Tryptophan and Sterols from Salvia limbata

Background: Salvia limbata is an aromatic herbaceous plant and grows widely in Iran Turkey and Afghanistan. In the previous study, six flavones together with rosmarinic acid were isolated from the ethyl acetate and methanol extracts of S. limbata. In this report, we focused on the isolation and identification of the glycosylated sterols and the main accumulated amino acid of the species S. limbata, which has not been previously reported. Methods: Aerial parts of the plant were dried, cut into small pieces and extracted with ethyl acetate and methanol by percolation at room temperature. The separation process was carried out using several chromatographic methods. Structural elucidation was based on NMR data, in comparison with those reported in the literature. Results: The isolated compounds (Figure 1) from the ethyl acetate and MeOH extracts of S. limbata were identified as beta-sitosterol (1), stigmasterol (2), daucosterol (3), stigmasterol 3- O-glucoside (4) and tryptophan (5) by comparison of their NMR spectral data with those reported in the literature Conclusions: S. limbata can accumulate the tryptophan as a major free amino acid together with sterols and their glucosides. Therefore, consumption of S. limbata (as a herbal tea or other preparations), which contains the essential amino acid tryptophan, might be useful for dietary deficiency of tryptophan.