SOME FACTORS INFLUENCING THE FREE FLUORIDE CONTENT IN BLACK TEA INFUSIONS

Fluoride is an essential micro-nutrient owing to its role in the prevention of dental caries. Chronic exposure to high levels of the ion (F-) results in both dental and skeletal fluorosis. A study was carried out to determine free fluoride content in tea ( Camellia sinensis ) infusions of different grades of black Cut, Tear and Curl (CTC) tea. Tea infusions, 1% w/v of 112 teas of different grades and origins, were prepared using boiling distilled water and their free fluoride contents quantified using a Fluoride Ion Selective Electrode (FISE) method. The free fluoride content of the teas was 0.37\ub10.04 \ub5g F- ml-1. Infusions of tea grades BP1 and BMF gave the highest (0.40\ub10.22 \ub5g F- ml-1) and lowest (0.32\ub10.10 \ub5g F- ml-1) free fluoride contents, respectively. There being no national and international Maxima Residue Limit (MRL) for fluoride in tea, all the teas analysed may be regarded to be safe for consumption with regard to their free fluoride contents based on the 1.5 \ub5g F- ml-1, World Health Organisation\u2019s (WHO) guideline for fluoride in drinking water. Further, the effects of tea grades and area of production, on the fluoride content in tea infusions were significant (P<0.05), hence the need to enact safety guidelines and monitor continuously the fluoride levels for all types of tea products to prevent excessive intake.Le Fluor est un micro-\ue9l\ue9ment essentiel lorsque consomm\ue9 en dessous de certains seuils eu \ue9gard \ue0 son r\uf4le dans la pr\ue9vention des caries dentaires. Par ailleurs, lorsqu\u2019utilis\ue9 en exc\ue8s, les ions (F-) entrainent une fluorose des dents et du squelette . Une \ue9tude \ue9tait men\ue9e pour d\ue9terminer la concentration en fluor libre des infusions de th\ue9 ( Camellia sinensis ) de diff\ue9rentes classes de the noir de la cat\ue9gorie CTC. Les infusions de th\ue9, 1% p/v de 112 th\ue9s de diff\ue9rentes classes et origines \ue9taient pr\ue9par\ue9es en utilisant une eau bouillante distill\ue9e et leurs concentrations en fluor libre quantifi\ue9es par la m\ue9thode dite de Fluoride Ion Selective Electrode (FISE). La concentration en fluor libre dans les th\ue9s \ue9tait de 0.37\ub10.04 \ub5g F-ml-1. Les classes de th\ue9 BP1 et BMF ont pr\ue9sent\ue9 respectivement des concentrations les plus \ue9lev\ue9es de (0.40\ub10.22 \ub5g F-ml-1) et moins elev\ue9es de (0.32\ub10.10 \ub5g F-ml-1) du fluor libre. Etant donn\ue9 que sur le plan national et international il n\u2019ya pas de Limite Maximale de R\ue9sidus (MRL) pour le fluor dans le th\ue9, tous les \ue9chantillons des th\ue9s analys\ue9s pourraient \ueatre consid\ue9r\ue9s comme appropri\ue9s \ue0 la consommation eu \ue9gard \ue0 leur concentrations en fluor libre sur base de 1.5 \ub5g F-ml-1 tel que recommand\ue9 par l\u2019Organisation Mondiale de la Sant\ue9 (OMS) pour l\u2019eau potable. En plus, les effets des classes du th\ue9 et les r\ue9gions productrices sur la concentration du fluor dans les infusions de th\ue9 \ue9taient significatives (P<0.05), d\u2019o\uf9 la n\ue9c\ue9ssit\ue9 de mettre sur pied des mesures de protection et faire le suivi r\ue9gulier des niveaux du fluor pour tous les types de produits de th\ue9 afin d\u2019\ue9viter une consommation excessive du fluor

ANTIOXIDANT, ANTIMICROBIAL AND SYNERGISTIC ACTIVITIES OF TEA POLYPHENOLS

Microbial resistance to antibiotics has become an increasing global problem and there is a need to find out novel potent antimicrobial agents with alternative modes of action as accessories to antibiotic therapy. This study investigated the antioxidant, antimicrobial and synergistic properties of tea polyphenols. The tea germplasm from Kenya, China and Japan that are grown in Kenya were characterised for their biochemical profiles. The total phenolic content, theaflavins and thearubigins content of different tea products used in this study were determined spectrophotometrically according to Folin-Ciocalteus and flavognost methods, respectively. The individual catechin contents were characterised by high performance liquid chromatography (HPLC) and identified according to their HPLC retention times, elution order and comparison with authentic standards. The antioxidant activity of tea polyphenols was determined spectrophotometrically on its ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The agar disc diffusion method was used to screen for antimicrobial and synergistic activities of the tea liquors. Black, green, purple coloured leaf and white (silvery tips) tea products differed significantly in the levels of total polyphenols, total catechins, catechins fractions, theaflavins and thearubigins (P<0.05). Green, purple coloured leaf (aerated) and black tea from terminal buds and white tea products analysed in this study exhibited slightly higher antioxidant activity than black tea. The different types of tea products exhibited significant influence on the inhibition zone diameters against bacteria and fungi exposed to the tea extracts. Methicillin and penicillinase resistant S. aureus ATCC 25923, C. albicans ATCC 90028 and a clinical isolate of C. neoformans were more susceptible to all tea extracts than E. coli and S. typhi . There was synergism between most tea extracts and penicillin G against methicillin and penicillinase resistant S. aureus ATTC 25923.La r\ue9sistance microbienne aux antibiotiques est devenue un probl\ue8me \ue9pineux au niveau global et il est n\ue9cessaire d\u2019identifier d\u2019autres agents antimicrobiens efficaces avec des modes alternatifs d\u2019action pour appuyer la th\ue9rapie antibiotique. Cette \ue9tude \ue9tait men\ue9e sur les antioxydants et les propri\ue9t\ue9s antimicrobiennes et synerg\ue9tiques des polyph\ue9nols du th\ue9. Les germoplasmes de th\ue9 en provenance du Kenya, de la Chine et du Japon cultiv\ue9s au Kenya ont fait l\u2019objet d\u2019une caract\ue9risation de leurs profiles biochimiques. La teneur ph\ue9nolique totale ainsi que les th\ue9aflavines et les th\ue9arubigines dans les diff\ue9rents produits de th\ue9 utilis\ue9s dans cette \ue9tude \ue9taient d\ue9termin\ue9e par spectrophotom\ue9trie respectivement sur base des m\ue9thodes dites de Folin-Ciocalteus et flavognost. Les teneurs individuelles en cat\ue9chine \ue9taient caract\ue9ris\ue9es par chromatographie liquide \ue0 haute performance (HPLC) et identifi\ue9es sur base de leurs temps de r\ue9tention de HPLC, de l\u2019ordre d\u2019\ue9lution en comparaison avec les standards normaux. L\u2019activit\ue9 antioxydante des polyph\ue9nols de th\ue9 \ue9tait d\ue9termin\ue9e par spectrophotom\ue9trie sur base de sa capacit\ue9 \ue0 capter le radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). La m\ue9thode de diffusion sur disque d\u2019agar \ue9tait utilis\ue9e pour tester les activit\ue9s microbiennes et synerg\ue9tiques des extraits du th\ue9. Les feuilles de th\ue9 de couleurs noir, verte, pourpre et les extraits du th\ue9 blanc diff\ue9raient significativement du point de vue niveaux de polyph\ue9nols totaux, des cat\ue9chines totales, des fractions de cat\ue9chines, des th\ue9aflavines et des th\ue9arubigines (P<0.05). Les feuilles de couleurs verte et pourpre ainsi que les th\ue9s noirs issues des bourgeons terminaux et extraits du th\ue9 blanc analys\ue9s dans cette \ue9tude ont montr\ue9 une activit\ue9 antioxydante l\ue9g\ue8rement sup\ue9rieure \ue0 celle du th\ue9 noir. Les diff\ue9rents types d\u2019extraits de th\ue9 ont montr\ue9 une influence significative sur les diam\ue8tres des zones de contamination une fois expos\ue9s \ue0 des bact\ue9ries ou des champignons. Staphylococcus aureus ATCC 25923, C. albicans ATCC 90028 et un isolant clinique de C. neoformans r\ue9sistants \ue0 la m\ue9thicilline et \ue0 la p\ue9nicillinase \ue9taient les plus susceptibles \ue0 tous les extraits de th\ue9 en comparaison avec E. coli et S. typhi . Il y avait un synergisme entre la plupart d\u2019extraits de th\ue9 et la p\ue9nicilline G contre S. aureus ATTC 25923 r\ue9sistant \ue0 la m\ue9thicilline et \ue0 la p\ue9nicillinase

KENYAN PURPLE TEA ANTHOCYANINS ABILITY TO CROSS THE BLOOD BRAIN BARRIER REINFORCING BRAIN ANTIOXIDANT CAPACITY IN MICE

Studies on antioxidants as neuroprotective agents have been hampered by the impermeability of the blood brain barrier (BBB) to many compounds. However, previous studies have shown that a group of tea ( Camellia sinensis ) flavonoids, the catechins, are brain permeable and neuroprotective. Despite this remarkable observation, there exists no data on the bioavailability and pharmacological benefits of tea anthocyanins (ACNs) in the brain tissue. This study investigated the ability of Kenyan purple tea ACNs to cross the BBB and boost the brain antioxidant capacity. Mice were orally administered with purified and characterised Kenyan purple tea ACNs or a combination of Kenyan purple tea ACN\u2019s and coenzyme-Q10, at a dose of 200 mg kg-1 body weight in an experiment that lasted for 15 days. Twenty four hours post the last dosage of antioxidants, CO2 was used to euthenise the mice. Then the brain was excised and used for various biochemical analyses. Kenyan purple tea ACNs significantly (P<0.05) raised brain Glutathione (GSH) levels, implying a boost in brain antioxidant capacity. Notably, ACN metabolites were detected in brain tissue of ACN fed mice. This is the first demonstration that Kenyan purple tea ACNs can cross the BBB, reinforcing the brain\u2019s antioxidant capacity. Hence, there is need to study ACNs as suitable candidates for dietary supplements that could support antioxidant capacity in the brain and have potential to provide neuroprotection in neurodegenerative conditions.Les \ue9tudes sur les antioxydants comme agents neuroprotecteurs ont \ue9t\ue9 handicap\ue9es par l\u2019imperm\ue9abilit\ue9 de la barri\ue8re de sang du cerveau (BBB) \ue0 plusieurs produits. Par ailleurs, les \ue9tudes ant\ue9rieurs ont montr\ue9 qu\u2019un groupe de flavono\uefdes du th\ue9 ( Camellia sinensis ) , les cat\ue9chines, permettent la perm\ue9abilit\ue9 du cerveau et prot\ue8gent les nerfs. Malgr\ue9 cette observation importante, il n\u2019ya pas de donn\ue9es sur la biodisponibilit\ue9 et les vertus pharmacologiques des anthocyanines du th\ue9 (ACNs) dans le tissue du cerveau. Cette \ue9tude a \ue9valu\ue9 l\u2019aptitude des anthocyanines du th\ue9 pourpre du Kenya de traverser le BBB et am\ue9liorer la capacit\ue9 antioxydante du cerveau. Des rats \ue9taient oralement administr\ue9s des anthocianines du th\ue9 pourpre purifi\ue9s et caract\ue9ris\ue9s ou une combinaison des ACNs avec le coenzyme-Q10, \ue0 une dose de 200 mg kg-1 de poids vif dans un essai d\u2019une dur\ue9e de 15 jours. Vingt quatre heures apr\ue8s le dernier dosage d\u2019antioxydants, le CO2 \ue9tait utilis\ue9 pour euthanasier les rats. Ensuite, le cerveau \ue9tait excis\ue9 et soumis \ue0 diverses analyses biochimiques. Les ACNs ont augment\ue9 significativement (P<0.05) les niveaux du Glutathione (GSH) du cerveau,,ce qui implique une am\ue9lioration de la capacit\ue9 antioxydante du cerveau. Remarquablement, les m\ue9tabolites ACN \ue9taient d\ue9tect\ue9s dans le tissu des rats nourris aux ACNs. Ceci est la premi\ue8re d\ue9monstration que les anthocyanines (ACNs) du th\ue9 pourpre Kenyan peuvent franchir la barri\ue8re h\ue9mato-enc\ue9phalique (BHE), renfor\ue7ant ainsi la capacit\ue9 antioxydante du cerveau. Ainsi, le besoin s\u2019impose de les \ue9tudier comme des candidats appropri\ue9s pour les aliments de suppl\ue9ment qui pourraient renforcer la capacit\ue9 antioxydante dans le cerveau et avoir le potentiel d\u2019offrir la neuroprotection dans les conditions neurod\ue9g\ue9n\ue9ratrices

Nucleolar and nucleolus organiser regions activity in tea as visualised by silver staining

Nucleoli and Nucleolus regions (NORs) in diploid, triploid and tetraploid tea (Camellia sinensis L.) were stained using a simplified technique of silver staining based on the colloidal two-stage method. Nucleoli were visualised in interphase nuclei as black spots against a yellow background. The mode of nucleolar number corresponded to multiples of the somatic cell number and was a good marker for ploidy. Mitotic metaphase chromosomes were stained yellow to golden brown with strongly contrasting NORs appearing as black segments.Les zones nucleolees et nucleoles (NORs) dans le the diploide, triploide et tetraploide (Camellia sinensis L.) etaient teintes en se servant d'une technique simplifie d'argentage basee sur la methode collodale a deux stades. Les nucleoles etaient visualisees en interphase de nucleis comme des taches noires sur font jaune. Le mode du nombre nucleolaire correspondait au nombre de cellules somatiques multiples et constituait un bon marqueur de ploidie. Des chromosomes mitotiques en metaphase etaient teintes de couleur jaune or a brune or contrastant avec les NORs qui apparaissent comme de segments noirs

Sustainability of smallholder tea growing in Kenya

Although tea was introduced in Kenya in 1903, Africans (natives) were barred from growing the crop until after independence in 1963 when the legislation was repealed. Africans started growing tea under the smallholder tea growing scheme which developed very rapidly. In Kenya, the smallholder tea sector, managed by the Kenya Tea Development Agency Ltd (KTDA), own over 80% land under tea producing over 60% made tea (mt) in Kenya. The Kenya tea is grown in prime lands capable of producing over 6000 kg mt per hectare per year under good cropping weather. However, smallholder teas yield on the average less than 2000 kg mt per hectare per year due to use of inappropriate agronomic and cultural practices resulting from low adaptation and adoption of developed and recommended research technologies. For sustainable smallholder tea sector, it is necessary that tea production technologies developed through extensive research are disseminated and adopted in the tea sector. This can be achieved through an effective and knowledgeable extension service. Smallholders need to plant elite varieties with high yield and quality potentials using correct planting spacing and should prune at the correct pruning height using proper implements. Gappy tea fields need infilling soon after pruning. Fertilizer application is mandatory in tea production and use of NPK fertilizers is recommended in Kenya. KTDA should continue availing the fertilizer on credit and on time. A mechanism is needed to ensure farmers are enrolled for the fertilizer facility and obtained fertilizers are applied on tea, not competing crops. The high smallholder tea quality is partly attributed to fine plucking standard in the sector. The plucking of two leaves and a bud standard should be maintained to sustain the quality. Also effective control of weeds, pests and diseases or management systems are necessary for high and quality tea production. Factory capacity problems should be addressed so that the green leaf production does not exceed processing capacity and vice versa. There is need for good road network and vehicles to ensure that harvested leaves arrive in the factory in good condition even during rainy seasons. Sustainable green tea leaf production requires that farmers are paid adequately and on time to enable them to tend the crop. Regular reviews of green leaf payment and use of correct payment modules ensure sustaining tea production. However, smallholder tea sector is faced with challenges in rising costs of production, especially labour and energy costs. Since tea consumption world wide is not rising as fast as production, the smallholder tea sector needs to intensify tea marketing, market research and product diversification.This item was scanned with a HP 4850 Scanjet at 300 dpi and consists of 23 pages

Potential Male Gametophyte Competition Among Camellia sinensis Genotypes in Isolated Biclonal Seed Orchards

Male fertility of crop plants is a function of pollen production and viability. In breeding, it is a requirement that there be similar fertilities among breeding parents within seed orchards. An in-vitro germination method was used in this study to determine variation in pollen viability among eight tea ( Camellia sinensis ) genotypes, over three flowering seasons in four isolated biclonal seed orchards located at two sites. The effect of environmental conditions on pollen germination was also studied on two popular genotypes, i.e. AHP SC31/37 (an assamica variety) and GW Ejulu-L (a sinensis variety) that were planted in both sites. Significant variation (P < 0.05) in pollen viability among the eight genotypes indicated a potential for male gametophyte competition. There was significant genotype by environment interaction and positive correlation between pollen viability and temperature. Pollen germination was, however, not affected by rainfall and humidity. The variations in pollen viability may contribute to the variable genetic composition of seed produced in the isolated seed orchards of tea.La fertilité mâle de plantes culturales est fonction de la production et de la viabilité polliniques. Lors de culture, il est une nécessité que les seuils de fertilité soient similaires parmi les parents des cultures au sein de vergers de semences. Une méthode de germination in vitro était utilisée dans cette étude en vue de déterminer la variation en viabilité de pollen parmi 8 génotypes de thé ( Camellia sinensis ) de par 3 saisons de floraison dans 4 vergers de semences bi clonaux situés au niveau de 2 sites. Les effets des conditions environnementales sur la germination du pollen étaient également étudiées; sur 2 génotypes populaires c&apos;est-à-dire AHP SC 31/37 (une variété assamica) et GW Ejulu – L (une variété sinensis) qui étaient plantées sur les 2 sites. Des variations significatives (P < 0,05) en viabilité de pollen parmi les 8 génotypes indiquaient un potentiel pour la compétition de gamétophyte mâle. Il y avait une interaction significative genotype par environnement et une corrélation positive entre viabilité de pollen et température. La germination du pollen n&apos;était cependant pas affectée par les pluies ou par l&apos;humidité. Les variations en viabilité de pollen pourraient contribuer à la composition génétique variable de semences produites dans les vergers isolés de semences de thé

Endotoxin-like effects in acute phase response to Trypanosoma brucei brucei infection are not due to gastrointestinal leakage

Trypanosomosis is mainly an immunological and inflammatory response mediated by increased levels of proinflammatory 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