Green Tea Extract

green tea, green tea extract

Green tea extract, extracted from the leaves of this evergreen, highly branched shrub, plays a central role in many aspects of our lives. From drug extraction to use in cosmetics and health products, this extract has a diverse range of applications. In this article, we will take a closer look at the botany of Camellia sinensis, the ingredients of green tea extract as well as its impressive effects and applications, but also possible side effects and the quality of the extracts. In the process, we will find out how this natural gift of nature plays an important role in many aspects of our modern lives.



The plant genus Camellia LINNÉ comprises about 80 different species and belongs to the tea family (Theaceae). The sought-after tea leaves come exclusively from Camillia sinensis (L.) O. KUNTZE. Originally from the mountainous regions of Southeast Asia, this ancient cultivated plant is no longer found in its natural habitat. Green tea extract, obtained from the leaves of this evergreen and highly branched plant, exhibits considerable diversity both morphologically and in terms of its constituents due to its cross-pollination. The exact delimitation of the different species turns out to be a challenging task. However, in practice, the distinction between green tea extract var. sinensis and green tea extract var. assamica has proven to be effective. Nowadays, mainly hybrids of these two species are cultivated, which grow bushy and can reach heights of up to one meter. Tea is commercially harvested at latitudes between 45° north and 30° south. The leading tea growing countries are India, China, Sri Lanka, Turkey, Russia, Indonesia and Japan.

Green tea itself is an evergreen, heavily branched shrub that grows tree-like in its natural form. The leaves are alternate, leathery to the touch and have a dark green color. For the production of tea as a drug, the young, downy-haired leaves of the tea bush (Theae folium) are used, as they are of the highest quality. These leaves are distinguished according to the following quality criteria:

Imperial: Only the uppermost, not yet unfolded leaf, also known as peko tip.

Fine: peko tip and two leaves (“two and a bud”).

Coarse: peko tip and three leaves.

Harvesting takes place throughout the year in tropical regions and seasonally in temperate zones. Nowadays, harvesting can also be done by machine, although the most selective harvesting is still done by hand.

The leaves obtained can be processed in different ways, depending on their fermentation state:

Fermented = Black tea (Theae nigrae folium).

Non-fermented = green tea (Theae viridis folium).

Semi-fermented = Oolong tea.

Green tea is produced by treating the fresh leaves with superheated steam for a few minutes in rotating cylindrical vessels or by inactivating the stubborn enzymes in shallow iron pans. This is followed by machine rolling of the leaves, reduction of the water content to 50% by drying, rolling again and final drying in the sun.


Ingredients of green tea extract:

It consists of a diverse range of ingredients that shape its health benefits and flavor. The main components of tea leaves and thus the extract include polyphenols, purine alkaloids (methylxanthines), amino acids, polysaccharides, proteins, and lipids. In addition, organic acids, volatiles, vitamins, and minerals are present in smaller amounts.

Polyphenols represent the dominant group of major constituents, accounting for about 25 to 35% of the total. Within the polyphenols, flavonoids, which include catechins and flavonols, are of particular importance. Catechins make up the majority of polyphenols, accounting for 17 to 30% of the total. Various catechins are present in green tea in different proportions, including (±)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), and (-)-epicatechin gallate (ECG). In addition, (-)-catechin gallate, (-)-gallocatechin, and (-)-gallocatechin gallate were identified.

The catechin content varies considerably depending on the developmental stage of the leaves. It peaks at about 26% in the tip buds and decreases down the leaf sequence. In the lower part of the shoot axis, the catechin content averages only about 5%. This decrease is caused by the degradation of (-)-epigallocatechin gallate and (-)-epicatechin gallate, so harvesting young leaves is of great importance.

Green tea extract also contains free flavonols such as kaempferol, quercetin, and myricetin, with their di- and triglycosides present in higher concentrations of about 1.5 to 1.7%. Other constituents include free gallic acid and theogallin. Phenolic acids such as caffeic acid, p-coumaric acid, ellagic acid, and the depsides p-coumaroylquinic acid and chlorogenic acid have also been detected in fresh tea leaves.

Caffeine, as the main purine alkaloid, is naturally present in tea. The content of caffeine hardly differs significantly between black tea, green tea, and oolong tea. This content is also dependent on the stage of development of the leaves and reaches the highest value in the young top buds with more than 4%. In addition to caffeine, theobromine and theophylline are also present in green tea extract.

Amino acids make up about 4% of green tea extract, with theanine, a characteristic amino acid of green tea, making up the largest percentage. It is followed by amino acids such as aspartic acid, glutamic acid, arginine, and asparagine.

On average, green tea extract contains about 0.28% vitamin C (ascorbic acid). In comparison, black tea and oolong tea have much lower amounts of vitamin C due to the fermentation process.

Other volatiles in the extract include linalool, d-cadinene, geraniol, benzyl alcohol, indole and nerolidol. Linalool represents the major component of these volatiles at about 20% and contributes significantly to the aroma of the tea.


Effects and applications of green tea extract

The versatile properties of green tea extract are widely used in cosmetic and pharmaceutical formulations. In particular, the antioxidant characteristics of green tea polyphenols are emphasized, which play a significant role in cosmetics. In addition, the antimicrobial and anti-irritant effects contribute to the beneficial properties.

The antioxidant properties of catechins have been researched in numerous studies and are mainly based on two mechanisms:

Catechins complex with free divalent metal ions, which are necessary for the formation of oxygen free radicals.

Catechins also act as effective radical scavengers against oxygen, peroxy and hydroxy radicals, which can cause DNA damage and damage to other cellular molecules, as well as initiate lipid peroxidation.

The most active compound in green tea extract is epigallocatechin gallate, which has comparable antioxidant activities to the synthetic antioxidants butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA). These synthetic compounds should be avoided in modern cosmetics today.

Clinical studies have shown that topically applied green tea extract can not only protect against UV radiation-induced skin damage, but also delay genetic cell changes and inhibit tumor formation. This protective effect on the skin is mainly attributed to the antioxidant properties of catechins.

It also shows deodorizing effects against methyl mercaptan, trimethylamine and cigarette smoke. Both laboratory experiments (in vitro) and studies with living organisms (in vivo) have demonstrated the odor-inhibiting properties of polyphenols. For example, chewing candies containing 0.1% green tea extract after eating garlic was observed to reduce bad breath.

The antibacterial properties of green tea extract against various bacteria and fungi have application potential, especially in aluminum-free deodorant products and foot care products.

In addition, green tea extracts can be used in dental care products and mouthwashes due to their anticariogenic (caries-inhibiting) and deodorizing effects.


Lead substances and quality of extracts

Catechins represent the main constituents of green tea extract, accounting for 17 to 30% of the dry mass. Since the efficacy is based on the content of catechins, several catechins should be analyzed to characterize the extracts. Meanwhile, there are also highly concentrated extracts containing 90% catechins. If a product’s effect performance on catechins is to be claimed, such a highly concentrated product can be used.


Green tea extract: versatile applications and positive properties

Green tea extract is a versatile natural product, rich in ingredients such as polyphenols, catechins, caffeine, amino acids and more. This unique composition gives it impressive antioxidant properties that are especially valued in skin care and pharmaceutical applications. As a skin protectant, green tea extract provides protection from UV radiation, can slow skin aging and possibly inhibit the development of skin tumors. Additionally, it has an odor-reducing effect and is useful for preventing bad breath and plaque formation. A significant benefit is that green tea extract has no known side effects when used topically, underscoring its safe use in a variety of products. Looking to add high-quality products with green tea extract to your cosmetic line? Ask Cosmacon.




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