Oxidative Degradations of the Side Chain of Unsaturated Ent-labdanes. Part I.

Espinoza, Luis; Altamirano, Héctor Carrasco; Fritis, Mauricio Cuellar; Araya, Claudio; Marín, Karen Catalán

doi:10.3390/12030318

Cited by 4 publications

(4 citation statements)

References 22 publications

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“…Previously we reported the isolation and structural determination of the mixture of ent -labdanes 1 - 2 from Calceolaria inamoena and the preparation of derivatives 3 and 8 [ 13 , 14 ]. In the saponification reaction used for preparation of diterpenyl synthon 4 , a new compound 11 was obtained when acidic conditions were used, presumably due to a transesterification reaction and the presence of ethyl acetate in the workup procedure, nevertheless the target diol 4 could be obtained under partial neutralization conditions ( Scheme 1 ).…”

Section: Resultsmentioning

confidence: 99%

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Synthesis and Antitumor Activity of Diterpenylhydroquinone Derivatives of Natural Ent-Labdanes

et al. 2010

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Two new compounds 2β-acetoxy-15-phenyl-(22,25-acetoxy)-ent-labda-8(17), 13(E)-diene (9) and 2β-hydroxy-15-phenyl-(22,24,26-trimethoxy)-ent-labda-8(17),13(E)-diene (10) have been prepared by an Electrophilic Aromatic Substitution (EAS) reaction between diterpenyl allylic alcohols and 1,4-hydroquinone or 1,3,5-trimethoxybenzene using BF3.Et2O as a catalyst. These compounds, along with a series of natural ent-labdanes 3-8, have been evaluated for their in vitro cytotoxic activities against cultured human cancer cells of PC-3 and DU-145 human prostate cancer, MCF-7 and MDA-MB-231 breast carcinoma and dermal human fibroblasts (DHF). Some compounds displayed inhibition at µM IC50 values.

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Section: Resultsmentioning

confidence: 99%

“…Natural ent -labdanes 1-2 were isolated from Calceolaria inamoena and transformed into diterpenyl allylic alcohol derivative 4 by a reported procedure [ 13 , 14 ].…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Antitumor Activity of Diterpenylhydroquinone Derivatives of Natural Ent-Labdanes

et al. 2010

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“…From 2.93 g of the acetate mixture 5 - 6 , 0.292 g of diol 9 (11.3% yield), 0.527 g (yield 20.4%) of a 9 - 10 mixture and 1.43 g (55.4% yield) of diol 10 were obtained. The structures of compounds 9 and 10 were mainly established by 1 H- and 13 C-NMR spectroscopic data (see Experimental section) and compared with those reported for acetates 5 and 6, respectively [ 21 ]. The proportion of geometrical isomers in the mixture were determined as 9 : 10 =0.2:1 (ratio calculated based on the integrals of the H-17a and H-17b signals in the 1 H-NMR spectrum).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Two New Hemisynthetic Diterpenylhydroquinones from Natural Ent-Labdanes

et al. 2009

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The synthesis and structural determination of two new diterpenylhydroquinones: 2β-acetoxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-diene (1) and 2β-hydroxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-diene is reported (2). These compounds were obtained by coupling via Electrophilic Aromatic Substitution (EAS) of 1,4-hydroquinone with primary or tertiary allyl alcohol derivatives of the natural ent-labdanes 3 and 4. With this new method, the best results were observed when mixtures of the primary alcohol derivatives 5-6 (26% yield of compound 1) and diol derivatives 9-10 (28% yield of compound 2) were used.

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“…Traditionally, various species of the genus Calceolaria are used as bactericidal agents, for treating stomach aches and as sweeteners [ 16 , 17 , 18 ]. Previous investigations reported about the isolation and structural determination of the mixture of ent -labdanes and the preparation of derivatives from Calceolaria inamoena [ 19 , 20 , 21 ] and the evaluation of the in vitro cytotoxic activities against cultured human cancer cells [ 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

Diterpenylhydroquinones from Natural ent-Labdanes Induce Apoptosis through Decreased Mitochondrial Membrane Potential

et al. 2013

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In this study, we examined the cytotoxic effects of seven ent-labdane derivatives 1–7 (0–100 μM) in different human cancer cell lines. Our results showed that compounds 1–3 exhibited significant dose-dependent inhibition on the growth of the three different human cell lines, according to the sulphorhodamine B assay and produced morphological changes consistent with apoptosis, as confirmed by Hoestch 3342 staining analysis. They induced apoptosis in various cancer cell lines, as shown by nuclear condensation and fragmentation and caspase 3 activation. Such induction was associated with the depletion of mitochondrial membrane potential. These activities led to the cleavage of caspases and the trigger of cell death process. Overall, the compounds showed potent proapoptotic effects on the two different cancer cell lines, suggesting that the compounds deserve more extensive investigation of their potential medicinal applications.

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Oxidative Degradations of the Side Chain of Unsaturated Ent-labdanes. Part I.

Cited by 4 publications

References 22 publications

Synthesis and Antitumor Activity of Diterpenylhydroquinone Derivatives of Natural Ent-Labdanes

Synthesis and Antitumor Activity of Diterpenylhydroquinone Derivatives of Natural Ent-Labdanes

Synthesis of Two New Hemisynthetic Diterpenylhydroquinones from Natural Ent-Labdanes

Diterpenylhydroquinones from Natural ent-Labdanes Induce Apoptosis through Decreased Mitochondrial Membrane Potential

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