Preparation of Lycium barbarum Active Glycopeptide and Investigation of Its Apoptotic Effects on Melanoma

Introduction: The increasing number of studies have shown that Lycium barbarum polysaccharides possess anti-tumor effects. However, the determination of the active ingredients and their mechanism against melanoma inhibition are still unknown. Methods: In this study, we aimed to investigate the mechanisms of action of Lycium barbarum active glycopeptide (LBAG) on melanoma. LBAG was extracted and isolated from the fruit of Lycium barbarum using aqueous alcoholic precipitation and identified using ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry. Various assays including cell apoptosis, cell cycle analysis, colony formation assay, cell scratch test, flow cytometry, and Western blot were performed to evaluate the effects of LBAG on melanoma. Results: The results showed that LBAG has a molecular weight of 10-15 kDa and contains Man, Rha, GlcA, Glc, Gal, and Ara18 amino acids. Treatment with LBAG significantly decreased B16 cell proliferation and induced cell cycle arrest at the G0/G phase, accompanied by the accumulation of reactive oxygen species. Western blot analysis revealed that the phosphorylation of P38-MAPK and AKT, as well as the expression of N-acetyl-L-cysteine, were related to cell apoptosis and cell cycle regulation. In mouse xenografts, LBAG inhibited tumor growth through the P38-MAPK and AKT signaling pathways. Conclusion: In conclusion, the anti-melanoma activity of LBAG may induce apoptosis in cancer cells through ROSmediated activation of the P38-MAPK and AKT signaling pathways. These findings provide a foundation for further research on the anti-melanoma potential of LBAG.