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Phytol is a diterpene constituent of many essential oils, belonging to the group of unsaturated acyclic alcohols. Although phytol possesses antimycobacterial and anti-inflammatory effects, no reports of a gastrointestinal action are available from the literature. Due to the well-known shortcomings of classical anti-ulcer drugs (e.g. side effects or relapses), natural products may offer an attractive alternative. In this study, a potential gastroprotective activity of phytol was evaluated using acute and chronic ulcer models in rats. Phytol 12.5, 25 and 50 mg/kg, administered orally 1 h prior to induction of gastric lesions by absolute ethanol, inhibited the lesion area by 96, 90 and 95%, respectively. When lesions were induced by ischemia and reperfusion, phytol 12.5 and 25 mg/kg per os decreased the lesion areas by 89 and 46%, respectively. In the third acute ulcer model (lesions induced by ibuprofen), phytol 12.5 mg/kg reduced the lesion area by 55%. Phytol restored the decreased level of reduced glutathione, the increased levels of myeloperoxidase and malondialdehyde and the decreased levels of catalase and superoxide dismutase in rats with gastric ulcer induced by ethanol to levels obtained in vehicle group. Finally, in a chronic model in which gastric ulcer was induced by acetic acid directly instilled into the stomach, phytol administered orally over a time period of 7 days at 12.5, 25, 50 and 100 mg/kg reduced lesion areas by 84, 81, 83 and 68%. Our data suggest a gastroprotective and cicatrizing effect of phytol, possibly associated with its antioxidant effect.

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Phytol (Pyt), a diterpenoid, possesses many important bioactivities. This study evaluates the anticancer effects of Pyt on sarcoma 180 (S-180) and human leukemia (HL-60) cell lines. For this purpose, cells were treated with Pyt (4.72, 7.08, or 14.16 µM) and a cell viability assay was performed. Additionally, the alkaline comet assay and micronucleus test with cytokinesis were also performed using doxorubicin (6 µM) and hydrogen peroxide (10 mM) as positive controls and stressors, respectively. Results revealed that Pyt significantly reduced the viability and rate of division in S-180 and HL-60 cells with IC50 values of 18.98 ± 3.79 and 1.17 ± 0.34 µM, respectively. Pyt at 14.16 µM exerted aneugenic and/or clastogenic effects in S-180 and HL-60 cells, where the number of micronuclei and other nuclear abnormalities (e.g., nucleoplasmic bridges and nuclear buds) were frequently observed. Moreover, Pyt at all concentrations induced apoptosis and showed necrosis at 14.16 µM, suggesting its anticancer effects on the tested cancer cell lines. Taken together, Pyt showed promising anticancer effects, possibly through inducing apoptosis and necrosis mechanisms, and it exerted aneugenic and/or clastogenic effects on the S-180 and HL-60 cell lines.

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Tocopherols are potent membrane-bound antioxidant molecules that are paramount for plant physiology and also important for human health. In the past years, chlorophyll catabolism was identified as the primary source of phytyl diphosphate for tocopherol synthesis by the action of two enzymes, PHYTOL KINASE (VTE5) and PHYTHYL PHOSPHATE KINASE (VTE6) that are able to recycle the chlorophyll-derived phytol. While VTE5 and VTE6 were proven essential for tocopherol metabolism in tomato fruits, it remains unknown whether they are rate-limiting steps in this pathway. To address this question, transgenic tomato plants expressing AtVTE5 and AtVTE6 in a fruit-specific manner were generated. Although ripe transgenic fruits exhibited higher amounts of tocopherol, phytol recycling revealed a more intimate association with chlorophyll than with tocopherol content. Interestingly, protein-protein interactions assays showed that VTE5 and VTE6 are complexed, channeling free phytol and phytyl-P, thus mitigating their cytotoxic nature. Moreover, the analysis of tocopherol accumulation dynamics in roots, a chlorophyll-devoid organ, revealed VTE5-dependent tocopherol accumulation, hinting at the occurrence of shoot-to-root phytol trafficking. Collectively, these results demonstrate that phytol recycling is essential for tocopherol biosynthesis, even in chlorophyll-devoid organs, yet it is not the rate-limiting step for this pathway under normal growth conditions.

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Plasmodium falciparum is the etiological agent of human malaria, one of the most widespread diseases in tropical and subtropical regions. Drug resistance is one of the biggest problems in controlling the disease, which leads to the need to discover new antimalarial compounds. One of the most promissory drugs purposed is fosmidomycin, an inhibitor of the biosynthesis of isoprene units by the methylerythritol 4-phosphate (MEP) pathway, which in some cases failed in clinical studies. Once formed, isoprene units are condensed to form longer structures such as farnesyl and geranylgeranyl pyrophosphate, which are necessary for Heme O and A formation, ubiquinone, and dolichyl phosphate biosynthesis as well as for protein isoprenylation. Even though the natural substrates of polyprenyl transferases and synthases are polyprenyl pyrophosphates, it was already demonstrated that isoprenoid alcohols (polyprenols) such as farnesol (FOH) and geranylgeraniol (GGOH) can rescue parasites from fosmidomycin. This study better investigated how this rescue phenomenon occurs by performing drug-rescue assays. Similarly, to FOH and GGOH, it was observed that phytol (POH), a 20-carbon plant isoprenoid, as well as unsaponifiable lipid extracts from foods rescue parasites from the antimalarial effect of fosmidomycin. Contrarily, neither dolichols nor nonaprenol rescue parasites from fosmidomycin. Considering this, here we characterized the transport of FOH, GGOH, and POH. Once incorporated, it was observed that these substances are phosphorylated, condensed into longer isoprenoid alcohols, and incorporated into proteins and dolichyl phosphates. Through proteomic and radiolabelling approaches, it was found that prenylated proteins are naturally attached to several isoprenoids, derived from GGOH, dolichol, and POH if exogenously added. Furthermore, the results suggest the presence of at least two promiscuous protein prenyltransferases in the parasite: one enzyme which can use FPP among other unidentified substrates and another enzyme that can use GGPP, phytyl pyrophosphate (PPP), and dolichols, among other substrates not identified here. Thus, further evidence was obtained for dolichols and other isoprenoid products attached to proteins. This study helps to better understand the apicoplast-targeting antimalarial mechanism of action and a novel post-translational modification of proteins in P. falciparum.

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Annona macroprophyllata Donn (A. macroprophyllata) is used in traditional Mexican medicine for the treatment of cancer, diabetes, inflammation, and pain. In this work, we evaluated the antitumor activity of three acyclic terpenoids obtained from A. macroprophyllata to assess their potential as antilymphoma agents. We identified the terpenoids farnesyl acetate (FA), phytol (PT) and geranylgeraniol (Gg) using gas chromatography-mass spectroscopy (GC-MS) and spectroscopic (1H, and 13C NMR) methods applied to petroleum ether extract of leaves from A. macroprophyllata (PEAm). We investigated antitumor potential in Balb/c mice inoculated with U-937 cells by assessing brine shrimp lethality (BSL), and cytotoxic activity in these cells. In addition, to assess the potential toxicity of PEAm, FA, PT and Gg in humans, we tested their acute oral toxicity in mice. Our results showed that the three terpenoids exhibited considerable antilymphoma and cytotoxic activity. In terms of lethality, we determined a median lethal dose (LD50) for thirteen isolated products of PEAm. Gg, PT and AF all exhibited a higher lethality with values of 1.41 ± 0.42, 3.03 ± 0.33 and 5.82 ± 0.58 µg mL-1, respectively. To assess cytotoxic activity against U-937 cells, we calculated the mean cytotoxic concentration (CC50) and found that FA and PT were closer in respect to the control drug methotrexate (MTX, 0.243 ± 0.007 µM). In terms of antilymphoma activity, we found that FA, PT and Gg considerably inhibited lymph node growth, with median effective doses (ED50) of 5.89 ± 0.39, 6.71 ± 0.31 and 7.22 ± 0.51 mg kg-1 in females and 5.09 ± 0.66, 5.83 ± 0.50 and 6.98 ± 0.57mg kg -1 in males, respectively. Regarding acute oral toxicity, we classified all three terpenoids as category IV, indicating a high safety margin for human administration. Finally, in a molecular docking study of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, we found binding of terpenoids to some amino acids of the catalytic site, suggesting an effect upon activity with a resulting decrease in the synthesis of intermediates involved in the prenylation of proteins involved in cancer progression. Our findings suggest that the acyclic terpenoids FA, PT, and Gg may serve as scaffolds for the development of new treatments for non-Hodgkin's lymphoma.

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Salmonella is an important foodborne pathogen, and it is unable to produce the quorum sensing signaling molecules called acyl-homoserine lactones (AHLs). However, it synthesizes the SdiA protein, detecting AHL molecules, also known as autoinducer-1 (AI-1), in the external environment. Exogenous AHLs can regulate specific genes related to virulence and stress response in Salmonella. Thus, interfering with quorum sensing can be a strategy to reduce virulence and help elucidate the cell-to-cell communication role in the pathogens' response to extracellular signals. This study aimed to evaluate the influence of the quorum sensing inhibitors furanone and phytol on phenotypes regulated by N-dodecanoyl homoserine lactone (C12-HSL) in Salmonella enterica serovar Enteritidis. The furanone C30 at 50 nM and phytol at 2 mM canceled the alterations promoted by C12-HSL on glucose consumption and the levels of free cellular thiol in Salmonella Enteritidis PT4 578 under anaerobic conditions. In silico analysis suggests that these compounds can bind to the SdiA protein of Salmonella Enteritidis and accommodate in the AHL binding pocket. Thus, furanone C30 and phytol act as antagonists of AI-1 and are likely inhibitors of the quorum sensing mechanism mediated by AHL in Salmonella.

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ETHNOPHARMACOLOGICAL RELEVANCE: The leaves, bark, and roots of Gallesia integrifolia are consumed in folk medicine through infusion, decoction, and topical preparation by crushing because of its pharmacological properties in several peripheral system disorders, including microbial infections. The presence of various molecules in different parts of the plant likely confers this species' fungicidal action, but scientific evidence is lacking. Vulvovaginal candidiasis mainly affects women of reproductive age. When left untreated, it can cause pregnancy complications. Currently available antifungals often cause undesirable side effects. New alternative therapeutic strategies based on medicinal plants have been proposed. AIM: To investigate the antifungal activity of G. integrifolia against vulvovaginal candidiasis secretion in pregnant women. MATERIALS AND METHODS: Antifungal activity was determined by the minimum inhibitory concentration (MIC), determined by broth microdilution method using Candida spp (NEWP1210), C. albicans (CCCD-CC001), C. tropicalis (CCCD-CC002) standard and clinical isolates from pregnant women with vulvovaginal candidiasis. Nystatin and fluconazole were used as positive controls. The chemical composition of essential oils that were extracted from leaves, flowers, and fruits of G. integrifolia was determined by gas chromatography coupled to mass spectrometry. Reverse docking was used to suggest a possible target in Candida. Conventional docking was used to identify the most probable compound that inhibits fungal growth. RESULTS: A total of 24 compounds were identified, accounting for ∼99% of volatile constituents in the essential oils. Leaves of G. integrifolia contained 3,5-dithiahexanol-5,5-dioxide (40.93%), flowers contained methionine ethyl ester (46.78%), and fruits contained 2,8-dithianonane (54.01%) as the most abundant compounds. The MICs of essential oils of leaves, flowers, and fruits of G. integrifolia against standard strains of Candida spp, C. albicans, and C. tropicalis ranged from 13.01 to 625.00 µg/mL. The essential oil of flowers more effectively inhibited Candida spp. Essential oils of leaves and flowers were similar to fluconazole against C. albicans. Essential oils of flowers and fruits were similar to fluconazole against C. tropocalis. In Candida yeast species that were isolated from vaginal secretion samples from pregnant patients, the MICs of leaves and flowers ranged from 52.08 to 5000.00 µg/mL. The essential oil of leaves (277.77 µg/mL) was the most active against C. albicans. No significant differences were found between the essential oils of leaves and flowers against C. glabrata. Docking simulations suggested that phytol in leaves and flowers was responsible for the antimicrobial effect. CONCLUSION: The present results suggest the potential therapeutic use of G. integrifolia, especially its leaves and flowers, against Candida and vulvovaginal candidiasis.

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Malaria is one of the most widespread parasitic diseases, especially in Africa, Southeast Asia and South America. One of the greatest problems for control of the disease is the emergence of drug resistance, which leads to a need for the development of new antimalarial compounds. The biosynthesis of isoprenoids has been investigated as part of a strategy to identify new targets to obtain new antimalarial drugs. Several isoprenoid quinones, including menaquinone-4 (MK-4/vitamin K2), α- and γ-tocopherol and ubiquinone (UQ) homologs UQ-8 and UQ-9, were previously detected in in vitro cultures of Plasmodium falciparum in asexual stages. Herein, we described for the first time the presence of phylloquinone (PK/vitamin K1) in P. falciparum and discuss the possible origins of this prenylquinone. While our results in metabolic labeling experiments suggest a biosynthesis of PK prenylation via phytyl pyrophosphate (phytyl-PP) with phytol being phosphorylated, on the other hand, exogenous PK attenuated atovaquone effects on parasitic growth and respiration, showing that this metabolite can be transported from extracellular environment and that the mitochondrial electron transport system (ETS) of P. falciparum is capable to interact with PK. Although the natural role and origin of PK remains elusive, this work highlights the PK importance in plasmodial metabolism and future studies will be important to elucidate in seeking new targets for antimalarial drugs.

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α-tocopherol is found in high concentrations in avocado fruit mesocarp, however, its accumulation and genetic control during maturation and ripening has not been elucidated. Based in the relevance of VTE1 and VTE5 genes in tocopherol biosynthesis and aiming to determine the association between tocopherol accumulation and expression of tocopherol biosynthetic genes, gene expression of VTE1 and VTE5 were evaluated through the time during three developmental stages: before harvest at 100, 160 and 220 days after flowering (DAF) and after harvest (220 DAF + 5) in two contrasting avocado genotypes (San Miguel and AVO40). San Miguel reached the highest levels at 220 DAF, whereas AVO40 increased α-tocopherol only after ripening (220 DAF + 5). A genome-wide search for VTE1 and VTE5 allowed to identify one and three genes, respectively. Both genotypes showed contrasting patterns of gene expression. Interestingly, AVO40 showed a highly positive correlation between α-tocopherol levels and gene expression of VTE1 and all VTE5 variants. On the other hand, San Miguel showed only a positive correlation between α-tocopherol level and VTE1gene expression.

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The aim of this study was to evaluate the chemical composition and the larvicidal activity of Brunfelsia uniflora leaf and flower extracts against Aedes aegypti larvae. Twenty-four compounds were found in the leaf extract, and the major compounds were phytol (23.1%), 9,12,15-octadecatrienoic acid, ethyl ester (21.3%), and hexadecanoic acid, ethyl ester (12.8%). In the flower extract, twenty-four compounds were also identified and the major compounds were α-amyrin (35.7%), ß-amyrin (16.4%), and (EE)-geranyl linalool (9.6%) by gas chromatography coupled to mass spectrometry. The larvicidal activity was evaluated by larval immersion test. The lethal concentrations (LC) obtained from leaf extract were LC50 = 4.89 and LC99.9 = 11.14 mg/mL and from flower extract were LC50 = 3.82 and LC99.9 = 11.03 mg/mL, and the positive control presented LC50 = 0.40 and LC99.9 = 1.14 mg/mL. Thus, B. uniflora extracts are promising alternatives to control A. aegypti larvae.

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