Study on in vitro Inhibitory Activity of the Extracts from 9 Kinds of TCM for Dredging Collaterals and Dispelling Wind on Xanthine Oxidase / 中国药房

ABSTRACT

OBJECTIVE：To study in vi tro inhibitory act ivities of 9 kinds of TCM for dredging collaterals and dispelling wind on xanthine oxidase （XO），and to screen TCM with outstanding activity. METHODS ：Using xanthine as substrate and xanthinase as reaction enzyme ，allopurinol as positive control ，with water extract and methanol extract （hereinafter referred to as “ethanol extract”）from the stem and leaves of Hedera nepalensis ，the whole plant of Piper wallichii ，the fruits of Rubus corchorifolius ，the root of Caragana sinica ，the root of Wisteria sinensis ，the root of Rubus crataegifolius ，the bark of Catalpa ovata ，the root of Campsis grandiflora ，the stem of P. hancei （hereinafter referred to by plant name ）and petroleum ether ，dichloromethane，ethyl acetate，n-butanol and water fraction of active extract as the objects ，inhibition rate of each sample to XO was detected by spectrophotometry；IC50values were calculated with Graphpad prism 6.0 software to screen active extract/fraction. Double reciprocal method was used to determine the type of enzyme inhibition. RESULTS ：Among 9 kinds of TCM and 18 kinds of the extracts ，the inhibitory rates to XO of 500 μg/mL extracts from each TCM（except for ethanol extract of P. wallichii ），250 μg/mL water extract and ethanol extract of H. nepalensis ，P. wallichii ，R. corchorifolius and P. hancei ，250 μg/mL water extract of C. ovata ，250 μ g/mL ethanol extract of C. sinica ，R. crataegifolius and C. grandiflora ，125 μ g/mL ethanol extract of C. sinica and R. crataegifolius，62.5 μg/mL ethanol extract of C. sinica were more than 50％. The IC 50 value of the ethanol extract from C. sinica was 43.43 μg/mL，which was lower than the extracts of other TCM ，and which was the active extract. The IC 50 values of petroleum ether，dichloromethane，ethyl acetate ，n-butanol and water fracti on of ethanol extract from C. sinica were ＞200，193.35，7.67， 14.80 and ＞200 μg/mL，respectively. The IC 50 value of ethyl XO was competitive-noncompetitive inhibition ， which was different from competi tive inhibition of positive control. CONCLUSIONS：The ethanol extracts of C. sinica ，R. crataegifolius ，P. wallichii ，R. corchorifolius ，P. hancei ，H. nepalensis and the water extracts of H. nepalensis ，P. wallichii ，C. ovata show certain inhibitory activity in vitro to XO ，especially ethanol extract of C. sinica . The ethyl acetate fraction of the ethanol extract of C. sinica has similar inhibitory activity to allopurinol but their inhibition types are different.