Anti-inflammatory and cytotoxic carbazole alkaloids from Murraya kwangsiensis. (February 2020) - Chen, Yuemei
Abstract: Chemical investigation of the traditional Chinese medicine, Murraya kwangsiensis, led to the isolation of 16 undescribed biscarbazole alkaloids, kwangsines A–M, two undescribed natural products, (+/−)-bispyrayafoline C, and 19 known monomeric analogues. (±)-Bispyrayafoline C and (±)-kwangsines A–C are four pairs of biscarbazole atropisomers, and they were separated by chiral HPLC to obtain the optically pure compounds. The structures of the undescribed compounds were elucidated on the basis of HRESIMS and NMR data analysis. Their absolute configurations were assigned via comparison of the specific rotation, ECD exciton coupling method, as well as comparison of experimental and calculated ECD data. A compound showed significant inhibition on NO production in lipopolysaccharide-stimulated BV-2 microglial cells, and four compounds exhibited moderate cytotoxicities against HepG2 cells, with IC50 values less than 20 μM. Graphical abstract: Sixteen undescribed bicarbazole alkaloids, two undescribed natural bispyranocarbazoles, along with 21 known analogues were isolated from Murraya kwangsiensis . Image 1 Highlights: Sixteen undescribed biscarbazole alkaloids were isolated from Murraya kwangsiensis. Four pairs of biscarbazole atropisomers were chirally separated. One compound showed significant inhibitory activity against NO production in BV-2 cells. Four compounds exhibited moderate cytotoxicities against HepG2 cells.