title: UV-B induced changes in the secondary metabolites of Morus alba L. leaves.
abstract: Ultraviolet-B (UV-B) radiation is harmful to plants and human beings. Many secondary metabolites, like flavonoids, alkaloids, and lignin, are UV-B absorbing compounds, which can protect the genetic material of plants. Furthermore, they are active components of herbal drugs. UV-B radiation can activate the self-protective secondary metabolism system. The results of this paper provide a method to induce bioactive secondary metabolites from mulberry leaves (Morus alba L.) by UV-B irradiation in vitro. Five significantly different chromatographic peaks were found by HPLC fingerprint after induction, from which two active compounds were identified: One was chalcomoracin, a natural Diels-Alder type adduct with antibacterial activity; the other one was moracin N, which is a precursor of chalcomoracin. Their contents were 0.818 mg/g and 0.352 mg/g by dry weight, respectively.
authors.affiliation: The Key Laboratory of Biomedical Engineering Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China. guxida@zju.edu.cn
authors.forename: Xi-Da
authors.initials: XD
authors.lastname: Gu
authors.forename: Ming-Yao
authors.initials: MY
authors.lastname: Sun
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Fu
authors.forename: Lei
authors.initials: L
authors.lastname: Cui
authors.forename: Run-Ze
authors.initials: RZ
authors.lastname: Chen
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Zhang
authors.forename: Jing-Kui
authors.initials: JK
authors.lastname: Tian
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis; D001572:Benzofurans / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D031625:Morus / Q000378:metabolism* / Q000528:radiation effects; D018515:Plant Leaves / Q000378:metabolism* / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; D001572:Benzofurans; C550211:chalcomoracin