Isolation, bioevaluation and RP-HPLC method development for the chemical constituents of aerial parts of Scutellaria prostrata Jacq. ex Benth

Scutellaria (Lamiaceae), commonly known as skullcaps, is one of the most popular and multi-purpose herb used in China traditionally for treatment of inflammation, hypertension, cardiovascular diseases, bacterial and viral infections. Chemical investigation of methanolic extract of aerial parts of Scutellaria prostrata, a perennial herb growing as a lonely species in Kashmir Himalaya, led to the isolation of eight known constituents viz. chrysin (1), acteoside (2), martynoside (3), leucosceptoside A (4), complanatin (5), daucosterol (6), stigmasterol (7) and 1-hexacosanol (8). The isolated compounds were characterized on the basis of spectral data. A simple RP-HPLC isocratic elution method comprising of MeOH:Water (35:65) was was developed for the compounds depicting clear baseline separation with reasonable retention time and no tailing and fronting of peaks which were highly symmetric and well resolved for all analytes. was observed.. Only two compounds viz., 1 and 5 showed significant antioxidant activity at 100 µM in both DPPH and FRAP assay. All the isolated compounds exhibited dose-dependent cytotoxic effects against four different human cancer cell lines viz. pancreatic (Mia-Paca-2), lung (A-549), breast (MCF-7) and leukemia (HL-60), when tested at different concentrations (10-100 μM). Compounds 1 and 7 showed promising antitubercular activity against Mycobacterium tuberculosis (H37Rv) strain with MIC values of 25 μg/ml and 12.5 μg/ml. Based on the results obtained we can safely conclude that the developed method along with the biological screening can serve as a quality control method for standardisation of Scutellaria prostate and platform for deeper understanding of pharmacological importance of this medicinal plant.