title: Human Intervention Study to Assess the Effects of Supplementation with Olive Leaf Extract on Peripheral Blood Mononuclear Cell Gene Expression.
abstract: Olive leaf extract (OLE) has been used for many years for its putative health benefits, but, to date, scientific evidence for the basis of these effects has been weak. Although recent literature has described a link between ailments such as cardiovascular disease, diabetes and cancer and a protective effect of polyphenols in the OLE, the mode of action is still unclear. Here, we describe a double-blinded placebo (PBO)-controlled trial, in which gene expression profiles of peripheral blood mononuclear cells from healthy male volunteers (n= 29) were analysed to identify genes that responded to OLE, following an eight-week intervention with 20 mL daily consumption of either OLE or PBO. Differences between groups were determined using an adjusted linear model. Subsequent analyses indicated downregulation of genes important in inflammatory pathways, lipid metabolism and cancer as a result of OLE consumption. Gene expression was verified by real-time PCR for three genes (EGR1,COX-2andID3). The results presented here suggest that OLE consumption may result in health benefits through influencing the expression of genes in inflammatory and metabolic pathways. Future studies with a larger study group, including male and female participants, looking into direct effects of OLE on lipid metabolism and inflammation are warranted.
authors.affiliation: Discipline of Nutrition and Dietetics, The University of Auckland, Auckland 1142, New Zealand. abos517@aucklanduni.ac.nz.
authors.forename: Anna
authors.initials: A
authors.lastname: Boss
authors.affiliation: Discipline of Nutrition and Dietetics, The University of Auckland, Auckland 1142, New Zealand. ben.kao@auckland.ac.nz.|Auckland Cancer Research Society, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1142, New Zealand. ben.kao@auckland.ac.nz.
authors.forename: Chi Hsiu-Juei
authors.initials: CH
authors.lastname: Kao
authors.affiliation: Auckland Cancer Research Society, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1142, New Zealand. p.murray@auckland.ac.nz.
authors.forename: Pamela M
authors.initials: PM
authors.lastname: Murray
authors.affiliation: Institute of Medical Genetics, UHW Main Building, Cardiff University, Cardiff CF10 3XQ, UK. MarlowG@cardiff.ac.uk.
authors.forename: Gareth
authors.initials: G
authors.lastname: Marlow
authors.affiliation: Food Nutrition & Health Team, Food & Bio-Based Products Group, AgResearch Limited, Palmerston North 4442, New Zealand. matthew.barnett@agresearch.co.nz.
authors.forename: Matthew P G
authors.initials: MP
authors.lastname: Barnett
authors.affiliation: Discipline of Nutrition and Dietetics, The University of Auckland, Auckland 1142, New Zealand. l.ferguson@auckland.ac.nz.|Auckland Cancer Research Society, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1142, New Zealand. l.ferguson@auckland.ac.nz.
authors.forename: Lynnette R
authors.initials: LR
authors.lastname: Ferguson
mesh_terms: D019587:Dietary Supplements; D005786:Gene Expression Regulation / Q000187:drug effects*; D063990:Gene Ontology; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D058977:Molecular Sequence Annotation; D031658:Olea / Q000737:chemistry*; D020411:Oligonucleotide Array Sequence Analysis; D010919:Placebos; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D010919:Placebos; D010936:Plant Extracts; D012333:RNA, Messenger
keywords: inflammation; nutraceutical; polyphenols; transcriptomics