Inhibitory effects of Cinnamomi Cortex and cinnamaldehyde on oxygen-derived free radical-induced vasocontraction in isolated aorta of spontaneously hypertensive rats
自然発症高血圧ラット(SHR)摘出胸部大動脈におけるキサンチン-キサンチンオキシダーゼ(XOD)誘発血管収縮反応に対する桂皮エキスおよびケイヒアルデヒド(CA)の収縮抑制作用についてオルガンバス法を用いて検討した。キサンチン-XOD誘発血管収縮反応は,SHR対照群と比較して,桂皮エキス(10^g/ml)前処置群,CA(10^M)前処置群で,有意に抑制されていた。キサンチン-XOD収縮反応時のトロンボキサンB_2(TXB_2)産生量は,SHR対照群と比較して,桂皮エキス(10^g/ml)群,CA(10^M)群で,有意に抑制されていた。CAのTX産生抑制の機序を検討するため,フォスフォリパーゼA_2(PLA_2)誘発血管収縮反応に対する収縮抑制作用について検討したところ,PLA_2誘発血管収縮反応はSHR対照群と比較して,CA(10^M)群で,有意に抑制されていた。PLA_2収縮反応時のTXB_2産生量は,SHR対照群と比較してCA(10^M)群で,有意に抑制されていた。以上のことから,桂皮は,血管収縮因子であるTXA_2抑制作用を持つ生薬である可能性が示唆された。 We examined the inhibiting effect of Cinnamomi Cortex extract (CCE) and cianamaldehyde (CA) against vasocontraction induced by oxygen-derived free radicals produced by the xanthine-xanthine oxidase (XOD) system in the thoracic aortic ring of the spontaneously hypertensive rat (SHR), using the organ bath method in vitro. The vasocontraction induced by xanthine-XOD in the CCE (10^g/ml) and CA (10^M) treatment groups were significantly lower than that in the control group. Further, the amounts of thromboxane B_2 (TXB_2) produced in the vasocontractive response in the CCE (10^g/ml) and CA (10^M) treatment groups were significantly lower than that in the control group. For the purpose of examining the mechanism of the inhibiting effect of CA against thromboxane production, the inhibiting effect of CA against the vasocontraction induced by phospholipase A_2 (PLA_2) was examined. The vasocontraction induced by PLA_2 in the CA (10^M) treatment group was significantly lower than that in the control group. Moreover, the amount of TXB_2 produced by the vasocontractive response in the CA (10^M) treatment group was significantly lower than that in the control group. From the above findings, it is suggested that Cinnamomi Cortex is an agent which exerts an inhibitory effect on the vasocontractive factor (TXA_2) in vitro
