Neural cell protective compounds isolated from Phoenix hanceana var. formosana.
A platform for screening drugs for their ability to protect neuronal cells against cytotoxicity was developed. Nerve growth factor (NGF) differentiates PC12 cells into nerves, and these differentiated PC12 cells enter apoptosis when challenged with 6-hydroxydopamine (6-OHDA). A screening spectrophotometer was used to assay cytotoxicity in these cells; pretreatment with test samples allowed identification of compounds that protected against this neuronal cytotoxicity. The 95% ethanol extract of Phoenix hanceana Naudin var. formosana Beccari. (PH) showed potential neuroprotective activity in these assays. The PH ethanol extract was further fractionated by sequential partitioning with n-hexane, ethyl acetate (EtOAc), n-butanol (n-BuOH), and water. Subsequent rounds of assaying resulted in the isolation of ten constituents, and their structures were characterized by various spectroscopic techniques and identified by comparison with previous data as: isoorientin (1), isovitexin (2), veronicastroside (3), luteolin-7-O-beta-d-glucopyranoside (4), isoquercitrin (5), tricin-7-neohesperidoside (6), tricin-7-O-beta-d-gluco-pyranoside (7), (+)-catechin (8), (-)-epicatechin (9), and orientin 7-O-beta-d-glucopyranoside (10). Among these compounds, isovitexin (2), luteolin-7-O-beta-d-glucopyranoside (4) and (+)-catechin (8) showed significant neuroprotective activity in cell viability (WST-8 reduction), anti-apoptosis (Annexin V-FITC/propidium iodide double-labeled flow cytometry), and cellular ROS scavenging assays (besides isovitexin (2)), as well as a decreased caspase-8 activity in 6-OHDA-induced PC12 cells. Hence, isovitexin (2), luteolin-7-O-beta-d-glucopyranoside (4), and (+)-catechin (8) protected PC12 cells from 6-OHDA-induced apoptotic neurotoxicity.
Lin
Yi-Pei
YP
School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan.
Chen
Tai-Yuan
TY
Clinical Genomics and Proteomics Core Laboratory, Department of Medical Research, Chang Gung Memorial Hospital at Kaohsiung, Kaohsiung 833, Taiwan.
Tseng
Hsiang-Wen
HW
Biomedical Engineering Research Laboratories, Industrial Technology Research Institute, Hsinchu 30011, Taiwan.
Lee
Mei-Hsien
MH
Graduate Institute of Pharmacognosy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan; Center for Reproductive Medicine and Sciences, Taipei Medical University Hospital, Taipei 110, Taiwan. Electronic address: lmh@tmu.edu.tw.
Chen
Shui-Tein
ST
Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan; Institute of Biological Chemistry and Genomic Research Center, Academia Sinica, Taipei 11529, Taiwan.
D000818:Animals; D047310:Apigenin / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002392:Catechin / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D005960:Glucosides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D047311:Luteolin / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D019684:Magnoliopsida / Q000737:chemistry*; D015394:Molecular Structure; D018696:Neuroprotective Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D016627:Oxidopamine / Q000494:pharmacology*; D016716:PC12 Cells; D010946:Plants, Medicinal / Q000737:chemistry*; D011794:Quercetin / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D013237:Stereoisomerism; D013624:Taiwan
D005960:Glucosides; D018696:Neuroprotective Agents; C016527:isoquercitrin; D047310:Apigenin; D016627:Oxidopamine; D002392:Catechin; D011794:Quercetin; C057912:homoorientin; C049772:isovitexin; D047311:Luteolin