Secondary Metabolite Production in Callus Culture of Verbascum scamandri Murb.

Verbascum scamandri Murb. known as "Kazdağı Mullein" is an endemic species in Türkiye and is classified as an endangered (EN) species. The aim of this study is to establish an efficient callus culture for V. scamandri and analyze the amounts of verbascoside, luteolin, and aucubin metabolites of calli samples. Leaf explants were cultured on MS medium with cytokinin (BAP, Kin, 0, 0.5, 1, 2, 3 mg/L) and auxin (NAA, 2,4-D, 0, 0.1, 0.5, 1 mg/L), 1 g/L PVP, 3% sucrose, and 0.7% agar for callus induction. Callus tissue in MS with 2 mg/L Kin, 0.5 mg/L Kin+0.5 mg/L 2,4-D, 2 mg/L Kin+0.5 mg/L 2,4-D, and 3 mg/L Kin+0.5 mg/L 2,4-D was proliferated in MS basal medium containing PGR at the same concentrations and combinations as the callus induction media. Verbascoside, luteolin, and aucubin were quantified in leaf samples of the in vivo collected plants, leaf samples of in vitro growing plants, and calli using HPLC-DAD. According to the results, the verbascoside content in the leaf of collected plants was 7.03 mg/g, luteolin was 0.66 mg/g, and aucubin was 2.99 mg/g. The leaf of in vitro plants had 1.62 mg/g verbascoside, 0.18 mg/g luteolin, and 1.32 mg/g aucubin. Whereas, the maximum content of secondary metabolites in the callus samples was observed 13.77 mg/g verbascoside in MS medium with 2 mg/L Kin, 0.51 mg/g luteolin in MS medium with 2 mg/L Kin+0.5 mg/L 2,4-D, and 9.32 mg/g aucubin in 0.5 mg/L Kin+0.5 mg/L 2,4-D.