@article {1016, title = {Inhibitory Effects of Tea Leaf and Medicinal Plant Extracts on Enteric Pathogenic Bacteria Growth, Oxidation and Epithelial Cell Adhesion}, journal = {Pharmacognosy Research}, volume = {14}, year = {2022}, month = {December 2021}, pages = {71-81}, type = {Original Article}, chapter = {71}, abstract = {

Background: Diarrhea disease was noted by WHO as the major target for control that the leading cause of diarrhea diseases are enteric pathogenic bacteria. Biological properties of tea leaf and medicinal plant which promoted the alternative way to inhibit enteric pathogenic bacteria. Objectives: To investigate antibacterial activity of tea leaf combined with medicinal plant extracts for inhibition of growth and the adhesion of enteric pathogenic bacteria on epithelial cells. Materials and Methods: Among the Camellia sinensis tea leaves; green, oolong and black tea, and 14 medicinal plants examined, aqueous and ethanolic extracts demonstrated growth inhibition against Escherichia coli, Salmonella typhi, Shigella dysenteriae, Staphylococcus aureus and Vibrio cholerae. Antioxidation, phenolics and flavonoids contents were also determined. Tea leaf and medicinal plant extracts were combined for the development of herbal tea that subsequently evaluated the inhibition of bacterial adhesion on epithelial cells. Results: The aqueous and ethanolic extracts of green tea and Garcinia cowa showed effectiveness against all enteric pathogenic bacteria, especially the fraction of ethanolic extracts that revealed the greatest bactericidal activity. Moreover, the ethanolic extract of green tea showed the highest content of phenolics and flavonoids, which also correlated with the antioxidant activity. In addition, the ethanolic extract of G. cowa had the highest flavonoid content. Hence, the combination of green tea with G. cowa extract revealed its effectiveness against enteric pathogenic bacteria and had an inhibitory effect against the adhesion of bacteria on epithelial cells. Conclusion: Herbal tea, the combination of green tea and G. cowa extract exhibited the beneficial antibacterial and antioxidant activities, which could be considered as an alternative treatment for enteric pathogenic bacteria infections and promote health benefits.

}, keywords = {Antioxidation, Cell adhesion, Enteric pathogenic bacteria, Herbal tea, Medicinal plant, Tea leaf.}, doi = {10.5530/pres.14.1.11}, url = {https://phcogres.com/fulltext/v14i1/105530pres14111.html}, author = {Thida Kaewkod and Wilaiporn Songkhakul and Yingmanee Tragoolpua} } @article {854, title = {Studies on the Effect of Processing Methods on the Antihyperglycemic activity of Herbal Teas from Leaves of Vernonia amygdalina Del}, journal = {Pharmacognosy Research}, volume = {1}, year = {2009}, month = {January 2010 }, pages = {256-260}, type = {Original Article}, chapter = {256}, abstract = {

The leaves of Vernonia amygdalina Del (Asteraceae) was processed into herbal tea using the black and green tea processing techniques. The green tea obtained was used as such while a portion of the black tea was flavored with O. basilicum or O. gratissimum. Methanol extracts of the flavored and unflavored herbal teas, obtained by cold maceration, were subjected to pharmacological studies for antihyperglycemic activity in alloxan diabetic rats and pytochemical analysis. Results showed that single oral administration of the tea extracts reduced blood glucose level of diabetic rats to varying the extents. Extract of green tea (GTE) caused a moderate reduction in blood glucose levels while black tea (BTE) evoked a mild dose-related effect. Extracts of the flavored tea caused significant (P\<0.05) reductions in blood glucose levels. While the effect of extract of O. basilicum flavored tea (BTOBE) was dose-related, that of O. gratissimum flavored tea (BTOGE) was non-dose-related. A comparison of the magnitude of reduction in blood glucose level showed the order of potency: BTOBE\>BTOGE\>GTE\>BTE. Phytochemical analysis showed relative presence of alkaloids, saponins, tannins, flavonoids, steroids and terpenoids with GTE having the highest concentration of these constituents. These findings suggest that black tea technique may be preferred for processing leaves of V. amygdalina into herbal tea since it preserved the antihyperglycemic activity. Green tea method may reduce the antihyperglycemic effect even though it preserves the phytochemical constituents better than black tea technique. Flavoring of black tea with Ocimum spp enhances the antihyperglycemic effect due to their inherent hypoglycemic activity.

}, keywords = {Antihyperglycemic, Black tea, Green tea, Herbal tea, Ocimum spp, Vernonia amygdalina}, doi = {Nil}, author = {Okafor G.I and Okoli C.O and Odo A.S and Kelechi N.R} }