Have you ever seen serrated tea leaves? Scaly buds? In recent years, more and more tea stores have been selling teas from Camellia Taliensis, a species of tea plant commonly found in the wild. Some sellers refer to these teas as low in caffeine. However, it is a cousin of the famous Camellia Sinensis, the most commonly used tea plant, and it is known that the vast majority of tea leaves are rich in caffeine.
This issue was already topical in the 2000s. In 2008, Gao et al. investigated the caffeine composition in the leaves of green teas from cultivated Camellia sinensis var. Assamica (a caffeine-rich tea species) and wild Camellia Taliensis. The authors showed that both batches of tea leaves contained caffeine (2.32 and 2.94% caffeine) at levels close to those reported in tea research (2% to 3% on average).
More recently, Zhang et al. studied the genetic signature of Camellia Taliensis with Camellia Sinensis that allows the synthesis of caffeine. The plant transforms a molecule called xanthosine into different products such as theobromine, until it reaches the final molecule: caffeine.
The genetic code of the plant will dictate its performance to achieve these transformations. The genetic signature of Camellia Taliensis for the synthesis of caffeine would be close to Camellia Sinensis, and could even be more efficient in some parts of the plant like flowers and buds. This can be explained by the fact that caffeine is a chemical defense molecule against pests. Camellia Taliensis being a wild species, it must be able to protect itself by producing defense molecules.
So if Camellia Taliensis contains caffeine like its cousin, why do some sellers sell it as a "low caffeine" tea?
Just as there is great variation between Camellia Sinensis in terms of caffeine, so too does Camellia Taliensis. Ogino et al., who specialize in the study of tea plants, were interested in Japanese Camellia Taliensis that contained more theobromine (precursor of caffeine) than caffeine. After establishing crosses between tea plants resulting in a hybrid tea plant called Taliensis-akame, the authors showed that this Camellia Taliensis possesses a marker ("CafLess TCS1") in one of the caffeine synthesis genes. This marker prevents the expression of the gene, the tea leaves do not carry out correctly the synthesis of caffeine.
Beware, the buds and leaves of Camellia Taliensis teas may contain as much caffeine as other tea leaves. To be able to indicate that these teas have less caffeine, a chemical analysis of the leaves must be performed. Indeed, some Camellia Taliensis can produce less caffeine depending on their initial genetic status and how the tea plants have reproduced (in contact with other less caffeinated tea plants, etc).
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