Steroidal Saponins from the Bulbs of Chinese Onion ( Allium chinense G. Don) and Their Antiproliferation Potential

Chinese onion (Allium chinense G. Don) is a widely consumed edible vegetable across East Asia, recognized for its dual use as both a food and a medicinal resource. Its bulbs are recognized as dietary resources that are rich in bioactive steroidal saponins. This study conducted a systematic phytochemical investigation of Chinese onion bulbs, leading to the isolation of 20 steroidal saponins, including 13 previously undescribed compounds. Antiproliferative screening against gastric cancer (AGS) cells established that compound 1 possesses potent cytotoxicity. Mechanistic evaluations revealed that 1 suppressed AKT phosphorylation, triggered excessive intracellular reactive oxygen species (ROS) accumulation, and induced mitochondrial dysfunction, ultimately activating caspase-dependent apoptosis. Molecular docking and cellular thermal shift assay (CETSA) suggested a potential interaction between compound 1 and AKT. These findings significantly expand the chemical diversity of Chinese onions and highlight their steroidal saponins as promising dietary leads for gastric cancer intervention through the AKT-mediated oxidative stress and mitochondrial apoptosis pathways.