{Author}: Chen Li;Zhao Wei;Jiang Hong Lei;Zhou Jian;Chen Xiao Ming;Lian Yun Yang;Jiang Hong;Lin Feng*

{Journal}: Tetrahedron
{Year}: 2018
{Volume}: 74

{Issue}: 30

{Pages}: 4151-4154

{Keywords}:Anti-anaerobic bacteria activity; Hypoxia-selectivecytotoxicity; Micromonospora chalcea FIM02-523;Rakicidins;Structures elucidation

{Abstract}: Rakicidins G-I (1–3), three new cyclic depsipeptides including a long aliphatic chain without terminal methyl branching were isolated from culture broth of Micromonospora chalcea FIM 02–523, along with rakicidin E (4). Their structures were elucidated by extensive NMR and HR-ESI-MS analyses. Compounds 1–4 were evaluated for their cytotoxic activities against HCT-8 and PANC-1 human tumor cell lines under the hypoxic and normoxic conditions. They were approximately 18.2–20.3-fold more cytotoxic under hypoxic than under normoxic conditions on PANC-1, and compared with 7.4–8.7-fold more cytotoxic under hypoxic than under normoxic conditions on HCT-8. Meanwhile, compounds 1–3 were also tested inhibitory activities against gram positive anaerobic bacteria and the results exhibited MIC values in the range of 0.125–8 μg/mL.