Bioassay-guided isolation of anti-inflammatory, antinociceptive and wound healer glycosides from the flowers of Verbascum mucronatum Lam.

Abstract

The leaves, flowers and whole aerial parts of Verbascum L. species have been used to treat respiratory problems, haemorrhoids and other types of inflammatory conditions in traditional Turkish medicine. In order to evaluate this traditional information, the anti-inflammatory, antinociceptive and wound healing activities of Verbascum mucronatum Lam. which is used as haemostatic in Turkish folk medicine were investigated. In vivo inhibitory effect of the extracts on the carrageenan-induced hind paw edema model in mice was studied for the assessment of anti-inflammatory activity. Moreover, the wound healing potential of the plant were evaluated by using in vivo wound healing experimental models, i.e. incision and excision models on mice and rats, were comparatively assessed with a reference ointment Madecassol(®). Skin samples were also evaluated histopathologically. The results of these experimental studies exhibited that Verbascum mucronatum displays anti-inflammatory, antinociceptive and wound healing activities. Through bioassay-guided fractionation and isolation procedures four iridoid glucosides, ajugol (1), aucubin (2), lasianthoside I (3), catalpol (4), two saponins, ilwensisaponin A (5) and C (6) and a phenylethanoid glycoside, verbascoside (7) were isolated and their structures were elucidated by spectral techniques. Verbascoside (7) was found to possess significant wound healing activity as well as antinociceptive and anti-inflammatory potentials, per os without inducing any apparent acute toxicity or gastric damage. The experimental study revealed that Verbascum mucronatum displays remarkable antinociceptive, anti-inflammatory and wound healing activities.