Diterpenoid Dimers Research Articles

Aphadilactones A–D, Four Diterpenoid Dimers with DGAT Inhibitory and Antimalarial Activities from a Meliaceae Plant

Aphadilactones A-D (1-4), four diastereoisomers possessing an unprecedented carbon skeleton, were isolated from the Meliaceae plant Aphanamixis grandifolia. Their challenging structures and absolute configurations were determined by a combination of spectroscopic data, chemical degradation, fragment synthesis, experimental CD spectra, and ECD calculations. Aphadilactone C (3) with the 5S,11S,5'S,11'S configuration showed potent and selective inhibition against the diacylglycerol O-acyltransferase-1 (DGAT-1) enzyme (IC50 = 0.46 ± 0.09 μM, selectivity index > 217) and is the strongest natural DGAT-1 inhibitor discovered to date. In addition, compounds 1-4 showed significant antimalarial activities with IC50 values of 190 ± 60, 1350 ± 150, 170 ± 10, and 120 ± 50 nM, respectively.

Cytotoxic cassaine diterpenoid–diterpenoid amide dimers and diterpenoid amides from the leaves of Erythrophleum fordii

Detailed phytochemical investigation from the leaves of Erythrophleum fordii resulted in the isolation of 13 compounds, including three cassaine diterpenoid–diterpenoid amide dimers ( 1, 3 and 5), and seven cassaine diterpenoid amides ( 6 and 8– 13), together with three previously reported ones, erythrophlesins D ( 2), C ( 4) and 3 β-hydroxynorerythrosuamide ( 7). Compounds 1, 3 and 5 are further additions to the small group of cassaine diterpenoid dimers represented by erythrophlesins A–D. Their structures were determined by analysis of extensive one- and two-dimensional NMR experiments and ESIMS methods. Cytotoxic activities of the isolated compounds were tested against HCT-8, Bel-7402, BGC-823, A549 and A2780 human cancer cell lines in the MTT test. Results showed that compounds 1 and 3– 5 exhibited significantly selective cytotoxic activities (IC 50 < 10 μM) against these cells, respectively.

Cassaine diterpenoid dimers isolated from Erythrophleum succirubrum with TRAIL-resistance overcoming activity

Activity-guided fractionation of Erythrophleum succirubrum for TRAIL resistance-overcoming activity led to the isolation of four new cassaine diterpenoid dimers, named erythrophlesins A–D ( 1– 4). Their structures were elucidated by spectral data to show that they have an unsymmetrical dimeric structure through an ester bond between two cassaine diterpenoids. These new compounds were revealed to have a significant reversal effect on TRAIL resistance in human gastric adenocarcinoma (AGS) cells.

Degraded diterpenoids from the stem bark of Neoboutonia mannii

Neoboutomannin ( 1), a degraded diterpenoid dimer, and manniorthoquinone ( 2), another degraded diterpenoid, have been isolated from the stem bark of Neoboutonia mannii Benth (Euphorbiaceae), together with the known 3-acetylaleuritolic acid ( 3), 3,6-dihydroxy-9-methoxy-1,7-dimethylphenanthrene ( 4) and sitosterol 3- O-β- d-glucopyranoside ( 5). Their structures were elucidated on the basis of spectral studies and comparison with published data. Compounds 1, 3, 4 and 5 were evaluated for their antibacterial and antifungal activities. 1, 3 and 4 were active against Enterococcus faecalis, Staphylococcus aureus, Proteus mirabilis and three Candida species, Candida albicans ATCC 9002, Candida tropicalis and Candida parapsilosis. Compound 5 was inactive against all the bacterial and fungal species used.

Abietane diterpenoid dimers from the roots of Salvia prionitis

Three abietane diterpenoid dimers, bisprioterones A–C ( 1– 3), were isolated from roots of the Chinese folk medicinal plant Salvia prionitis Hance (Labiatae). Compounds 1– 3 possessed two different abietane diterpenoid skeleta, which were linked via either a C–C single bond ( 1 and 2) or an ether bridge ( 3). Their structures were elucidated by analysis of 1D and 2D NMR spectroscopic data. The structure of 1 was further confirmed by a single-crystal X-ray diffraction determination.

Two new diterpenoid dimers, fritillebinide D and E, from bulbs of Fritillaria ebeiensis

Two new ent-kaurane diterpenoid dimers, fritillebinide D (1) and fritillebinide E (2), were isolated from bulbs of Fritillaria ebeiensis G.D. Yu et G.Q. Ji. Their structures have been determined to be ent-3g -acetoxy-kauran-16g , 17-acetal ent-3g -acetoxy-16g -kauran-17(R)-aldehyde (1) and ent-3g -acetoxy-kauran-16g ,17-acetal ent-3g -acetoxy-16g -kauran-17(S)-aldehyde (2) by means of spectral analysis.

Structures of Two Diterpenoid Dimers from Bulbs of Fritillaria ebeiensis

A new ent-kaurane diterpenoid dimer, fritillebinide C (1) together with one known diterpenoid dimer fritillebinide B (2) were isolated from the bulbs of Fritillaria ebeiensis G.D. Yu et G.Q. Ji. Compound 1 has been determined to be ent-3β-acetoxy-kauran-16β, 17-acetal entβ-kauran-17(S)-aldehyde (1) by means of spectral analysis and chemical evidence.

Structural Elucidations of Two Ent-Kaurane Dimers from Bulbs of Fritillaria ebeiensis var. purpurea

A novel ent-kaurane diterpenoid dimer, fritillebinide B (1) together with one known diterpenoid dimer fritillebinide A (2) were isolated from the bulbs of Fritillaria ebeiensis var. purpurea G.D. Yu et P. Li. Compound 1 has been established to be ent-3β-acetoxy-kauran-16β,17-acetal ent-16β-kauran-17(R)-aldehyde (1) by means of spectral analysis and chemical evidence.

Structures of Two New Diterpenoid Dimers from Bulbs of Fritillaria ebeiensis

Two new ent-kauranoid diterpenoid dimers, fritillebin C (1) and fritillebin D (2), were isolated from the bulbs of Fritillaria ebeiensis G.D. Yu and G.Q. Ji. Their structures were determined to be ent-16β-hydroxy-kauran-17-yl ent-16β-kauran-17-oate (1); ent-16α-hydroxy-kauran-17-yl ent-16β-kauran-17-oate (2) by means of spectral analysis and chemical evidence.

Structures of Three New Diterpenoids, Fritillebic Acid and Fritillebins A and B, from Bulbs of Fritillaria ebeiensis G. D. Yu et G. Q. JI.

A new diterpenoid, fritillebic acid (1) and four new diterpenoid dimers, fritillebins A (2) and B (3), and fritillebinides A and B, were isolated from a crude drug, bulds of Fritillaria ebeiensis G. D. Yu et G. Q. JI. The structures of compounds 1-3 were determined to be ent-3β-acetoxy-16β-kauran-17-oic acid (1), ent-16β-hydroxykauran-17-yl ent-3β-acetoxy-16β-kauran-17-oate (2), and ent-3β-acetoxy-16β-hydroxykauran-17-yl ent-3β-acetoxy-16β-kauran-17-oate (3), respectively, on the basis of spectroscopic and chemical evidence.