Cytotoxic Bisnor- and Norditerpene Dilactones Having 7α,8α-Epoxy-9,11-enolide Substructure from Podocarpus macrophyllus D. DON

Kimihiko Sato, Yasunori Inaba, Hyun-Sun Park, Toshiyuki Akiyama, Tetsuo Koyama, Haruhiko Fukaya, Yutaka Aoyagi, Koichi Takeya
2009 Chemical and pharmaceutical bulletin  
Podocarpus macrophyllus D. DON (Podocarpaceae) (Japanese name: Inumaki) is a dioecious evergreen tree distributed in the subtropical areas of south eastern China, Taiwan, and Japan. From this plant, flavonoids, bisflavonoids, norditerpenoids, and ecdysons have been obtained. 1-4) In our recent study, several bisnor-and norditerpenoids having potent cytotoxic activities against P388 murine leukemia cells were isolated and their structures were determined. 5-7) In the present study, from the root
more » ... and bark of this plant, we isolated fourteen new bisnor-and norditerpenoides, makilactones E-R, along with thirteen known ones. This paper describes the isolation and structural elucidation of those new bisnor-and norditerpenoides, revision of the structures of two of the thirteen known ones isolated and their cytotoxic activities. Results and Discussion Dried root of Podocarpus macrophyllus D. DON (22.66 kg) was extracted with MeOH (45 lϫ3) at room temperature. The combined MeOH extract was concentrated and the residue (614 g) was subjected to Diaion ® HP-20 resin column chromatography (10 cmϫ40 cm) eluting sequentially with H 2 O/MeOH (1 : 0, 1 : 1, 1 : 4, 0 : 1) and acetone (each 5 l). By silica gel column chromatography (CHCl 3 -MeOH) and subsequent repeated reversed-phase HPLC (MeCN-H 2 O, MeOH-H 2 O), the fraction eluted with H 2 O/MeOH (1 : 1) (71.6 g) gave ten new bisnor-and norditerpenoids, makilactones E [(1) 1.8 mg], F [(2) 13.0 mg], G [(3) 95.0 mg], J [(6) 9.6 mg], K [(7) 13.0 mg], L [(8) 6.0 mg], M [(9) 2.0 mg], O [(11) 6.0 mg], P [(12) 1.2 mg] and Q [(13) 64.0 mg] and four known bisnor-and norditerpenoides, podolactone B 9) [(15) 23.0 mg], rakanmakilactone H 7) [(20) 12.0 mg], inumakilactone A 7) [(21) 3.5 mg] and inumakilactone A 15-O-b-D-glucoside 2) [(23) 6.8 g]. By analogous chromatographic separation, the fraction eluted with H 2 O/MeOH (1 : 4) (82.4 g) gave makilactones H [(4) 3.3 mg], I [(5) 11.0 mg], N [(10) 3.9 mg] and R [(14) 15.6 mg] along with known ones, inumakilactone B 10) [(16) 24.0 mg], 3-deoxy-2a-hydroxynagilactone E 11) [(18) 62.0 mg], nagilactone E 11) [(19) 46.0 mg], salignone M 12) [(22) 9.4 mg], podolactone D 5) [(24) 6.5 mg] and rakan-makilactone C 6) [(27) 4.0 mg]. By the procedures described above, a MeOH extract of the bark of this plant gave three known norditerpenoids, nagilactone G 8) [(17) 7.0 mg], rakanmakilactone D 6) [(25) 11.8 mg] and sellowin B 13) [(26) 1.3 mg]. Makilactone E (1) was isolated as colorless needles, mp 283°C. The molecular formula was determined to be C 18 H 21 O 8 Cl from the [MϩNa] ϩ ion peak at m/z 423.0815 in HR-electrospray ionization (ESI)-MS. IR absorption bands for hydroxyl and, g-lactone and d-lactone carbonyl groups were observed at 3437 cm Ϫ1 , 1765 cm Ϫ1 and 1715 cm Ϫ1
doi:10.1248/cpb.57.668 pmid:19571410 fatcat:v55p5vxygfdrpiswvobfutiwhi