Phorbol esters in seed oil of Jatropha curcas L. (saboodam in Thai) and their association with cancer prevention: from the initial investigation to the present topics

Anti-inflammatory activity of Jatropha curcas L. in brain glial cells primary cultures

ETHNOPHARMACOLOGICAL RELEVANCE

Jatropha curcas L. (Euphorbiaceae), a medicinal plant known in Brazil as "Pinhão Manso", is highly adaptable, being cultivated in different tropical and subtropical regions of the world. Antimicrobial, antioxidant and antiinflammatory activities have been attributed to different parts of the plant. In the central nervous sytem (CNS), neuroinflammation is mediated by glial cells, mainly by astrocytes and microglia, a process that plays an important role in neurodegenerative diseases and other CNS disorders. In this study, we investigated the anti-inflammatory activity of the methanolic extract obtained from the leaves of J. curcas L. (MEJc) in primary cultures of glial cells submited to inflammatory stimulus.

MATERIALS AND METHODS

Primary cultures of glial cells obtained from the cerebral cortex of neonate Wistar rats were treated with MEJc (0.1-50,000 μg mL^-1) and its fractions (F_nJc) (0.1 μg mL^-1) with or without lipopolysaccharide of Escherichia coli (LPS) (1 μg mL^-1). Cell viability was determined with MTT test. Modifications in glial cell morphology were investigated by means of phase contrast microscopy and May-Grünwald staining. The reactivity of astrocytes and microglia were investigated with immunocytochemistry for GFAP, Iba1 and transcription factor NF-kB, as well as with Greiss reaction to determine the nitric oxide (NO) production.

RESULTS

MEJc at 0.1-1000 μg mL^-1 was non-toxic to glial cells and the DE₅₀ was 10.794 μg mL^-1. The treatment with LPS induced the activation of astrocytes and microglia marked by morphological modifications and changes in the expression of GFAP and Iba1, as well as the increase in NF-kB expression and NO production. Treatment with MEJc inhibited the morphological modifications, changes in GFAP and Iba1 expression, and the increase in NF-kB and NO production induced by LPS.

CONCLUSION

This study demonstrates that the MEJc and its fractions modulate inflammatory response of astrocytes and microglia to LPS and may be considered as a potential therapeutic strategy for neuroinflammation-related diseases.

Chemical analysis of callus extracts from toxic and non-toxic varieties of Jatropha curcas L

Jatropha curcas L. belongs to Euphorbiaceae family, and it synthesizes flavonoid and diterpene compounds that have showed antioxidant, anti-inflammatory, anticancer, antiviral, antimicrobial, antifungal and insecticide activity. Seeds of this plant accumulate phorbol esters, which are tigliane type diterpenes, reported as toxic and, depending on its concentration, toxic and non-toxic varieties has been identified. The aim of this work was to characterize the chemical profile of the extracts from seeds, leaves and callus of both varieties (toxic and non-toxic) of Jatropha curcas, to verify the presence of important compounds in dedifferentiated cells and consider the possibility of using these cultures for the massive production of metabolites. Callus induction was obtained using NAA (1.5 mg L⁻¹) and BAP (1.5 mg L⁻¹) after 21 d for both varieties. Thin layer chromatography analysis showed differences in compounds accumulation in callus from non-toxic variety throughout the time of culture, diterpenes showed an increase along the time, in contrast with flavonoids which decreased. Based on the results obtained through microQTOF-QII spectrometer it is suggested a higher accumulation of phorbol esters, derived from 12-deoxy-16-hydroxy-phorbol (m/z 365 [M+H]⁺), in callus of 38 d than those of 14 d culture, from both varieties. Unlike flavonoids accumulation, the MS chromatograms analysis allowed to suggest lower accumulation of flavonoids as the culture time progresses, in callus from both varieties. The presence of six glycosylated flavonoids is also suggested in leaf and callus extracts derived from both varieties (toxic and non-toxic), including: apigenin 6-C-α-L-arabinopyranosyl-8-C-β-D-xylopyranoside (m/z 535 [M+H]⁺), apigenin 4′-O-rhamnoside (m/z 417 [M+H]⁺), vitexin (m/z 433 [M+H]⁺), vitexin 4′-O-glucoside-2″-O-rhamnoside (m/z 741 [M+H]⁺), vicenin-2 (m/z 595 [M+H]⁺), and vicenin-2,6″-O-glucoside (m/z 757 [M+H]⁺).

Quantitative Proteome Analysis of Jatropha curcas L. Genotypes with Contrasting Levels of Phorbol Esters

The phorbol esters in the seeds of Jatropha curcas are a major hindrance to the full exploitation of the potential of this oil crop as a source of raw material for the production of biodiesel. Here, various quantitative proteomic strategies are used to establish the proteomes of roots, leaves, and endosperm of two genotypes of J. curcas with contrasting levels of phorbol esters in the seeds. In total 4532, 1775, and 503 proteins are identified respectively in roots, leaves, and endosperm, comprising 5068 unique proteins; of this total, 185 are differentially abundant in roots, 72 in leaves, and 20 in the endosperm. The biosynthetic pathways for flavonoids and terpenoids are well represented in roots, including the complete set of proteins for the mevalonate and non-mevalonate/Deoxyxylulose 5-Phosphate pathways, and proteins involved in the branches which lead to the synthesis tricyclic diterpenoids and gibberellins. Also, casbene synthase which catalyzes the first committed step in the biosynthesis of tigliane-type diterpenes is identified in roots of both genotypes, but not in leaves and endosperm. This dataset will be a valuable resource to explore the biochemical basis of the low toxicity of Jatropha genotypes with low concentration of phorbol esters in the seeds.

Functional characterization of the Hyles euphorbiae hawkmoth transcriptome reveals strong expression of phorbol ester detoxification and seasonal cold hardiness genes

Background

The European spurge hawkmoth, Hyles euphorbiae (Lepidoptera, Sphingidae), has been intensively studied as a model organism for insect chemical ecology, cold hardiness and evolution of species delineation. To understand species isolation mechanisms at a molecular level, this study aims at determining genetic factors underlying two adaptive ecological trait candidates, phorbol ester (TPA) detoxification and seasonal cold acclimation.

Method

A draft transcriptome of H. euphorbiae was generated using Illumina sequencing, providing the first genomic resource for the hawkmoth subfamily Macroglossinae. RNA expression levels in tissues of experimental TPA feeding larvae and cooled pupae was compared to levels in control larvae and pupae using 26 bp RNA sequence tag libraries (DeepSuperSAGE). Differential gene expression was assessed by homology searches of the tags in the transcriptome.

Results

In total, 389 and 605 differentially expressed transcripts for detoxification and cold hardiness, respectively, could be identified and annotated with proteins. The majority (22 of 28) of differentially expressed detox transcripts of the four 'drug metabolism' enzyme groups (cytochrome P450 (CYP), carboxylesterases (CES), glutathione S-transferases (GST) and lipases) are up-regulated. Triacylglycerol lipase was significantly over proportionally annotated among up-regulated detox transcripts. We record several up-regulated lipases, GSTe2, two CESs, CYP9A21, CYP6BD6 and CYP9A17 as candidate genes for further H. euphorbiae TPA detoxification analyses. Differential gene expression of the cold acclimation treatment is marked by metabolic depression with enriched Gene Ontology terms among down-regulated transcripts almost exclusively comprising metabolism, aerobic respiration and dissimilative functions. Down-regulated transcripts include energy expensive respiratory proteins like NADH dehydrogenase, cytochrome oxidase and ATP synthase. Gene expression patterns show shifts in carbohydrate metabolism towards cryoprotectant production. The Glycolysis enzymes, G1Pase, A1e, Gpi and an Akr isoform are up-regulated. Glycerol, an osmolyte which lowers the body liquid supercooling point, appears to be the predominant polyol cryoprotectant in H. euphorbiae diapause pupae. Several protein candidates involved in glucose, glycerol, myo-inositol and potentially sorbitol and trehalose synthesis were identified.

Conclusions

A majority of differently expressed transcripts unique for either detoxification or cold hardiness indicates highly specialized functional adaptation which may have evolved from general cell metabolism and stress response.The transcriptome and extracted candidate biomarkers provide a basis for further gene expression studies of physiological processes and adaptive traits in H. euphorbiae.