State Key Laboratory of Natural Medicines, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, China.
J Ethnopharmacol. 2012 May 7;141(1):322-30. doi: 10.1016/j.jep.2012.02.038. Epub 2012 Feb 28.
Puerarin is the most abundant isoflavonoid in Radix Puerariae (Gegen), which has been prescribed as a medicinal herb for treating fever in China for a long history.
The present study aimed at evaluating the antipyretic effect of puerarin and revealing the related mechanisms.
Lipopolysaccharide (LPS)-induced fever in rats was used to assess the antipyretic effect of puerarin. After an intraperitoneal injection of LPS (100μg/kg), body temperature was tested every 30min up to 8h. Different doses of puerarin (25, 50, 100mg/kg) were intraperitoneally administered 30min before LPS injection. In vitro, LPS-stimulated RAW 264.7 cells were treated with various concentrations of puerarin (25-200μM). The pyrogenic mediators, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), prostaglandin E(2) (PGE(2)) and nitric oxide (NO), were examined on both transcription and expression levels. Furthermore, the influences of the activation of nuclear factor-kappa B (NF-κB) and the phosphorylation of mitogen-activated protein kinases (MAPKs) by puerarin were assayed by western blot.
The intraperitoneal administration of puerarin at test doses clearly demonstrated apparent antipyretic effect through the declines in body temperature elevated by LPS in rats. The in vitro data showed that puerarin inhibited the production of IL-1β, TNF-α, IL-6, PGE(2) and NO; moreover, the RT-PCR analysis and the western blot analysis indicated that puerarin regulated the transcriptional level via suppression of NF-κB activation and blockade of MAPK signal pathway.
In summary, the antipyretic property of puerarin might result, at least in part, from an inhibition of endogenous pyrogen production and expression. Taken in this sense, our findings provide an explanation for puerarin acting as an important constituent in Gegen, thus, provide scientific basis for the wide use of Radix Puerariae in China as a traditional antipyretic.
葛根素是葛根（葛根）中含量最丰富的异黄酮，在中国长期以来一直被用作治疗发热的草药。
本研究旨在评价葛根素的解热作用，并揭示其相关机制。
采用脂多糖（LPS）诱导发热大鼠模型评价葛根素的解热作用。腹腔注射 LPS（100μg/kg）后，每 30min 测量体温，直至 8h。LPS 注射前 30min 腹腔注射不同剂量的葛根素（25、50、100mg/kg）。在体外，用不同浓度的葛根素（25-200μM）处理 LPS 刺激的 RAW 264.7 细胞。检测发热介质白细胞介素-1β（IL-1β）、肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）、前列腺素 E2（PGE2）和一氧化氮（NO）的转录和表达水平。此外，通过 Western blot 测定葛根素对核因子-κB（NF-κB）激活和丝裂原活化蛋白激酶（MAPKs）磷酸化的影响。
在测试剂量下腹腔给予葛根素，明显通过降低 LPS 诱导的大鼠体温，显示出明显的解热作用。体外数据表明，葛根素抑制 IL-1β、TNF-α、IL-6、PGE2 和 NO 的产生；此外，RT-PCR 分析和 Western blot 分析表明，葛根素通过抑制 NF-κB 激活和阻断 MAPK 信号通路来调节转录水平。
综上所述，葛根素的解热特性可能至少部分归因于内源性致热原产生和表达的抑制。从这个意义上说，我们的发现为葛根素作为葛根的重要成分提供了一个解释，从而为葛根在中国作为传统解热剂的广泛应用提供了科学依据。
