We are also working on same aspects. Kenya has introduced this purple anthocyanins rich tea. We observed higher anthocyanins content than older leaves. There are two three papers of Kerio et al 2012, 2013 for tea anthocyanins.

We are working on its isolation, purification and characterisation and other biochemicals aspects on anthocyanin rich teas.

Anthocyanins in grapes are produced independent of light and UV exposure. Flavonols in the other hand are completely dependent on UV exposure.

I am going to analyze Japanese Matcha (several types) next week for anthocyanin content among other things, but the point is, all those green teas we obtain from specialized teashops here in Germany, and they tend to trade their commodity at high-end prices. The price justification comes exactly from supposedly young shaded leaves etc.

I am no expert in tea leaves, but in fruits temperature/climate often plays a larger role in anthocyanin content than light exposure. If you wanted to compare UV exposure I would compare quercetin or another flavonol's content.

I saw this paper that might have some indication on how to judge old versus new tea leaves:

"Changes in Epigallocatechin-3-O-(3-O-methyl) Gallate and Strictinin Contents of Tea (Camellia sinensis L.) Cultivar ‘Benifuki’ in Various Degrees of Maturity and Leaf Order" Food Science and Technology Research

Vol. 10 (2004) No. 2 P 186-190

Hi,

You formulated a good hypothesis. Maybe you should test it.

But remember while testing it that exposure to sunlight is not the only factor leading to anthocyanin biosynthesis and accumulation.

It depends on plant cultivar.

In addition, plant stress caused by water, cold, nutrient shortage (eg: nitrogen) and microbiological attack may induce anthocyanin production.

There may be further factors.

Hope it helps

As a matter of fact in fruits (apple, v.g.) anthocyanines biosynthesis is sun exposure dependent and a total red apple is very difficult to obtain because it is necessary the direct incidence of radiation and not only to the clarity. So the shorter wavelengths of UV are involved in the process for sure

As an observation, when trees turn colors in the fall before losing their leaves, tree cultivars with red leaves seem to have red leaves throughout the tree, no matter their location in relation to sunlight. My point is that many leaves contain anthocyanins regardless of their UV exposure, so your hypothesis would need to be confirmed in a controlled experiment and not from store-bought products.

I totally agree with Alexander: be very careful with samples of comercial origin.

Have you tried searching the web for this reference: "Anthocyanins in Leaves", by Kevin Gould?

Hai, I also do some anthocyanins in plants - screen the extract using UV-Vis spectrophotometer first and study on the maximum absorbtions at anthocyanin absorbtion range, test for total anthocyanins and finally make a specific antyocyanin calibrations Spectro, HPLC etc. If you have concentrated extract just put on the FTIR and study the pattern. Just to share.

Well, I also agree because small fruits like jabuticaba are plain ofo anthocyanins even growiing in the forest withourt direct sunlight. Then both cases could happen. But I am more interested in the stability of anthocyanins considering pH and temperature because the red fruits can be used to improve functionql properties of other juices. Sorry, the question was about tea and not juices....

Of course it would be nice to have an experiment with vegetating tea plants, but last time I checked there were no tea cultivation areas in Germany.:) So I thought may be those of you who have the experience or/and opportunity to work with Camellia sinensis in situ would have some idea…

I have an experience with in vitro and ex vitro cultures of Stevia rebaudiana. During the extended daylight experiments the plantlets acquired some reddish color on their leaves. Later we experimentally confirmed increased accumulation of anthocyanins in the plant tissue as a reaction on the prolonged daylight. In that case biosynthesis of anthocyanins was correlating with biosynthesis of steviol glycosides the sweet tasting compounds in S. rebaudiana.

Concerning the teas (white and green), nobody expects those plants to be cultivated in complete darkness and of course there would be always some presence of anthocyanins in the plant tissue. The point is we detected the concentrations of these compounds that are way too high (like 1/3 of those in Blueberries). Next week I am going to re-run the experiment with some new green tea selections.

We extracted anthocyanins using acidic mobile phase such as 0.05%TFA in methanol followed by column chromatography. Characterization was performed using UPLC/MS/MS and NMR.

In my own experience with the expression of anthocyanins in T. cacao leaves (cocoa/chocolate) we found expression in leaves from highly expressed (dark red young leaves) in some genotypes through no expression at all (pale green young leaves) in others. Moreover, these observations were supported by HPLC analyses. Conclusion: without knowing genotypic variations in anthocyanin expression among different tea cultivars, it would be difficult to use anthocyanins as a marker for quality.

Hello Friends, I totally agree with Luis Cabrita that there are various factors that are responsible for the accumulation of anthocyanins wether physical, chemical and genetic as well. I also agree with Yaroslav Shevchenko and belived that his experiments with stivia shows that anthocyanins might as markers in shade grown tea Vs UV exposed ones. But in case of tea theanine act as a very good marker to study quality of teas (green and white) on basis of shade grown and light exposed tea.

Because your question is about the use of anthocyanins as quality indicators for white and green teas so I think for that particular reason you should chose theanine as better option than that of anthocyanins.

There are numerous papers looking at the effect of light intensity on anthocyanin formation. These paper might be of some interest: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1082886/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3210953/

http://harvardforest.fas.harvard.edu/sites/harvardforest.fas.harvard.edu/files/leaves/Leaf_physiology_anthocyanin.pdf

http://onlinelibrary.wiley.com/store/10.1111/j.1601-5223.1969.tb01840.x/asset/j.1601-

5223.1969.tb01840.x.pdf;jsessionid=6F3B5EB4927A07032D07F173C19C536F.d02t04?v=1&t=hidiaxln&s=97cbc6ae7e6537c8a7bcc073ddd2a20bb584a38d

http://www.plantphysiol.org/content/133/3/1296.full

http://treephys.oxfordjournals.org/content/21/1/1.full.pdf

I recently peer reviewed a manuscript that suggested harvesting of some tea varietals for their anthocyanin content might better be carried out in the afternoon rather than the early morning which is the customary time harvesting occurs. The tradition of early morning harvesting may be more due to the cooler temperatures in tropical/sub-tropical climates than concern for the phytochemical composition. The paper needed revision so hopefully the authors can address comments that would improve the manuscript.