Squamins C–F, four cyclopeptides from the seeds of Annona globiflora

• Published in: Phytochemistry (Oxford) Vol. 194; p. 112839
• Main Authors: Sosa-Rueda, Javier, Domínguez-Meléndez, Vanihamin, Ortiz-Celiseo, Araceli, López-Fentanes, Fernando C., Cuadrado, Cristina, Fernández, José J., Daranas, Antonio Hernández, Cen-Pacheco, Francisco
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 01.02.2022; Elsevier
• Subjects: Amino Acid Sequence; Annona - chemistry; Annona globiflora Schltdl; Annonaceae; Antineoplastic Agents, Phytogenic - pharmacology; Biochemistry & Molecular Biology; Cyclopeptides; Cytotoxic activity; HeLa Cells; Humans; Life Sciences & Biomedicine; Peptides, Cyclic - pharmacology; Phytochemicals - pharmacology; Plant Sciences; Science & Technology; Seeds - chemistry; Annona globiflora Schltdl; Annonaceae; Cyclopeptides; Cytotoxic activity; STEREOCHEMISTRY; CONFIGURATION; DIASTEREOISOMERS
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2021.112839

Four cyclic octapeptides, squamins C–F, were isolated from the seeds of Annona globiflora Schltdl. These compounds share part of their amino acid sequence, -Pro-Met(O)-Tyr-Gly-Thr-, with previously reported squamins A and B. Their structures were determined using NMR spectroscopic techniques together with quantum mechanical calculations (QM-NMR), ESI-HRMS data and a modified version of Marfey's chromatographic method. All compounds showed cytotoxic activity against DU-145 (human prostate cancer) and HeLa (human cervical carcinoma) cell lines. Clearly, A. globiflora is an important source of bioactive molecules, which could promote the sustainable exploitation of this undervalued specie. Four previously undescribed cyclopeptides, squamins C–F, were isolated from the seeds of Annona globiflora Schltdl. with cytotoxic activity against the cell lines, DU-145 and HeLa. [Display omitted] •Squamins C–F, first report of cyclopeptides in Annona globiflora.•The structures were determined by computational and spectroscopic methods (QM-NMR).•Cytotoxic activity against the cell lines: DU-145 and Hela, in the range of 8–25 μM.