Phytochemical fingerprints combined with bioautographic enzyme inhibition and antitumor activity of Verbascum (Scrophulariaceae) and Ajuga (Lamiaceae) plant extractives on skin squamous cell carcinoma

The genera Verbascum and Ajuga with multiple traditional therapeutical uses are rich in phenolic compounds with potential anti-inflammatory, antioxidant and immunomodulatory properties [1]. The aim of this study was to screen the phytochemical and biological potential of the species V. nigrum L. and A. chia Schreb. for prevention and treatment of nonmelanoma skin cancer as part of a joint research project on multitarget activity of plant extract [2]. Methanol (MeOH) extraction of the aerial parts of A. chia and V. nigrum was followed by fractionation by RP-C18 flash chromatography. The phytochemical characterization was assessed by UPLC-DAD-ESI-MS and HPTLC. The latter was linked to (bio)autographic acetylcholinesterase inhibition and DPPH assays. Cytotoxic evaluation of HaCaT and A431 cells treated with extracts and fractions was done by MTT assay, followed by immunofluorescence microscopy. V. nigrum extract contains potential AchE inhibitors. Both plants show presence of antioxidant compounds. Based on UV and MS data we identified for A. chia with high probability luteolin-7-O-glucoside, apigenin and verbascoside and for V. nigrum, verbascoside, harpagoside and possible aucubin derivatives. V. nigrum extract, 100% MeOH and 50% MeOH fractions induced A431 cell apoptosis and decreased the cell invasion. The A. chia extract did not exhibit any cytotoxicity on A431 cell line. None of extracts exhibited cytotoxicity on HaCaT cells. Acknowledgements: Sciex-HMSch CRUS Switzerland No. 13.218 & N. Ciocirlan and V. Ghendov for plant material identification (Botanical Garden of Academy of Sciences of Moldova). References: [1] Nichols JA et al. Arch Dermatol Res 2010; 302: 71 – 8 [2] Millsop J et al. Dermatol Res Pract 2013; 2013: 837152