Vasospastic diseases have long troubled people's lives and threatened people's physical and mental health (Alford et al., 2011; He et al., 2023; Su et al., 2021). Long-term medication is generally needed for diseases with occasional vasospasm (such as coronary spasm and cerebral vasospasm), and diseases with sustained elevation of vascular tension (such as hypertension, diabetes and hyperlipidemia). The therapeutic drugs for these cardiovascular diseases should be low-toxic or non-toxic, and can be used for a long time without insufferable side effects. Most current clinically available drugs fail to satisfy this requirement, while teas and tea extracts are very competent for this requirement because of their efficiency and low-toxicity (Bedrood et al., 2018; Zhao et al., 2022). Epidemiological investigations show an inverse correlation between tea consumption and risks of cardiovascular diseases (Peluso and Serafini, 2017; Yang et al., 2022; Zamani et al., 2022) and all-cause mortality among generally healthy adults (Chen et al., 2022; Kuriyama et al., 2006).

Green teas are very popular, and green tea leaves are crucial for the quality of various teas because they are conventionally used as raw materials to produce various other teas, such as black tea, dark tea, Puer tea and Tieguanyin tea. Most clinical studies showed that chronic consumption of green tea reduced human blood pressures and improved vascular relaxant responsiveness (Gao et al., 2022; Li et al., 2019; Tinahones et al., 2008; Ye et al., 2022). Animal studies confirmed that green tea extracts induced or improved vasodilator response in various vascular beds and lowered blood pressures (Lim et al., 2003). Better understanding of pharmacological characteristics of teas and the underlying mechanisms is essential to individual health in daily tea consumption and food supplement therapy with tea extracts. Anji white tea (Anjibaicha in Chinese) is a representative green tea with high reputation and is highly revered for its fine taste, but its vascular effect characteristics and the underlying mechanisms have not been well understood.

Catechins are the main flavonoids found in green tea beverages (Del Rio et al., 2004), while (−)-epigallocatechin gallate (EGCG) is the most abundant catechin in green tea infusions (Cabrera et al., 2006; Sang et al., 2011). EGCG is recommended for clinical use for hypertension (Parn et al., 2022), diabetes (Wan et al., 2022) and kidney diseases (Kanlaya and Thongboonkerd, 2019). Oral administration of EGCG to human volunteers induced hypotension (Chatree et al., 2021) and increased efficacy of oral hypotensive nifedipine (Shi et al., 2018). Nevertheless, the reports about its vascular effects are rather inconsistent and even conflicting. EGCG was reported to be vasorelaxant in adrenoceptor agonist-precontracted rat aorta (Alvarez et al., 2006; Lorenz et al., 2015) and rat mesenteric artery (Kim et al., 2007). Contrarily, other studies showed that EGCG had no vasodilator effect or even potentiated the precontractions in rat aorta and porcine coronary artery (Campos-Toimil and Orallo, 2007; Li et al., 2011; Lim et al., 2003; Obara et al., 2011). Clarification of the contribution of each component of tea to the integrated effects of tea is significant for researching and developing new therapeutic drugs.

To evaluate the potential benefits of the daily drinking of green tea and the practical use of EGCG as food supplementary, we studied and compared the vasomotion effects of Anji white tea with those of EGCG in rat different arteries stimulated with various stimuli. Anji white tea water soaking solution (AJWT) was prepared in a similar way as a daily tea-making process for green teas. Voltage-gated Ca2+ channels (VGCCs) (Tykocki et al., 2017) and voltage-gated K+ (Kv) channels (Ohanyan et al., 2015) are crucial in regulating tone of arterial smooth muscle cells (ASMCs). To explore the mechanisms underlying their vasomotion effects, the influences of AJWT and EGCG on the functions and the expressions of VGCCs and Kv channels were also comparatively studied in ASMCs isolated either from fresh rat coronary arteries (RCAs) or from RCAs which had been cultured with AJWT or EGCG.