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.
The study revealed that mesembrine plays a crucial role in kanna's ability to exert anti-depressant effects, acting similarly to a monoamine releasing agent.