title: Effect of kumquat (Fortunella crassifolia) pericarp on natural killer cell activity in vitro and in vivo.
abstract: Natural killer (NK) cells play a key role in innate immune defense against infectious disease and cancer. A reduction of NK activity is likely to be associated with increased risk of these types of disease. In this study, we investigate the activation potential of kumquat pericarp acetone fraction (KP-AF) on NK cells. It is shown to significantly increase IFN-γ production and NK cytotoxic activity in human KHYG-1 NK cells. Moreover, oral administration of KP-AF significantly improves both suppressed plasma IFN-γ levels and NK cytotoxic activity per splenocyte in restraint-stressed mice. These results indicate that raw kumquat pericarp activates NK cells in vitro and in vivo. To identify the active constituents, we also examined IFN-γ production on KHYG-1 cells by the predicted active components. Only β-cryptoxanthin increased IFN-γ production, suggesting that NK cell activation effects of KP-AF may be caused by carotenoids such as β-cryptoxanthin.
authors: a Interdisciplinary Graduate School of Agriculture and Engineering , University of Miyazaki , Miyazaki , Japan.
authors: Kiyoko
authors: K
authors: Nagahama
authors: Nozomu
authors: N
authors: Eto
authors: Tomofumi
authors: T
authors: Shimojo
authors: Tomomi
authors: T
authors: Kondoh
authors: Keiko
authors: K
authors: Nakahara
authors: Yoichi
authors: Y
authors: Sakakibara
authors: Keiichi
authors: K
authors: Fukui
authors: Masahito
authors: M
authors: Suiko
mesh_terms: D000818:Animals; D065366:Cryptoxanthins / Q000008:administration & dosage / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects; D007371:Interferon-gamma / Q000097:blood; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology; D051379:Mice; D010936:Plant Extracts / Q000008:administration & dosage* / Q000737:chemistry; D027821:Rutaceae / Q000737:chemistry*
chemical_list: D065366:Cryptoxanthins; D010936:Plant Extracts; D007371:Interferon-gamma
keywords: Fortunella crassifolia; interferon-γ; kumquat pericarp; natural killer activity; restraint stress