Anticholinesterase, antioxidant, analgesic and anti-inflammatory activity assessment of Xeranthemum annuum L. and isolation of two cyanogenic compounds.

BACKGROUND

Xeranthemum annuum L. (Asteraceae) (XA) is an ornamental and medicinal species with limited bioactivity and phytochemical data.

OBJECTIVE

Identification of anticholinesterase, antioxidant, anti-inflammatory and analgesic effects of the flower and root-stem (R-S) extracts of XA.

METHODS

Anticholinesterase (at 100 μg mL-1) and antioxidant (at 1000 μg mL-1) effects of various extracts were evaluated via microtiter assays, while anti-inflammatory and analgesic effects of the R-S extracts were tested using carrageenan-induced hind paw oedema (100 and 200 mg kg-1) and p-benzoquinone (PBQ) writhing models (200 mg kg-1) in male Swiss albino mice. The R-S ethanol extract of XA was subjected to isolation studies using conventional chromatographic methods.

RESULTS

Most of the extracts showed inhibition over 85% against butyrylcholinesterase and no inhibition towards acetylcholinesterase. The flower chloroform and the R-S ethyl acetate extracts were most effective (97.85 ± 0.94% and 96.89 ± 1.09%, respectively). The R-S ethanol extract displayed a remarkable scavenging activity against DPPH (77.33 ± 1.99%) and in FRAP assay, while the hexane extract of the R-S parts possessed the highest metal-chelating capacity (72.79 ± 0.33%). The chloroform extract of the R-S caused a significant analgesic effect (24.4%) in PBQ writhing model. No anti-inflammatory effect was observed. Isolation of zierin and zierin xyloside, which were inactive in anticholinesterase assays, was achieved from the R-S ethanol extract.

CONCLUSIONS

This is the first report of anticholinesterase, antioxidant, analgesic and anti-inflammatory activities and isolation of zierin and zierin xyloside from XA. Therefore, XA seems to contain antioxidant and BChE-inhibiting compounds.