Hawk tea is a medicinal herbal and caffeine-free drink, and it is one of the most popular beverages in South China, attracting about 30 million consumers. According to the raw materials and processing methods, Hawk tea can be divided into four major categories, namely laoying cha, bai cha, dashu cha, and insect-fermented tea. Hawk tea has multiple bioactive components, such as free amino acids, vitamins, microelements, polysaccharides, polyphenols, and essential oils, especially flavonoids. Hawk tea shows notably bioactivities, including hepatoprotection, hyperglycemia, antiinflammatory, antioxidant, and antibacterial. Hawk tea has many benefits for our health, including detoxification, detumescence, and reduction of blood sugar and blood lipid. In this chapter, we will introduce the present resource situation, traditional and current process technology, phytochemicals, and pharmacological activities of Hawk tea and hope to lay a scientific basis for developing and utilizing this local beverage.
As a herbal tea of minorities in Southern China for many centuries, Hawk tea is described as having the effect of "relieving cough, sputum, asthma, the summer heat and thirst" in Compendium of Materia Medica. Hawk tea is made mainly from the stems and leaves of Lauraceae, including Litsea, Actinodaphne and Machilus, among which Litsea Coreana is the most common one. Litsea Coreana mainly grows in Dalou Shan of Guizhou, where people call it as "white hawk tea" or "white tea" and enjoy its excellent taste. Comparatively, the Litsea Coreana which is found in Yunnan, Guizhou, Sichuan, Anhui and some other places has a relatively bitter taste and is enjoyed by less people.There are two forms of common Litsea Coreana: one is tender stems and leaves which are directly infused for drinking after being sunned, dried or baked; the other is tea sand, a kind of black faeces produced by Lepidoptera that eats old leaves of Litsea Coreana during its storation,which can also be infused for drinking
Folks believe that Litsea Coreana has the effect of relieving internal heat and swellings, improving eyesight and intelligence, promoting the secretion of saliva and quenching thirst. Its safety has also been proved by the long history of drinking this kind of tea. Recently, Pharmacology studies showed that Litsea Coreana could resist oxidation and inflammation, reduce blood sugar and blood fat, regulate immunity, and had some other effect. Composition test showed that its main active substances were phenol, some kinds of volatile oil and amino acids.
The pharmacological effect of Litsea Coreana
The pharmacological effect of Litsea Coreana comes mainly from its flavonoids, terpenoids and polyphenolic substances. As the studies on its pharmacological effect had mainly focused on overall research, no one was reported on pharmacological effect of any specific compound.
The effect of reducing blood sugar Animal experiments suggested that undiluted tea could reduce the blood sugar of experimental hyperglycemias mice by feeding them with the dose of 20g/kg for consecutive 6 weeks. It could also reduce the mice's blood fat, whose effect was not as significant as that of reducing blood sugar.
The protection of cardiovascular system Generally speaking, flavonoids have some protective effect on cardiovascular system, but it was also shown that Litebamine, a non-alkaloid constituent from the stems of Litsea Coreana, could prevent coronary heart disease by inhibiting the adhesion and migration of smooth muscles
The effect of anti-oxidation The significance of this effect, which was much higher than that of green tea with the same concentration, was positively correlated with the concentration of tea.
The anti-inflammatory effect of flavonoids from Litsea Coreana
The treatment of Non-alcoholic Steatohepatitis
Picking shoots and leaves in spring. It can be made as wild hawk Tea.