The Inhibition of α-Amylase by Tea Polyphenols

The inhibition of α-amylase from human saliva by polyphenolic components of tea and its specificity was investigated in vitro. Four kinds of green tea catechins, and their isomers and four kinds of their dimeric compounds (theaflavins) produced oxidatively during black tea production were isolated. They were (?)-epicatechin (EC), (?)-epigallocatechin (EGC), (?)-epicatechin gallate (ECg), (?)-epigallocatechin gallate (EGCg), (?)-catechin (C), (?)-gallocatechin (GC), (?)-catechin gallate (Cg), (?)-gallocatechin gallate (GCg), theaflavin (TF1), theaflavin monogallates (TF2A and TF2B), and theaflavin digallate (TF3). Among the samples tested, EC, EGC, and their isomers did not have significant effects on the activity of α-amylase. All the other samples were potent inhibitors and the inhibitory effects were in the order of TF3>TF2A>TF2B>TFl>Cg> GCg > ECg > EGCg. The inhibitory patterns were noncompetitive except for TF3.     

High Level of Genetic Diversity Among the Selected Accessions of Tea (Camellia sinensis) from Abandoned Tea Gardens in Western Himalaya

To revive cultivation of the tea unique to the western Himalayan region, it is important to evaluate the seed-derived bushes available in the area's abandoned gardens. This study used quantitative leaf characters, catechin content, and AFLP markers to assess these China cultivar type bushes. Compared with other China cultivar germplasm, these accessions showed a higher level of diversity among themselves. Among the quantitative morphological characters, leaf length is important in distinguishing the accessions studied, with a high loading value in the principal component analysis. The catechins and AFLP markers displayed the genetic makeup of the accessions. Other than total catechins, the trihydroxylated catechins showed a high loading value in differentiating the accessions. The genetic control of the ratio of dihydroxylated and trihydroxylated catechins is found to be based on a correlation with AFLP markers. The genetic similarity between Kangra Asha and Kangra Jat suggests that Kangra Jat must be descended from Kangra Asha. Kangra Jat is well adapted to local environmental conditions, as is evident from its high catechin content.     

cis- and trans-Linalool 3,7-Oxides and Methyl Salicylate Glycosides and (Z)-3-Hexenyl β-D-Glucopyranoside as Aroma Precursors from Tea Leaves for Oolong Tea

Two new alcoholic aroma precursors, cis- and trans-linalool 3,7-oxides 6-O-β-D-apiofuranosyl-β-D-glucopyranosides (1 and 2), as well as two already known compounds, (Z)-3-hexenyl β-D-glucopyranoside (3) and methyl salicylate 6-O-β-D-xylopyranosyl-β-D-glucopyranoside (β-primeveroside: 4), and another new monoterpendiol glycoside, 8-hydroxygeranyl β-primeveroside (5) have recently been isolated as aroma precursors in tea leaves (Camellia sinensis var. sinensis cv. Maoxie) ready for oolong tea processing.     

Inhibition of nitrification by waste tea (‘Tea Fluff’)

Summary Ammonium fertilizer applied to tea soils is readily converted to nitrate by the nitrifying bacteria in soil. Excess nitrate in soil could undergo rapid leaching losses under high rainfall conditions. Data is presented in this paper to show that waste tea could be effectively used to retard and delay nitrate production and thereby prevent loss of nitrogen as nitrate by leaching. Evidence is also presented to show that waste tea readily liberates ammonium nitrogen in soil.     

Do Strigolactones Regulate Bud Winter Dormancy and Charactrisitc Secondary Metabolism in Tea?

Tea (Camellia sinensis [L.] O. Kuntze.) is an important cash crop, which mainly uses tender shoots and young leaves for manufacturing. Due to the marketing characteristic that earlier made tea has higher price, the time of the breaking of winter dormancy buds in spring is extremely important in tea industry. Strigolactones are a group of carotenoids-derived metabolites which regulates bud outgrowth, shoot branching, tiller angle and environmental stress responses. The role of strigolactones in tea plant was briefly summarized in the current review, with an emphasis of the association of strigolactones on bud ecodormancy and shoot branching. The involvement of strigolactones on the biosynthesis of the tea characteristic metabolites flavonoids, caffeine and theanine were also discussed. Moreover, recent advances on the biosynthesis of strigolactones and its regulation by microRNAs and environmental stresses were also presented. This review provides a basis for future investigations underlying the mechanisms of strigolactones on bud winter dormancy and tea secondary metabolism.     

(Z)-3-Hexenyl-β-d-glucopyranoside in Fresh Tea Leaves as a Precursor of Green Odor

The glycoside fraction from fresh tea leaves was acetylated and separated by silica gel column chromatography.

A crystalline product was identified as (Z)-3-hexenyl-(tetra-O-acetyl)-β-d-glucopyranoside from spectrometric data which were identical with those of an authentic synthesized sample in all respects.

There are two possible processes for the formation of the greenish odor of plant materials, these being a biosynthetic process from the lipid and enzymatic hydrolysis of (Z)-3-hexenyl-β-d-glucoside.     

Solution Structure of Human Cardiac Troponin C in Complex with the Green Tea Polyphenol, (?)-Epigallocatechin 3-Gallate

Heart muscle contraction is regulated by Ca²⁺ binding to the thin filament protein troponin C. In cardiovascular disease, the myofilament response to Ca²⁺ is often altered. Compounds that rectify this perturbation are of considerable interest as therapeutics. Plant flavonoids have been found to provide protection against a variety of human illnesses such as cancer, infection, and heart disease. (−)-Epigallocatechin gallate (EGCg), the prevalent flavonoid in green tea, modulates force generation in isolated guinea pig hearts (Hotta, Y., Huang, L., Muto, T., Yajima, M., Miyazeki, K., Ishikawa, N., Fukuzawa, Y., Wakida, Y., Tushima, H., Ando, H., and Nonogaki, T. (2006) Eur. J. Pharmacol. 552, 123–130) and in skinned cardiac muscle fibers (Liou, Y. M., Kuo, S. C., and Hsieh, S. R. (2008) Pflugers Arch. 456, 787–800; and Tadano, N., Yumoto, F., Tanokura, M., Ohtsuki, I., and Morimoto, S. (2005) Biophys. J. 88, 314a). In this study we describe the solution structure of the Ca²⁺-saturated C-terminal domain of troponin C in complex with EGCg. Moreover, we show that EGCg forms a ternary complex with the C-terminal domain of troponin C and the anchoring region of troponin I. The structural evidence indicates that the binding site of EGCg on the C-terminal domain of troponin C is in the hydrophobic pocket in the absence of troponin I, akin to EMD 57033. Based on chemical shift mapping, the binding of EGCg to the C-terminal domain of troponin C in the presence of troponin I may be to a new site formed by the troponin C·troponin I complex. This interaction of EGCg with the C-terminal domain of troponin C·troponin I complex has not been shown with other cardiotonic molecules and illustrates the potential mechanism by which EGCg modulates heart contraction.Cardiovascular disease (CVD)² is the number one cause of morbidity and mortality in western culture. In the United States, ∼1 in 3 deaths in 2004 were caused by CVD (1). In heart failure, the ability of the heart to distribute blood throughout the body is perturbed, and there is a growing interest to develop drugs that directly regulate the response of the myofilament to Ca²⁺. Regulation of muscle contraction is triggered by Ca²⁺ binding to troponin. The troponin complex is situated at regular intervals along the thin filament, which is made up of two elongated polymers, f-actin and tropomyosin. The backbone of the thin filament is composed of actin molecules arranged in a double helix with tropomyosin wound around actin as a coiled-coil. Anchored at every seventh actin molecule is the heterotrimeric troponin complex, which consists of troponin C (TnC), troponin I (TnI), and troponin T (TnT). TnC is the Ca²⁺-binding subunit of troponin and has four EF-hand helix-loop-helix motifs. TnI is the inhibitory subunit of troponin. It regulates the actin-myosin cross-bridge formation by flipping between TnC and actin in a Ca²⁺-dependent manner. At low levels of cytosolic Ca²⁺, TnI is bound to actin, causing tropomyosin to sterically block the binding of the actomyosin cross-bridges. On the other hand, when Ca²⁺ concentration is high, TnI translocates from actin to TnC inducing tropomyosin to change its orientation on actin so that the actin-myosin interaction may occur. The subunit TnT fetters the troponin complex to the thin filament by way of its association with TnI (for reviews on contraction see Refs. 2–5).The large number of structural studies on troponin and the thin filament has helped gain insight into the molecular mechanism of muscle contraction. TnC is a dumbbell-shaped protein that consists of terminal domains connected by an elongated flexible linker, as shown by solution NMR (6). The overall folds of the terminal domains of skeletal TnC (sTnC) and cardiac TnC (cTnC) are very similar (7–9). The apo state of the N-domain of sTnC (sNTnC) and cTnC (cNTnC) reveals that the domain is in a “closed” conformation, such that the hydrophobic core of the protein is buried (8, 10, 11). In the skeletal system, sNTnC “opens” when two Ca²⁺ ions bind (8, 10, 11). Alternatively, cNTnC contains only one functional Ca²⁺-binding site, and its global conformation does not change as significantly as in sNTnC (11). Nonetheless, Ca²⁺ binding promotes the association of the switch region of cTnI (residues 147–163) with cNTnC. cTnI-(147–163) forms an α-helix when associated with cNTnC and has been elucidated by NMR in the solution structure of cNTnC·Ca²⁺·cTnI-(147–163) (12) and by the x-ray crystallography structure of cTnC·3Ca²⁺·cTnI·-(31–210)·cTnT-(183–288) (13). The interaction of cTnI-(147–163) with cNTnC·Ca²⁺ is essential to draw the inhibitory (cTnI-(128–147)) and C-terminal (cTnI-(163–210)) regions of cTnI away from actin. cTnI-(128–147) is not visualized in the cardiac structure, probably due to disorder (13). In the skeletal crystal structure of sTnC·4Ca²⁺·sTnI-(1–182)·sTnT-(156–262), however, the inhibitory region of sTnI is visualized and makes electrostatic contacts with the central helix connecting the N- and C-terminal lobes of cTnC (14). The C-domain (CTnC) of both sTnC and cTnC has two functional binding sites for Ca²⁺ and remains largely unstructured without Ca²⁺ bound. The folding of this domain occurs in the presence of Ca²⁺ (15, 16). Throughout the relaxation-contraction cycle, cCTnC is Ca²⁺-saturated with both Ca²⁺-binding sites occupied (cCTnC·2Ca²⁺) and is associated with the anchoring region of cTnI (cTnI-(34–71)). The crystal structure of cTnC·3Ca²⁺·cTnI·-(31–210)·cTnT-(183–288) shows cTnI-(34–71) is α-helical when bound with cCTnC·2Ca²⁺(13). The interaction of cCTnC·2Ca²⁺ with cTnI-(34–71) is the primary site in which cTnC is tethered to the thin filament.In light of the importance of the Ca²⁺-dependent cTnI-cTnC interaction in the signaling of muscle contraction, the design of drugs that modulate this interaction would be useful in the treatment of heart disease. Compounds that treat CVD through modulation of the activity of cTnC are called Ca²⁺ sensitizers or desensitizers, depending on whether they positively or negatively influence its function. These drugs are safer than other currently prescribed medicines that alter the cytosolic Ca²⁺ homeostasis (such as milrinone and dobutamine), which may cause arrhythmia or death with prolonged usage.The potential therapeutic advantage of Ca²⁺ (de)sensitizers has led to the development of a number of compounds that target cTnC. Compounds have been identified that elicit their activity through binding either cNTnC or cCTnC. Levosimendan and pimobendan are examples of molecules that increase heart muscle contractility through binding to cNTnC. Conversely, the molecule W7 decreases contractility via its interaction with cNTnC. For recent reviews on the molecular mechanism of these compounds and others see Refs. 17–19. The discovery of small molecules that bind to cCTnC to elicit their Ca²⁺-sensitizing effects suggests that cCTnC is also a suitable target for the development of therapeutics. The Ca²⁺ sensitizer, EMD 57033, is approved for the treatment for heart failure in dogs and binds to cCTnC·2Ca²⁺(20). In the NMR structure of cCTnC·2Ca²⁺·EMD 57033, EMD 57033 is associated in the hydrophobic cavity of cCTnC·2Ca²⁺ (21). The interaction of EMD 57033 with cCTnC is stereospecific for the (+)-enantiomer and explains why the (−)-enantiomer is inactive (22). Because EMD 57033 has been shown to bind cCTnC·2Ca²⁺ concurrently with cTnI-(128–147) but not with cTnI-(34–71) (23), one postulate is that EMD 57033 acts as a Ca²⁺ sensitizer by weakening the interaction of cTnI-(34–71) with cCTnC·2Ca²⁺, thus increasing the propensity of cTnI-(128–147) to bind cCTnC·2Ca²⁺ in vivo. The dilated cardiomyopathy (DCM) mutation, G159D, of cCTnC has renewed interest in the role of the C-lobe for regulation in contraction. The mutation has been identified to decrease the sensitivity of the thin filament to Ca²⁺ (24). The source of the DCM phenotype of G159D might come from the modulation of the interaction of cCTnC·2Ca²⁺ with cTnI-(34–71) (25).Green tea (Camellia sinensis) is one of the most widely consumed beverages in the world, and several epidemiological studies have linked the consumption of tea with a decrease in CVD (26, 27). (−)-Epigallocatechin gallate (EGCg) is a polyphenol that exists abundantly in unfermented teas and has been identified as a modulator of heart contraction through its interaction with cTnC (28–30). Here we use NMR spectroscopy to elucidate the three-dimensional structure of the cCTnC·2Ca²⁺·EGCg complex. The solution structure reveals that EGCg binds at the hydrophobic core of cCTnC inducing a small structural “opening.” We also use two-dimensional NMR spectroscopy to monitor the binding of EGCg to cCTnC·2Ca²⁺ and cCTnC·2Ca²⁺·cTnI-(34–71). Because EGCg and cTnI-(34–71) can bind cCTnC concurrently, the inotropic effect of EGCg may stem from its modulation of the cTnI-(34–71)-cCTnC·2Ca²⁺ interaction. The solution structure of cCTnC·2Ca²⁺·EGCg provides insight into the mechanism in which EGCg might influence heart contraction. These results taken with previous research on the Ca²⁺ sensitizer EMD 57033 and the DCM mutation G159D bring into question the dogma that cNTnC is the exclusive site for regulation of contraction in cTnC.     

trans- and cis-Linalool 3,6-Oxide 6-O-β-d-Xylopyranosyl-β-d-glucopyranosides Isolated as Aroma Precursors from Leaves for Oolong Tea

New glycosidic aroma precursors (1 and 2) of the main volatile constituents, trans- and cis-linalool 3,6-oxides (linalool oxides I and II), were isolated from oolong tea leaves (Camellia sinensis var. sinensis cv. Maoxie). The isolation was guided by an enzymatic hydrolysis with acetone powder prepared from fresh tea leaves (cv. Yabukita) followed by GC or GC-MS analyses. Chromatographic purification of hot water extracts of the tea leaves on active charcoal, Amberlite XAD-2, and Sephadex LH-20 columns as well as HPLC gave two new glycosides, trans- and cis-linalool 3,6-oxide 6-O-β-d-xylopyranosyl-β-d-glucopyra-nosides (1 and 2).     

Tea stalks – a novel agro-residue for the production of tannase under solid state fermentation by Aspergillus niger JMU-TS528

A novel agro-residue, tea stalks, was tested for the production of tannase under solid-state fermentation (SSF) using Aspergillus niger JMU-TS528. Maximum yield of tannase was obtained when SSF was carried out at 28 °C, pH 6.0, liquid-to-solid ratio (v/w) 1.8, inoculum size 2 ml (1?×?10⁸ spores/ml), 5 % (w/v) ammonium chloride as nitrogen source and 5 % (w/v) lactose as additional carbon source. Under optimum conditions, tannase production reached 62 U/g dry substrate after 96 h of fermentation. Results from the study are promising for the economic utilization and value addition of tea stalks.     

A Computational Exploration of the Interactions of the Green Tea Polyphenol (–)-Epigallocatechin 3-Gallate with Cardiac Muscle Troponin C

Thanks to its polyphenols and phytochemicals, green tea is believed to have a number of health benefits, including protecting from heart disease, but its mechanism of action at the molecular level is still not understood. Here we explore, by means of atomistic simulations, how the most abundant of the green tea polyphenols, (–)-Epigallocatechin 3-Gallate (EGCg), interacts with the structural C terminal domain of cardiac muscle troponin C (cCTnC), a calcium binding protein that plays an important role in heart contractions. We find that EGCg favourably binds to the hydrophobic cleft of cCTnC consistently with solution NMR experiments. It also binds to cCTnC in the presence of the anchoring region of troponin I (cTnI(34–71)) at the interface between the E and H helices. This appears to affect the strength of the interaction between cCTnC and cTnI(34–71) and also counter-acts the effects of the Gly159Asp mutation, related to dilated cardiomyopathy. Our simulations support the picture that EGCg interacting with the C terminal domain of troponin C may help in regulating the calcium signalling either through competitive binding with the anchoring domain of cTnI or by affecting the interaction between cCTnC and cTnI(34–71).     

Dose-dependent Incorporation of Tea Catechins, (–)-Epigallocatechin-3-gallate and (–)-Epigallocatechin,into Human Plasma

Tea catechins, (–)-epigallocatechin-3-gallate (EGCg) and (–)-epigallocatechin (EGC), have been reported to suppress oxidation of plasma low density lipoprotein (LDL) in vitro. If dietary catechins can be efficiently incorporated into human blood plasma, anti-atherosclerotic effects in preventing oxidative modification of LDL would be expected. In this study, a newly developed chemiluminescence detection-high pressure liquid chromatography (CL-HPLC) method for measuring plasma catechins was used and the incorporation of EGCg and EGC into human plasma was investigated. Healthy subjects orally ingested 3, 5, or 7 capsules of green tea extract (corresponding to 225, 375, and 525 mg EGCg and 7.5, 12.5, and 17.5 mg EGC, respectively). The plasma EGCg and EGC concentrations before the administration were all below the detection limit (< 2 pmol/ml), but 90 min after, significantly and dose-dependently increased to 657, 4300, and 4410 pmol EGCg/ml, and 35, 144, and 255 pmol EGC/ml, in the subjects who received 3, 5, and 7 capsules, respectively. Both EGCg and EGC levels detected in plasma corresponded to 0.2–2.0% of the ingested amount. Catechin intake had no effect on the basal level of endogenous antioxidants (α-tocopherol, β-carotene, and lycopene) or of lipids in plasma. These results suggested that drinking green tea daily would contribute to maintain plasma catechin levels sufficient to exert antioxidant activity against oxidative modification of lipoproteins in blood circulation systems.     

Tea polyphenols inhibit rat vascular smooth muscle cell adhesion and migration on collagen and laminin via interference with cell–ECM interaction

Occlusive lesions of atherosclerosis are the consequence of focal accumulation within the innermost layer of the artery of leukocytes from the circulation and smooth muscle cells (SMCs) from the underlying media. Tea polyphenol especially (−)-Epigallocatechin-3-gallate (EGCG) has been shown to have cardiovascular protective effect. However, the effects of other catechins such as (+)-catechin, and (−)-epicatechin-3-gallate (ECG) on SMC’s functions have not been fully understood. In the present study, we investigate the effects of tea catechins on SMC adhesion and migration. Our results indicate that EGCG and ECG but not (+)-catechin were able to inhibit SMC adhesion on collagen and laminin, two abundant extracellular matrix (ECM) proteins expressed in physiological and pathological conditions. Further analyses indicate that EGCG could bind laminin more than collagen. Moreover, EGCG could inhibit SMC adhesion to integrin β1 Ab and affect SMC’s β1 integrin expression, suggesting it affects SMC’s cellular components. In migration experiment, laminin- and PDGF-BB-induced SMC migration were both inhibited by EGCG in a dose-dependent manner. Taken together, the data presented here provide evidence showing that among these tea catechins, EGCG and ECG are relatively effective inhibitors on SMC–ECM interaction and their action mechanisms are through interference with SMC’s integrin β1 receptor and binding to ECM proteins.     

What potential is there for regeneration of native species from the soil seed bank in Coast Tea Tree‐dominated scrub?

Shrub encroachment generally causes the loss of native species in herbaceous‐dominated communities. The ability of the original ecosystem to return to its pre‐encroachment state (i.e. its ecological resilience) will be partially contingent on the capacity of these species to regenerate from soil‐stored seed. Coast Tea Tree (Leptospermum laevigatum) has formed a dense scrub in many areas previously dominated by grassy woodland, and hence, managers need guidance about the effectiveness of strategies designed to recover the pre‐encroachment vegetation. In this context, we ask: what is the potential of species stored in the soil seed bank to return following Tea Tree removal? A germination experiment was undertaken using soil collected from dense stands of Tea Tree that had been long established. Heat/smoke was applied to soils to simulate the effects of a fire on the soil seed bank, while leaf litter treatments were used to mimic both undisturbed stands and stands where shrubs have been slashed where litter creates a physical barrier to emergence. We found the soil seed bank was dominated by exotic forbs (83% of all germinants) and contained few grasses. Heat and smoke decreased total species density but increased species diversity through the suppression of common exotics. Our data suggest that slashing would result in germination being dominated by exotic flora, but using fire would likely reduce that dominance. However, we conclude that recovery by much of the original flora after site occupation by Coast Tea Tree may be contingent on mechanisms other than soil‐stored seeds.     

Safety Evaluation of Fluoride Content in Tea Infusions Consumed in the Azores—a Volcanic Region with Water Springs naturally Enriched in Fluoride

Tea is the second most commonly consumed beverage in the world. It is well recognized that the consumption of tea in high quantities can promote the development of fluorosis. The main objective of this study is to estimate the exposure to fluoride in the Azores through drinking tea prepared with water from different volcanic locations, by i) investigating the fluoride (F) content of various commercial brands of tea (Camellia sinensis) marketed in Azores and ii) comparing tea releasing rates of F according to brewing time, considering the fluoride concentration in the different types of water used for the infusion. Fluoride contents were determined by ion-selective electrode in 30 samples of drinking water from three different locations and in 450 samples of tea (black and green tea) from three different brands. Fluoride concentration in water ranged from 0.29 to 1.56 ppm (Porto Formoso and Sete Cidades village, respectively). Fluoride concentrations increased with brewing time, reaching the highest values in the Azorean black and green tea infusions. For all the studied brands, a negative correlation was found between tea fluoride contents and the pH of the water used to prepare the infusion. Fluoride concentration in infusions was significantly associated with the background fluoride concentration in drinking water. Since the fluoride concentration in groundwater varies accordingly to the geological conditions and tea consumption can contribute to fluoride intake, it is important to define the limits for tea consumption, particularly in fluoride-rich areas.

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Graphical Abstract Fluoride concentrations in black and green tea for 3 minutes of brewing time and, association between fluoride concentration and pH with brewing time

     

Purification and Partial Characterization of β-Glucosidase from Fresh Leaves of Tea Plants （Camellia sinensis （L.） O. Kuntze）

β-Glucosidases are important in the formation of floral tea aroma and the development of resistance to pathogens and herbivores in tea plants. A novel β-glucosidase was purified 117-fold to homogeneity,with a yield of 1.26%, from tea leaves by chilled acetone and ammonium sulfate precipitation, ion exchange chromatography (CM-Sephadex C-50) and fast protein liquid chromatography (FPLC; Superdex 75, Resource S). The enzyme was a monomeric protein with specific activity of 2.57 U/mg. The molecular mass of the enzyme was estimated to be about 41 kDa and 34 kDa by SDS-PAGE and FPLC gel filtration on Superdex 200, respectively. The enzyme showed optimum activity at 50℃ and was stable at temperatures lower than 40℃. It was active between pH 4.0 and pH 7.0, with an optimum activity at pH 5.5, and was fairly stable from pH 4.5 to pH 8.0. The enzyme showed maximum activity towards pNPG, low activity towards pNP-Galacto, and no activity towards pNP-Xylo.     

Black Tea Extract and Its Theaflavin Derivatives Inhibit the Growth of Periodontopathogens and Modulate Interleukin-8 and β-Defensin Secretion in Oral Epithelial Cells

Over the years, several studies have brought evidence suggesting that tea polyphenols, mostly from green tea, may have oral health benefits. Since few data are available concerning the beneficial properties of black tea and its theaflavin derivatives against periodontal disease, the objective of this study was to investigate their antibacterial activity as well as their ability to modulate interleukin-8 and human β-defensin (hBD) secretion in oral epithelial cells. Among the periodontopathogenic bacteria tested, Porphyromonas gingivalis was found to be highly susceptible to the black tea extract and theaflavins. Moreover, our data indicated that the black tea extract, theaflavin and theaflavin-3,3’-digallate can potentiate the antibacterial effect of metronidazole and tetracycline against P. gingivalis. Using lipopolysaccharide-stimulated oral epithelial cells, the black tea extract (100 μg/ml), as well as theaflavin and theaflavin-3,3’-digallate (50 μg/ml) reduced interleukin-8 (IL-8) secretion by 85%, 79%, and 86%, respectively, thus suggesting an anti-inflammatory property. The ability of the black tea extract and its theaflavin derivatives to induce the secretion of the antimicrobial peptides hBD-1, hBD-2 and hBD-4 by oral epithelial cells was then evaluated. Our results showed that the black tea extract as well as theaflavin-3,3’-digallate were able to increase the secretion of the three hBDs. In conclusion, the ability of a black tea extract and theaflavins to exert antibacterial activity against major periodontopathogens, to attenuate the secretion of IL-8, and to induce hBD secretion in oral epithelial cells suggest that these components may have a beneficial effect against periodontal disease.