New neo-Clerodane Diterpenoid Alkaloids from Scutellaria barbata with Cytotoxic Activities

• DOI: 10.1248/cpb.56.207
• Publication Date: 2008-02-01T05:50:20Z
• Authors: Sheng-Jun Dai; Dong-Dong Liang; Yan Ren; Ke Liu; Li Shen
• Keywords: Magnetic Resonance Spectroscopy; Plants, Medicinal; Molecular Structure; Plant Extracts; Scutellaria; Spectrometry, Mass, Fast Atom Bombardment; Antineoplastic Agents, Phytogenic; 01 natural sciences; KB Cells; Diterpenes, Clerodane; 0104 chemical sciences; 3. Good health; Methylene Blue; Alkaloids; Cell Line, Tumor; Humans; Spectrophotometry, Ultraviolet; Diterpenes; Drug Screening Assays, Antitumor; HT29 Cells; Nuclear Magnetic Resonance, Biomolecular; Chromatography, High Pressure Liquid; Drugs, Chinese Herbal

Two new neo-clerodane diterpenoid alkaloids, scutebarbatine O (1) and 6-O-nicotinoylscutebarbatine G (2), were isolated from the whole plant of Scutellaria barbata. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR analyses. In vitro, compounds 1 and 2 showed cytotoxic activities against three human tumor cell lines, namely, HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells, and with IC(50) values in the range of 2.1-5.7 microM.