title: Phenolic compounds responding to zinc and/or cadmium treatments in Gynura pseudochina (L.) DC. extracts and biomass.
abstract: Gynura pseudochina (L.) DC. is a Zn/Cd hyperaccumulative plant. In an in vivo system under controlled plant age, this research reveals that phenolic compounds and lignification play beneficial roles in protecting G. pseudochina from exposure to an excess of Zn and/or Cd, and Zn reduces Cd toxicity under the dual treatments. The total phenolic content (TPC), total flavonoid content (TFC), and half-maximal inhibitory concentration (IC50) values correspond to the metal dose-response curves. Liquid chromatography-electrospray ionization-quadrupole time of flight-tandem mass spectrometry (LC-ESI-QTOF-MS/MS) is used to characterize phenolic compounds and their glycosides, which could play roles in antioxidant activities and in the esterification of the cell wall, especially derivatives of p-coumaric and caffeic acid. Confocal laser scanning microscopy (CLSM) and micro X-ray fluorescence (μ-XRF) imaging revealed that the accumulation of Zn and Cd in the cell wall involves flavonoid compounds. Low extractable pools of Cd and Zn in the leaf extracts indicate that these elements are tightly bound to the plant biomass structures. The bulk X-ray absorption near edge structure (XANES) spectra indicate that Zn2+and Cd2+dominate with O and S ligands, which could be provided by cell walls, phenolic compounds, and sulphur protein. Consequently, the benefit of these results is to support the growth of G. pseudochina for phytoremediation in a Zn- and/or Cd-contaminated site.
authors.affiliation: Department of Biology, Faculty of Science, Mahasarakham University, Khamriang, Kantarawichai, Maha Sarakham 44150, Thailand.
authors.forename: Bodin
authors.initials: B
authors.lastname: Mongkhonsin
authors.affiliation: Department of Biology, Faculty of Science, Mahasarakham University, Khamriang, Kantarawichai, Maha Sarakham 44150, Thailand. Electronic address: woranan.n@msu.ac.th.
authors.forename: Woranan
authors.initials: W
authors.lastname: Nakbanpote
authors.affiliation: Department of Green and Sustainable Chemistry, Tokyo Denki University, Senju-Asahicho, Adachi, Tokyo, 120-8551, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Hokura
authors.affiliation: Science Laboratory Centre, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand.
authors.forename: Nitra
authors.initials: N
authors.lastname: Nuengchamnong
authors.affiliation: Department of Biology, Faculty of Science, Mahasarakham University, Khamriang, Kantarawichai, Maha Sarakham 44150, Thailand.
authors.forename: Suthira
authors.initials: S
authors.lastname: Maneechai
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D019659:Asteraceae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018533:Biomass; D002104:Cadmium / Q000494:pharmacology* / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D010946:Plants, Medicinal; D013052:Spectrometry, X-Ray Emission; D053719:Tandem Mass Spectrometry; D015032:Zinc / Q000494:pharmacology* / Q000633:toxicity
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D002104:Cadmium; D015032:Zinc
keywords: Cadmium; Confocal microscopy; Micro-XRF; Phenolic compounds; XANES; Zinc