Rapid and selective screening for toxic phorbol esters in Jatropha curcas seed oil using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry

Untargeted Metabolomic Analysis of Leaves and Roots of Jatropha curcas Genotypes with Contrasting Levels of Phorbol Esters

AIMS

Phorbol esters (PE) are toxic diterpenoids accumulated in physic nut (Jatropha curcas L.) seed tissues. Their biosynthetic pathway remains unknown, and the participation of roots in this process may be possible. Thus, we set out to study the deposition pattern of PE and other terpenoids in roots and leaves of genotypes with detected (DPE) and not detected (NPE) phorbol esters based on previous studies.

OUTLINE OF DATA RESOURCES

We analyzed physic nut leaf and root organic extracts using LC-HRMS. By an untargeted metabolomics approach, it was possible to annotate 496 and 146 metabolites in the positive and negative electrospray ionization modes, respectively.

KEY RESULTS

PE were detected only in samples of the DPE genotype. Remarkably, PE were found in both leaves and roots, making this study the first report of PE in J. curcas roots. Furthermore, untargeted metabolomic analysis revealed that diterpenoids and apocarotenoids are preferentially accumulated in the DPE genotype in comparison with NPE, which may be linked to the divergence between the genotypes concerning PE biosynthesis, since sesquiterpenoids showed greater abundance in the NPE.

UTILITY OF THE RESOURCE

The LC-HRMS files, publicly available in the MassIVE database (identifier MSV000092920), are valuable as they expand our understanding of PE biosynthesis, which can assist in the development of molecular strategies to reduce PE levels in toxic genotypes, making possible the food use of the seedcake, as well as its potential to contain high-quality spectral information about several other metabolites that may possess biological activity.

Implications of Jatropha curcas L. cake feed on swine health: A microbiota-gut-brain axis perspective

The safety of Jatropha curcas L. cake (JCC) in animal feed remains under scrutiny, despite the advent of low phorbol ester (PE) variants. This study investigates the impact of low PE JCC on swine health when used as a protein feed. Pigs were fed a 5% JCC diet with a PE concentration of 0.98 mg/kg, which surprisingly still induced toxicity. Symptoms included depression, decreased food intake, increased diarrhea, along with hypothalamus and colon lesions. The toxicity was associated with a decrease in antioxidant enzymes, an increase in inflammatory cytokines in the hypothalamus, plasma, and colon, and a rise in pro-inflammatory colon microbes and metabolites. Disturbances in neurotransmitters further suggest that this toxicity is related to disruption of the microbiota-gut-brain axis, indicating that JCC's toxic elements are not solely due to PE. The sensitivity of pigs to JCC underscores the need for thorough detoxification prior to its use as feed. These findings significantly contribute to the discourse on the safety of low PE JCC in animal feed, highlighting implications for both the feed industry and public health.

Oral and Topical Anti-Inflammatory Activity of Jatropha integerrima Leaves Extract in Relation to Its Metabolite Profile

Jatropha integerrima Jacq., family: Euphorbiaceae, is used in India and subtropical Africa to treat different skin conditions. In this study we evaluated the anti-inflammatory activity of J. integerrima leaves extract (JILE) using rat paw edema model. The extract was administered orally (200 and 400 mg/kg) or applied topically as creams at 2.5, 5, and 10% strength. Four hours post-treatment, maximum reduction of edema volume by 63.09% was observed after oral administration of JILE (400 mg/kg) as compared to indomethacin with 60.43%. The extract anti-inflammatory effect was accompanied by a decrease in NO, prostaglandin PGE2, TNF-α and PKC levels by 19, 29.35, 16.9, and 47.83%, respectively. Additionally, topical applications of JILE showed dose dependent reduction in paw edema and resulted in normalized levels of PGE2, TNF-α, and PKC when used as 10% cream. Signs of inflammations were reduced or absent from paw tissue of animals receiving JILE either orally or topically. Finally, liquid chromatography/mass spectrometry analysis of JILE resulted in the annotation of 133 metabolites including 24 diterpenoids, 19 flavonoids, 10 phenolic acid conjugates, 8 cyclic peptides, 6 phytosterols, 4 sesquiterpenes, and 4 coumarins. Several of the annotated metabolites have known anti-inflammatory activity including vitexin, isovitexin, fraxitin, scopeltin, stigmasterol, and many diterpenoidal derivatives.

Acetonitrile Adducts of Tranexamic Acid as Sensitive Ions for Quantification at Residue Levels in Human Plasma by UHPLC-MS/MS

The quantitative analysis of pharmaceuticals in biomatrices by liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is often hampered by adduct formation. The use of the molecular ion resulting from solvent adducts for quantification is uncommon, even if formed in high abundance. In this work, we propose the use of a protonated acetonitrile adduct for the quantitative analysis of tranexamic acid (TXA) by LC-MS/MS. The high abundance of the protonated acetonitrile adduct [M + ACN + H]⁺ was found to be independent of source-dependent parameters and mobile phase composition. The results obtained for TXA analysis in clinical samples were comparable for both [M + ACN + H]⁺ and [M + H]⁺, and no statistically significant differences were observed. The relative stability and structure of the [M + ACN + H]⁺ ions were also studied by analyzing probable structures from an energetic point of view and by quantum chemical calculations. These findings, and the studied fragmentation pathways, allowed the definition of an acetimidium structure as the best ion to describe the observed acetonitrile protonated adduct of TXA.

LC-MS Identification, Isolation, and Structural Elucidation of Anti-HIV Tigliane Diterpenoids from Wikstroemia lamatsoensis

Structurally diverse tigliane diterpenoids have drawn significant research interest for drug discovery over many decades. Using LC-MS-guided fractionation and separation, the first phytochemical investigation on Wikstroemia lamatsoensis led to the isolation of eight tiglianes (1-8), including two new compounds, wikstrocin D (1) and wikstrocin E (2). The new structures were elucidated based on extensive physicochemical and spectroscopic analyses. The characteristic ESIMS/MS fragmentations of tiglianes 1-8 were also summarized. Among the isolated tiglianes, three compounds (8, 5, and 7) showed the most potent anti-HIV activity, with IC₅₀ values of 0.18, 3.8, and 12.8 nM, respectively.

Monitoring casbene synthase in Jatropha curcas tissues using targeted proteomics

BACKGROUND

Casbene synthase (CS) is responsible for the first committed step in the biosynthesis of phorbol esters (PE) in the Euphorbiaceae. PE are abundant in the seeds of the biofuel crop Jatropha curcas and its toxicity precludes the use of the protein-rich cake obtained after oil extraction as an animal feed and the toxicity of the fumes derived from burning PE containing biofuel is also a matter of concern. This toxicity is a major hindrance to exploit the potential of this crop as a source of raw material to produce biodiesel. For this reason, the current research on J. curcas is mainly focused on the understanding of the biosynthesis and site of synthesis of PE, as an avenue for the development of genotypes unable to synthesize PE in its seeds.

RESULTS

Here, we present targeted proteomics assays (SRM and PRM) to detect and quantify CS in leaves, endosperm, and roots of two J. curcas genotypes with contrasting levels of PE. These assays were based on the use of reference isotopic labeled synthetic peptides (ILSP) predicted from 12 gene models of CS from the J. curcas genome.

CONCLUSION

Our targeted proteomics methods were able to detect and quantify, for the first time, CS gene products and demonstrate the distribution of CS isoforms only in roots from J. curcas genotypes with a high and low concentration of PE. These methods can be expanded to monitor CS, at the protein level, in different tissues and genotypes of J. curcas.

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]⁺).