Acetic acid-induced abdominal writhing
Intraperitoneal injection of acetic acid induced 100.1±3.9 writhings in a period of 20 min. Pre-treatment of mice with V. cymosa extracts in doses of 10, 30 and 100 mg/kg induced a dose-response reduction on total number of contortions. The most potent extract was VB (Figure 1). Even at 10 mg/kg, VB significantly reduced in 25% (100.1±3.9 writhings in control group versus 73.4±4.0 writhings in extract-treated group) the number of writhings. At the doses of 30 and 100 mg/kg there was significant effect to all three fractions, VD, VA and VB (Figure 1).