Rare diphenylheptanoid-phenylheptanoid hybrids with α-glucosidase inhibitory effects from the pollen of Typha angustifolia

Two rarely occurring diphenylheptanoid-phenylheptanoid hybrid dimers (1 and 2) and one new oxygenated fatty acid (3), as well as two known fatty acid analogues (4 and 5), were isolated from the 70% EtOH extract of the pollen of Typha angustifolia. Their planar structures were established by interpretation of MS and NMR spectroscopic data, and the absolute configurations of 1 and 2 were determined by Mosher's method and quantum chemical TD-DFT calculations of ECD spectra. An in vitro anti-diabetic evaluation of these isolates revealed that compounds 1 and 2 exhibited promising inhibitory activity against α-glucosidase with IC₅₀ values of 11.85 ± 0.69 and 17.06 ± 3.08 μM, respectively. It is the first report on both diphenylheptanoid constituents and α-glucosidase inhibitors from the title plant, which represents a significant phytochemical progress of this herbal species and may serve as a reference for its future medicinal applications.