Inhibitory activity of Scorzonera latifolia and its components on enzymes connected with healing process

Ethnopharmacological relevance: Scorzonera latifolia (Fisch. & Mey.) DC. (Asteraceae) grows naturally in Eastern Anatolia, northeastern Iran, and Caucasus. Latex of S. latifolia roots is used in Turkish folk medicine for its analgesic effects, externally to cure infertility in women, and internally as an antihelmintic. The milk obtained from the stem of the Scorzonera species is used for wound healing activity. Antinociceptive, anti-inflammatory, wound-healing, antioxidant, and antimicrobial activities have previously been reported for S. latifolia.

Aim of the study: A methanol extract of the aerial parts of Scorzonera latifolia that had been shown to possess wound-healing activity, was used to elucidate the possible mechanism of the wound-healing activity and to identify the compound(s) responsible for the effect by means of bioassay-guided fractionation.

Materials and methods: The wound-healing activity potential of methanol extract of S. latifolia was detected by evaluating the inhibitory activity on the collagenase, hyaluronidase and elastase, which play important roles in the wound-healing process. Succesive fractionation of the methanol extract using petroleum ether, chloroform, ethyl acetate, respectively, and the residual wateryielded four respective fractions. The ethyl acetate part, which was determined as the most active fraction, was selected for further separation using chromatographic techniques.

Results: Ethylacetate fraction exhibited significant inhibitory activities on collagenase and elastase. Chromatographic separation of the ethylacetate extract yielded an active subfraction, from which was used to isolate quercetin-3-O-β-apiofuranosyl-(1'''→2'')-β-D-glucopyranoside (1), quercetin-3-O-α-rhamnopyranosyl-(1→6)-β-D-galactopyranoside (2), isoorientin (3), and 7-methylisoorientin (4). Of the compounds tested, 7-methylisoorientin (4) exerted inhibitory activity on collagenase and elastase, while quercetin-3-O-β-apiofuranosyl-(1'''→2'')-β-glucopyranoside (1) inhibited collagenase only. None of the fractions, or isolated compounds showed any inhibitory effect on hyaluronidase. It must be mentioned, that in vitro tests showed that compounds 1-4 inhibit the collagenase and elastase and could help wound-healing process. However, the inhibititory effect of the methanol extract appears to be greater than that of both of the ethylacetate fraction, subfraction G and the isolated compounds, which suggest that a synergistic interaction of several compounds could be responsible for the wound-healing activity of the aerial parts of S. latifolia.