RESUMEN

BACKGROUND: An animal model was used to study the health benefits inherent in tea fortified alcoholic beverages fed to laboratory mice. OBJECTIVES: An investigation of the effects of tea fortified alcoholic beverages 12% alcohol (v/v) on antioxidant capacity and liver dysfunction indicators in white Swiss mice including packed cell volume (PCV), albumin, total protein, alkaline phosphatase (ALP) and glutathione (GSH) was carried out. METHODS: Plain, black, green and purple tea fortified alcohols were developed with varying tea concentrations of 1, 2 and 4 g/250 mL in 12% v/v. Control alcoholic beverages without teas were also developed. A permit (number IRC/13/12) was obtained for the animal research from the National Museums of Kenya, Institute of Primate Research prior to the start of the study. Alcoholic beverages were orally administered every 2 days for 4 weeks at 1 mL per mouse, and thereafter animals were euthanised and liver and blood samples harvested for analyses. Assays on body weight (bwt), packed cell volume (PCV) albumin, total protein, ALP and GSH were performed. Results were statistically analysed using GraphPad statistical package and significant differences of means of various treatments determined. RESULTS: Consumption of tea fortified alcohols significantly decreased (p=0.0001) bwt at 0.32-9.58% and PCV at 5.56-22.75% for all teas. Total protein in serum and liver of mice fed on different tea fortified alcohols ranged between 6.26 and 9.24 g/dL and 2.14 and 4.02 g/dL, respectively. Albumin, ALP and GSH range was 0.92-2.88 µg/L, 314.98-473.80 µg/L and 17.88-28.62 µM, respectively. Fortification of alcoholic beverages lowered liver ALP, replenished antioxidants and increased liver albumin, improving the nutritional status of the mice. CONCLUSIONS: The findings demonstrate tea's hepatoprotective mechanisms against alcohol-induced injury through promotion of endogenous antioxidants. The beneficial effects of tea in the fortified alcoholic beverages could be used to develop safer alcoholic beverages.

RESUMEN

Several studies have demonstrated that tea flavonoids protect cells and tissues against free radicals which have been implicated in the etiology of oxidative stress-related disease disorders. However, black tea is commonly consumed with additives that could otherwise affect the bioavailability of the active tea molecules. In this study, the biochemical parameters of Kenyan teas were determined and the effect of added milk and sweeteners on the antioxidant activity of Kenyan teas was investigated. The effect of tea antioxidants on glutathione (GSH) was also evaluated in vivo in a time series study using Swiss mice. Green teas had the highest levels of total polyphenols, total and individual catechins, while black teas had high levels of total thearubigins, total theaflavins and theaflavin fractions. The antioxidant activity was high in green teas though some of the black teas were as efficacious as the green teas. The addition of milk, sugar and honey significantly (p<0.05) decreased the antioxidant activity of tea in a concentration-dependent manner. Addition of the sweetener, stevia (Stevia rebaudiana Bertoni), showed no significant (p>0.05) influence on the antioxidant activity of tea and therefore can be recommended as a preferred sweetener for tea. Significantly (p<0.001) higher levels of GSH were observed in plasma than in other tissues. GSH levels were generally highest 2h after tea consumption, which indicates the need to repeatedly take tea every 2h to maximise its potential health benefits.

Asunto(s)

Antioxidantes/análisis , Aditivos Alimentarios/análisis , Glutatión/metabolismo , Leche/química , Edulcorantes/análisis , Té/química , Animales , Biflavonoides/análisis , Camellia sinensis/química , Carbohidratos/química , Catequina/análogos & derivados , Catequina/análisis , Femenino , Flavonoides/análisis , Análisis de los Alimentos , Manipulación de Alimentos , Miel/análisis , Ratones , Modelos Animales , Extractos Vegetales/análisis , Polifenoles/análisis , Stevia/química

RESUMEN

The Kenyan tea industry wishes to diversify its tea products, and in line with this, anthocyanin - rich teas were developed at the Tea Research Foundation of Kenya. These teas have purple-coloured leaves and the green colour is masked. In total, 12 accessions of the purple leaf coloured teas and 2 standard tea varieties were studied. Clones Hanlu and Yabukita are Chinese and Japanese tea varieties, respectively, known for good green tea, and they were used as reference standards. Little if any research had been done to characterize the quality of these purple leaf coloured teas and this study investigated their total polyphenols (TPP), catechins, caffeine, gallic acid and theanine. These are the major green tea quality parameters. Results showed that the new Kenyan tea clones had higher total polyphenols than had the reference standard tea varieties, which had 17.2% and 19.7% while the lowest among the Kenyan clones was 20.8%. On catechin quality index, K-purple and TRFK 91/1 showed high index values of 15.9 and 13.3, respectively, while clones TRFK 83/1 and 73/5 showed low index values of 0.74 and 1.0, respectively. Hanlu had the highest caffeine level with 2.42% while clones TRFK KS 3, TRFK KS 2 and TRFK 83/1 had relatively high caffeine levels among the purple leaf coloured teas, with 2.33%, 2.22% and 2.21%, respectively. Clone TRFK 73/5 had the lowest caffeine content, with 1.16%. Theanine analysis showed that most purple leaf coloured teas had more theanine than had the reference standard clones, except TRFK 83/1 and K-purple, which were lower than the reference standard clones. The implication of the green tea chemical quality parameters is also discussed. It is concluded that all the studied clones/varieties have above the minimum 14% of total polyphenols. Clones K-purple and TRFK 91/1 showed high green tea quality indices with the latter doubling with high levels of theanine; hence its highly recommended for green tea manufacture.

Asunto(s)

Camellia sinensis/química , Extractos Vegetales/análisis , Hojas de la Planta/química , Cafeína/análisis , Camellia sinensis/clasificación , Catequina/análisis , Flavonoides/análisis , Ácido Gálico/análisis , Kenia , Polifenoles , Control de Calidad

RESUMEN

Black (aerated) and green (unaerated) tea products, processed from 10 green and 18 purple leaf coloured cultivars of Kenyan origin, and two tea products, from the Japanese cultivars, Yabukita and Yutakamidori, were assayed for total polyphenols (TP) content, individual catechin profiles and in vitro antioxidant capacity (AA). In addition, the phenolic content of the tea products was determined using the Folin-Ciocalteu phenol reagent. Catechin fractions were identified using reverse phase high performance liquid chromatography (HPLC) with a binary gradient elution system. The AA% of the tea products was determined using a 2,2'-diphenyl picrylhydrazyl (DPPH) radical assay method. The results showed that TPs, catechin profiles and antioxidant activities were significantly (p≤0.05) higher in unaerated than in aerated teas. Tea products from the purple leaf coloured tea cultivars had levels of TPs, total catechin (TC) and antioxidant activities similar to those from the green leaf coloured cultivars, except for teas from the Japanese cultivars that were very low in the assayed parameters. Caffeine content was significantly (p≤0.05) lower in products from the purple leaf coloured cultivars than in those from the green leaf coloured tea cultivars. Antioxidant activity (%) was higher in tea products from the Kenyan germplasm than in those from the Japanese cultivars. Antioxidant potency of tea products was significantly (r=0.789(∗∗), p≤0.01) influenced by the total anthocyanin content of the purple leaf coloured cultivars. Cyanidin-3-O-glucoside was the anthocyanin most highly correlated with AA% (r=0.843(∗∗), p≤0.01 in unaerated tea). Total catechins in the unaerated products from the green leaf coloured tea cultivars were also significantly correlated with antioxidant capacity (r=0.818(∗∗), p≤0.01). Results from this study suggest that the antioxidant potency of teas is dependent on the predominant flavonoid compound, the type of tea cultivar and the processing method.

Asunto(s)

Antioxidantes/análisis , Camellia sinensis/química , Catequina/análisis , Extractos Vegetales/análisis , Hojas de la Planta/química , Polifenoles/análisis , Antioxidantes/aislamiento & purificación , Catequina/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Polifenoles/aislamiento & purificación

RESUMEN

Napier stunt phytoplasma (16SrXI and 16SrIII) in eastern Africa is a serious threat to the expansion of Napier grass (Pennisetum purpureum) farming in the region, where it is widely cultivated as fodder in zero grazing livestock systems. The grass has high potential for bio-fuel production, and has been adopted by farmers as a countermeasure to cereal stem borer Lepidoptera, since it attracts and traps the insect. Diagnosis of stunt phytoplasma have been largely by nested polymerase chain reaction (nPCR) targeting the 16S rRNA gene. However, the method is laborious, costly and technically demanding. This investigation has developed a simpler but effective phytoplasma diagnostic tool, called; loop-mediated isothermal amplification of DNA (LAMP). The assay was tested on 8 symptomatic and 8 asymptomatic plants, while its detection limit was compared to nested PCR using samples serially diluted from 3 ng/µl to 0.38 pg/µl. Molecular typing of LAMP products was determined by BsrI restriction digestion and Southern blot analysis. The assay sensitivity, positive and negative predictive values were estimated, while the specificity was tested on 11 phytoplasma groups. LAMP was specific to 5 phytoplasma groups: 16SrVI, X, XI and XVI. BsrI restriction digestion produced two predicted fragments, and there was specific binding of probe DNA to the LAMP amplicons in Southern blot analysis. The assay sensitivity was 100%, while the positive and negative predictive values were 63 and 100% respectively. LAMP was 20-fold more sensitive than nested PCR. This study validates LAMP for routine diagnosis of Napier stunt and other closely related phytoplasmas.

Asunto(s)

Técnicas Bacteriológicas/métodos , ADN Bacteriano/aislamiento & purificación , Técnicas de Amplificación de Ácido Nucleico/métodos , Pennisetum/microbiología , Phytoplasma/aislamiento & purificación , Enfermedades de las Plantas/microbiología , África Oriental , ADN Bacteriano/genética , Phytoplasma/genética , Sensibilidad y Especificidad , Temperatura

RESUMEN

Trypanosomosis is mainly an immunological and inflammatory response mediated by increased levels of pro-inflammatory cytokines. Evidence suggests that pathological changes produced during infection with trypanosomes could be initiated by nonspecific endotoxin-like substances in trypanosomes and/or Gram-negative secondary bacterial infection. Studies in trypanosome-infected rats indicate damage to the gastrointestinal tract (GIT) accompanied by increased leakage of the GIT mucosa. The current study was carried out to determine the in vivo response to endotoxin-like substances of Trypanosoma brucei brucei. To this purpose we neutralized the entrance of endotoxin through the GIT using polymyxin-B treatment and monitored the plasma concentration of the acute phase proteins SAP and Hp. The results in this study, where infection was performed in the presence of oral antibiotic that is not absorbed from GIT and which binds to and inactivates endotoxin, show that the elevated plasma levels of endotoxin-like activity and the resulting acute phase response indicated by an increase in levels of Hp and SAP, are due to trypanosome infection. Results obtained in the present study indicate that GIT is not the major source of elevated plasma endotoxin-like activity levels and the observed acute phase response was due to an increase in the levels of acute phase proteins SAP and haptoglobin. Therefore trypanosomes are responsible for the elevated plasma endotoxin-like activity levels and the subsequent systemic acute phase response in the host.

Asunto(s)

Proteínas de Fase Aguda/metabolismo , Endotoxinas/sangre , Tracto Gastrointestinal , Haptoglobinas/metabolismo , Componente Amiloide P Sérico/metabolismo , Trypanosoma brucei brucei/patogenicidad , Tripanosomiasis Africana , Reacción de Fase Aguda/fisiopatología , Animales , Femenino , Tracto Gastrointestinal/inmunología , Tracto Gastrointestinal/fisiopatología , Ratones , Tripanosomiasis Africana/inmunología , Tripanosomiasis Africana/parasitología , Tripanosomiasis Africana/fisiopatología

RESUMEN

An in vivo study was carried out to determine the effect of different types of Kenyan tea extracts on male Swiss albino mice infected with Trypanosoma brucei brucei isolate KETRI 2710. The isolate produced a similar clinical picture after a pre-patent period of 5 days post-infection (DPI). Parasitemia levels in the untreated mice and those given different teas developed exponentially at similar rates reaching similar densities at the peak of parasitemia 8 DPI. Between 9 and 13 DPI parasitemia decreased more rapidly in tea treated compared to the untreated mice which indicated that tea lowered parasitemia level. Anaemia indicated by a fall in erythrocyte packed cell volume (PCV) occurred within 4 DPI and remained below the normal levels until the terminal stages of the disease. A significant difference (P<0.05) was observed 11 DPI between the tea treated and the untreated mice indicating that tea enhanced resistance to erythrocyte destruction. Mice treated with tea exhibited significantly (P<0.01) reduced parasite-induced hypoalbuminemia as compared to the untreated. Since albumin is a negative acute phase protein, it shows a decrease during inflammatory conditions and therefore its elevation in the mice given tea in this study clearly demonstrated that tea ameliorated inflammation induced by T. b. brucei. Although green and white teas were superior in most of these characteristics, black tea, which is the principle tea product from Kenya, displayed remarkable properties some even comparable to those of green tea. Interestingly, tea was more efficacious than dexamethasone an established anti-inflammatory drug, demonstrating its therapeutic potential.

Asunto(s)

Inflamación , Parasitemia , Extractos Vegetales/farmacología , Té/química , Trypanosoma brucei brucei/efectos de los fármacos , Tripanosomiasis Africana , Anemia/diagnóstico , Animales , Inflamación/tratamiento farmacológico , Inflamación/inmunología , Inflamación/parasitología , Inflamación/fisiopatología , Kenia , Masculino , Ratones , Parasitemia/tratamiento farmacológico , Parasitemia/inmunología , Parasitemia/parasitología , Extractos Vegetales/administración & dosificación , Extractos Vegetales/uso terapéutico , Albúmina Sérica/metabolismo , Resultado del Tratamiento , Tripanocidas/administración & dosificación , Tripanocidas/farmacología , Tripanocidas/uso terapéutico , Trypanosoma brucei brucei/patogenicidad , Tripanosomiasis Africana/tratamiento farmacológico , Tripanosomiasis Africana/inmunología , Tripanosomiasis Africana/parasitología , Tripanosomiasis Africana/fisiopatología

RESUMEN

Genetic maps are a vital tool in cultivar improvement programmes for woody perennial tree crops such as tea (Camellia sinensis). A population thought to be derived from two known, noninbred parents was scored for RAPD and AFLP markers, in order to develop a linkage map. However, a very high proportion of the markers exhibited unexpected segregation ratios in the light of their configurations in the parents, and an exploratory statistical analysis revealed patterns in the marker scores which can most easily be explained by the hypothesis of three male parents contributing pollen to this cross. We discuss the evidence for this and the subsequent analysis required to assemble the markers from the female parent into the first linkage map for tea. The map has 15 linkage groups of three or more markers, agreeing with the haploid chromosome number of tea. The statistical methods that revealed the subpopulations are easy to apply routinely, and may prove a useful diagnostic tool for the analysis of noninbred mapping populations.

Asunto(s)

Mapeo Cromosómico , Filogenia , Té/clasificación , Té/genética , Cruzamientos Genéticos , Cartilla de ADN , Polimorfismo Genético , Técnica del ADN Polimorfo Amplificado Aleatorio , Mapeo Restrictivo/métodos

RESUMEN

Camellia sinensis is a beverage tree crop native to Southeast Asia and introductions have been made into several nonindigenous countries. No systematic assessment of genetic variability in tea has been done anywhere. In this study, random amplified polymorphic DNA (RAPD) analysis was used to estimate genetic diversity and taxonomic relationships in 38 clones belonging to the three tea varieties, assamica, sinensis, and assamica ssp. lasiocalyx. Extensive genetic variability was detected between species, which was partitioned into between and within population components. Seventy percent of the variation was detected within populations. Analyses based on band sharing separated the three populations in a manner consistent with both the present taxonomy of tea and with the known pedigrees of some clones. RAPD analysis also discriminated all of the 38 commercial clones, even those which cannot be distinguished on the basis of morphological and phenotypic traits.

Asunto(s)

Té/genética , Secuencia de Bases , ADN de Plantas/genética , Variación Genética , Genotipo , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Especificidad de la Especie

RESUMEN

Within 3 weeks of culture, excised cotyledon expiants of Camellia sinensis (L.) O. Kuntze produced somatic embryos without intermediate callus when cultured in Murashige and Skoog's basal medium with 30 g(-1) sucrose. In medium without plant growth regulators, up to 60% of the cultures developed somatic embryos. Embryogenic competence was reduced by increasing concentrations of plant growth regulators tested (i.e. kinetin, 6-benzylaminopurine, and indole butyric acid). The somatic embryos developed, grew to maturity without being subcultured within 6-8 weeks. Secondary embryogenesis was not observed. Germination of isolated mature somatic embryos was low in medium without plant growth regulators. Up to 53% and 60% germination occurred when medium impregnated with kinetin at 1.8 mgl(-1) or 1.0 mgl(-1) 6-benzylaminopurine were used respectively. Callus was also routinely produced when cotyledons were cultured in MS basal medium with auxins (2,4-dichlorophenoxyacetic acid and indole acetic acid). Callus induction was however, also achieved in plant growth regulator free medium. Indirect somatic embryogenesis was not induced in the present study.