Isolation And Bioactivity Of Natural Products From Three Medicinal Plants

Three medicinal plants, Casearia balansae (Flacourtiaceae), Ajuga decumbens (Labiatae), and Excoecaria cochinchinensis (Euphorbiaceae) were chemically investigated and their anticancer and antifungal activities have been evaluated. A total of40compounds including15new ones were obtained by classical column chromatography, preparative thin layer chromatography, and HPLC. The structures were determined on the basis of NMR, MS, UV, IR, and single-crystal X-ray crystallographic analysis. The clerodane diterpenoids from C. balansae showed outstanding antiproliferative activity against PC-3and DU145cancer cell lines.Ten new clerodane-type diterpenes, caseabalansins A-J (1-10), one new triterpenoid,22β-hydroxy-9,11-epoxy-9,10-seco-9,19-cyclolanost-2,5(10),25-trien-1-one (11), as well as seven known diterpenoids, rel-(2R,4R,5S,8R,9R,10S,18R,19R)-18,19-diacetoxy-18,19-epoxy-2-hydroxy-cleroda-13(16),14-diene (12), rel-(2S,5R,6R,8S,9S,10R,18S,19S)-18,19-diacetoxy-18,19-epoxy-6-methoxy-2-(2ξ-methylbutanoyloxy)-cleroda-3,13(16),14-triene (13), rel-(2R,4S,5R,8S,9S,10R,18S,19R)-2,18,19-triacetoxy-18,19-epoxy-cleroda-13(16),14-diene (14), rel-(2S,5R,6R,8S,9S,10R,18S,19R)-18,19-diacetoxy-18,19-epoxy-6-hydroxy-2-(2ξ-methylbutanoyloxy)-cleroda-3,13(16),14-trien e (15), caseamembrin A (16), casearlucin B (17), and phytol (18) were obtained from the twigs and leaves of Casearia balansae. The structures of these new compounds were established on the basis of extensive1D and2D NMR spectroscopie data analysis. Compounds1-4,8,9,12,13,15, and17showed significant cytotoxic activity against the PC-3and DU145cancer cell lines. Four new rearranged abietane diterpenoid hydroquinones, ajudecumins A-D (19-22), together with two known rearranged abietane diterpenoids, ajuforrestins A (23) and B (24), three neo-clerodane diterpenoids, dihydroclerodin (25), clerodinins C (26) and D (27), four megastigmane derivatives,(6R,7E,9R)-9-hydroxy-4,7-megastigmadien-3-one (28),(3S,5R,6S,7E)-5,6-epoxy-3-hydroxy-7-megastigmen-9-one (29),(6E,PS)-9-hydroxy-4,6-megastigmadien-3-one (30),6-hydroxy-4,7-megastigmadiene-3,9-dione (31), two flavonoids, luteolin (33) and acacetin (34) as well as a bisabolene sesquiterpenoid, glecholone (32) were isolated from the aerial parts of Ajuga decumbens. Their structures were established on the basis of extensive spectroscopic analysis and the stereochemistry of19was confirmed by single-crystal X-ray diffraction analysis. Among the diterpenoids, compounds19and21exhibited weak inhibitory activity on the proliferation of human breast cancer MCF-7cells.Six known compounds, kaempferol (35), retigeric acid B (36), ursolic acid (37), baccatin (38), p-sitosterol (39), and β-carotene (40) were isolated from the stems and leaves of Excoecaria cochinchinensis. Their structures were elucidated by spectroscopic analysis.