The anti-inflammatory and analgesic activities of the ethyl acetate extract of Viburnum taitoense Hayata

Abstract

Ethnopharmacological relevanceViburnum taitoense Hayata has been used as folk medicine by the minority people in Southwestern China for a long history, especially in Guangxi Zhuang Autonomous Region. The minority in Guangxi including Zhuang, Miao and Yao people use the ethanol extract of V. taitoense Hayata to treat the fracture, kill the pain of rheumatism because of its definite therapeutic effects. Aim of the studySo far, the scientific investigation of V. taitoense Hayata is done very little. Here, we first prepared the ethyl acetate extract of V. taitoense (EEVt), secondly measured the contents of phenols, flavonoids, and terpenoids in EEVt, and thirdly, the anti-inflammatory and analgesic activities of EEVt were investigated by invitro model of RAW 264.7 cells and invivo models of inflammation and pain in rats and mice. Materials and methodsThe contents of phenols, flavonoids, and terpenoids in EEVt were determined by UV spectrophotometry, respectively. The anti-inflammatory effect of EEVt (5, 25, 50, 100, and 200 μg/mL) in vitro was tested by determining its inhibitory effect on the nitric oxide production of RAW264.7 cells activated by lipopolysaccharide (LPS). The anti-inflammatory and analgesic effects of EEVt in vivo were investigated in the following experimental rats and mice models: carrageenan-induced paw edema, corton-oil-induced ear edema, acetic acid writhing test, and formalin pain test. ResultsThe contents of total phenolic, total flavonoids, and total triterpenoids in V. taitoense were measured to be 3.46 ± 0.04%, 2.38 ± 0.04%, and 14.96 ± 0.17%, respectively. In vitro test showed that EEVt at different tested dosages (5, 25, 50, 100, and 200 μg/mL) had no significant toxicity to RAW264.7 macrophages. At dosages of 37.5 and 75 μg/mL of EEVt significant inhibitory (p < 0.001) on the productions of nitric oxide (NO). High dosage (200 μg/mL) of EEVt displayed highly significant inhibitory (p < 0.001) on the productions of proinflammatory cytokines IL-6, IL-1β, and TNF-α from the LPS-induced RAW264.7 macrophages. EEVt showed obvious anti-inflammatory activity at different time points after carrageenan injection (p < 0.05) in vivo test, and its anti-inflammatory activity reached the strongest 4 h. Similarly, through the ear swelling test, EEVt (200 mg/kg) showed significant (p < 0.05) anti-inflammatory activity. Besides, formalin and acetic acid writhing experiments also showed that EEVt has significant (p < 0.05) analgesic activity. ConclusionEEVt was confirmed to be definite anti-inflammatory and analgesic effects, and the phytochemicals of EEVt was disclosed to be rich in triterpenoids, which was worthy to be further investigated.