title: Effect of Phyllanthus amarus Extract on 5-Fluorouracil-Induced Perturbations in Ribonucleotide and Deoxyribonucleotide Pools in HepG2 Cell Line.
abstract: The aim of this study was to investigate the antitumor activities ofPhyllanthus amarus(PHA) and its potential of herb-drug interactions with 5-Fluorouracil (5-FU). Cell viability, ribonucleotides (RNs) and deoxyribonucleotides (dRNs) levels, cell cycle distribution, and expression of thymidylate synthase (TS) and ribonucleotide reductase (RR) proteins were measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS) method, flow cytometry and Western blot analysis, respectively. Our standardized PHA extract showed toxicity to HepG2 cells at high concentrations after 72 h exposure and induced G2/M cell cycle arrest. Combined use of 5-FU with PHA resulted in significant decreases in ATP, CTP, GTP, UTP and dTTP levels, while AMP, CMP, GMP and dUMP levels increased significantly compared with use of 5-FU alone. Further, PHA could increase the role of cell cycle arrest at S phase induced by 5-FU. Although PHA alone had no direct impact on TS and RR, PHA could change the levels of RNs and dRNs when combined with 5-FU. This may be due to cell cycle arrest or regulation of key enzyme steps in intracellular RNs and dRNs metabolism.
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicines, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau SAR, China. guojianrumust@gmail.com.
authors.forename: Jian-Ru
authors.initials: JR
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicines, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau SAR, China. qqchen@must.edu.mo.
authors.forename: Qian-Qian
authors.initials: QQ
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicines, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau SAR, China. wklam@must.edu.mo.
authors.forename: Christopher Wai-Kei
authors.initials: CW
authors.lastname: Lam
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicines, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau SAR, China. cywang@must.edu.mo.
authors.forename: Cai-Yun
authors.initials: CY
authors.lastname: Wang
authors.affiliation: Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), China Pharmaceutical University, Nanjing 210009, China. fengguoxu@cpu.edu.cn.
authors.forename: Feng-Guo
authors.initials: FG
authors.lastname: Xu
authors.affiliation: Guangxi Key Laboratory of Traditional Chinese Medicine Quality Standards, Guangxi Institute of Traditional Medical and Pharmaceutical Sciences, Nanning 530022, China. liubuming@aliyun.com.
authors.forename: Bu-Ming
authors.initials: BM
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicines, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau SAR, China. Wzhang@must.edu.mo.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
keywords: 5-fluorouracil; Phyllanthus amarus extract; deoxyribonucleotides; ribonucleotides