Eastern Asia. The Chinese Pharmacopoeia records more than 100 herbal formulae containing Angelica roots. There are two common sources of Angelica roots, Angelica sinensis from China and A. gigas from Korea. The two species of Angelica roots differ in their chemical compositions, pharmacological properties and clinical efficacy. 1H-NMR metabolic profiling has recently emerged as a promising quality control method for food and herbal chemistry. We explored the use of 1H-NMR metabolic profiling for the quality control of Angelica Radix. Unlike previous work, we performed the metabolic profiling on hot water extracts, so as to mimic the clinically relevant preparation method. Unsupervised principle component analyses of both the full spectral profile and a selection of targeted molecules revealed a clear differentiation of three types of Angelica roots. In addition, the levels of 13 common metabolites were measured. Statistically significant differences in the levels of glucose, fructose and threonine were found between different sources of Angelica. Ferulic acid, a marker commonly used to evaluate Angelica root, was detected in our samples, but the difference in ferulic acid levels between the samples was not statistically significant. Overall, we successfully applied 1H-NMR metabolic profiling with water extraction to discriminate all three sources of Angelica roots, and obtained quantitative information of many common metabolites.