Antimicrobial and anti-oxidant activities of quinoline alkaloids from Pseudomonas aeruginosa BCC76810

Twelve 4-hydroxyquinoline derivatives (1-12) and three phenazine alkaloids (13-15) have been isolated from Pseudomonas aeruginosa BCC76810. All these compounds, except compounds 6, 7, 9, and 11, are known. The new quinolines are 2-((Z)-undec-4'-enyl)-4-hydroxyquinoline (6), 2-(3'-(2'-hexylcyclopropyl) propyl)-4-hydroxyquinoline (7), 2-n-octyl-4-hydroxyquinoline N-oxide (9), and 2-((Z)-undec-4'-enyl)- 4-hydroxyquinoline N-oxide (11). Their structures were elucidated based on the spectroscopic information, such as 1D, 2D NMR, UV, and HRESIMS data. 4-Hydroxyquinolines (1-6) and 4-hydroxyquinoline- N-oxides (8-11) exhibited antimalarial activity against Plasmodium falciparum, K1 strain (IC50 0.25-2.07 mu g/mL) with moderate to weak cytotoxicity against cancerous (KB, MCF-7, NCI-H187) and non-cancerous (Vero) cells. In addition, 4-hydroxyquinoline N-oxides also displayed anti-Bacillus cereus and antioxidant activities. (C) 2016 Phytochemical Society of Europe. Published by Elsevier Ltd. All rights reserved.