RESUMEN
The present study was conducted to evaluate the anticorrosive and antioxidant activities of essential oil from Withania frutescens L. In the present study, the extraction of Withania frutescens L. essential oil (Wf-EO) was conducted using hydrodistillation before being characterized by gas chromatographic analysis (GC/MS) and flame ionization detector (GC/FID). Four bioassays were used for antioxidant testing including 2,2-diphenyl-1-picrylhydrazyl (DPPH), total antioxidant capacity (TAC), ferric reducing antioxidant power (FRAP), and ß-carotene bleaching. The inhibiting effect of Wf-EO on the corrosion behavior of mild steel in 1.0 M HCl was conducted by using polarization curves and electrochemical impedance spectroscopy techniques. The yield of Wf-EO was 0.46% including 175 compounds identified by GC-MS. The oil was mostly constituted of camphor (37.86%), followed by thujone (26.47%), carvacrol (6.84%), eucalyptol (3.18%), and linalool (2.20%). The anti-free radical activity of Wf-EO was 34.41 ± 0.91 µg/ml (DPPH), 9.67 ± 0.15 mg/ml (FRAP), 3.78 ± 0.41 mg AAE/g (TAC), and 89.94 ± 1.44% (ß-carotene). The Wf-EO showed potent antioxidant activity in all bioassays used for testing. The anticorrosion activity, polarization curves as well as EIS diagrams indicated that the Wf-EO exhibited anticorrosive properties and reacted as a suitable corrosion inhibitor in an acidic medium.
RESUMEN
Statistical modeling of the corrosion inhibition process by twenty-one pyridazine derivatives for mild steel in acidic medium was investigated by the quantitative structure property relationship (QSPR) approach. This modeling was established by the correlation between the corrosion inhibition efficiency (IE %) and a number of the electronic and structural properties of these inhibitors such as: the E HOMO (highest occupied molecular orbital energy), the E LUMO (lowest unoccupied molecular orbital energy), the energy gap (E L-H ), the dipole moment (µ), the hardness (η), the softness (σ), the absolute electronegativity (χ), the ionization potential (IP), the electron affinity (EA), the fraction of electrons transferred (ΔN), the electrophilicity index ω the molecular volume (V m ), the logarithm of the partition coefficient (Log P), and the molecular mass (M), in addition to the inhibitor concentration (C i ). The structure electronic properties was calculated by the use of the density functional theory method (DFT), at B3LYP/6-31G (d, p) level of theory and the analysis of dimensionality and redundancy as well as the test of collinearity between descriptors are carried out using principal component analysis (PCA). Whereas, the correlation between EI % and molecular structure is performed through the development of tree mathematical models, based-QSPR approaches: the partial least squares regression (PLS), the principal component regression (PCR) and the artificial neural networks (ANN). Indeed, the statistical quantitative results revealed that PCR and ANN were the most relevant and predictive models in comparison with the PLS model. This pertinence was demonstrated by using leave one-out cross-validation as an efficient method for testing the internal stability and predictive capability of said models with a high cross-validated determination coefficient R 2 cv = 0.92 and predicted determination coefficient R 2 pred = 0.92 and R 2 pred = 0.90 for PCR and ANN respectively; in addition to an extrapolation test set as an external validation with a significant external coefficient of determination: R 2 test = 0.94 and R 2 test = 0.92, for the two correspondingly models.
RESUMEN
The aim of this study was to achieve the best extraction efficiency of the hydroethanolic extract of Zea mays hairs. The impacts of ethanol concentration, extraction time, and solvent /material ratio were studied in relation to the performance of Zea mays extracts by ultrasonic extraction at 50 kHz and room temperature. All extracts were quantitatively characterized in terms of polyphenol content. Response surface methodology (RSM) was carried out to optimize the extraction process and increase extraction efficiency. In the experiments, different concentrations of ethanol:water were used. The efficiency of the extraction process was determined from an analysis of variance (ANOVA). The maximum extraction efficiency of the hydroethanolic extraction (31.37%) and the quantitative value of the polyphenol content (257.87 mg EAG/g extract) were obtained using a treatment time of 40 min, an ethanol:water (70 : 30), and a solvent/material ratio (11 mL/g). The results obtained indicate that ultrasonic-assisted extraction is an effective method for extracting natural compounds from Zea mays, thus allowing the full use of this abundant and inexpensive industrial waste.
