Comparison of Antimicrobial and Antioxidant Activities of Four Different Tea Extracts (original) (raw)
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Antimicrobial properties of teas and their extracts in vitro
Tea has recently received the attention of pharmaceutical and scientific communities due to the plethora of natural therapeutic compounds. As a result, numerous researches have been published in a bid to validate their biological activity. Moreover, major attention has been drawn to antimicrobial activities of tea. Being rich in phenolic compounds, tea has the preventive potential for colon, esophageal, and lung cancers, as well as urinary infections and dental caries, among others. The venture of this review was to illustrate the emerging findings on the antimicrobial properties of different teas and tea extracts, which have been obtained from several in vitro studies investigating the effects of these extracts against different microorganisms. Resistance to antimicrobial agents has become an increasingly important and urgent global problem. The extracts of tea origin as antimicrobial agents with new mechanisms of resistance would serve an alternative way of antimicrobial chemotherapy targeting the inhibition of microbial growth and the spread of antibiotic resistance with potential use in pharmaceutical, cosmetic, and food industries.
Antimicrobial and antioxidant activities of Tea plant
Novel Research in Microbiology Journal
Many complementary and alternative medicines have enjoyed increased popularity in recent decades. Efforts to validate their use have seen their putative therapeutic properties, which come under increasing scrutiny in vitro and in some cases in vivo. One of such products is tea and its tree oil (TTO); which is a secondary metabolite derived from tea plant (Melaleuca alternifolia). Both black and green tea has several polyphenolic compounds with possible antibacterial effects. It is employed largely due to its antimicrobial properties, and is incorporated as the active ingredient in many topical formulations used to treat cutaneous infections, in addition to being marketed as a remedy for various ailments. The essential oil of M. alternifolia exhibits broad-spectrum antimicrobial potential. The TTO may help to treat severe yeast infections. Results also suggested that TTO exerts a greater bactericidal potency against biofilm-grown methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-sensitive Staph. aureus (MSSA) strains. Moreover, tea has inhibitory efficacy against the carcinogenic bacteria.
Antioxidant and antimicrobial activities of white, green and black tea extracts
Acta Alimentaria, 2013
In the present study, the antioxidant and antimicrobial activities of three tea (Camellia sinensis) types (white tea-WT, green tea-GT, and black tea-BT) were compared and the relationships between total phenolic, tannin and fl avonoid contents were determined. Regardless of the assays used, the highest total phenolic content (313.3±1.41 μg GAE/mg extract), total fl avonoid (16.98±0.27 μg QE/mg extract) and total tannin content (266.79±2.59 μg TAE/ mg extract) were determined in green tea extract, which also demonstrated the highest antioxidant capacity. Black tea extract showed the lowest phenolic content and antioxidant capacity. The EC 50 value of DPPH scavenging activity was in the order of: ascorbic acid >GT>BHA>WT>BT>BHT. While the tea extracts exhibited antibacterial activity against Staphylococcus aureus, no inhibitory effects were observed against Escherichia coli and Salmonella enteritidis. All extracts exhibited antifungal activity against two afl atoxigenic moulds Aspergillus parasiticus NRRL 2999 and NRRL 465. The antibacterial activity of tea extracts decreased in the following order: GT>WT>BT DPPH scavenging activity strongly correlated with total phenolic content, reducing power, antimicrobial activity against S. aureus, A. parasiticus NRRL 2999, A. parasiticus NRRL 465 (P<0.05). These data suggest that green tea extract is more effective than white and black tea extracts as a potential source of natural antioxidants.
The in vitro antimicrobial activity of crude ethanol, methanol, hexane and aqueous extracts of commercial tea types such as fennel (Foeniculum sp.), senna (Cassia sp.), basil-rosemary (Ocimum sp.-Rosmarinus sp), daisy (Bellis sp.) and sage (Salvia sp) against pathogen fungi (Colletotrichum coccodes, Epicoccum nigrum, Scopulariopsis brevicaulis) and foodborne pathogen bacteria (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Bacillus cereus, Klebsiella pneumoniae, Enterobacter sp.) were investigated with disk diffusion method. Senna (Cassia sp.) exhibed the most effective antimicrobial activity in both ethanolic and methanolic extracts. The best antimicrobial effect (30.6 mm) against E. nigrium was seen in methanolic senna (Cassia sp.) extract. The results of the study indicate that commercial tea types have showed various levels of antimicrobial activity depend on the type of solvent used in the extraction procedure.
Molecular Nutrition & Food Research, 2007
Tea leaves produce organic compounds that may be involved in the defense of the plants against invading pathogens including insects, bacteria, fungi, and viruses. These metabolites include polyphenolic compounds, the six so-called catechins, and the methyl-xanthine alkaloids caffeine, theobromine, and theophylline. Postharvest inactivation of phenol oxidases in green tea leaves prevents oxidation of the catechins, whereas postharvest enzyme-catalyzed oxidation (fermentation) of catechins in tea leaves results in the formation of four theaflavins as well as polymeric thearubigins. These substances impart the black color to black teas. Black and partly fermented oolong teas contain both classes of phenolic compounds. A need exists to develop a better understanding of the roles of polyphenolic tea compounds in food and medical microbiology. This overview surveys and interprets our present knowledge of activities of tea flavonoids and teas against foodborne and other pathogenic bacteria, virulent protein toxins produced by some of the bacteria, virulent bacteriophages, pathogenic viruses and fungi. Also covered are synergistic, mechanistic, and bioavailability aspects of the antimicrobial effects. Further research is suggested for each of these categories. The herein described findings are not only of fundamental interest, but also have practical implications for nutrition, food safety, and animal and human health.
Investigation of antimicrobial effects of tea leaf extract on microorganisms in culture media
2014
Regarding to the fact that using synthesis antimicrobial components in food stuffs has undesirable impacts including mutation, toxicological effects, and carcinogenesis in human body, they are being omitted from previously used antimicrobial components list; therefore, preparation and production of natural anti-bacterial components as a substitute seem to be necessary. Tea leaf has been recognized as a substance for antibacterial activity against the effect of microorganisms in the present research, antibacterial activity (paper-disc method), determination of the minimum inhibitor concentration and minimum microbe bactericide concentration (Agar and Broth Dilution Method) of tea water extract in three repetitions on Staphylococcus aureus (PTCC:1112), Escherichia coli (PTCC:1330) Penicillium sp. (PTCC:5251) and Clostridium perfringenes (PTCC: 1651) microorganisms were investigated. Based on the results of antimicrobial activity, Staphylococcus aureus showed the highest sensitivity an...
Tarım Bilimleri Dergisi, 2009
Polyphenol content, polyphenol yield, antioxidant and antibacterial activities of methanol, ethanol and water extracts and their crude, ethyl acetate and water fractions derived from fresh tea leaves (FTL) and green tea (GT) were evaluated. Ethyl acetate fractions of ethanolic extracts contained the highest polyphenol content in FTL and GT samples (680.2 and 560.8 mg gallic acid equivalent g-1 dry extract, respectively). For each of 3 extraction solvents, ethyl acetate fractions always had highest polyphenol content, for both teas. Ethyl acetate fractions of water extracts of FTL and GT had highest antioxidant activity (80.8 and 78.6 g ascorbic acid 100g-1 dry extract). A rather high correlation coefficient (R 2 = 0.9376 for FTL and 0.9783 for GT) was obtained between antioxidant activity to total polyphenol content for both tea. Ethyl acetate fractions of extracts showed antibacterial activity on S. aureus and B. cereus. Crude extract of FTL were also effective on S. aureus.
In-vitro antimicrobial and synergistic properties of water soluble green and black tea extracts
African journal of microbiology research
Green and black teas extracts are known for their antibacterial activity against many pathogenic microorganisms. Studies have demonstrated that tea possess potential antimicrobial activity with efficacy against a number of clinically relevant pathogens. However, these studies have been carried out using tea grown in Asia but very few on Kenyan teas which have superior qualities. These studies have been necessitated by the need to combat the recent rise of drug-resistant human pathogens which is becoming a common occurrence in the world making easily manageable infections to become life threatening illnesses. There is need therefore to conduct fruitful research that will unravel the properties of medicinal compounds especially in tea which may have significant antimicrobial properties against drug resistant organisms. This study evaluated the antimicrobial activity of water soluble green and black tea extracts from a high quality Kenyan tea clone TRFK 6/8 against antibiotic resistant...