Chemopreventive Agents from Physalis minima Function as Michael Reaction Acceptors

BACKGROUND: The fruits of some varieties of genus Physalis have been used as delicious fruits and functional food in the Northeast of China. MATERIALS AND METHODS: To reveal the functional material basis, we performed bioactivity-guided phytochemical research and chemopreventive effect assay of the constituents from Physalis minima. RESULTS: It was demonstrated that the ethyl acetate extract of P. minima L. (EEPM) had potential quinone reductase (QR) inducing activity with induction ratio (IR, QR induction activity) value of 1.47 ± 0.24, and glutathione binding property as potential Michael reaction acceptors (with an α, β-unsaturated ketone moiety). Furthermore, bioactivity-guided phytochemical research led eight compounds (1–8), which were elucidated as 3-isopropyl-5-acetoxycyclohexene-2-one-1 (1), isophysalin B (2), physalin G (3), physalin D (4), physalin I (5), physordinose B (6), stigmasterol-3-O-β-D-glucopyranoside (7) and 5α-6β-dihydroxyphysalin R (8) on the basis of nuclear magnetic resonance spectroscopy analyses and HRESIMS. Then, isophysalin B (2) and physordinose B (6) showed significant QR inducing activity with IR value of 2.80 ± 0.19 and 2.38 ± 0.46, respectively. SUMMARY: An ultra-performance liquid chromatographic method with glutathione as the substrate was used to detect the Michael reaction acceptors in extracts of Physalis minima (EPM). We investigated the chemical constituents of EPM guided by biological activity method. Isophysalin B (1) and physordinose B (6) showed strong quinone reductase inducing activity with induction ratio values of 2.80 ± 0.19 and 2.38 ± 0.46. This study generated useful information for consumers and many encourage researchers to utilize edible fruits from Physalis as a source of phytochemicals. Abbreviations used: EPM: Extracts of Physalis minima, EEPM: Ethyl acetate extract of Physalis minima L., GSH: Glutathione, MRAs: Michael reaction acceptors, QR: Quinone reductase.