Taxifolin Glycoside Blocks Human ether-a-go-go Related Gene K+ Channels

Taxifolin glycoside is a new drug candidate for the treatment of atopic dermatitis (AD). Many drugs cause side effects such as long QT syndrome by blocking the human ether-a-go-go related gene (hERG) K+ channels. To determine whether taxifolin glycoside would block hERG K+ channels, we recorded hERG K+ currents using a whole-cell patch clamp technique. We found that taxifolin glycoside directly blocked hERG K+ current in a concentration-dependent manner (EC50=9.6+/-0.7 microM). The activation curve of hERG K+ channels was negatively shifted by taxifolin glycoside. In addition, taxifolin glycoside accelerated the activation time constant and reduced the onset of the inactivation time constant. These results suggest that taxifolin glycoside blocks hERG K+ channels that function by facilitating activation and inactivation process.

The Effects of Acer ginnala Leaves Extraction on the Atopic Dermatitis-like Skin Lesions in NC/Nga Mice / 대한피부과학회지

BACKGROUND: Atopic Dermatitis (AD) is a chronic relapsing inflammatory skin disease that is usually observed in patients with an individual or familial history of atopic diseases, and AD is precipitated by environmental factors, including mite antigens. AD is known to be generated by an imbalance of both Th1 and Th2 cytokines. However, the exact etiology of AD is unclear. The leaves of Acer ginnala (AGL) have been demonstrated to have an anti-oxidant effect. OBJECTIVE: We wanted to investigate the effect of AGL on AD-like skin lesions and the other factors related to an immune response. METHODS: The AGL was applied to the AD-like skin lesions on the backs of NC/Nga mice. The efficacy of AGL in the NC/Nga mice was evaluated by the changes of severity of the skin lesions (a modified SCORAD). Blood was collected from the retro-orbital area and the abdominal vena cava. The levels of eosinophils, immunoglobulin (Ig) E and Th2-related cytokines in the blood were measured. RESULTS: The topical application of AGL suppressed the development of AD-like skin lesions. The percent of blood eosinophils was decreased after treatment with AGL. The serum IgE and Th2-related cytokine levels were decreased after treatment with AGL compared with those treated with base cream (the vehicle treated AD group). The IL-4, IL-5 and IL-13 levels were lower than those of the vehicle treated AD group. CONCLUSION: The findings suggest that AGL may exert an inhibitory effect on atopic dermatitis.