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.

Physicochemical and nutritional properties of twenty three traditional rice (Oryza sativa L.) varieties of Sri Lanka

Objective: To evaluate the physicochemical and nutritional properties of selected traditional rice varieties of Sri Lanka. Methods: Twenty three rice varieties were selected. All the varieties were studied for grain colour, grain size and shape as physicochemical properties, while for nutritional properties, moisture, crude ash, crude protein, crude fat and total carbohydrate contents were studied. Only selected set of varieties were studied for total, soluble and insoluble dietary fiber. These properties were studied using internationally accepted standard techniques. Results: The results showed significant (P < 0.05) difference in the physicochemical and nutritional properties of the studied varieties. Out of 23 varieties tested, 20 varieties were red rices, while the rest were white rices. The grain size and shape were mostly medium bold (30%) and short bold (56%). The mean moisture, crude ash, crude protein, crude fat and total carbohydrate contents of selected varieties varied from (10.42 ± 0.25)% to (12.33 ± 0.02)%, (1.30 ± 0.14)% to (1.92 ± 0.05)%, (10.59 ± 0.12)% to (13.27 ± 0.32)%, (2.18 ± 0.10)% to (4.12 ± 0.28)% and (81.42 ± 0.25)% to (85.66 ± 0.24)%, respectively. The selected varieties had total, soluble and insoluble dietary fiber contents in the range of 4.2%–6.9%, 0.8%–2.1%and 3.1%–4.8%, respectively. The varieties Pachchaperumal, Suduru samba, Wanni Dahanala, Gonabaru and Sudu Heeneti had the highest crude protein, crude fat, crude ash, total carbohydrate and dietary fiber contents, respectively. Conclusions: Selected traditional rice varieties of Sri Lanka had physicochemical properties preferred by consumers and nutritional properties with dietary importance.

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.

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.

Anti-diabetic related health food properties of traditional rice(Oryza sativa L.)in Sri Lanka

Objective:To evaluate a range of anti-diabetic related properties and some consumer preferred physicochemical properties of selected Sri Lankan traditional rice varieties.Methods:Sudu Heeneti,Goda Heeneti,Masuran and Dik Wee varieties were used in this study.Anti-diabetic related properties of bran extracts of selected varieties were studied for methylglyoxal mediated protein glycation inhibition,acetyl and butyryl-cholinesterase inhibition in vitro and anti-hyperglycemic activity in vivo.Further,selected varieties were studied for starch hydrolysis rate in vitro.Physicochemical properties including grain color,size,shape,crude protein,crude fat,ash,dietary fiber and total carbohydrate contents were studied.Results:Brans of selected varieties had significant(P<0.05)and dose dependent methylglyoxal mediated protein glycation inhibition[IC_(50):(174.77±6.65)to(342.87±0.43)μg/mL]and acetyl[IC_(50):(37.00±0.68)to(291.00±3.54)μg/mL]and butyryl-cholinesterase[IC_(50):(18.50±0.60)to(96.60±0.56)μg/mL]inhibitory activities.Further,Sudu Heeneti,Masuran and Dik Wee had low starch digestion rate(52.40±1.44 to 53.76±1.19)indicating that these varieties may be low glycemic index rices.Brans of Masuran tested in rat model showed anti-hyperglycemic activity.Physicochemical properties studied showed that selected varieties were red in color and grain size and shape were mostly medium and bold respectively.Moisture,crude protein,crude fat,ash and total carbohydrate contents varied significantly(P<0.05)among the varieties.Conclusions:It is concluded that selected varieties could be promoted as physicochemically sound rices with a range of anti-diabetic related properties in the management of diabetes and its complications.