Effects of an aqueous extract of cocoa on nitric oxide production of macrophages activated by lipopolysaccharide and interferon-gamma.
OBJECTIVE
Macrophages are the primary targets of bacterial lipopolysaccharide (LPS). The effects of cocoa extract on production of nitric oxide (NO) by murine J774.1 macrophages activated by LPS and interferon-gamma (IFN-gamma) were examined.


METHODS
Cocoa was suspended in heated water and centrifuged, and the supernatant was then filtered. Nitrite was measured as a quantitative indicator of NO by spectrophotometry. LPS (1.0 mg/mL) and IFN-gamma (100 U/mL) were added to cultured macrophages with 0.05% cocoa extract, 0.25% cocoa extract, or pure water. NO synthesis by macrophages was significantly inhibited by cocoa extract (P < 0.01).


RESULTS
The inhibitory effect increased with concentration of the extract (P < 0.01). IFN-gamma (100 U/mL) and, later, LPS (100 microgram/mL) were added, together with 2.0% cocoa or pure water, to cultured macrophages. An inhibitory effect on NO production was observed on addition of only IFN-gamma, but more significant effects were obtained with addition of LPS (P < 0.01) and addition of both was most effective (P < 0.01).


CONCLUSIONS
These data suggested that cocoa extract contains a suppressor of NO production in murine macrophages activated by LPS and IFN-gamma. This effect does not appear to be caused merely by neutralization of LPS.
Ono
Kazuyuki
K
Department of Emergency and Critical Care Medicine, Saitama Medical Center, Saitama Medical School, Saitama, Japan. ono_eme@saitama-med.ac.jp
Takahashi
Toshio
T
Kamei
Masanori
M
Mato
Takashi
T
Hashizume
Shuichi
S
Kamiya
Shigeru
S
Tsutsumi
Haruhiko
H
D000818:Animals; D002099:Cacao / Q000737:chemistry*; D002478:Cells, Cultured; D007371:Interferon-gamma / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D010936:Plant Extracts / Q000494:pharmacology
D008070:Lipopolysaccharides; D010936:Plant Extracts; D009569:Nitric Oxide; D007371:Interferon-gamma