An experimental study of the anti-dysmenorrhea effect of Chinese herbal medicines used in Jin Gui Yao Lue

Abstract Ethnopharmacological relevance Dang-Gui-Shao-Yao-San (当归芍药散) and Gui-Zhi-Fu-Ling-Tang (桂枝茯苓汤) and among the herbal medicines commonly used to treat primary dysmenorrhea with proven record of effectiveness. Aim of this study This study aims to assess the effectiveness of herbal medicines on relieving primary dysmenorrhea in a murine model and to delineate a plausible mechanism. Materials and methods Herbal medicines in the form of pills (Wan) or capsules, including Gui-Zhi-Fu-Ling capsule, Gui-Zhi-Fu-Ling-Wan, Jia-Wei-Xiao-Yao-Wan, and Shao-Fu-Zhu-Yu capsule were purchased from local drug stores in Nanjing. Dang-Gui-Shao-Yao-San filled from a local hospital. The identity of the drugs was validated by HPLC profiling. Female ICR mice were used for an induced dysmenorrhea model. The severity of dysmenorrhea was evaluated and scored, the motor coordination and balance affected by induced dysmenorrhea was assessed by a Rotarod test. Uterine inflammation and edema were examined after histological and immunohistochemical staining. The effect of the drugs on COX2 activity was evaluated enzymatically. Results The Chinese herbal medicines at dosages relevant to recommended uses in humans relieved painful responses, including abdominal wall contraction, pelvic twisting and/or rear limb stretching. The treatment also improved motor coordination, extending the time staying on a rotating rod from 2.64 ± 0.38 min of oxytocin-induced group to 8.59 ± 1.45 (DGSYs), 9.50 ± 1.47 (GZFLc), 8.04 ± 1.87 (GZFLw), 9.91 ± 1.62 (JWXYw), and 8.20 ± 1.35 min (SFZYc), respectively. H&E staining showed that treatment with ibuprofen or Chinese herbal medicines markedly decreased edema and inflammatory cell infiltration in uterine tissues. The treatment did not significantly affect pattern of COX2 staining. In an in vitro enzymatic assay, the Chinese herbal medicines showed strong inhibitory activity against cyclooxygenase-2. The aqueous extracts from P. lactiflora or P. suffruticosa, two of the common components in the formulae tested, also showed anti-dysmenorrhea activity in the rotarod assay. Conclusion The study demonstrates that traditionally used Chinese herbal medicines are effective against induced-dysmenorrhea. These herbal medicines relieve dysmenorrhea symptoms likely though inhibition of cyclooxygenase activity.