Efficient extraction and isolation of skimmianine from New Caledonian plant Medicosma leratii and evaluation of its effects on apoptosis, necrosis, and autophagy

•An optimized extraction and purification of Medicosma leratii is proposed.•Ultrasound assisted extraction gave the highest yields for skimmianine.•Two furoquinoline and two acridone alkaloids were isolated by HPCCC.•The crude extract and skimmianine were potent pro-apoptosis inducers HeLa cells.•Skimmianine augmented the pro-apoptotic properties of sorafenib.