Abstract

The macrocyclic lathyrane diterpenes, latilagascenes D–F (1–3) and jolkinol B (4), were isolated from the methanol extract of Euphorbia lagascae, and evaluated for multidrug resistance reversing activity on mouse lymphoma cells. All compounds displayed very strong activity compared with that of the positive control, verapamil. The structure–activity relationship is discussed. The evaluation of compounds 1 and 4, and of latigascenes A-C (5–7), isolated from the same species, as apoptosis-inducers was also carried out. Compound 1 was the most active. Furthermore, in the model of combination chemotherapy, the interaction between the doxorubicine and latilagascene B (6) was studied in vitro, on human MDR1 gene transfected mouse lymphoma cells, showing that the type of interaction was synergistic. Latilagascenes D–F (1–3) are new compounds whose structures were established on the basis of spectroscopic methods, including 2D NMR experiments (COSY, HMQC, HMBC and NOESY).

Graphical abstract

Three new lathyrane diterpenes and jolkinol B, isolated from Euphorbia lagascae, have shown powerful anti-MDR activity in cancer cells. Two of these compounds and other lathyrane derivatives were evaluated as apoptosis inducers. Moreover, the antiproliferative effects of the anticancer drug doxorubicin in combination with latilagascene B were studied.

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Keywords: Macrocyclic lathyrane diterpenes; Euphorbia lagascae; Apoptosis; Multidrug resistance; P-glycoprotein; Antiproliferative

Article Outline

1. Introduction

2. Results and discussion

2.1. Structure elucidation of compounds

2.2. Biological activity

3. Experimental

3.1. General experimental procedures

3.2. Plant material

3.3. Extraction and isolation

3.3.1. Latilagascene D [(2R*, 3S*, 4R*, 5R*, 6R*, 9S*,11S*,15R*)-16-benzoyloxi-15β-cinnamoyloxy-5α,6β-epoxy-3β-hydroxy-14-oxolathyr-12E-ene] (1)

3.3.2. Latilagascene E [(2R*, 3S*, 4R*, 5R*, 6R*, 9S*,11S*,15R*)-16-benzoyloxi-15β-cinnamoyloxy-5α,6β-epoxy-3β,20-dihydroxy-14-oxolathyr-12E-ene] (2)

3.3.3. Latilagascene F [(2R*, 3S*, 4R*, 5R*, 6R*, 9S*, 11S*, 15R*)-15β-benzoyloxy-5α,6β-epoxy-3β-hydroxy-14-oxolathyr-12E-ene] (3)

3.3.4. Jolkinol B [(2R*, 3S*, 4R*, 5R*, 6R*, 9S*, 11S*,15R*)-15β-cinnamoyloxy-5α,6β-epoxy-3β-hydroxy-14-oxolathyr-12E-ene] (4)

3.4. Assay for MDR reversal effect

3.4.1. Cells

3.4.2. Assay for rhodamine 123 accumulation test

3.5. Assay for antiproliferative effect

3.6. Checkerboard microplate method as a model for combination therapy

3.7. Assay for apoptosis induction

Acknowledgements

References