Joost™ - Open Source - libb
http://opensource.joost.com/libb
"We have been developing a triple store called B, a very low level C library. One of its uses is as a backend store for redland."
Cocoa Bindings for Redland
http://kianga.kcore.de/2004/redland-objc
"These are Objective-C/Cocoa bindings for the Redland RDF Application Framework."