Background: Extensive bioactivities of alkaloids from the genus Macleaya (Macleaya cordata (Willd.) R. Br. and Macleaya microcarpa (Maxim.) Fedde) have been widely reported, as well as more and more concerned from the scientific communities. However, systematic research on the phytochemical information of M. microcarpa is incomplete. The aim of this study was to rapidly and conveniently qualitative analyze alkaloids from M. microcarpa by ultra-performance liquid chromatography/quadrupole-time-of-fight mass spectrometry (UHPLC–Q-TOF-MS) using accurate mass weight and characteristic fragment ions, furthermore separate and identify the main alkaloids, test antitumor activity in vitro and antiangiogenic activity in vivo. Results: A total of 14 alkaloids from fruits of M. microcarpa were identified by UHPLC–Q-TOF-MS, including 5 protopines, 2 benzophenanthridines, 1 dimer, 1 dihydrobenzophenanthridines and 5 unknown structure compounds. Two major alkaloids were isolated by various column chromatographic methods. Their structures were determined by NMR data and related literatures. The two major alkaloids were evaluated for intro cytotoxic activities against HL-60, MCF-7, A-549, and in vivo antiangiogenic activity using transgenic zebrafish. Conclusions: Current qualitative method based on UHPLC–Q-TOF-MS technique provided a scientific basis for isolation, structural identification, and in vitro or in vivo pharmacological further study of alkaloids from M. microcarpa in the future.

Mitochondrial dysfunction is a hallmark of Parkinson’s disease (PD), but how impaired mitochondrial homeostasis drives the selective death of dopaminergic neurons is still poorly understood. At the center of this problem lies the mitochondrial protein import machinery—the TOM and TIM23 translocases—which doubles as a stress-sensing hub that coordinates two distinct quality control pathways. When import is compromised, the kinase PINK1 accumulates on the mitochondrial surface, recruits Parkin to ubiquitinate outer membrane proteins, and triggers mitophagy. Meanwhile, the stress sensor DELE1 is cleaved and released to the cytosol, where it activates the HRI kinase to phosphorylate eIF2α and engage the integrated stress response (ISR). These two pathways are not independent. Recent work shows they engage in antagonistic crosstalk: the DELE1–HRI–ISR axis suppresses PINK1/Parkin-dependent mitophagy by preserving mitochondrial import efficiency, acting as a molecular brake on organelle clearance. The balance between these pathways is governed by the SIFI E3 ubiquitin ligase complex, which targets both DELE1 and HRI for degradation. Disruption of SIFI causes progressive neurodegeneration in humans. Here we synthesize the structural, biochemical, and genetic evidence that defines the TOM/TIM–PINK1/Parkin–DELE1/HRI signaling axis, examine how its dysregulation contributes to dopaminergic neuron vulnerability, and evaluate therapeutic strategies targeting mitochondrial import stress in PD.