Publications by authors named "Letícia Monteiro Farias"

3 Publications

  • Page 1 of 1

Irradiance-driven 20-hydroxyecdysone production and morphophysiological changes in Pfaffia glomerata plants grown in vitro.

Protoplasma 2021 Jan 25;258(1):151-167. Epub 2020 Sep 25.

Departamento de Biologia Vegetal/BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.

Pfaffia glomerata possesses potential pharmacological and medicinal properties, mainly owing to the secondary metabolite 20-hydroxyecdysone (20E). Increasing production of biomass and 20E is important for industrial purposes. This study aimed to evaluate the influence of irradiance on plant morphology and production of 20E in P. glomerata grown in vitro. Nodal segments of accessions 22 and 43 (Ac22 and Ac43) were inoculated in culture medium containing MS salts and vitamins. Cultures were maintained at 25 ± 2 °C under a 16-h photoperiod and subjected to irradiance treatments of 65, 130, and 200 μmol m s by fluorescent lamps. After 30 days, growth parameters, pigment content, stomatal density, in vitro photosynthesis, metabolites content, and morphoanatomy were assessed. Notably, Ac22 plants exhibited 10-fold higher 20E production when cultivated at 200 μmol m s than at 65 μmol m s, evidencing the importance of light quantity for the accumulation of this metabolite. 20E production was twice as high in Ac22 as in Ac43 plants although both accessions responded positively to higher irradiance. Growth under 200 μmol m s stimulated photosynthesis and consequent biomass accumulation, but lowered carotenoids and anthocyanins. Furthermore, increasing irradiance enhanced the number of palisade and spongy parenchyma cells, enhancing the overall growth of P. glomerata. Graphical abstract.
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http://dx.doi.org/10.1007/s00709-020-01558-1DOI Listing
January 2021

Blue and red light affects morphogenesis and 20-hydroxyecdisone content of in vitro Pfaffia glomerata accessions.

J Photochem Photobiol B 2020 Jan 24;203:111761. Epub 2019 Dec 24.

Departamento de Biologia Vegetal/BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG, Brazil. Electronic address:

The combination of different colors from light-emitting diodes (LEDs) may influence growth and production of secondary metabolites in plants. In the present study, the effect of light quality on morphophysiology and content of 20-hydroxyecdysone (20E), a phytoecdysteroid, was evaluated in accessions of an endangered medicinal species, Pfaffia glomerata, grown in vitro. Two accessions (Ac22 and Ac43) were cultured in vitro under three different ratios of red (R) and blue (B) LEDs: (i) 1R:1B, (ii) 1R:3B, and (iii) 3R:1B. An equal ratio of red and blue light (1R:1B) increased biomass accumulation, anthocyanin content, and 20E production (by 30-40%). Moreover, 1R:1B treatment increased the size of vascular bundles and vessel elements, as well as strengthened xylem lignification and thickening of the cell wall of shoots. The 1R:3B treatment induced the highest photosynthetic and electron transport rates and enhanced the activity of oxidative stress-related enzymes. Total Chl content, Chl/Car ratio, and NPQ varied more by accession type than by light source. Spectral quality affected primary metabolism differently in each accession. Specifically, in Ac22 plants, fructose content was higher under 1R:1B and 1R:3B treatments, whereas starch accumulation was higher under 1R:3B, and sucrose under 3R:1B. In Ac43 plants, sugars were not influenced by light spectral quality, but starch content was higher under 3R:1B conditions. In conclusion, red and blue LEDs enhance biomass and 20E production in P. glomerata grown in vitro.
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http://dx.doi.org/10.1016/j.jphotobiol.2019.111761DOI Listing
January 2020

Assessment of the phenolic content, mutagenicity and genotoxicity of ethanolic extracts of stem bark and leaves from A. St.-hil.

Drug Chem Toxicol 2020 Sep 13;43(5):539-545. Epub 2018 Sep 13.

Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Viçosa, MG, Brazil.

is a plant species whose stem bark is used as bitter tonic beverage. The phytochemical analysis, as well as quantification of phenolic constituents and antioxidant activity of ethanolic extracts from stem bark, and leaves were conducted. The extracts were tested for mutagenicity (Ames test) and DNA-damaging activity (Plasmid Cleavage test). Leaves recorded the largest amount of flavonoids. The performed high-performance liquid chromatography (HPLC) showed flavonoids such as isorhamnetin and strychnobiflavone (phytochemical markers of the investigated species) in stem barks, but not in leaves. The proanthocyanidin content and antioxidant activity were significantly higher in stem barks than in leaves. Stem bark and leaf extracts presented mutagenic activity against TA98 and TA100 strains with, and without, metabolic activation (S9). The Plasmid Cleavage test did not indicate DNA-damaging activity. Our results suggest that extracts deriving from should be used with extreme caution, mainly the stem bark extract, which is widely used in folk medicine.
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http://dx.doi.org/10.1080/01480545.2018.1515218DOI Listing
September 2020
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