Evaluation of the analgesic activities of the crude aqueous extract and fractions of Shao Fu Zhu Yu decoction

Context: Shao Fu Zhu Yu decoction (SFD), a well-known Chinese medicine, has been used for the treatment of primary dysmenorrhea in China for more than 200 years. Objective: A crude water extract and four fractions from SFD were evaluated for their analgesic activities for the purpose of validating the ethnomedical use of SFD. Material and method: The analgesic activities were studied by measuring nociception using acetic acid-induced abdominal contractions, the hot-plate test, formalin-induced licking and oxytocin-induced writhing in estrogen-treated mouse models. Prostaglandin E-2 and nitric oxide production in cultured lipopolysaccharide (LPS)-treated macrophage cells were determined. Chemical components were separated and identified in the SFD analgesic fractions using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS). Results: Oral SFD exerted significant analgesic activities in all nociceptive models except the hot-plate test. The activity-guided fractionation demonstrated that the SFD-40% fraction was the most potent with marked inhibition of pain responses at a dose of 54 mg/kg in vivo, and significantly inhibited prostaglandin E-2 and nitric oxide production in LPS-treated mouse peritoneal macrophages in vitro. Further UPLC-MS analysis showed the presence of several chemical components in the SFD-40% fraction, including ferulic acid, paeoniflorin, typhaneoside, and isorhamnetin-3-O-neohesperidoside. Discussion and conclusion: These results demonstrated that SFD has significant peripheral analgesic activities, mainly attributed to the SFD-40% fraction, and supports the use of SFD in traditional Chinese medicine.