Department of Pharmaceutical Science and Department of Life and Pharmaceutical Sciences, Kyung Hee University, 1 Hoegi, Dongdaemun-ku, Seoul, Korea.
Acta Pharmacol Sin. 2010 Jun;31(6):718-24. doi: 10.1038/aps.2010.42. Epub 2010 May 10.
To explore whether intestinal microflora plays a role in anti-pruritic activity of baicalin, a main constituent of the rhizome of Scutellaria baicalensis (SB).
Baicalin was anaerobically incubated with human fecal microflora, and its metabolites, baicalein and oroxylin A, were isolated. The inhibitory effect of baicalin and its metabolites was accessed in histamine- or compound 48/80-induced scratching behavior in mice.
Baicalin was metabolized to baicalein and oroxylin A, with metabolic activities of 40.2+/-26.2 and 1.2+/-1.1 nmol.h(-1).mg(-1) wet weight of human fecal microflora, respectively. Baicalin (20, 50 mg/kg) showed more potent inhibitory effect on histamine-induced scratching behavior when orally administered than intraperitoneally. In contrast, baicalein and oroxylin A had more potent inhibitory effect when the intraperitoneally administered. The anti-scratching behavior activity of oral baicalin and its metabolites was in proportion to their inhibition on histamine-induced increase of vascular permeability with oroxylin A more potent than baicalein and baicalin. In Magnus test using guinea pig ileum, oroxylin A is more potent than baicalein and baicalin in inhibition of histamine-induced contraction. The anti-scratching behavioral effect of oral baicalin was significantly reduced when oral antibiotics were simultaneously administered, whereas the effect of baicalein and oroxylin A were not affected.
Oral baicalin may be metabolized by intestinal microflora into baicalein and oroxylin A, which ameliorate pruritic reactions through anti-histamine action.
探讨黄芩苷（黄芩的主要成分）的抗瘙痒活性是否与肠道菌群有关。
将黄芩苷与人体粪便微生物群进行厌氧孵育，分离其代谢物黄芩素和大黄素 A。评估黄芩苷及其代谢物对组胺或化合物 48/80 诱导的小鼠搔抓行为的抑制作用。
黄芩苷代谢为黄芩素和大黄素 A，其代谢活性分别为 40.2+/-26.2 和 1.2+/-1.1 nmol.h(-1).mg(-1) 人体粪便微生物群湿重。黄芩苷（20、50 mg/kg）口服时对组胺诱导的搔抓行为的抑制作用强于腹腔内给药。相比之下，腹腔内给药时，黄芩素和大黄素 A 的抑制作用更强。口服黄芩苷及其代谢物的抗搔抓行为活性与其对组胺诱导的血管通透性增加的抑制作用成正比，其中大黄素 A 的作用强于黄芩素和黄芩苷。在豚鼠回肠 Magnus 试验中，大黄素 A 对组胺诱导的收缩的抑制作用强于黄芩素和黄芩苷。同时口服抗生素会显著降低口服黄芩苷的抗搔抓行为作用，而黄芩素和大黄素 A 的作用不受影响。
口服黄芩苷可能被肠道菌群代谢为黄芩素和大黄素 A，通过抗组胺作用改善瘙痒反应。
