Discovery of spiroindolediketopiperazine alkaloids from Penicillium sp. KYS-32 as dual inhibitors of ABCB1 and ABCG2 to reverse multidrug resistance - Yu-Lei Zhu; Ying Li; Xiang-Yu Liu; Yan-Ping Zhu; Jian-Min Yue; Jin-Hai Yu (Phytochemistry, 2026)