Key message
Blue and yellow light affected metabolism and the morphology. Blue and red promote the DOXP/MEP pathway.
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gene expression was increased in plants cultivated under blue, promoting ...artemisinin content.
Artemisinin-based combination therapies are the most effective treatment for highly lethal malaria. Artemisinin is produced in small quantities in the glandular trichomes of
Artemisia annua
L. Our aim was to evaluate the effect of light quality in
A. annua
cultivated in vitro under different light qualities, considering anatomical and morphological changes, the volatile composition, artemisinin content and the expression of two key enzymes for artemisinin biosynthesis. Yellow light is related to the increase in the number of glandular trichomes and this seemed to positively affect the molecular diversity in
A. annua
. Yellow light-stimulated glandular trichome frequency without triggered area enhancement, whereas blue light stimulated both parameters. Blue light enhanced the thickness of the leaf epidermis. The B-promoting effect was due to increased cell size and not to increased cell numbers. Green and yellow light positively influenced the volatile diversity in the plantlets. Nevertheless, blue and red light seemed to promote the DOXP/MEP pathway, while red light stimulates MVA pathway. Amorpha-4,11-diene synthase gene expression was significantly increased in plants cultivated under blue light, and not red light, promoting artemisinin content. Our results showed that light quality, more specifically blue and yellow light, positively affected secondary metabolism and the morphology of plantlets. It seemed that steps prior to the last one in the artemisinin biosynthesis pathway could be strongly influenced by blue light. Our work provides an alternative method to increase the amount of artemisinin production in
A. annua
without the use of transgenic plants, by the employment of blue light.
The extensive marine biodiversity has proved to be a promising source of substances with biomedical potential. In this study, the cytotoxicity of the Brazilian octocoral Phyllogorgia dilatata ...(Gorgoniidae) was evaluated against two tumor cell lines and three bacterial strains. The methanol/dichloromethane crude extract presented no antibacterial activity up to the highest concentration tested (512 µg/mL), however it revealed a noteworthy antiproliferative effect against HCT-116 (80%) and MCF-7 (54%) cell lines at 50 μg/mL. Therefore, guided by the cytotoxic activity, a multistep chemical fractionation of the extract provided the subfraction 5 (PDPH2-5) with IC50 values of 3.18 and 17.80 μg/mL against HCT-116 and MCF-7, respectively. The LC-HRMS/MS analysis of PDPH2-5 showed ions of m/z 219.1742 and 219.1743, characterized as (E,E) and (Z,E) germacrone, after a LC-DAD-SPE/NMR analysis of the hexanic fraction and comparisons of NMR data with the literature. Previously reported assessments to the cytotoxic activity of the (E,E)-diastereoisomer disclosed higher IC50 values than that obtained for the PDPH2-5 fraction, suggesting, herein, a potentiated effect of the diastereoisomeric mixture. Such remark encourage further bioactivity studies with stereoisomer mixtures and reduce the urge for compound isolation.
Recently, structural elucidation of natural products has undergone a revolution. The combined use of different modern spectroscopic methods has allowed obtaining a complete structural assignment of ...natural products using small amounts of sample. However, despite the extraordinary ongoing advances in spectroscopy, the mischaracterization of natural products has been and remains a recurrent problem, especially when the substance presents several stereogenic centers. The misinterpretation of nuclear magnetic resonance (NMR) data has resulted in frequent reports addressing structural reassignment. In this context, a great effort has been devoted to developing quantum chemical calculations that simulate NMR parameters accurately, allowing to achieve a more precise spectral interpretation. In this work, we employed a protocol for theoretical calculations of
H NMR chemical shifts and coupling constants using density functional theory (DFT), followed by the application of the DP4+ method to revisit the structure of Heliannuol L, a member of the Heliannuol class, isolated from Helianthus annuus. Our results indicate that the originally proposed structure of Heliannuol L needs a stereochemical reassignment, placing the hydroxyl bonded to C10 in the opposite side of the methyl and hydroxyl groups bonded to C7 and C8, respectively.
Abstract Access to genetic resources (GR) and/or traditional knowledge associated with genetic resources (ATK) has been regulated in Brazil since 2001. The law 13,123 / 2015 determined a significant ...change in the theme, mainly on the rules of distribution of benefits obtained for conservation and sustainable use of biodiversity, the access to technology and technology transfer, the exploitation of products or reproductive material from the GR or ATK and consignment to the outside of part or all the living or dead organism shipped for GR. The implementation of international treaties on GR and ATK for research, biotechnological development and bioprospecting have been causing difficulties for Brazilian researchers, mainly due to the lack of information and dissemination available for compliance with the legislation. In this work, the members of the Committee for Access to Genetic Resources and Associated Traditional Knowledge of the Federal Fluminense University (UFFGEN) - Brazil, and collaborators performed a critical reflection on the new law, helping Brazilian researchers with information necessary to understand the changes made by the new legislation, especially in the field of Biotechnology associated with Brazilian Biodiversity.
This study aims the anatomical description and chemical characterization of aerial parts of Clusia criuva Cambess., Clusiaceae in addition to the evaluation of the antioxidant activity of crude ...extracts, correlated to the flavonoid content. The morphological characterization was performed using traditional techniques of plant anatomy. For phytochemical studies, crude extracts were obtained by static maceration and analyzed by thin layer chromatography. The antioxidant activity and the flavonoids content were determined by colorimetric methods involving, respectively, 2,2-diphenyl-1-picrylhydrazyl free radical and aluminum chloride. C. criuva has uniseriate epidermis, paracytic stomata, hypostomatic leaves, cuticular flanges and cordiform vascular cylinder with accessory bundles. Chemical prospecting confirmed the abundant presence of terpenes and phenols in the extracts of leaves and of fruits. The methanolic extract of seeds showed the lowest EC50 value, but the methanolic extract of pericarps exhibited the highest maximum antioxidant activity. The results suggested a high percentage of flavonoids in the hexanic extract of pericarps, however, this could represent, in fact, the presence of benzophenones. Secretory ducts and the shape of the midrib are diagnostic for C. criuva. The antioxidant activity is not directly related to the flavonoids. The results indicate the importance of future studies with C. criuva chemical constituents.
According to the World Health Organization, half of the World's population, approximately 3.3 billion people, is at risk for developing malaria. Nearly 700,000 deaths each year are associated with ...the disease. Control of the disease in humans still relies on chemotherapy. Drug resistance is a limiting factor, and the search for new drugs is important. We have designed and synthesized new 2-(trifluoromethyl)1,2,4triazolo1,5-apyrimidine derivatives based on bioisosteric replacement of functional groups on the anti-malarial compounds mefloquine and amodiaquine. This approach enabled us to investigate the impact of: (i) ring bioisosteric replacement; (ii) a CF₃ group substituted at the 2-position of the 1,2,4triazolo1,5-apyrimidine scaffold and (iii) a range of amines as substituents at the 7-position of the of heterocyclic ring; on in vitro activity against Plasmodium falciparum. P. falciparum dihydroorotate dehydrogenase (PfDHODH) through strong hydrogen bonds. The presence of a trifluoromethyl group at the 2-position of the 1,2,4triazolo1,5-apyrimidine ring led to increased drug activity. Thirteen compounds were found to be active, with IC₅₀ values ranging from 0.023 to 20 μM in the anti-HRP2 and hypoxanthine assays. The selectivity index (SI) of the most active derivatives 5, 8, 11 and 16 was found to vary from 1,003 to 18,478.
Nuclear magnetic resonance (NMR) spectroscopy can provide detailed information about the chemical structure and stereochemistry of a molecule. However, this technique alone may not always be ...sufficient to assign with confidence the relative configuration of a secondary metabolite. In some cases, additional experiments, such as the Density Functional Theory (DFT) calculation of the chemical shifts for the molecule, may be necessary to support the assignment. An endoperoxide (
1
) isolated from
Plakortis angulospiculatus
has a structure containing four stereogenic centers. The stereochemistry of
1
was proposed based on the biogenetic pathway and optical rotation correlations. Herein, we describe the structure analysis of the natural
1
by quantum NMR calculations for the first time.
Nuclear magnetic resonance (NMR) spectroscopy can provide detailed information about the chemical structure and stereochemistry of a molecule.
This experiment encourages students to use deductive reasoning skills to understand the correlation between different techniques used in a chemistry laboratory and to extract and analyze curcuminoids ...using natural products and processed food from a grocery store. Turmeric pigments were used to teach continuous or discontinuous extraction, vacuum or atmospheric pressure distillation, and thin-layer chromatography (TLC) in an introductory organic chemistry laboratory course in three laboratory sessions of 3–4 h each. Pigment extracts from the rhizome of turmeric, commercial dehydrated vegetable soup, and chicken-flavored instant bouillon (with turmeric as an ingredient) were used. The three techniques were discussed in the first laboratory session before students proposed a methodology to identify pigments in food extracts through a problem-based format. Students were assessed in a final exam where they presented a more detailed discussion of the chemistry laboratory techniques used. These results were compared to exam results from previous years. On the basis of students’ and teacher’s feedback, the sequence of laboratory experiments was considered interesting, and students were motivated to participate more actively during instruction.
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The chemical investigation of the Brazilian marine sponge Plakortis angulospiculatus led to the isolation of the new peroxide-derived polyketide plakilactone J (1). The structure of ...(−)-1 was established by means of HRMS and NMR analysis, while its absolute configuration was unambiguously determined as (4R,6R) by vibrational circular dichroism spectroscopy and density functional theory calculations.
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