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Inhibitory effects of green tea and a constituent of green tea, epigallocatechin‐3‐gallate (EGCG) on nitric oxide production in macrophages
Author(s) -
Basu Arpita,
Beverly Kandice,
Lucas Edralin A.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a368-b
Subject(s) - nitric oxide , green tea , nitrite , chemistry , green tea extract , food science , catechin , griess test , epigallocatechin gallate , antioxidant , lipopolysaccharide , viability assay , biochemistry , in vitro , polyphenol , biology , nitrate , immunology , organic chemistry
Green tea has been widely consumed as a healthful beverage and its active constituent, EGCG, is a potent antioxidant and anti‐inflammatory agent. This study aimed to elucidate the effects of green tea or EGCG (0.39, 0.78, 1.56, 3.13, 6.25, 12.5, 25, or 50μg/mL) on nitric oxide production in murine macrophage cells following lipopolysaccharide (LPS) challenge. Different concentrations of green tea in media (0.15, 0.3, 0.63, 1.25, 2.5, 5, 10, or 20%) were prepared from a stock (2.12 g of green tea leaves brewed in 240mL of H 2 O). RAW 264.7 murine macrophages were cultured in DMEM supplemented with 10% fetal bovine serum and 1% penicillin. Following a 24‐hour treatment with green tea or EGCG, cells were challenged with LPS (500ng/mL) for the next 24 hours and cell viability (resazurin assay) and nitrite concentrations (Griess reaction) were measured. In comparison to the control (LPS), 10% and 20% green tea caused a significant reduction in nitrite levels (49.7±5.1, 27.3±4.3, & 13.1±2.3 μg/mL, respectively; P ≤ 0.05). In case of EGCG, significant inhibitions were noted at 25 & 50μg/mL, versus control (22.4±2.6, 3.4±0.64, & 47.7±4.93 μg/mL, respectively; P ≤ 0.05). Both green tea and EGCG at their highest concentrations (20% & 50μg/mL, respectively) affected cell viability versus controls, whereas, no differences were noted among the other groups. Thus, green tea and EGCG inhibit nitric oxide production at higher doses, which may explain their anti‐inflammatory effects, and warrants further research as a therapeutic strategy in clinical practice. This study was funded by CHES, OSU.