Accroding to the report by WHO, cancer is a leading cause of death worldwide, and accounting for nearly 10 million deaths in 2020. [1]. So far, surgery, chemotherapy and radiotherapy are still the main methods of treating tumors. [2,3]. Chemotherapy is an effective treatment method, especially for some tumors that tend to spread throughout the body and those that have metastasized. [4,5]. However, most clinical antitumor drugs cause great side effects. [[6], [7], [8]]. At the same time, there is also the possibility of tumor resistance and recurrence. [9,10]. Consequently, there is an urgent need to discover potential new anti-tumor drugs.

Sambutoxin derivatives are typical representatives of 4-hydroxy-2-pyridone, they have generated considerable attention for excellent biological activity. [[11], [12], [13]]. For example, (−)-sambutoxin [11], ilicicolin H [14], and leporin B [15] have a 4-hydroxy-5-phenyl-2-pyridone skeleton and have shown cytotoxic, antitumor, and antimicrobials activities. [11,14,15]. In Aug 2021, a series of sambutoxin derivatives were isolated by our research group from a marine mangrove endophytic fungus Talaromyces sp. CY-3. [16]. Recently, several containing 4-hydroxy-5-phenyl-2-pyridone skeleton analogues were found to have potential anticancer activity. In order to obtain a series of sambutoxin derivatives, discover new anticancer reagent and investigate the structure-activity relationship (SAR). Inspired by OSMAC strategy, Talaromyces sp. CY-3 was cultured in PDB medium under artificial simulation marine conditions different from previously.

To obtain a family of sambutoxin homologs, a visible molecular network was established by the LC-MS/MS of the extracts of Talaromyces sp. CY-3 for rapidly tracking and deduplication (Fig. 1). Guided by MS/MS-based molecular networking through the GNPS platform. [17,18]. A small clusters of compounds were tracked for isolation with m/z 336 [M + H]+, 352 [M + H]+, 422 [M + H]+, 424 [M + H]+, 434 [M + H]+, 438 [M + H]+, 440 [M + H]+, 452 [M + H]+, 454 [M + H]+ and 470 [M + H]+, led to the isolation of five new sambutoxins (1–2, 4, 8–9) and seven known analogues (3, 5–7, 10–12) (Fig. 2).

Herein, we report details of the isolation, structure elaboration, cytotoxicity to tumor cell lines of sambutoxins (1–12) and the antitumor molecular mechanism of 10.