**4.2 Anti-cancer effects**

Scented tea has inhibitory effects on various cancers, such as liver, skin, stomach, lung, oral, breast, pancreatic and colon cancers [53–55], due to the presence of polyphenols and their oxidation products and caffeine. Tea polyphenols have strong anti-oxidant properties, scavenge free radicals in the body and can block the synthesis of carcinogens, such as ammonium nitrite. The inhibitory effects of scented tea on cancer are achieved via anti-oxidation, induction of apoptosis and regulation of gene expression. In addition, scented tea contains a large amount of chlorogenic acid and related derivatives, which have shown anti-cancer activity against U937 human histiocytic lymphoma cells, KB human oral cancer cells, MCF-7 breast cancer cells and WI38 lung fibroblast cells [56]. Chlorogenic acid can inhibit colon cancer by inducing the production of reactive oxygen species, lung cancer cells by affecting the expression of apoptosis-related genes and liver, oral, gastric, cervical and breast cancers [57–59]. Kawabata et al. [60] used azomethane to induce a rat model of colon cancer and found that ferulic acid could reduce the incidence of colon cancer in rats. Protocatechuic acid can reduce the enzyme activity of MCF-7, A549 non-small cell lung cancer cells, HepG2 human liver cancer cells, HeLa cervical cancer cells and LNCaP prostate cancer cells, effectively penetrate cancer cells, inhibit lactate dehydrogenase activity and damage the mitochondrial membrane potential and also inhibit MMP-2 secretion to prevent its metastasis in human gastric cancer AGS cells [61]. Studies have found that caffeic acid mainly exerts its anti-cancer effects by affecting the mRNA regulatory network and up-regulating levels of mitochondrial reactive oxygen species in tumour cells [62]. Studies have also shown that isochlorogenic acid A has an inhibitory effect on human ovarian cancer cells, skin melanoma cells, central nervous system tumour cells and colorectal cancer cells [63].

## **4.3 Hypoglycaemic effects**

Diabetes is one of the most common chronic diseases seen in clinical medicine its the incidence has gradually increased in young people. The blood glucose levels of individuals fluctuate; however, stable blood glucose levels are an important evaluation index of individual physical health. Scented tea can improve the ability of vanadate to

regulate blood glucose. Vanadate suspended in jasmine scented tea has hypoglycaemic effects and can stably and effectively maintain blood glucose at a normal levels within a few weeks [64]. Studies have shown that drinking jasmine scented tea significantly reduces blood glucose [18]. Starch (polysaccharide) in food is digested into oligosaccharides by salivary amylase and pancreatic amylase, converted to glucose by α-glucosidase in the small intestine and finally absorbed. Studies have found that osmanthus tea extract has an inhibitory effect on α-glucosidase [65]. The presence of phenolic compounds in honeysuckle scented tea extract was shown to reduce blood sugar levels in sucrose hyperglycaemic mice and an alloxan diabetes mouse model [66].
