Green tea (Camellia sinensis; lǜ chá) extracts have been shown to possess anti-oxidant and anti-inflammatory effects in various cell types. Green tea extract (GTX) has been shown to significantly inhibit the activity of collagenase-3 (matrix metalloproteinase-13 (MMP-13)) in vitro. MMPs, such as MMP-9, are known to be involved in many inflammatory diseases including periodontal disease. GTX and a major catechin, epigallocatechin-gallate (EGCG), were examined for their ability to inhibit purified MMP-9 activity and its release from stimulated neutrophils. Methanol extract of Green tea and commercially purchased EGCG (>95 % purity) were tested in vitro for their ability to inhibit MMP-9 activity and/or its release from neutrophils using a β-casein cleavage assay and gelatin zymography, respectively. Statistical analysis was performed by Student's t-test. GTX and EGCG at 0.1% (w/v) completely inhibited the activity of MMP-9. In addition, GTX and EGCG (0.1 %) significantly inhibited (p < 0.001) the release of MMP-9 from formyl-Met-Leu-Phe (FMLP)-stimulated human neutrophils by 62.01% ± 6.717 and 79.63% ± 1.308, respectively. The inhibitory effects of GTX and EGCG occurred in unstimulated neutrophils (52.42% ± 3.443 and 62.33% ± 5.809, respectively). When the inhibitory effect of EGCG was further characterized, it significantly inhibited the release of MMP-9 from the FMLP-stimulated human neutrophils in a dose-dependent manner. The effects of GTX and EGCG on MMPs could be extrapolated to clinical/in vivo studies for the development of oral care products to prevent or treat chronic inflammatory diseases including periodontal diseases.
Keywords: Epigallocatechin-gallate; Green tea catechin; Matrix metalloproteinases; Neutrophils; Periodontal diseases.