Fabián Espitia-Almeida

Prof. Dr. Fabián Espitia-Almeida

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Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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19 April 2020 in Molecules
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FEFabián Espitia-Almeida
Fabián Espitia-Almeida
CUCarlos Díaz Uribe
Carlos Díaz Uribe
WVWilliam Vallejo
William Vallejo
DGDoris Gomez-Camargo
Doris Gomez-Camargo
Arnold Rafael Romero BohórquezArnold Rafael Romero Bohórquez
Arnold Rafael Romero Bohórquez
In this study, a family of porphyrins based on 5,10,15,20-Tetrakis(4-ethylphenyl)porphyrin (1, Ph) and six metallo-derivatives (Zn2+(2, Ph-Zn), Sn4+(3, Ph-Sn), Mn2+ (4, Ph-Mn), Ni2+ (5, Ph-Ni), Al3+ (6, Ph-Al), and V3+ (7, Ph-V)) were tested as photosensitizers for photodynamic therapy against Leishmania braziliensis and panamensis. The singlet oxygen quantum yield value (ΦΔ) for (1–7) was measured using 1,3-diphenylisobenzofuran (DPBF) as a singlet oxygen trapping agent and 5,10,15,20-(tetraphenyl)-porphyrin (H2TPP) as a reference standard; besides, parasite viability was estimated by the MTT assay. After metal insertion into the porphyrin core, the ΦΔ increased from 0.76–0.90 and cell viability changed considerably. The ΦΔ and metal type changed the cytotoxic activity. Finally, (2) showed both the highest ΦΔ (0.90) and the best photodynamic activity against the parasites studied (IC50 of 1.2 μM).

7 January 2022 in BioMetals
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FEFabián Espitia-Almeida
Fabián Espitia-Almeida
CDCarlos Díaz-Uribe
Carlos Díaz-Uribe
WVWilliam Vallejo
William Vallejo
DGDoris Gómez-Camargo
Doris Gómez-Camargo
Arnold Rafael Romero BohórquezArnold Rafael Romero Bohórquez
Arnold Rafael Romero Bohórquez
ESEduardo Schott
Eduardo Schott

18 May 2024 in Heliyon
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RMRobinson Martínez-Castro
Robinson Martínez-Castro
JFJiress Flórez-Santiago
Jiress Flórez-Santiago
RVRoger Valle-Molinares
Roger Valle-Molinares
JCJulián Cabrera-Barraza
Julián Cabrera-Barraza
FEFabián Espitia-Almeida
Fabián Espitia-Almeida
The neem tree (Azadirachta indica A. Juss) is grown mainly for shade, fuel, and numerous non-timber forest products using its leaves, fruit, and bark. It produces an essential oil that is used as a source for obtaining bioinsecticides, with a broad spectrum of action in agricultural production. Its bioinsecticidal activity is due to the presence of triterpenes, such as azadirachtin, a product in continued growth of the global biopesticide market. Optimal conditions for neem oil extraction using response surface methodology (RSM) and microwave-assisted extraction (MAE) methods have been defined. However, the extraction conditions for these methods tend to consume high volumes of organic solvent and long extraction times. The aim of the present study is to determine the optimal conditions for the extraction of azadirachtin from neem seeds in a hydroalcoholic medium using MAE and RSM with a Box-Behnken design (BBD). A BBD was applied to evaluate the effects of the factors, magnetron voltage (X1), extraction time (X2), and pH of the extraction medium (X3), on the yield of the azadirachtin extraction process. The effect of each variable on the extraction yield was studied independently, considering the pure coefficients (linear and quadratic) on the three levels that were studied in the experiments. Moreover, the study experiments were conducted in triplicate, data were presented as mean and standard deviation, homogeneity of variances was estimated using Levene's test, and a two-way ANOVA with Tukey's post hoc analysis was performed to identify the experimental conditions that allowed us to find the highest extraction yield and to analyze whether the response surface model adequately described our data. The most significant effects of the model correspond to quadratic and interaction effects (p < 0.0001); the quadratic terms voltage (X1), extraction time (X2), and pH (X3); and the interaction effects between voltage-pH (X1*X3) and time-pH (X2*X3), which had a significant influence on the model. Moreover, a canonical analysis was performed. The optimal conditions were as follows: 69.22 V, 6.89 min, and a pH value of 4.35, coinciding with the zones shown in the contour plots. Furthermore, the response obtained at the optimal conditions was 37.5 μg of azadirachtin per gram of pretreated seed.

26 July 2023 in Pharmaceuticals
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FEFabián Espitia-Almeida
Fabián Espitia-Almeida
RVRoger Valle-Molinares
Roger Valle-Molinares
Elkin Navarro QuirozElkin Navarro Quiroz
Elkin Navarro Quiroz
LPLeonardo Pacheco-Londoño
Leonardo Pacheco-Londoño
NGNataly Galan-Freyle
Nataly Galan-Freyle
The growing emergence of microbes resistant to commercially available antibiotic therapies poses a threat to healthcare systems worldwide. Multiple factors have been associated with the increasing incidence of hospital-acquired infections caused by antibiotic-resistant pathogens, including the indiscriminate use of broad-spectrum antibiotics, the massive application of antibiotics in hospitals as a prophylactic measure, self-medication, and nonadherence to pharmacological therapies by patients. In this study, we developed a novel treatment to mitigate the impact of microbial resistance. We synthesized a benzoporphyrin derivative, 5,10,15,20-tetrakis (4-ethylphenyl) porphyrin (TEtPP), with a reaction yield close to 50%. TEtPP exhibited excellent photophysical properties (Φf = 0.12 ± 0.04 and ΦΔ = 0.81 ± 0.23) and was thereby assessed as a potential agent for antibacterial photodynamic therapy. The photophysical properties of the synthesized porphyrin derivative were correlated with the assayed antimicrobial activity. TEtPP showed higher activity against the MRSA strain under irradiation than in the absence of irradiation (minimum inhibitory concentration (MIC) = 69.42 µg/mL vs. MIC = 109.30 µg/mL, p < 0.0001). Similar behavior was observed against P. aeruginosa (irradiated MIC = 54.71 µg/mL vs. nonirradiated MIC = 402.90 µg/mL, p < 0.0001). TEtPP exhibited high activity against S. aureus in both the irradiated and nonirradiated assays (MIC = 67.68 µg/mL vs. MIC = 58.26 µg/mL, p = 0.87).

23 April 2025 in Molecules
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YLYeira P. Lopez-Lora
Yeira P. Lopez-Lora
NGNataly Galan-Freyle
Nataly Galan-Freyle
NFNatally S. Vidal Figueroa
Natally S. Vidal Figueroa
ACAntony Andres Cardozo-Puello
Antony Andres Cardozo-Puello
AHAntonio Acosta Hoyos
Antonio Acosta Hoyos
LPLeonardo Pacheco-Londoño
Leonardo Pacheco-Londoño
Spermatozoa were isolated from the seminal fluid using washing (wash), post-capacitation (POS), and swim-up (SU) techniques, followed by analysis through Surface-Enhanced Raman Spectroscopy (SERS). Density gradient and swim-up methods were applied to 35 semen samples to validate sperm quality. The resulting spectra showed notable variations at 408 cm−1 (S–S stretch attributed to lysozyme) and 728 cm−1 (associated with DNA alterations and methylation). These spectral markers were incorporated into partial least squares discriminant analysis (PLS-DA) models to distinguish among sperm populations prepared by different methods. One PLS-DA model differentiated wash from POS and SU, attaining 86% sensitivity and 91% accuracy. Another model distinguished between POS and SU, achieving 77% sensitivity and 74% accuracy. The combined use of SERS and multivariate analysis offers a promising alternative for assessing sperm quality, supported by motility assessments in 35 validated samples. This approach could enhance both the accuracy and efficiency of reproductive diagnostics.

8 November 2021 in F1000Research
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FEFabián Espitia-Almeida
Fabián Espitia-Almeida
CDCarlos Diaz-Uribe
Carlos Diaz-Uribe
WVWilliam Vallejo
William Vallejo
DGDoris Gomez-Camargo
Doris Gomez-Camargo
Arnold Rafael Romero BohórquezArnold Rafael Romero Bohórquez
Arnold Rafael Romero Bohórquez
CLCristian Linares-Flores
Cristian Linares-Flores
Background:Photodynamic therapy activity against different biological systems has been reported for porphyrins. Porphyrin modifications through peripheral groups and/or by metal insertion inside the ring are main alternatives for the improvement of its photo-physical properties. In this study, we synthesized and characterized 5,10,15,20-tetrakis(4-bromophenyl)porphyrin and the dicloro-5,10,15,20-tetrakis(4-bromophenyl)porphyrinato Sn(IV). Methods:Metal-free porphyrin was synthesized using the Alder method, while the Sn(IV)-porphyrin complex was prepared by combining metal-free porphyrin with stannous chloride in DMF; the reaction yields were 47% and 64% respectively. Metal-free porphyrin was characterized by UV-Vis, FT-IR, ESI-mass spectrometry and13C-NMR. Additionally, the Sn(IV) -porphyrin complex was characterized using UV-Vis and FT-IR. Cyclic voltammetry tests in four different solvents. The fluorescence quantum yield (Φf) was measured using fluorescein as a standard, the singlet oxygen quantum yield (ΦD) was estimated using the standard 5,10,15,20-(tetraphenyl)porphyrin (H2TPP) and the quencher of singlet oxygen 1,3-diphenylisobenzofuran (DPBF). Results:UV-Vis assay showed typical Q and Soret bands for porphyrin and its metallo-porphyrin complex. Compounds showed photoluminescence at the visible range of electromagnetic spectrum. The inclusion of the metal in the porphyrin core changed the Φffrom 0.15 to 0.05 and the ΦDincreased from 0.55 to 0.59. Finally, the effect of the compounds on the viability ofL. panamensiswas evaluated by means of the MTT test. The results showed that both compounds decreased the viability of the parasite; this inhibitory activity was greater under light irradiation; the porphyrin compound had IC50of 16.5 μM and the Sn(IV)-porphyrin complex had IC50of 19.2 μM. Conclusion:The compounds were synthesized efficiently, their characterization was carried out by different spectroscopy techniques and their own signals were evidenced for both structures, both compounds decreased the cell viability ofL. panamensis.