Phloroglucinol Derivatives with Protein Tyrosine Phosphatase 1B Inhibitory Activities from Eugenia jambolana Seeds

Fifteen new phloroglucinol derivatives, jamunones A-O (1-8 and 10-16, respectively), along with one known analogue spiralisone C (9), were isolated from Eugenia jambolana seeds. Their structures were elucidated by detailed nuclear magnetic resonance and mass spectrometry spectroscopic data interpretation. Compounds 1-9, 11, 12, and 14-16 inhibited protein tyrosine phosphatase 1B activity with IC50 values ranging from 0.42 to 3.2 mu M.