Gabriela Valenzuela-Barra Gabriela Valenzuela-Barra

Dr. Gabriela Valenzuela-Barra Gabriela Valenzuela-Barra


Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 October 2024 in Foods
Verified
Journal Article
Open access
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AVAntonio Vega-Galvez
Antonio Vega-Galvez
APAlexis Pastén
Alexis Pastén
EUElsa Uribe
Elsa Uribe
NMNicol Mejias
Nicol Mejias
MAMichael Araya
Michael Araya
CVCARLA VERGARA
CARLA VERGARA
Cauliflower (Brassica oleraceae L. var. Botrytis Linnaeus) has various health benefits due to its rich bioactive compound content. However, this fresh vegetable faces challenges related to its perishability and short shelf life. This study explores the effect of five drying methods, namely vacuum drying (VD), convective drying (CD), infrared drying (IRD), low-temperature vacuum drying (LTVD) and vacuum freeze-drying (VFD), on the bioactive compounds and health-promoting properties of cauliflower. Analyses of amino acids, hydroxycinnamic acid and its derivatives, glucosinolates, and isothiocyanates, as well as evaluations of their anti-inflammatory, antiproliferative, and neuroprotective properties, were conducted based on these five drying methods. The results revealed that samples treated with VFD and IRD had a higher content of amino acids involved in GSL anabolism. Moreover, VFD samples retained hydroxycinnamic acid derivatives and glucosinolates to a greater extent than other methods. Nonetheless, the CD and VD samples exhibited higher antiproliferative and neuroprotective effects, which were correlated with their high sulforaphane content. Overall, considering the retention of most bioactive compounds from cauliflower and the topical inflammation amelioration induced in mice, VFD emerges as a more satisfactory option.

30 November 2025 in Molecules
Verified
Journal Article
Open access
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KMKatia Yanina Fernández Moreno
Katia Yanina Fernández Moreno
GMGabriela Maturana
Gabriela Maturana
SBSofía Blanco-Haros
Sofía Blanco-Haros
UNUlises Norambuena-Jopia
Ulises Norambuena-Jopia
GVGabriela Valenzuela-Barra Gabriela Valenzuela-Barra
Gabriela Valenzuela-Barra Gabriela Valenzuela-Barra
JBJessica Bravo
Jessica Bravo
Quitral (Tristerix corymbosus), a Chilean and Argentine parasitic mistletoe, is traditionally used by Mapuche natives to treat stomach ulcers, nervous disorders, and cholesterol reduction, although scientific support is scarce. Methanolic and chloroform extracts from its leaves and stems were prepared. Chemical analysis included antioxidant capacity assays (ORAC-FL and DPPH) and chromatographic determinations. The antimicrobial activity was tested against nine bacteria and two yeast strains. Additionally, cytotoxicity (hemolysis) and toxicity (against Caenorhabditis elegans) assays were performed. The results revealed that the methanolic leaf extracts had the highest ORAC-FL value, with DPPH assays showing solvent-dependent differences. Thirty-one compounds were tentatively identified, of which 61% were phenolic compounds, primarily flavonoids like quercetin and its derivatives. Antimicrobial results showed activity against Gram-positive bacteria (Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and Enterococcus faecalis), but not against yeast Candida guillermondii and Candida tropicalis. Methanolic extracts induced dose-dependent erythrocyte hemolysis, while chloroform extracts showed no relevant cytotoxicity. Toxicity against Caenorhabditis elegans was also dose-dependent for methanolic extracts; leaf extract reduced survival at 50 mg mL−1 after 24 h. These findings partially validate some traditional uses, highlight the importance of solvent polarity in extraction and biological effects, and establish quitral as a flavonoid source.

19 July 2024 in Plants
Verified
Journal Article
Open access
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BJBairon Jorquera
Bairon Jorquera
GVGabriela Valenzuela-Barra Gabriela Valenzuela-Barra
Gabriela Valenzuela-Barra Gabriela Valenzuela-Barra
AMAilin Mayorga
Ailin Mayorga
JMJessica Mejía
Jessica Mejía
GNGabriel Núñez
Gabriel Núñez
Raquel BridiRaquel Bridi
Raquel Bridi
Propolis is a complex mixture formed from exudates that bees collect from plants and then mix with beeswax and their own salivary enzymes. Chilean propolis is characterized by the presence of phenolic compounds, which are considered responsible for the biological activities. The endemic species Escallonia pulverulenta (Ruiz and Pav.) Pers. [Escalloniaceae] is a recognized source of exudate to produce propolis. This study reports for the first time the chemical profile and antibacterial activity of E. pulverulenta exudate and leaves, as well as two samples of Chilean propolis. Palynological and morphological analysis showed the presence of E. pulverulenta as one of the main species in the propolis samples. UPLC-MS/MS analyses enabled the identification of phenolic acids in the leaves and in the propolis. Conversely, flavonoids are mainly present in exudates and propolis. Quercetin is the most abundant flavonol in the exudate, with similar concentrations in the propolis samples. Nevertheless, the main compound present in both samples of propolis was the flavanone pinocembrin. The antibacterial results obtained for exudate and propolis have shown a similar behavior, especially in the inhibition of Streptococcus pyogenes. These results show the importance of the exudates collected by the bees in the chemical composition and antibacterial capacity of propolis.

3 October 2025 in Antioxidants
Verified
Journal Article
Open access
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AVAntonio Vega-Galvez
Antonio Vega-Galvez
APAlexis Pastén
Alexis Pastén
EUElsa Uribe
Elsa Uribe
NMNicol Mejias
Nicol Mejias
ICIsadora Corco
Isadora Corco
TTTamar Toledo
Tamar Toledo
For the first time, the effect of low-temperature vacuum drying (LTVD) on wild murta (Ugni molinae Turcz) was evaluated, in comparison with freeze-drying (FD) and vacuum drying (VD), to assess their capacity to preserve bioactive compounds and associated bioactivities. Murta was dried using LTVD at 20, 30, and 40 °C under a constant vacuum of 10 mbar, where FD and VD at 60 °C (VD 60) were included as comparative methods. The content of fatty acids and tocols, along with the retention of bioactive compounds and their antioxidant, anti-inflammatory, cytotoxic, and α-glucosidase inhibitory activities, were systematically analyzed. LTVD- and VD-dried murta exhibited higher polyunsaturated-to-saturated fatty acid ratios (>9.0) and markedly greater tocol contents, whereas FD maintained a more balanced ratio (<5.0) but with lower tocol levels. While FD was most effective in preserving catechin, higher levels of other phenolic compounds were observed in samples dried by LTVD at 20 and 40 °C, as well as VD 60, possibly due to the release of bound forms during processing. The drying method significantly influenced murta bioactivity. LTVD 30 preserved the highest antioxidant capacity, while topical anti-inflammatory effects on skin lesions varied by pathway, with LTVD 40 being the most effective in the TPA model and FD in the AA model. These effects were evaluated only using a topical inflammation model in BALB/c mice of both sexes; dietary effects were not assessed in this study. Regarding other bioactivities, VD 60 extracts excelled in both cytotoxic and α-glucosidase inhibitory effects, whereas FD extracts were the most effective against AGS cells and LTVD 20 against α-glucosidase. In conclusion, LTVD emerges as a promising alternative to FD and VD, showing potential to preserve bioactive compounds and key bioactivities of wild murta, although further studies are needed to elucidate the underlying mechanisms.

31 May 2026 in Veterinary Sciences
Verified
Journal Article
Open access
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MJMartina Jacobs
Martina Jacobs
NVNoelia Valdivia
Noelia Valdivia
MVMartín Antonio Varas
Martín Antonio Varas
PPPaola Andrea Ramos Pizarro
Paola Andrea Ramos Pizarro
FBFlavia Alejandra Bruna
Flavia Alejandra Bruna
JBJessica Bravo
Jessica Bravo
Background/Objectives: The increasing emergence of antimicrobial-resistant Staphylococcus pseudintermedius has limited the effectiveness of conventional therapies for canine pyoderma, highlighting the need for alternative topical strategies. This study aimed to develop hydrogels incorporating essential oils (EOs) from Peumo (Cryptocarya alba) and Tepa (Laureliopsis philippiana) as potential topical treatments against Staphylococcus pseudintermedius skin infections in veterinary medicine. Methods: EOs were obtained by steam distillation, chemically characterized by gas chromatography–mass spectrometry (GC–MS), and evaluated for antibacterial activity against S. pseudintermedius strains. Carbopol®-based hydrogels incorporating the EOs of C. alba (HCA), L. philippiana (HLP), and a control vehicle (HVE) were formulated and characterized in terms of physicochemical properties, microbiological safety, and stability under accelerated and refrigerated conditions. Preclinical dermal safety was evaluated in BALB/c mice by repeated topical administration for five days. The analysis included clinical observation, skin irritation scoring, and histological analysis. Additionally, a preliminary microbiological evaluation was conducted in client-owned dogs with superficial pyoderma to assess the performance of the formulations in the target species. Skin lesion swabs were collected at baseline and after 21 days of treatment, followed by bacterial culture and automated identification using the VITEK® system. Bacterial detection and bacterial load were evaluated to determine changes in microbiological status over the treatment period. Results: GC–MS analysis identified sabinene and eucalyptol as the main compounds in CA-EO, and linalool, eucalyptol, and safrole in L. philippiana EO. Both EOs exhibited moderate antibacterial activity against S. pseudintermedius (inhibition zones 4.9–10.8 mm; MIC ≥ 2.048 mg mL−1). The hydrogels were microbiologically safe. Among formulations, HLP demonstrated superior physical stability and comparable rheological properties to the vehicle. In vivo safety evaluation demonstrated no signs of systemic toxicity, behavioral alterations, or skin irritation, and histological analysis confirmed preserved skin architecture without evidence of inflammation or tissue damage. In the preliminary microbiological evaluation in dogs, all animals were positive for Staphylococcus spp. at baseline. On Day 21, bacterial elimination was observed in the active treatment groups, but not in the HVE group, with elimination rates of 50.0% for Inveclor® and 25.0% for both HCA and HLP. In parallel, HLP showed the highest proportion of dogs reaching minimal bacterial load levels (75%), followed by Inveclor® (50.0%) and HCA (37.5%), whereas no dogs in the vehicle group reached this category. Conclusions: EOs from C. alba and L. philippiana presented antibacterial activity and were successfully incorporated into microbiologically safe hydrogel formulations. Notably, HLP demonstrated superior stability and a favorable preclinical safety profile, supporting its potential. In the preliminary microbiological evaluation in dogs, numerical differences in bacterial elimination and bacterial load categories were observed among groups; however, these differences were not statistically significant and should be interpreted as exploratory.

7 May 2026 in Antioxidants
Verified
Journal Article
Open access
PDF file
Vicente Gregorio Valenzuela-BassVicente Gregorio Valenzuela-Bass
Vicente Gregorio Valenzuela-Bass
EGElva Zenaida Gonzales-Nieto
Elva Zenaida Gonzales-Nieto
GVGabriela Valenzuela-Barra Gabriela Valenzuela-Barra
Gabriela Valenzuela-Barra Gabriela Valenzuela-Barra
MCMiguel Angel Varas Condori
Miguel Angel Varas Condori
Angélica Reyes-JaraAngélica Reyes-Jara
Angélica Reyes-Jara
Adriano Costa de CamargoAdriano Costa de Camargo
Adriano Costa de Camargo
Murtilla pomace (the by-product generated during juice production) shows a high phenolic content. Recovering phenolics from murtilla pomace is a sustainable approach towards zero waste. In this study, murtilla pomace was subjected to enzyme-assisted extraction using Viscozyme. The extracts were analyzed for TPC and phenolic profile. Antioxidant activity was evaluated by chemical-based assays and the antioxidant property was demonstrated for the first time in an ozone-induced oxidation process applied to a raw fish model system. Enzymatic pretreatment with Viscozyme increased the total phenolic content by up to 57%. The antioxidant activity also increased upon enzymatic treatment. The concentration of quercetin was positively affected, while the content of rutin decreased upon enzymatic pretreatment, likely reflecting the enzymatic hydrolysis biotransforming rutin glycoside into quercetin aglycone. Phenolics from murtilla pomace obtained upon enzyme-assisted extraction were shown to be effective as natural antioxidants against ozone-induced oxidation in salmon. Therefore, enzyme-assisted extraction may be an environmentally friendly strategy in the recovery of these natural antioxidants.