In vitro antifungal activity againstCandidaspecies of Sri Lankan orthodox black tea (Camellia sinensisL.) belonging to different agro-climatic elevations

Objective:To investigate the antifungal potential of different grades of Sri Lankan orthodox black tea [orange pekoe, broken orange pekoe fannings (BOPF) and Dust No. 1] belonging to the three agro-climatic elevations (low, mid and high). Methods: Antifungal activity was assessedin vitro using methanolic extracts (300μg/disc) and agar disc diffusion bioassay technique against threeCandida species,Candida albicans (C. albicans),Candida glabrata(C. glabrata), andCandida tropicalis. ketoconazole and itraconazole mixture was used as positive control (10μg/disc) and methanol was used as the negative control. The minimum inhibitory concentrations were also determined using standard protocols. Results: None of the extracts were effective againstCandida tropicalis. Furthermore, orange pekoe grade tea belonging to all agro-climatic elevations did not induce any antifungal activity againstC. albicans andC. glabrata as well. Conversely, Dust No. 1 belonging to all three agro-climatic elevations and low-grownBOPF showed moderate antifungal activity againstC. albicans andC. glabrata. Interestingly, the severity of the antifungal effect varied with agro-climatic elevations. The minimum inhibitory concentrations ranged from 64.00–128.00μg/mL againstC. glabrata and 128.00-256.00μg/mL againstC. albicans. Conclusions:Sri Lankan Dust No. 1 andBOPF have marked antifungal activityin vitro and offer promise to be used as a supplementary beverage in prophylaxis and during drug treatment in candidiasis.

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.