Effect of Brewing Water on the Antioxidant Capacity of Green Tea Infusion with DPPH Assay

Brewing water plays a crucial role in flavor and potential healthy functions of tea infusion. In this study, seven water samples with different physicochemical properties were selected to brew green tea. Results showed that the brewing water with higher minerals level and pH value would reduce the yield of catechins in tea infusion, which in turn caused the decrease of antioxidant activity to a large extent. Besides, it was found that EGCG, as a major contributor to the antioxidant activity of green tea infusion, was influenced differently by different metal ions, among which Ca2+/Mg2+ could enhance the antioxidant activity of EGCG solutions with different concentration through synergistic effect, particularly Ca2+, and the effect was more markable at a higher EGCG concentration. These results offered theoretical direction to the selection of tea brewing water for consumers and gave a new sight to the effects of metal ions on the antioxidant capacity of EGCG.

Neuroprotective effects of Lippia javanica (Burm.F.) Spreng. Herbal tea infusion on Lead-induced oxidative brain damage in Wistar rats

Background Though Lippia javanica (Burm.f.) Spreng antioxidant activity has been demonstrated, its effect in protecting the brain from lead (Pb)-induced oxidative damage is unknown. This study investigated the effect of L. javanica against Pb-induced oxidative stress, inflammation, apoptosis and acetylcholinesterase activity in rat’s brain. Methods L. javanica herbal tea infusion was prepared, its phytochemical constituent was revealed by liquid chromatography-Mass spectrometer (LC-MS) and was administered simultaneously with Pb. Four groups of male Wistar rats (n = 5/group) were used: control received distilled water; Pb-acetate group received 50 mg Pb/ Kg bodyweight (bw), treatment group received 50 mg Pb/ Kg Pb-acetate + 5 ml/kg bw L. javanica and L. javanica group received 5 ml/Kg bw of L. javanica tea infusion only. After 6 weeks of treatment, oxidative status, acetylcholinesterase activity, inflammation and apoptosis was assessed in brain tissue which was also histologically examined. Results Mean brain and heart weight was reduced (p < 0.05) while liver and spleen weights were increased (p < 0.05) in Pb exposed animals but were prevented by L. juvanica treatment. Treatment with L. javanica increased (p < 0.05) overall brain antioxidant status (glutathione and superoxide dismutase activities) and reduced lipid peroxidation (p < 0.05) compared to the Pb exposed animals. Pro-inflammatory cytokine tumour necrotic factor-alpha, pro-apoptosis Bax protein and anticholinesterase activity were reduced (p < 0.05) in Pb-L. javanica treated animals compared to the Pb exposed group. Histological examination confirmed neuroprotective effects of L. javanica as evidenced by reduced apoptosis/necrosis and inflammation-induced vacuolization and oedema in the hippocampus. The L. javanica treatment alone had no detrimental effects to the rats. LC-MS analysis revealed L. javanica to be rich in phenolics. Conclusions This study demonstrated that L. javanica, rich in phenolics was effective in reducing Pb-induced brain oxidative stress, inflammation, apoptosis, acetylcholinesterase activity and neuronal damage.

Roasted Tartary Buckwheat Bran as a Material for Producing Rutin-Rich Tea Beverages

Tartary buckwheat bran, a byproduct of buckwheat milling, is commonly treated as waste. The present study examined the rutin content during successive infusions of roasted Tartary buckwheat bran and grain to develop a functional Tartary buckwheat tea. Samples (6 g) of roasted Tartary buckwheat bran and grain were rinsed with 300 mL of hot water (>95 °C) for 0.5 min. For the first infusion test, the tea infusion sample of roasted Tartary buckwheat bran contained a distinctly higher amount of rutin (389 mg/L) than that of the roasted Tartary buckwheat grain (68 mg/L). Overall, rutin was more effectively extracted from roasted Tartary buckwheat bran, as compared to roasted Tartary buckwheat grain.

Athrixia phylicoides tea infusion (bushman tea) improves adipokine balance, glucose homeostasis and lipid parameters in a diet-induced metabolic syndrome rat model

Background Central obesity and insulin resistance are associated with metabolic syndrome (MetS) which is aggravated by diet and sedentary lifestyle. Athrixia phylicoides (AP) is reported by rural communities to have medicinal benefits associated with MetS such as obesity and type 2 diabetes. This study was aimed to investigate the effects of AP on diet-induced MetS in Wistar rats to validate its ethnopharmacological use. Methods AP was profiled for phytochemicals by LC-MS. After induction of MetS with high energy diet (HED), 30 male rats were divided into five treatment groups (n = 6): normal diet control, HED control, HED + AP 50 mg/Kg BW, HED + AP 100 mg/Kg BW and HED + 50 mg/Kg BW metformin. The rats were treated daily for 8 weeks orally after which weight gain, visceral fat, total cholesterol, free fatty acids (FFAs) and adipokine regulation; leptin: adiponectin ratio (LAR) were assessed. Also, glucose homeostatic parameters including fasting blood glucose (FBG), oral glucose tolerance test (OGTT), glucose transporter 4 (GLUT 4), insulin and homeostatic model assessment of insulin resistance (HOMA-IR) were determined. Results Findings showed that AP was rich in polyphenols. The HED control group showed derangements of the selected blood parameters of MetS. AP reversed diet-induced weight gain by reducing visceral fat, total blood cholesterol and circulating FFAs (p ≤ 0.05). Treatment with AP improved adipokine regulation depicted by reduced LAR (p<0.05). Treatment with AP improved parameters of glucose homeostasis as demonstrated by reduced FBG and HOMA-IR (p ≤ 0.05) and increased GLUT 4 (p<0.05). Conclusion Athrixia phylicoides tea infusion was shown to possess anti-obesity and anti-inflammatory properties, improved glucose uptake and reduce insulin resistance in diet-induced MetS in rats which could be attributed to its richness in polyphenols. Therefore, AP could have potential benefits against type 2 diabetes and obesity which are components of MetS validating its ethnopharmacological use.

Effect of Ferrous Ion on Heat-Induced Aroma Deterioration of Green Tea Infusion

Aroma deterioration is one of the biggest problems in processing tea beverages. The aroma of tea infusion deteriorates fast during heat sterilization and the presence of ferrous ion (Fe2+) aggravates it. The underlying mechanism remains unveiled. In this study, Fe2+ was verified to deteriorate the aroma quality of green tea infusion with heat treatment. Catechins were necessary for Fe2+-mediated aroma deterioration. By enhancing the degradation of catechins, Fe2+ dramatically increased the production of hydrogen peroxide (H2O2). Fe2+ and H2O2 together exacerbated the aroma of green tea infusion with heat treatment. GC-MS analysis revealed that the presence of Fe2+ enhanced the loss of green/grassy volatiles and promoted the formation of new volatiles with diversified aroma characteristics, resulting in a dull scent of green tea infusion. Our results revealed how Fe2+ induced aroma deterioration of green tea infusion with heat treatment and could help guide tea producers in attenuating the aroma deterioration of tea infusion during processing.

Screening and Identification of the Botanical Attractant From a Chinese Tea for Aedes Albopictus Oviposition

Background: The use of oviposition attractants is a promising approach to control populations of mosquito vectors at the source; however, the knowledge on oviposition stimulation in Aedes albopictus is very limited. In recent years, tea bags have been proven to attract Aedes aegypti to lay eggs, but the sources of tea are wide and varied; moreover, the factors and mechanisms in tea bags that attract mosquitoes remain unclear.Methods: The effects of three kinds of Chinese tea, nonfermented, fully fermented and postfermented, were comparatively evaluated for their ability to attract mosquito oviposition at dose of 5g/L, 1.5g/L and 0.5g/L, respectively. The attractants in the Liu-pao tea infusion were isolated with gas chromatography–mass spectrometry (GC-MS).Results: Among the three types of fermented teas, the Guangxi Liu-pao tea infusion was a successful oviposition attractant for Ae. albopictus at all the dose tested, and the average OAIs of 5 g/L Liu-pao tea soaked for 7 d and 14 d were 0.73 and 0.67, respectively. Further, in one month of soaking 0.5g/L Liu-Pao tea, the average oviposition activity indexes (OAIs) for Ae.aegypti of soaking for 21 d and 28 d were 0.89 and 0.63, respectively. Functional analyses showed that the compound cedrol at 1 mg/L tested for Ae. albopictus, the average OAI was 0.38.Conclusion: Liu-pao tea can effectively attract Ae. albopictus to lay eggs, and cedrol is one of the ingredients attracting Aedes mosquitoes to lay eggs. These results shed light on the development of Aedes mosquito oviposition attractants and will help to develop innovative monitoring and prevention strategies for Aedes-borne diseases.