Analgesic and anti-inflammatory activity of the extracts from Cyperus rotundus Linn rhizomes

The rhizome part of Cyperus rotundus has been shown to contain 5-hydroxymethyl furfural (HMF) (1), methyl ferulate (MF) (2), (E)-ferulaldehyde (FA) (3), and N-trans-feruloyl tyramine (NTF) (4).These known compounds are being reported for the first time from this plant and their structures were determined by physical properties and spectroscopic analyses. The present study was designed to investigate the analgesic and anti-inflammatory activities of methanol, chloroform and ethyl acetate extracts of C. rotundus. All the extract displayed significant analgesic effect in acetic acid and hot plate pain models in a dose dependent manner. As compared with the other extracts, the ethyl acetate extract (500 mg/kg) was the most effective in the analgesic test similar to standard drugs. In writhing test, ethyl acetate extract (500 mg/kg) showed significantly, inhibiting pain by 73.44 %, similar to aspirin which showed 76.47 % inhibition at the dose of 100 mg/kg i.p. In hot plate test, ethyl acetate extract (500 mg/kg) produced maximum possible analgesia of 12.72 ± 1.15 sec at 90 min, whilst morphine sulfate (5 mg/kg) showed 13.83 ± 1.15 sec. Similarly, carrageenan-induced paw volume was significantly reduced by ethyl acetate extract (500 mg/kg) at 2.20 ± 1.18 4 h after administration similar to that of diclofenac sodium which showed 2.24 ± 1.18 at the dose of 100 mg/kg. The data justify the traditional use of Cyperus rotundus as medicinal plant which has a potential source of bioactive molecules to treat inflammatory diseases.