Objective: To evaluate the in vitro effects and interactions of active fractions in Yaotongning capsule (YTNC) by utilizing interleukin-1β (IL-1β) activated chondrocytes. Method: Six samples were prepared by mixing different active fractions including alkaloids

flavonoids

saponins

volatile oil

hydrous extract and polysaccharides according to the formulating principle and the ratio of materials in YTNC. Chondrocytes were obtained from six seven-day rats using collagenase II

before they were divided into three groups:control group (Dulbecco's modification of Eagle's medium Dulbecco (DMEM) containing 5% fetal bovine serum (FBS) and 0.02% Tween-80)

model group (DMEM containing 5% FBS

0.02% Tween-80 and 10 μg·L-1 IL-1β) and sample group (DMEM containing 5% FBS

0.02% Tween-80

10 μg·L-1 IL-1β and 9.77-0.08 mg·L-1 samples). After 48 h

the proliferations of chondrocytes were examined through cell counting kit-8 (CCK8) assay

when the intracellular level of glycosaminoglycan (GAG) was detected by 1

9-dimethylmethylene blue staining using a glycosaminoglycans (GAG) assay kit. A quantitative evaluation method was exerted to investigate the effect of each sample on IL-1β activated chondrocytes. Result: The comparison of EC50 of YTNC sample and its partial prescriptions indicated that YTNC prescription had the most significant therapeutic effect on promoting proliferation and GAG synthesis in chondrocytes. Synergistic

antagonistic and additive action all could be observed followed by adding alkaloids

flavonoids

saponins

volatile oil

hydrous extract and polysaccharides to each partial prescription. Synergistic and additive effects between active fractions in YTNC prescription were observed

respectively. Conclusion: The therapeutic effect on osteoarthritis (OA) of YTNC without Chinese rice wine was obviously improved after the addition of Chinese rice wine

which indicated that the combination of active fractions in YTNC was reasonable.