Pauciflorins A–E, Unexpected Chromone–Monoterpene-Derived Meroterpenoids from Centrapalus pauciflorus
journal contributionposted on 2023-03-18, 13:06 authored by Gordana Krstić, Muhammad Bello Saidu, Petra Bombicz, Sourav De, Hazhmat Ali, István Zupkó, Róbert Berkecz, Umar Shehu Gallah, Dóra Rédei, Judit Hohmann
Five unusual meroterpenoids based on new carbon skeletons, pauciflorins A–E (1–5), were isolated by multistep chromatographic separations of a methanol extract of the aerial parts of Centrapalus pauciflorus. Compounds 1–3 are derived by the connection of a 2-nor-chromone and a monoterpene unit, whereas 4 and 5 are dihydrochromone–monoterpene adducts with a rarely occurring orthoester functionality. The structures were solved using 1D and 2D NMR, HRESIMS, and single-crystal X-ray diffraction. Pauciflorins A–E were evaluated for antiproliferative activity against human gynecological cancer cell lines, but were inactive (IC50 < 10 μM) in each case.