In an in vitro study published in 2015, researchers concluded that "a high-mesembrine Sceletium extract" may exert anti-depressant effects by acting as a monoamine releasing agent." As such, mesembrine likely plays a dominant role in the antidepressant effects of kanna.
Researchers discovered in 2015 that a concentrated Sceletium extract containing high levels of mesembrine may help alleviate depression by mimicking the action of a monoamine releasing agent. As such, mesembrine is thought to be the main contributor to kanna's antidepressant effects.