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Updated: Feb 14, 2026

Flavonoid Content During the Growth and Floral Development of Calendula officinalis L.
Published on: June 27, 2025
New geranyl flavonoids from the leaves of Artocarpus communis
Masamitsu Inoue1, Yuki Hitora1, Hikaru Kato1
1Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto, 862-0973, Japan.
Abstract:
Four new geranyl flavonoids 1-4 and four known flavonoids 5-8 were obtained from the leaves of Artocarpus communis collected in Indonesia. The planar structures of flavonoids were elucidated by analyses of MS and NMR spectroscopic data. Absolute configurations of 1 and 2 were determined by ECD spectroscopy. Analyses by HPLC with a chiral-phase column and ECD spectra confirmed that 3 and 4 were stereoisomeric mixtures and 7 and 8 were racemic mixtures. The compounds obtained in this study inhibited the enzymatic activities of ubiquitin-specific protease 7 (USP7) and the chymotrypsin-like activity of the proteasome. Among the geranyl flavonoids tested in this experiment, the USP7 inhibitory activity of 6 (IC50 value, 0.094 μM) was 55 times more potent than the commercially available positive control, P5091 (IC50 value, 5.2 μM).
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Leaving Groups
In general, in a nucleophilic substitution reaction, a nucleophile displaces a functional group, called the leaving group, from the substrate to give a substituted product. A leaving group departs the substrate molecule through heterolytic cleavage, taking the pair of electrons with it to become a relatively stable weak base in the form of an anion or a neutral molecule.
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