In vitro pancreatic lipase,cholesterol esterase and cholesterol micellization inhibitory activity of Sri Lankan low grown orthodox Orange Pekoe grade black tea(Camellia sinensis L.)

Objective:To access the pancreatic lipase,cholesterol esterase and cholesterol micellization inhibitory activities of Sri Lankan low grown orthodox Orange Pekoe grade black tea made from uppermost tender leaves and unopened buds of Camellia sinensis L.Methods:Black tea brew(BTB)was made according to International Organization for Standardization 3103 specifications and concentrations of BTB tested were 37.5,75.0,150.0,300.0 and 600.0μg/mL for antilipase and anti-cholesterol esterase assays and 0.25,0.50 and 1.00μg/mL for cholesterol micellization inhibitory assay.Results:The results showed that BTB of Sri Lankan low grown orthodox Orange Pekoe grade black tea has marked and dose-dependent(r^(2)=0.95)cholesterol micellization inhibitory activity in vitro comparable to epigallocatechin gallate,the reference drug used.In contrast,BTB had only mild but dose-dependent(r^(2)=0.94)inhibitory activity against pancreatic lipase and weak inhibitory effect(up to 13.17%)on pancreatic cholesterol esterase.Conclusions:It is concluded that consumption of BTB of Sri Lankan low grown orthodox Orange Pekoe grade tea as a beverage may be a useful strategy in the management of hyperlipidaemia.

In vitro antibacterial activity of Sri Lankan orthodox black tea(Camellia sinensis L.)belonging to different agro-climatic elevations

Objective:To investigate the antibacterial properties of three grades of orthodox Sri Lankan black tea belonging to the three agro-climatic elevations.Methods:Methanloic extracts of orange pekoe(OP),broken orange pekoe fannings(BOPF)and Dust No.1 belonging to three agro-climatic elevations(low,mid and high grown)were made and tested in vitro(concentration:300μg/disc)against Gram-positive pathogenic bacteria,Staphylococcus aureus(ATCC 25923)(S.aureus)and Bacillus cereus(ATCC 11778)(B.cereus),and two Gram-negative bacteria Pseudomonas aeruginosa(ATCC 9027)(P.aeruginosa)and Escherichia coli(ATCC 35218)(E.coli),using agar disc diffusion assay.Gentamycin(10μg/disc)was used as the positive control and methanol as the negative control.Minimum inhibitory concentration(MIC)values were evaluated,using micro dilution method.Results:None of the tea extracts exerted an antibacterial action against P.aeruginosa and E.coli.In contrast mild to moderate antibacterial activity was exerted against S.aureus and B.cereus.Further gentamycin exhibited strong antibacterial activity against all the four bacterial species.Further low MIC values were evident for tea samples against the two Gram-positive bacteria.The order of anti-bacterial activity for tea extracts was Dust No.1>BOPF>OP.Conclusions:It is concluded that Sri Lankan orthodox black tea belonging to Dust No.1,BOPF,and OP pocess in vitro antibacterial activity against S.aureus and B.cereus but not against Gram-positive bacteria P.aeruginosa and E.coli.

Sri Lankan black tea(Camellia sinensis L.)inhibits the methylglyoxal mediated protein glycation and potentiates its reversing activity in vitro

Objective:To evaluate inhibitory activity of methylglyoxal(MGO)mediated protein glycation and ability to potentiate its reversing activity and range of antioxidant properties of Sri Lankan low grown orthodox orange pekoe grade black tea.Methods:Freeze dried black tea brew(BTB)was used as the sample in this study.Antiglycation and glycation reversing activity was studied in bovine serum albumin(BSA)-MGO model.Antioxidant properties were studied using total polyphenolic content,total flavonoid content,2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid,1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power in vitro antioxidant assays.Results:The results demonstrated significant(P<0.05)and dose dependant inhibition of BSA-MGO glycation[IC_(50):(164.30±4.85)μg/mL],potentiating of its reversing activity[EC_(50):(235.39±5.37)μg/mL]and marked antioxidant properties[total polyphenolic content:(119.55±9.97)mg gallic acid equivalents/g BTB;total flavonoid content:(6.04±1.26)mg quercetin equivalents/g BTB;2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid,1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power:(3.29±0.06),(1.95±0.15)and(1.31±0.19)mmol Trolox equivalents/g BTB,respectively].No correlations were observed between antioxidant activity and BSA-MGO glycation.Conclusions:The novel properties observed for Sri Lankan orange pekoe grade black tea indicate its usefulness as a supplementary beverage in managing MGO and advanced glycation end products related diseases and ailments.