In the present study, twelve different types of commercial tea samples were assayed to determine their phenolic composition and antioxidant activity. Reverse phase high performance liquid chromatography using a binary gradient system was used for the identification and quantification of individual catechins. Subsequently, total phenolic content was determined spectrophotometrically according to the Folin-ciocalteus method. Total theaflavins and thearubigins were also determined. The radical scavenging behavior of the polyphenols on 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) was also studied spectrophotometrically. The results showed that total polyphenols, total catechins and antioxidant activity were significantly (P<0.05) different in the commercial tea samples. Green tea had the highest levels of catechins, total polyphenols and total antioxidant activity. White tea (silvery tip) a rare specialty type of tea was not significantly different from green tea. Statistical analysis showed an essential catechin content influence of the tea extracts on antioxidant activity. Epigallocatechin gallate (EGCG) was the most potent catechin and the most potent in antioxidant activity (r = 0.989***). Epigallocatechin (EGC) (r = 0.787, P<0.001), epicatechin (EC) + catechin (+C) and epicatechigallate (ECG) also showed significant (P<0.05) antioxidant activity. Black tea contained high levels of theaflavins and thearubigins, which accounted for most of the antioxidant potential in this type of tea product (r = 0.930*** and r = 0.930*** respectively). These results suggest that conversion of catechins during black tea processing did not affect the free-radical potency of black tea. Gallic acid (GA) also showed significant(r = 0.530*) contribution to the antioxidant activity in black tea. Green, black and white tea products processed from Kenyan tea cultivars originally selected for black tea had significantly (P<0.05) higher antioxidant activity than green tea processed from tea cultivars from Japan and China. These results seem to suggest that the cultivar type is critical in determining the antioxidant potency of tea product and that black teas processed from suitable cultivars could be potent in antioxidant activity when compared to green teas.

The occurrence of coinfections in human African trypanosomiasis (HAT) patients was investigated using a retrospective data of hospital records at the National Sleeping Sickness Referral Hospital in Alupe, Kenya. A total of 31 patients, 19 males and 12 females, were diagnosed with HAT between the years 2000 and 2009. The observed co-infections included malaria (100%), helminthosis (64.5%), typhoid (22.5%), urinary tract infections (16.1%), HIV (12.9%), and tuberculosis (3.2%). The species of helminthes observed included Ancylostoma duodenale (38.7%), Ascaris lumbricoides (45.7%), Strongyloides stercoralis (9.7%), and Taenia spp. (3.2%). The patients were also infected with Entamoeba spp. (32.3%) and Trichomonas hominis (22.6%) protozoan parasites. The main clinical signs observed at the point of admission included headache (74.2%), fever (48.4%), sleep disorders (45.2%), and general body pain (41.9%). The HAT patients were treated with suramin (early stage, 9/31) and melarsoprol (late stage, 22/31). In conclusion, the study has shown that HAT patients have multiple co-infections which may influence the disease pathogenesis and complicate management of HAT.

No abstract

This study was carried out to characterize total residual catechins and their fractions, polyphenolic contents and antioxidant activities of black teas enriched with high levels of theaflavin-3,3'digallate. The made teas were processed from eleven selected cultivars. A comparative study was carried out between the processed teas and those from commercially grown Kenyan cultivars in relation to the above chemical parameters. A correlation matrix analysis was also conducted to find out whether a relationship existed between the antioxidant activities and the said chemical parameters. The total residual catechins were found to range between 3.10% and 8.08%. The total polyphenol levels varied between 19.00% and 28.90%, while the antioxidant activities of the teas ranged from 82.70% to 91.70%. There was a significant p < 0.001 correlation between the antioxidant activity and total polyphenols (r = 0.8948). There was also a high correlation p < 0.001 between the antioxidant activity and total catechins (r = 0.8878). Out of the four catechin fractions, the antioxidant activity correlated most with EGCG (r = 0.8774). The total polyphenolic contents and antioxidant activities for most of the cultivars were comparable to those of the green tea reference standard. From the figures obtained, it can be concluded that the most of the newly developed black teas of the selected cultivars have higher quality and enhanced antioxidant activities and that they can be recommended for commercial production. S. Kimutai et al.

This study involved the selection of 11 cultivars out of 201 screened cultivars of fresh green and purple coloured tea leaves for use in the manufacture of black teas with optimized antioxidant activities. Individual cultivars containing a combination of high leaf concentrations of the catechin fractions; epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) were used in the processing of theaflavin-3,3' digallate (TF3) rich black tea. The black tea enrichment with TF3 was carried out through optimization of the processing conditions of each cultivar by varying the aeration times between 0 min and 80 min at an interval of 20 min. The differently processed teas were then assayed for the TF3 contents. The data analysis was carried out using the GENSTAT at p ≤ 0.05. The optimal processing time for Ejulu, TRFK 832/8, TRFK 831/11, TRFK 824/1, SC 31/37, SC 12/28, K-Purple and TRFK 6/8 was found to be 60 min while that of TRFK 301/6, TRFK 301/3 and TRFK 655/1 was 40 min. The optimal TF3 levels were found to range from 0.19% to 0.60%.