Discovery of Indole Alkaloids Crienamides A and B from Penicillium citrinum by a Simulated MS/MS-Guided Molecular Network Strategy

The building blocks-based molecular network (BBMN) strategy is effective for targeted natural product identification but depends on existing MS/MS data. To address this, we propose the simulated MS/MS-guided molecular network (SMMN) strategy, which combines virtual molecule design and MS/MS simulation to identify novel compounds containing target building blocks. We developed the MZmol Analyzer, a user-friendly web tool, to automate the SMMN strategy. Using this approach and the target 6-methyl-l-pipecolate (6-MeP), we identified two new indole alkaloid hybrids, crienamides A and B. In vitro immunosuppressive assays showed that both compounds inhibited ConA-induced cell proliferation, with IC₅₀ values of 2.86 ± 1.33 μM and 0.96 ± 1.22 μM, respectively.