Diabetic nephropathy-related active cyclic peptides from the roots of Brachystemma calycinum

Three new cyclic peptides, namely duanbanhuains A-C (1-3), were isolated from the roots of Brachystemma calycinum which is a traditional medicine used to treat rheumatic diseases. Their structures were identified by means of a suite of MS and NMR experiments. These compounds were purposely evaluated for their inhibitory effects on the release of MCP-1, IL-6, collagen IV and reactive oxygen species (ROS) against high-glucose-stimulated mesangial cells. The results showed that compounds 1 and 2 exhibited potent inhibition on the production of IL-6, collagen IV and ROS at the concentration of 10 mu M. (C) 2011 Elsevier Ltd. All rights reserved.