title: Naturally occurring Ngn2 promoter activators from Butea superba.
abstract: Neurogenin2 (Ngn2), an activator-type bHLH transcriptional factor, promotes differentiation of neural stem cells into neurons by transcription of pro-neural genes. To find neural stem cell accelerators from the extract library of natural resources, we used a two-step screening including a Ngn2 promoter reporter gene screening and differentiation assay screening of neural stem cells. A reporter gene assay that can detect Ngn2 promoter activity by luciferase expression was constructed using C3H10T1/2 cells. Using this primary cell-based screening, Butea superba was found to include Ngn2 promoter activators from our tropical plant extract libraries. Bioassay-guided fractionation of this plant extract led to the isolation of 18 natural products, including pterocarpans and isoflavonoids. Dehydromaackiain (1), formononetin (6), ()-variabilin (13), ()-medicarpin (14), rothindin (17) and ononin (18) showed 1.8–2.8 times higher Ngn2 promoter activity at 5 mM compared with control. Of active natural compounds, 30-methoxydaidzein (3) showed promotion of neurite outgrowth of C17.2 in a secondary screen. 30-Methoxydaidzein (3) increased mRNA expression of pro-neural transcriptional factors (Ngn2, Ngn1, NeuroD2), a mature neuron-specific enzyme GAD1 and a pro-neural neurotrophic growth factor neurotrophin 3 (NT3) in C17.2 neural stem cells.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan. midori_arai@chiba-u.jp.
authors.forename: Midori A
authors.initials: MA
authors.lastname: Arai
authors.forename: Kazune
authors.initials: K
authors.lastname: Koryudzu
authors.forename: Takashi
authors.initials: T
authors.lastname: Koyano
authors.forename: Thaworn
authors.initials: T
authors.lastname: Kowithayakorn
authors.forename: Masami
authors.initials: M
authors.lastname: Ishibashi
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D031290:Butea / Q000737:chemistry*; D002460:Cell Line; D015870:Gene Expression; D017930:Genes, Reporter; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D015533:Transcriptional Activation / Q000187:drug effects*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D009419:Nerve Tissue Proteins; D010936:Plant Extracts; C102938:Neurog2 protein, mouse