Chemoprotection: A review of the potential therapeutic antioxidant properties of green tea (Camellia sinensis) and certain of its constituents

Mitscher, Lester A.; Jung, Michael J.; Shankel, Delbert M.; Dou, Jinhui; Steele, Linda; Pillai, Segaran P.

doi:10.1002/(sici)1098-1128(199707)17:4<327::aid-med2>3.0.co;2-y

Cited by 150 publications

(94 citation statements)

References 117 publications

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“…However, since the present findings indicate that green tea catechins did not affect the proteolytic activity of thrombin, such an explanation is unlikely. An alternative explanation might be related to the antioxidant properties of green tea catechins [43]. Indeed, reactive oxygen species have been shown to activate MMP-2 and thrombin is a potent stimulator of the NADPH oxidasedependent formation of reactive oxygen species in VSMCs [32,33,[44][45][46].…”

Section: Discussionmentioning

confidence: 99%

Catechins prevent vascular smooth muscle cell invasion by inhibiting MT1-MMP activity and MMP-2 expression

Bedoui

Oak

Anglard

et al. 2005

Cardiovascular Research

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Objective: Regular consumption of green tea is associated with a reduced risk of mortality due to coronary diseases and cancer. The present study examined whether a green tea extract (GTE) inhibits activation of matrix metalloproteinase-2 (MMP-2), a major collagenase involved in vascular remodeling of atherosclerotic plaques, in vascular smooth muscle cells (VSMCs). Methods and results:The expression of MMP-2 was assessed by Northern and Western blot analyses in human aortic VSMCs. MMP-2 activity was evaluated by zymography, membrane-type1-MMP (MT1-MMP, MMP-14) activity by an enzymatic assay, and cell invasion by a modified Boyden chamber assay. The thrombin-induced activation of secreted MMP-2 was abolished by GTE and the green tea polyphenols (À)-epigallocatechin-3-gallate (EGCG) and (À)-epicatechin-3-gallate (ECG). GTE reduced the expression of MMP-2 mRNA and protein. GTE, EGCG and ECG directly inhibited cell-associated MT1-MMP activity, the physiological activator of MMP-2, in a reversible manner. Thrombin-stimulated VSMCs invasion was abolished by EGCG and ECG, and reduced by GTE. Conclusions: GTE inhibits thrombin-induced VSMCs invasion most likely by preventing MMP-2 expression and its activation by a direct inhibition of MT1-MMP. The ability of green tea to prevent cell invasion and matrix degradation might contribute to its protective effect on atherosclerosis and cancer.

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Section: Discussionmentioning

confidence: 99%

Catechins prevent vascular smooth muscle cell invasion by inhibiting MT1-MMP activity and MMP-2 expression

Bedoui

Oak

Anglard

et al. 2005

Cardiovascular Research

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“…Numerous in vitro and animal studies have demonstrated that polyphenols from tea possess antioxidant, antimutagenic, antidiabetic, hypocholesterolemic, antibacterial, anti-inflammatory, and cancer-preventive properties (23,41,70). Although tea is a source of fluoride and many other dietary trace elements, studies have demonstrated that tea polyphenols, rather than the fluoride content, contribute to its anticariogenic potential (31,55,72).…”

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confidence: 99%

“…The use of different culture media and growth conditions has also contributed to the variable antimicrobial effects of tea polyphenols. The in vitro investigations into the effects of tea polyphenols on cariogenic virulence factors have focused on GTFs activity, EPS production, and cell adherence (26,41,45,51). We hypothesized that the major antimicrobial monomeric component of tea polyphenols, epigallocatechin gallate (EGCg), contributes to the suppression of virulence factors of S. mutans other than GTFs.…”

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confidence: 99%

The Tea Catechin Epigallocatechin Gallate Suppresses Cariogenic Virulence Factors of Streptococcus mutans

Zhou

2011

Antimicrob Agents Chemother

269

242

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Streptococcus mutans, the primary etiologic agent of dental caries, possesses a series of virulence factors associated with its cariogenicity. Alternatives to traditional antimicrobial treatment, agents selectively inhibiting the virulence factors without necessarily suppressing the resident oral species, are promising. The anticariogenic properties of tea have been suggested in experimental animals and humans. Tea polyphenols, especially epigallocatechin gallate (EGCg), have been shown to inhibit the growth and glucosyltransferases activity of S. mutans. However, their effects on biofilm and cariogenic virulence factors of oral streptococci other than glucosyltransferases have not been well documented. In this study, we investigated the biological effect of EGCg on the virulence factors of S. mutans associated with its acidogenicity and acidurity. The antimicrobial effects of EGCg on S. mutans biofilm grown in chemically defined medium were also examined. EGCg inhibited growth of S. mutans planktonic cells at an MIC of 31.25 g/ml and a minimal bactericidal concentration (MBC) of 62.5 g/ml. EGCg also inhibited S. mutans biofilm formation at 15.6 g/ml (minimum concentration that showed at least 90% inhibition of biofilm formation) and reduced viability of the preformed biofilm at 625 g/ml (sessile MIC 80 ). EGCg at sub-MIC levels inhibited acidogenicity and acidurity of S. mutans cells. Analysis of the data obtained from real-time PCR showed that EGCg significantly suppressed the ldh, eno, atpD, and aguD genes of S. mutans UA159. Inhibition of the enzymatic activity of F 1 F o -ATPase and lactate dehydrogenase was also noted (50% inhibitory concentration between 15.6 and 31.25 g/ml). These findings suggest that EGCg is a natural anticariogenic agent in that it exhibits antimicrobial activity against S. mutans and suppresses the specific virulence factors associated with its cariogenicity.

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“…27 Green tea catechins have been extensively investigated in the last two decades. [28][29][30][31] Also, it is probably the most consumed beverage worldwide. 32 In addition, green tea contains a significant percentage of the purine alkaloid caffeine making it particularly suitable for the examination of our resin-based separation method.…”

Section: Resultsmentioning

confidence: 99%

Application of Phase-Trafficking Methods to Natural Products Research

Araya¹,

Montenegro²,

Mitscher³

et al. 2011

J. Nat. Prod.

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A novel simultaneous phase-trafficking approach using spatially separated solid-supported reagents (SSR) for rapid separation of neutral, basic, and acidic compounds from organic plant extracts with minimum labor is reported. Acidic and basic ion exchange resins were physically separated into individual sacks ("teabags") for trapping basic and acidic compounds respectively, leaving behind in solution neutral components of the natural mixtures. Trapped compounds were then recovered from solid phase by appropriate suspension in acidic or basic solutions. The feasibility of the proposed separation protocol was demonstrated and optimized with an "artificial mixture" of model compounds. In addition, the utility of this methodology was illustrated with the successful separation of the alkaloid skytanthine from Skytanthus acutus Meyen and the main catechins and caffeine from Camellia sinensis L. (Kuntze). This novel approach offers multiple advantages over traditional extraction methods, as it is not labor intensive, makes use of only small quantities of solvents, produces fractions in adequate quantities for biological assays, and can be easily adapted to field conditions for bioprospecting activities.In 1963, R. B. Merrifield revolutionized peptide synthesis by introducing solid-phase reagents. This brilliantly simple idea allowed the use of reagents in excess and simplified purification, leading to higher yields and fast isolation. 1 Subsequent elaboration using combinatorial techniques have led to peptide compound libraries of thousands of compounds. Since then, an impressive number of inventive modifications have been introduced in a wide range of fields in academia and industrial laboratories. [2][3] Particularly, organic chemists have taken advantage of specific interactions between small organic molecules and solid-supported reagents (SSR) to achieve quick purification of desired nonpeptide products applying creative phase-switching strategies. 4 Furthermore, the isolation process using solid-phase protocols only involves simple operations of filtration and solvent removal that are suitable for automation and high throughput applications and has found particular value in combinatorial chemistry laboratories. 5 Despite the multiple advantages of SSR for isolation of small synthetic organic molecules, this method has yet to find application in resolving natural product extracts. Ion-exchange resins have long been used for purification of particular natural products (i.e. quinine 6-7 ) at a scale only occasionally used in fractionation schemes. Few examples of applications to natural products research These methods require either a substantial investment or lengthy and tedious protocols, preventing their implementation, especially in the remote regions of current bioprospecting interest. Consequently, the need for applications that can generate samples conveniently with suitable quality for initial bioassay is of great current interest. Such a method should not only increase the relative concentration of p...

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Chemoprotection: A review of the potential therapeutic antioxidant properties of green tea (Camellia sinensis) and certain of its constituents

Cited by 150 publications

References 117 publications

Catechins prevent vascular smooth muscle cell invasion by inhibiting MT1-MMP activity and MMP-2 expression

Catechins prevent vascular smooth muscle cell invasion by inhibiting MT1-MMP activity and MMP-2 expression

The Tea Catechin Epigallocatechin Gallate Suppresses Cariogenic Virulence Factors of Streptococcus mutans

Application of Phase-Trafficking Methods to Natural Products Research

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