Study On The Antitumor Effects Of Streptocaulon Griffithii And Scutellaria Barbata & Quality Control Of Scutellaria Barbata

Traditional Chinese Medicines and natural plants are the important source of novel antitumor drugs. In this thesis, Streptocaulon griffithii and Scutellaria barbata were chosen as objects for exploring antitumor compounds and their mechanisms. We also established the methodology for quality control of Scutellaria barbata and its bioactive fraction.In our study, nine compounds from Streprocaulon griffithii exhibited antitumor activity by MTT assay. Griffithin, a new compound from this plant, inhibited the proliferation of several human cancer cells in vitro, with IC50 ranging from 0.17 μg.mL^-1 to 0.43 μg.mL^-1. Griffithin was shown to induce apoptosis in PC-3 cells by AO/EB double decoration assay and flow cytometry.Cell viability assay and MTT assay were used to screen five fractions of Scutellaria barbata. Methylene chloride extract and ethyl acetate extract showed antitumor activity. These two fractions were further separated. Bioassay-guided fractions led to the isolation of flavonoids with promising antitumor activities. Especially, apigenin (IC₅₀ 3.25¹1.54μg.mL^-1), luteolin (IC₅₀ 9.45^>25μg.mL^-1) and kaempferol (IC₅₀ 6.78²2.07μg.mL^-1) had promising antitumor activity against a broad spectrum of human tumor. The results indicated that total flavonoids of Scutellaria barbata was the main antitumor fraction.The fingerprint of Scutellaria barbata was established by HPLC. "Similarity Evaluation System for Chromatographic Fingerprint of TCM" was used to evaluate the similarity of Scutellaria barbata, and 12 common peaks were separated. Similarities were over 90.0% in Scutellaria barbata collected from eight different habitats. The relative standard deviations (RSD) of the repeatability, precision and stability were less than 3%. The method is accurate with good reproducibility and could be used for quality control of Scutellaria barbata.Finally, an HPLC method was established for fingerprinting and simultaneouslyquantitative analysis of four bioactive constituents, scutellarin, isoscutellarein-8-O-gIucuronide, isoscutellerein, luteolin in total flavonoids of Scutellaria barbata (FSB). The proposed method was verified to be simple, accurate, and sensitive, and could be applied to quality control of FSB.