Shen Y.-C.Wang C.-H.Cheng Y.-B.Wang L.-T.JIH-HWA GUHChien C.-T.Khalil A.T.2021-06-022021-06-0220041633864https://www.scopus.com/inward/record.uri?eid=2-s2.0-1642547025&doi=10.1021%2fnp0303658&partnerID=40&md5=609b658d7cc7e1a15e401bbaf38341c7https://scholars.lib.ntu.edu.tw/handle/123456789/564874Bioassay-guided fractionation of an EtOAc-soluble extract of Casearia membranacea has resulted in the isolation of six new clerodane diterpenes, caseamembrins A-F (1-6), and a known compound, rel-(2S,5R,6R,8S,9S,10R,18S,19R)-diacetoxy-18, 19-epoxy-6-hydroxy-2-(2-methylbutanoyloxy)cleroda-3,13(16),14-triene (7). The structures of 1-6 were established on the basis of extensive 1D and 2D NMR spectroscopic analysis. In addition, the new derivatives, 8 and 9, were prepared by acylation of 7 and 3, respectively. The isolated diterpenoids and their derivatives were tested against human prostate (PC-3) and hepatoma (Hep3B) cancer cells. Compounds 1, 3-5, and 7 exhibited cytotoxicity against both tumor cells, with IC50 values below 3 μM, while compounds 2, 6, 8, and 9 were less effective.[SDGs]SDG3caseamembrin a; caseamembrin b; caseamembrin c; caseamembrin d; caseamembrin e; caseamembrin f; Casearia membranacea extract; clerodane derivative; cytotoxic agent; diacetoxy 18,19 epoxy 6 hydroxy 2 (2 methylbutanoyloxy)cleroda 3,13(16),14 triene; diterpenoid; paclitaxel; unclassified drug; article; Casearia; Casearia membranacea; controlled study; cytotoxicity; drug efficacy; drug isolation; drug structure; drug synthesis; human; human cell; IC 50; liver cell carcinoma; plant leaf; prostate cancer; structure analysis; Acetylation; Antineoplastic Agents, Phytogenic; Casearia; Diterpenes, Clerodane; Drug Screening Assays, Antitumor; Humans; Inhibitory Concentration 50; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Plant Leaves; Plants, Medicinal; Taiwan; Tumor Cells, Cultured; Caseariajournal article10.1021/np0303658150434022-s2.0-1642547025