Simultaneous analysis of tea catechins, caffeine, gallic acid, theanine and ascorbic acid by micellar electrokinetic capillary chromatography

Aucamp, Jean P.; Hara, Yuko; Apostolides, Zeno

doi:10.1016/s0021-9673(00)00145-x

Cited by 113 publications

(74 citation statements)

References 17 publications

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“…We aim to develop our understanding of how EAAs affect survival while examining the potential of antioxidant supplementation to improve honeybee survival and alleviate the costs of high EAA intake. We use the major antioxidant found in green tea, epigallocatechin-3-gallate (EGCG) (Aucamp et al, 2000). Bees may encounter this antioxidant in nature because Chinese beekeepers regularly move hives to tea plantations (Zheng et al, 2011) and secondary metabolites, such as EGCG, are often present in pollen and nectar (Detzel and Wink, 1993).…”

Section: Introductionmentioning

confidence: 99%

Antioxidant supplementation can reduce the survival costs of excess amino acid intake in honeybees

Archer

Köhler

Pirk

et al. 2014

Journal of Insect Physiology

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Over-consuming amino acids is associated with reduced survival in many species, including honeybees. The mechanisms responsible for this are unclear but one possibility is that excessive intake of amino acids increases oxidative damage. If this is the case, antioxidant supplementation may help reduce the survival costs of high amino acid intake. We tested this hypothesis in African honeybees (Apis mellifera scutellata) using the major antioxidant in green tea, epigallocatechin-3-gallate (EGCG). We first determined the dose-range of EGCG that improved survival of caged honeybees fed sucrose solution. We then provided bees with eight diets that differed in their ratio of essential amino acids (EAA) to carbohydrate (C) (0:1, 1:250, (1:250, 1:100 EAA:C). That EGCG counteracted the lifespan reducing effects of eating low EAA diets suggests that oxidative damage may be involved in the association between EAAs and lifespan in honeybees. However, that EGCG had no effect on survival in bees fed high EAA diets suggests that there are other physiological costs of over-consuming EAAs in honeybees.

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Section: Introductionmentioning

confidence: 99%

Antioxidant supplementation can reduce the survival costs of excess amino acid intake in honeybees

Archer

Köhler

Pirk

et al. 2014

Journal of Insect Physiology

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“…Many studies have reported the L-theanine content in different teas [36]- [38]. In the current study, Kenyan green tea commercially available in the market (GTF) had an L-theanine content of 1.2 mg/g (0.12% d.w.).…”

Section: Resultsmentioning

confidence: 75%

“…Tea can be broadly classified according to the processing methods as; un-aerated tea (green tea), semi-aerated tea (Oolong tea), fully aerated tea (black tea) or post-aerated tea (pu-erh tea) [3]. The beverage has over time gained popularity as a "health drink" due to the numerous beneficial medicinal properties that have been attributed to its polyphenolic content as evidenced by in vitro and animal studies [4]- [6]. Indeed, a growing body of research describing many putative benefits of regular tea consumption such as antibacterial [7], antimicrobial [8] [9], anti-diabetic [10], antioxidant [11]- [14], anti-viral effects [15]- [17] among others have been reported.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Estimation of <i>γ</i>-Glutamylethylamide in Commercially Available Made Teas [<i>Camellia sinensis</i> (L.) O. Kuntze, Theaceae] in Kenya

Too¹,

Wanyoko²,

Kinyanjui³

et al. 2016

AJPS

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A study was carried out to quantitatively estimate the L-theanine content in 19 teas commercially available in the Kenyan market by High Performance Liquid Chromatography (HPLC). The test tea samples analyzed were green (n = 4), black (n = 8) and flavored (n = 7) teas from different origins viz., Kenya (n = 4), Uganda (n = 2), Tanzania (n = 5), Rwanda (n = 4), Cameroon (n = 1) and Sri-Lanka (n = 2) commercially available in the Kenyan market. The estimated Limit of Detection (LOD) of the current method was 0.01% L-theanine. The L-theanine content ranged from below the detection limit (<0.01% L-theanine) to 1.60% L-theanine on a dry weight (d.w) basis. Statistically significant differences (p < 0.05) were observed in the L-theanine contents of black, green and flavoured teas. Rwandan green tea contained the highest L-theanine content with 1.60% d.w. whereas six of the seven flavoured teas had very low theanine levels (<0.01%) that could not be quantified by the current method.

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“…It has been separated from other tea catechins, caffeine, gallic acid and ascorbic acid by micellar EKC using 25 mM phosphate buffer (pH 7.0) containing 100 mM SDS and 6% methanol (for dried tea leaf and black tea samples) or 5% methanol (for bottled tea samples). This method together with direct UV detection at 200 nm enabled the detection up to 2610 -5 M of theanine [22]. In addition, a CZE method using borax at pH 8.0 has also been used for the simultaneous separation of major components (theanine, catechins, caffeine, and ascorbic acid) in green tea infusions [23].…”

Section: Aliphatic Amino Acids With Nitrogen In the Side Chainmentioning

confidence: 99%

CE methods for the determination of non‐protein amino acids in foods

et al. 2007

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CE methods for the determination of non-protein amino acids in foodsIn addition to the 20 amino acids universally distributed as protein constituents in living organisms, there are other amino acids of non-protein origin that can be found in foods. The determination of these non-protein amino acids is interesting since they can be indicative of the quality and safety of foods. This work presents for the first time an updated and comprehensive review devoted to show the possibilities of capillary electrophoresis for the determination of non-protein amino acids in food samples. The results reported have been classified according to the chemical structure of the non-protein amino acid studied. Separation conditions as well as detection systems used have been detailed since most of these amino acidic compounds do not posses chromophore groups detectable by conventional UV-Vis detection, being in this case necessary a previous derivatization step. Finally, the application of microchip electrophoresis to the determination of non-protein amino acids in foodstuffs is also included in this review.

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Simultaneous analysis of tea catechins, caffeine, gallic acid, theanine and ascorbic acid by micellar electrokinetic capillary chromatography

Cited by 113 publications

References 17 publications

Antioxidant supplementation can reduce the survival costs of excess amino acid intake in honeybees

Antioxidant supplementation can reduce the survival costs of excess amino acid intake in honeybees

Quantitative Estimation of <i>γ</i>-Glutamylethylamide in Commercially Available Made Teas [<i>Camellia sinensis</i> (L.) O. Kuntze, Theaceae] in Kenya

CE methods for the determination of non‐protein amino acids in foods

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Simultaneous analysis of tea catechins, caffeine, gallic acid, theanine and ascorbic acid by micellar electrokinetic capillary chromatography

Cited by 113 publications

References 17 publications

Antioxidant supplementation can reduce the survival costs of excess amino acid intake in honeybees

Antioxidant supplementation can reduce the survival costs of excess amino acid intake in honeybees

Quantitative Estimation of &lt;i&gt;γ&lt;/i&gt;-Glutamylethylamide in Commercially Available Made Teas [&lt;i&gt;Camellia sinensis&lt;/i&gt; (L.) O. Kuntze, Theaceae] in Kenya

CE methods for the determination of non‐protein amino acids in foods

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Product

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Quantitative Estimation of <i>γ</i>-Glutamylethylamide in Commercially Available Made Teas [<i>Camellia sinensis</i> (L.) O. Kuntze, Theaceae] in Kenya