Furthermore, bruceine D (4) could improve the spinal muscular atrophy (SMA) through enhancing the survival of motor neuron 2 splicing defect contributed by a reduction in the expression of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) (Baek et al., 2019). Here, HNRNPA1 is linked to proximal spinal muscular atrophy.