Active compounds and anti-inflammatory activity of the methanolic extracts of the leaves and callus from Tilia americana var. mexicana propagated plants

Tilia americana var. mexicana is used in Mexican traditional medicine to treat anxiety and inflammatory processes. Several glycosides derived from quercetin and kaempferol, including tiliroside, isoquercetin, and quercetin-3--d-glucoside, were reported as the main anxiolytic compounds in this species; to our knowledge, compounds with anti-inflammatory effects have not been previously described. In this study, whole plants were obtained from rooted cuttings with indole-3-butyric acid (IBA) under greenhouse conditions. Multiple shoots and callus cultures were established from apical and axillary buds from T. americana var. mexicana cuttings. The apical buds (75%) were the best explant for shoot induction (2-3 shoots per explant) on Murashige and Skoog (MS) medium supplemented with 2.0mgL(-1) of 6-benzyl aminopurine plus 0.25mgL(-1) -naphthaleneacetic acid. Callogenesis occurred in both types of buds in the treatments constituted by thidiazuron with 0.1mgL(-1) IBA. High-performance liquid chromatography analysis of leaves and callus methanolic extracts allowed the identification of quercetin-3--d-glucoside and tiliroside anxiolytic compounds, and of the scopoletin anti-inflammatory compound. The methanolic leaf and callus extracts showed anti-inflammatory activities in a 12-O-tetradecanoylphorbol-13-acetate-induced ear edema model with median effective doses (ED50) of 0.38 and 1.73mg per ear for the leaf and callus extracts, respectively.