Anthelmintic and relaxant activities of Verbascum Thapsus Mullein

V. thapsus extracts were tested against roundworms (Ascaridia galli) and tapeworms (Raillietina spiralis). Each species of worm was placed into a negative control group, an albendazole treatment group, or a V. thapsus treatment group, and the time taken for paralysis and death was determined. In addition, relaxation activity tests were performed on sections of rabbit's jejunum. Plant extracts were tested on KCl-induced contractions and the relaxation activities were quantified against atropine. V. thapsus calcium chloride curves were constructed to investigate the mode of action of the plant extracts.

We detected flavonoids, saponins, tannins, terpenoids, glycosides, carbohydrates, proteins, fats and fixed oils in V. thapsus. For both species of worm, paralysis occurred fastest at the highest concentration of extract. The relative index values for paralysis in A. galli were 4.58, 3.41 and 2.08, at concentrations of 10, 20 and 40 mg/ml of plant extract, respectively. The relative index for death in A. galli suggested that V. thapsus extract is wormicidal at high concentration. Similarly, the relative indexes for paralysis and death in R. spiralis suggested that the extract is a more potent wormicidal agent than albendazole. The mean EC₅₀ relaxation activity values for spontaneous and KCl induced contractions were 7.5 ± 1.4 mg/ml (6.57-8.01, n = 6) and 7.9 ± 0.41 mg/ml (7.44-8.46, n = 6), respectively. The relaxation activity of the extract was 11.42 ± 2, 17.0 ± 3, 28.5 ± 4, and 128.0 ± 7% of the maximum observed for atropine at corresponding concentrations. The calcium chloride curves showed that V. thapsus extracts (3 mg/ml), had a mean EC₅₀ (log molar [calcium]) value of -1.9 ± 0.06 (-1.87 - -1.98, n = 6) vs. control EC₅₀ = -2.5 ± 0.12 (-2.37 - -2.56, n = 6), whereas the verapamil (0.1 μM) EC₅₀ was -1.7 ± 0.1 (-1.6 - -1.8, n = 6) vs. control EC₅₀ = -2.4 ± 0.09 (-2.3 - -2.47, n = 5).