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  1. Chan EWC, Wong SK, Chan HT
    J Integr Med, 2021 07;19(4):311-316.
    PMID: 33583757 DOI: 10.1016/j.joim.2021.01.001
    Tetrandrine (TET) and fangchinoline (FAN) are dominant bisbenzylisoquinoline (BBIQ) alkaloids from the roots of Stephania tetrandra of the family Menispermaceae. BBIQ alkaloids comprise two benzylisoquinoline units linked by oxygen bridges. The molecular structures of TET and FAN are exactly the same, except that TET has a methoxy (-OCH3) group, while FAN has a hydroxyl (-OH) group at C7. In this overview, the current knowledge on the chemistry, pharmacology and anticancer properties of TET and FAN have been updated. The focus is on colon and breast cancer cells, because they are most susceptible to TET and FAN, respectively. Against colon cancer cells, TET inhibits cell proliferation and tumor growth by inducing apoptosis and G1 cell cycle arrest, and suppresses adhesion, migration and invasion of cells. Against breast cancer cells, FAN inhibits cell proliferation by inducing apoptosis, G1-phase cell cycle arrest and inhibits cell migration. The processes involve various molecular mechanisms and signaling pathways. Some insights on the ability of TET and FAN to reverse multi-drug resistance in cancer cells and suggestions for future research are provided.
  2. Chan EWC, Wong SK, Chan HT
    J Integr Med, 2018 05;16(3):147-152.
    PMID: 29559215 DOI: 10.1016/j.joim.2018.03.001
    This short review provides an update of the anticancer and anti-inflammatory properties of casticin from Vitex species. Casticin is a polymethylflavone with three rings, an orthocatechol moiety, a double bond, two hydroxyl groups and four methoxyl groups. Casticin has been isolated from various tissues of plants in the Vitex genus: fruits and leaves of V. trifolia, aerial parts and seeds of V. agnus-castus and leaves of V. negundo. Studies have reported the antiproliferative and apoptotic activities of casticin from Vitex species. The compound is effective against many cancer cell lines via different molecular mechanisms. Studies have also affirmed the anti-inflammatory properties of casticin, with several molecular mechanisms identified. Other pharmacological properties include anti-asthmatic, tracheospasmolytic, analgesic, antihyperprolactinemia, immunomodulatory, opioidergic, oestrogenic, anti-angiogenic, antiglioma, lung injury protection, rheumatoid arthritis amelioration and liver fibrosis attenuation activities. Clinical trials and commercial use of the casticin-rich fruit extract of V. agnus-castus among women with premenstrual syndrome were briefly discussed.
  3. Apparoo Y, Wei Phan C, Rani Kuppusamy U, Chan EWC
    Brain Res, 2024 Feb 01;1824:148693.
    PMID: 38036238 DOI: 10.1016/j.brainres.2023.148693
    Oxidative stress can upset the antioxidant balance and cause accelerated aging including neurodegenerative diseases and decline in physiological function. Therefore, an antioxidant-rich diet plays a crucial role in healthy aging. This study aimed to identify and quantify mushrooms with the highest ergothioneine content through HPLC analysis and evaluate their anti-aging potential as a natural antioxidant and antisenescence in HT22 cells. Among the 14 evaluated mushroom species, Lentinula edodes (LE), shiitake mushroom contains the highest ergothioneine content and hence was used for the in-vitro studies. The cells were preincubated with ethanolic extract of ergothioneine-rich mushroom and the equimolar concentration of EGT on t-BHP-induced senescence HT22 cells. The extract was analyzed for its free radical scavenging properties using DPPH and ABTS methods. Then, the neuroprotective effect was conducted by measuring the cell viability using MTT. Senescence-associated markers and ROS staining were also analyzed. Our results revealed that a low dose of t-BHP reduces cell viability and induces senescence in HT22 cells as determined through β-galactosidase staining and expressions of P16INK4a, P21CIPL which are the markers of cellular senescence. However, the pretreatment with ethanolic extract of LE for 8 h significantly improved the cell viability, reversed the t-BHP-induced cellular senescence in the neuronal cells, and reduced the reactive oxygen species visualized through DCFH-DA staining. These results suggest that ergothioneine-rich mushroom is a potential candidate for anti-aging exploration through the elimination of senescent cells.
  4. Lim CSS, Chan EWC, Wong CW
    Int J Biol Macromol, 2024 Feb;259(Pt 2):129303.
    PMID: 38216018 DOI: 10.1016/j.ijbiomac.2024.129303
    Cellulose nanocrystals (CNC) conventionally involve highly concentrated sulphuric acid, which typically resulted in the formation of undesirable by-products. Although less corrosive mineral acids have been explored as alternatives, high concentrations are still required. In this study, CNC was successfully isolated from Leucaena leucocephala wood using mild sulphuric acid with acetic acid as protic solvent, and it was further studied with the addition of Lewis acids in the form of multivalent transition metal salts as co-catalyst. Selected divalent and trivalent transition metal salts including (Cr(NO3)3, Fe(NO3)3, Co(NO3)2, and Ni(NO3)2) were investigated. The morphology, chemical structure, particle size, and physicochemical properties of the CNCs were determined. Controlled depolymerization of cellulose was observed using transmission electron microscopy (TEM). Rod-like morphology for all CNCs was obtained during the hydrolysis process with the smallest CNC particles found at an average length of 278.1 ± 35.1 nm and a diameter of 13.4 ± 3.0 nm. The results showed that higher valence state metal ions resulted in better cellulose hydrolysis efficiency. In addition, the use of transition metal salt as a co-catalyst improved production efficiency and minimised carbonization of CNC while maintaining desired crystallinity and thermal properties.
  5. Chan EWC, Wong SK, Tangah J, Inoue T, Chan HT
    J Integr Med, 2020 May;18(3):189-195.
    PMID: 32115383 DOI: 10.1016/j.joim.2020.02.006
    Flavonoids are by far the most dominant class of phenolic compounds isolated from Morus alba leaves (MAL). Other classes of compounds are benzofurans, phenolic acids, alkaloids, coumarins, chalcones and stilbenes. Major flavonoids are kuwanons, moracinflavans, moragrols and morkotins. Other major compounds include moracins (benzofurans), caffeoylquinic acids (phenolic acids) and morachalcones (chalcones). Research on the anticancer properties of MAL entailed in vitro and in vivo cytotoxicity of extracts or isolated compounds. Flavonoids, benzofurans, chalcones and alkaloids are classes of compounds from MAL that have been found to be cytotoxic towards human cancer cell lines. Further studies on the phytochemistry and anticancer of MAL are suggested. Sources of information were PubMed, PubMed Central, ScienceDirect, Google, Google Scholar, J-Stage, PubChem and China National Knowledge Infrastructure.
  6. Lim WY, Cheng YW, Lian LB, Chan EWC, Wong CW
    J Food Sci Technol, 2021 Nov;58(11):4178-4184.
    PMID: 34538902 DOI: 10.1007/s13197-020-04886-5
    Undesired browning reaction catalyzed by polyphenol oxidase (PPO) has reduced the nutritional quality and customer acceptance of the products. The inhibitory effects of six coastal plants including Sonneratia alba, Rhizophora apiculata, Syzygium grande, Rhizophora mucronata, Hibiscus tiliaceus and Bruguiera gymnorhiza on PPO in banana, sweet potato and ginger were studied based on oxidation of pyrocatechol. Banana exhibited the highest PPO activity (141,600 U), followed by sweet potato (43,440 U) and ginger (26,880 U). Banana PPO was strongly inhibited by R. apiculata (70.87%) and sweet potato PPO was strongly inhibited by S. alba (82.00%). In general, most banana PPO was the most susceptible to inhibition with all inhibitors having inhibition higher than 60.00% at 0.5 mg/ml and ginger PPO was the least susceptible with all inhibitors showing less than 50.00% inhibition at 0.5 mg/ml. Coastal plant extracts are potentially to be developed as natural inhibitors for preventing enzymatic browning of fruits and vegetables.
  7. Chan EWC, Soon CY, Tan JBL, Wong SK, Hui YW
    J Integr Med, 2019 May;17(3):155-160.
    PMID: 30928277 DOI: 10.1016/j.joim.2019.03.003
    Ursolic acid (UA) is a pentacyclic triterpene of the ursane type. As a common chemical constituent among species of the family Lamiaceae, UA possesses a broad spectrum of pharmacological properties. This overview focuses on the anticancer properties of UA against breast cancer (BC) and colorectal cancer (CRC) that are most common among women and men, respectively. In vitro studies have shown that UA inhibited the growth of BC and CRC cell lines through various molecular targets and signaling pathways. There are several in vivo studies on the cytotoxic activity of UA against BC and CRC. UA also inhibits the growth of other types of cancer. Studies on structural modifications of UA have shown that the -OH groups at C3 and at C28 are critical factors influencing the cytotoxic activity of UA and its derivatives. Some needs for future research are suggested. Sources of information were from ScienceDirect, Google Scholar and PubMed.
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