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

Biologically active quinoline and quinazoline alkaloids part II

“…Several 4‐hydroxyquinoline alkaloids, including six known (2‐n‐octyl‐4‐hydroxyquinoline ( 110 ), 2‐ n ‐nonyl‐4‐hydroxyquinoline ( 111 ), 2‐ n ‐undecyl‐4‐hydroxyquinoline ( 112 ), 2‐(E)‐non‐1′‐enyl‐4‐hydroxyquinoline ( 113 ), n ‐heptyl‐4‐hydroxyquinoline N ‐oxide ( 116 ), 2‐ n ‐nonyl‐4‐hydroxyquinoline N ‐oxide ( 118 )) and four new (2‐((Z)‐undec‐4′‐enyl)‐4‐hydroxyquinoline ( 114 ), 2‐(3′‐(2′‐hexylcyclopropyl)propyl)‐4‐hydroxyquinoline ( 115 ), 2‐ n ‐octyl‐4‐hydroxyquinoline N ‐oxide ( 117 ) and 2‐((Z)‐undec‐4′‐enyl)‐4‐hydroxyquinoline N ‐oxide ( 119 )) compounds as well as 3‐ n ‐heptyl‐3‐hydroxyquinoline‐2,4(1H,3H)‐dione ( 120 ) (Figure ) from Pseudomonas aeruginosa BCC76810 were evaluated for antimalarial effects. Most of the 11 compounds, including both 4‐hydroxyquinolines ( 110 ‒ 114 ) and 4‐hydroxyquinoline‐ N ‐oxides ( 116 ‒ 119 ), exhibited activity against P. falciparum , K1 strain (IC 50 = 0.25‒2.07 μg/mL) with moderate to weak cytotoxicity against cancerous (KB, MCF‐7, NCI‐H187 (lung cancer)) and noncancerous (Vero) cells …”

“…Meanwhile, 4‐oxo‐1,4‐dihydroquinoline‐3‐carboxamide ( 149 ) (Figure ) from Nocardiopsis terrae YIM 90022 showed antimicrobial activity against S. aureus , B. subtilis , and E. coli with MICs of 64, 64, and 128 μg/mL and antifungal activity against P. oryzae with an MIC of 256 μg/mL . 4‐Hydroxyquinoline N ‐oxides also displayed anti‐ Bacillus cereus activity, and 5‐hydroxy‐4‐(chloromethyl)‐5,6,7,8‐tetrahydroquinoline ( 150 ) (Figure ) from a Belize extract inhibited the growth of pathogenic, saprophytic marine fungi, and marine bacteria …”

“…The furoquinoline alkaloid haplopine‐3,3′‐dimethylallyl ether, isolated from Vepris glomerata , has strong antioxidant effects, similar to and, in some instances, better than those of ascorbic acid.19 2 This alkaloid together with two additional furoquinoline alkaloids dictamnine and robustine inhibited superoxide anion generation (IC 50 = 13.0, 17.4, 32.8, 26.1 μM, respectively) and elastase release (IC 50 = 19.6, 12.1, 29.3, 32.2 μM, respectively) . In addition, various 4‐hydroxyquinoline N ‐oxides also displayed antioxidant activities, with 2‐ n ‐nonyl‐4‐hydroxyquinoline N ‐oxide showing the best antagonist activity . The nitrogen oxide group was essential for the activity, as well as the length of the alkyl chain.…”

“…Skimmianine showed weak antimicrobial oryzae with an MIC of 256 g/mL. 120 4-Hydroxyquinoline N-oxides also displayed anti-Bacillus cereus activity, 90 and planktonic cells and biofilms (MIC ≤32 g/mL). 123 However, the selectivities were much weaker (SI, 0.3-5) compared with those of fluconazole and caspofungin (>100).…”

“…191 the best antagonist activity. 90 The nitrogen oxide group was essential for the activity, as well as the length of the alkyl chain. The oxygen radical absorbance capacity (ORAC) value of cleistopholine, a quinoline alkaloid found in A. salzmannii, was 0.25 relative trolox equivalents.…”