Eh, the whole AMPK / muscle atrophy thing hasn't played out in human clinical settings, only in vitro studies have showed this. If you do intense exercise (which induces PGC-1a and modulates the suppression of muscle hypertrophy in cells) and eat protein throughout the day, there will be plenty of mTOR stimulation.
With all due respect to Biotest, berberine has far more impressive studies on it than cyanidin-3-glucoside. I'm not even sure there is one human in vivo study showing C3G's effects (or its possible absorption problems). Whereas berberine has been shown to be as effective as metformin in human studies, a well-known pharmaceutical for treating type II diabetes.