Euphol, a tetracyclic triterpene, from Euphorbia tirucalli induces autophagy and sensitizes temozolomide cytotoxicity on glioblastoma cells.[Pubmed: 29931585]

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Effect of Environmental Factors on Nuclear Organization and Transformation of Human B Lymphocytes.[Pubmed: 29626927]

Chromosomal translocations have long been known for their association with malignant transformation, particularly in hematopoietic disorders such as B-cell lymphomas. In addition to the physiological process of maturation, which creates double strand breaks in immunoglobulin gene loci, environmental factors including the Epstein-Barr and human immunodeficiency viruses, malaria-causing parasites (Plasmodium falciparum), and plant components (Euphorbia tirucalli latex) can trigger a reorganization of the nuclear architecture and DNA damage that together will facilitate the occurrence of deleterious chromosomal rearrangements.

Comparative Transcriptome Analysis Identifies Putative Genes Involved in Steroid Biosynthesis in Euphorbia tirucalli.[Pubmed: 29342957]

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Strictly Conserved Residues in Euphorbia tirucalli β-Amyrin Cyclase: Trp612 Stabilizes Transient Cation through Cation-π Interaction and CH-π Interaction of Tyr736 with Leu734 Confers Robust Local Protein Architecture.[Pubmed: 29214725]

The functions of Trp612, Leu734, and Tyr736 of Euphorbia tirucalli β-amyrin synthase were examined. The aliphatic variants (Ala, Val, Met) of Trp612 showed almost no activity, but the aromatic variants exhibited high activities: 12.5 % of the wild-type activity for the W612H variant, 43 % for W612F, and 63 % for W612Y. That is, the enzymatic activities of the variants increased in proportion to the increase in π-electron density. Thus, the major function of Trp612 is to stabilize transient cations through a cation-π interaction. The Phe and Tyr variants caused a distorted folding conformation, especially at the E-ring site, which generated the aberrantly cyclized products germanicol and lupeol. The L734G and L734A variants exhibited significantly decreased activities but yielded taraxerol in a high production ratio. The Val, Ile, and Met variants showed markedly high activities (56-78 % of wild-type activity); therefore, appropriate steric bulk is required at this position. The aliphatic variants of Tyr736 showed markedly decreased activities, but the Phe mutant exhibited high activity (67 %), which indicates that the π electrons are critical for catalysis. Homology modeling indicated that Tyr736 and Leu734 are perpendicular to the substrate and are situated face to face, which suggests that a CH-π interaction occurs between Tyr736 and Leu734, reinforcing the protein architecture, and that Tyr736 cannot stabilize cationic intermediates through a cation-π interaction.

Attenuation of nociceptive pain and inflammatory disorders by total steroid and terpenoid fraction of Euphorbia tirucalli Linn root in experimental in vitro and in vivo model.[Pubmed: 29063488]

The plant Euphorbia tirucalli Linn has been successfully used as a tribal folk medicine in India and Africa for the management of acute inflammatory, arthritic, nociceptive pain and asthmatic symptoms. The present study was conducted to assess the anti-inflammatory, analgesic, anti-asthmatic and anti-arthritic role of the total steroid and terpenoid rich fractions of the hydro-alcoholic extract of E. tirucalli root (STF-HAETR). STF-HAETR fraction demonstrated 71.25 ± 2.5 and 74.25 ± 5.1% protection against acetic acid-induced pain and central neuropathic pain at 75 and 100 mg/kg doses, respectively. It showed 96.97% protection against acute inflammation at 100 mg/kg with 1.6-fold better activity than the standard drug. The fraction exhibited such efficacy via inhibition of proinflammatory cytokines TNF-α, IFN-γ, by 61.12 and 65.18%, respectively, at 100 μg/mL. Inhibition of cyclooxygenase and Nitric oxide synthase in a dose-dependent manner affirms its analgesic and anti-inflammatory activity. The spectrophotometric analysis reveals that STF-HAETR induces ameliorative effect against heat-induced denaturation of Bovine serum albumin (BSA) and exhibits significant anti-proteinase activity. The plant fraction also demonstrated anti-asthmatic activity by displaying 62.45% protection against histamine induced bronchoconstriction or dyspnoea. Our findings suggest that STF-HAETR could be an effective safe therapeutic agent to treat nociceptive pain, acute inflammation, asthma, and arthritis which may authenticate its traditional use.

Euphorbia tirucalli β-Amyrin Synthase: Critical Roles of Steric Sizes at Val483 and Met729 and the CH-π Interaction between Val483 and Trp534 for Catalytic Action.[Pubmed: 28875584]

The functions of Val483, Trp534, and Met729 in Euphorbia tirucalli β-amyrin synthase were revealed by comparing the enzyme activities of site-directed mutants against that of the wild type. The Gly and Ala variants with a smaller bulk size at position 483 predominantly afforded monocyclic camelliol C, which suggested that the orientation of the (3S)-2,3-oxidosqualene substrate was not appropriately arranged in the reaction cavity as a result of the decreased bulk size, leading to failure of its normal folding into the chair-chair-chair-boat-boat conformation. The Ile variant, with a somewhat larger bulk, afforded β-amyrin as the dominant product. Intriguingly, various variants of Trp534 exhibited significantly decreased enzymatic activities and provided no aberrantly cyclized products, although the aromatic Phe and Tyr residues were incorporated and the steric sizes of the aliphatic residues were altered. Therefore, the Trp534 residue does not stabilize the transient cation through a cation-π interaction. Furthermore, the Trp residue, with the largest steric bulk among all natural amino acids, is essential for high enzymatic activity. Robust CH-π complexation between the Val483 and Trp534 residues is proposed herein. Altering the steric bulk at the Met729 position afforded the pentacyclic skeletons. Thus, Met729 is positioned at the E-ring formation site. More detailed insights into the functions of the Val483, Trp534, and Met729 residues are provided by homology modeling.

Pathway engineering for the production of β-amyrin and cycloartenol in Escherichia coli-a method to biosynthesize plant-derived triterpene skeletons in E. coli.[Pubmed: 28710558]

Cycloartenol is biosynthetically the first sterol skeleton, which is metabolized to phytosterols such as β-sitosterol and stigmasterol. β-Amyrin is the most commonly occurring aglycone skeleton for oleanane-type saponins such as glycyrrhizin and saikosaponins. It has been regarded that these cyclic triterpenes are unable to be produced in Escherichia coli, while no reports are available on their production with E. coli. Here, we describe a method to synthesize triterpene skeletons from higher plants, including cycloartenol and β-amyrin. We introduced into E. coli the biosynthetic pathway genes from farnesyl diphosphate (FPP) to cycloartenol or β-amyrin, which contained Arabidopsis (Arabidopsis thaliana)-derived squalene synthase (AtSQS) and squalene epoxidase (AtSQE) genes in addition to the Arabidopsis cycloartenol synthase (AtCAS1) gene, or the β-amyrin synthase (EtAS) gene of the petroleum plant Euphorbia tirucalli, along with the isopentenyl diphosphate isomerase (HpIDI) gene from a green algae Haematococcus pluvialis. The order of genes, HpIDI, AtSQS, AtSQE, driven by transcriptional read-through from a tac promoter to an rrnB terminator, was crucial for their functional expression in E. coli to produce cycloartenol or β-amyrin. The co-expression of a bacterial NADPH-regenerating gene (zwf or gdh) as well as bacterial redox partner protein genes (camA and camB, or NsRED and NsFER) was found to increase the amounts of these triterpenes several fold. The present study could open up opportunities not only to carry out functional analysis of a higher-plant-derived oxidosqualene cyclase (OSC) gene in E. coli but also to produce functional triterpenes that originate from medicinal or herbal plants.

Immobilization of Euphorbia tirucalli peroxidase onto chitosan-cobalt oxide magnetic nanoparticles and optimization using response surface methodology.[Pubmed: 28363649]

Euphorbia tirucalli peroxidase (ETP) was immobilized on chitosan beads having magnetic properties for the ease of separation and increasing the reusability of ETP for cost effective assay conditions. The present work reports immobilization of ETP on polymeric support chitosan-cobalt oxide beads subsequently activated with 0.05% cynuric chloride. The magnetic immobilized enzyme was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The immobilized ETP can be reused up to 10 cycles with retention of more than 60% activity. The optimum pH was shifted from 6.0 to 5.5 for soluble ETP to immobilized ETP and optimum temperature from 50°C and 55°C for the immobilized ETP. Based on response surface methodology, the optimal immobilization conditions obtained were: enzyme concentration, 2mg/286mg beads; optimal pH, 4.93; temperature, 28.88; cynuric chloride concentration, 0.17%; reaction time, 14.4h, which resulted 74.51% maximum immobilization. The enzyme magnetic nanoparticles could be separated magnetically for easy reuse. Immobilization of ETP onto the magnetic nanoparticles could be useful for biotechnological applications and bioassay due to its reusability and improved stability.