Spasmolytic activity of Phagnalon saxatile (L.) Cass. on the isolated rat ileum

The genus Phagnalon (Asteraceae) is represented by about 30 species, six of which are typical of the Mediterranean region [1]. Different Phagnalon spp. are used in traditional medicine: in the Negev desert these plants are used for the healing of burns among the Bedouins [2] and in the Palestinian area to treat asthma, headache and as an analgesic for toothache [3]. Phagnalon saxatile (L.) Cass. is one of the five suffruticous chamaephyte species growing wild in Southern Italy [4]. Since the plant is traditionally used in Sicily to treat abdominal spasms and since phytochemical and pharmacological information on this species is limited, we investigated the potential antispasmodic effect of a methanolic extract obtained from the flowering aerial parts of P. saxatile (PsE) in the rat ileum. For this study, aerial parts of P. saxatile were collected in Capo Zafferano (PA, Southern Italy). Plant material was sequentially extracted with petroleum ether, CHCl₃ and CH₃OH (% w/w: petroleum ether 1.89%, CHCl₃ 1.98% and CH₃OH 3.67%). The methanolic solution was concentrated obtaining a residue that was chromatographed on a Sephadex column, eluting with CH₃OH. Further purification by reverse HPLC gave pure apigenin 7-O-β-D glucopyranoside, luteolin 4'-O-β-D glucopyranoside, caffeic acid, chlorogenic acid, methyl chlorogenate, 3,5-di-O-caffeoylquinic acid and two hydroquinone glucosides. Pharmacological assay showed that PsE, at concentrations ranging from 1 to 100µM, inhibited in a concentration-dependent manner the contractions induced by acetylcholine in the isolated rat ileum (% inhibition: 1µg/ml 6.3±1.6; 3µg/ml 26.5±7; 10µg/ml 35.7±4; 30µg/ml 59±3; 100µg/ml 62.2±3. P<0.05at 3µg/ml and 10µg/ml; P<0.01at 30µg/ml and 100µg/ml, n=6). These preliminary results might provide a first pharmacological basis underlying the traditional use of this plant in the treatment of intestinal spasms.

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