Green tea composition, consumption, and polyphenol chemistry.

Methyl salicylate, a volatile liquid, also known as oil of winter-green, is made by a number of plants1–9. Here we show that methyl salicylate is a major volatile compound produced by tobacco plants inoculated with tobacco mosaic virus. Methyl salicylate is synthesized from salicylic acid, a non-volatile chemical signal required for the establishment of acquired resistance10 and local and systemic induction of antimicrobial pathogenesis-related proteins11. Methyl salicylate acts by being converted back to salicyclic acid. We conclude that methyl salicylate may function as an airborne signal which acitvates disease resistance and the expression of defence-related genes in neighbouring plants and in the healthy tissues of the infected plant.

Airborne signalling by methyl salicylate in plant pathogen resistance

https://cyberleninka.org/article/n/1136090.pdf

Tea aroma formation

Five years ago, in 1986, only a limited number of glycosidically bound volatiles were known and little could be reported on the distribution of those compounds in the plant kingdom. Since then an explosion of research activities in this field has led to the publication of many interesting results concerning structurally diverse terpenoid and non-terpenoid glycosides, their occurrence, and their role in different plant species. Up to now, about 200 different aglycone structures have been found in about 150 species belonging to 35 different families including ferns, gymnosperms, dicotyledons, and monocotyledons.



All the diverse results concerning the role of these compounds in the plants should not lead us into ascribing to them an exclusive role, such as being involved in essential oil metabolism, as early workers have postulated. Although considering new electron microscopical observations of a transformation of carbohydrate-rich substances into lipophilic droplets at the tonoplast of Mentha × piperita secretory cells, the range of possible roles should not be underestimated. New experimental work should not only provide new analytical data but should also attempt to throw more light on the role of the glycosides.

Glycosidically bound volatiles—a review 1986–1991

Volatile compounds are important components of tea aroma, a key attribute of sensory quality. The present review examines the formation of aromatic volatiles of various kinds of teas and factors influencing the formation of tea volatiles, including tea cultivar, growing environment and agronomic practices, processing method and storage of tea. The determination of tea volatiles and the relationship of active-aroma volatiles with the sensory qualities of tea are also discussed in the present paper.

https://www.mdpi.com/1420-3049/21/3/338/pdf

Recent Advances in Volatiles of Teas

A crude enzyme was extracted from fresh tea leaves and it showed β-glucosidase activity, using p-nitrophenyl-β-d-glucoside as a substrate. The non-volatile fraction of a hot-water extract from green tea was incubated with the crude enzyme extract at 37°C for 30 min. After this enzymatic hydrolysis, the formation of (Z)-3-hexenol, linalool oxide I, linalool, methyl salicylate, geraniol, benzyl alcohol and 2-phenylethanol was observed. Geranyl-β-d-glucoside was synthesized by the Koenigs–Knorr reaction. When it was reacted with the crude enzyme extract of tea leaves, geraniol was identified on GC as an enzymatic hydrolysis product. Thus, geranyl-β-d-glucoside seems to be the precursor of geraniol in tea leaves.

Studies on the Precursors of Monoterpene Alcohols in Tea Leaves

(1991). Benzyl Glucoside from Tea Leaves. Agricultural and Biological Chemistry: Vol. 55, No. 4, pp. 1205-1206.

Motoko Yano

Papers

Studies on the Precursors of Monoterpene Alcohols in Tea Leaves

Benzyl glucoside from tea leaves

Formation of Some Volatile Components of Tea