Monomeric Camelus dromedarius GSTM1 at low pH is structurally more thermostable than its native dimeric form.

Glutathione S‒transferases (GSTs) are multifunctional enzymes that play an important role in detoxification, cellular signalling, and the stress response. Camelus dromedarius is well-adapted to survive in extreme desert climate and it has GSTs, for which limited information is available. This study investigated the structure-function and thermodynamic properties of a mu-class camel GST (CdGSTM1) at different pH. Recombinant CdGSTM1 (25.7 kDa) was expressed in E. coli and purified to homogeneity. Dimeric CdGSTM1 dissociated into stable but inactive monomeric subunits at low pH. Conformational and thermodynamic changes during the thermal unfolding pathway of dimeric and monomeric CdGSTM1 were characterised via a thermal shift assay and dynamic multimode spectroscopy (DMS). The thermal shift assay based on intrinsic tryptophan fluorescence revealed that CdGSTM1 underwent a two-state unfolding pathway at pH 1.0-10.0. Its Tm value varied with varying pH. Another orthogonal technique based on far-UV CD also exhibited two-state unfolding in the dimeric and monomeric states. Generally, proteins tend to lose structural integrity and stability at low pH; however, monomeric CdGSTM1 at pH 2.0 was thermally more stable and unfolded with lower van't Hoff enthalpy. The present findings provide essential information regarding the structural, functional, and thermodynamic properties of CdGSTM1 at pH 1.0-10.0

Chemical Composition of Kickxia aegyptiaca Essential Oil and Its Potential Antioxidant and Antimicrobial Activities

The exploration of new bioactive compounds from natural resources as alternatives to synthetic chemicals has recently attracted the attention of scientists and researchers. To our knowledge, the essential oil (EO) of Kickxia aegyptiaca has not yet been explored. Thus, the present study was designed to explore the EO chemical profile of K. aegyptiaca for the first time, as well as evaluate its antioxidant and antibacterial activities, particularly the extracts of this plant that have been reported to possess various biological activities. The EO was extracted from the aerial parts via hydrodistillation and then characterized by gas chromatography-mass spectrometry (GC-MS). The extracted EO was tested for its antioxidant activity via the reduction in the free radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). In addition, the EO was tested as an antibacterial mediator against eight Gram-negative and Gram-positive bacterial isolates. Forty-three compounds were identified in the EO of K. aegyptiaca, with a predominance of terpenoids (75.46%). Oxygenated compounds were the main class, with oxygenated sesquiterpenes attaining 40.42% of the EO total mass, while the oxygenated monoterpenes comprised 29.82%. The major compounds were cuminic aldehyde (21.99%), caryophyllene oxide (17.34%), hexahydrofarnesyl acetone (11.74%), ar-turmerone (8.51%), aromadendrene oxide (3.74%), and humulene epoxide (2.70%). According to the IC50 data, the K. aegyptiaca EO revealed considerable antioxidant activity, with IC50 values of 30.48 mg L-1 and 35.01 mg L-1 for DPPH and ABTS, respectively. In addition, the EO of K. aegyptiaca showed more substantial antibacterial activity against Gram-positive bacterial isolates compared to Gram-negative. Based on the minimum inhibitory concentration (MIC), the EO showed the highest activity against Escherichia coli and Bacillus cereus, with an MIC value of 0.031 mg mL-1. The present study showed, for the first time, that the EO of K. aegyptiaca has more oxygenated compounds with substantial antioxidant and antibacterial activities. This activity could be attributed to the effect of the main compounds, either singular or synergistic. Thus, further studies are recommended to characterize the major compounds, either alone or in combination as antioxidants or antimicrobial agents, and evaluate their biosafety

Comparative Chemical Profiles of the Essential Oils from Different Varieties of Psidium guajava L.

Guava (Psidium guajava) leaves are commonly used in the treatment of diseases. They are considered a waste product resulting from guava cultivation. The leaves are very rich in essential oils (EOs) and volatiles. This work represents the detailed comparative chemical profiles of EOs derived from the leaves of six guava varieties cultivated in Egypt, including Red Malaysian (RM), El-Qanater (EQ), White Indian (WI), Early (E), El-Sabahya El-Gedida (ESEG), and Red Indian (RI), cultivated on the same farm in Egypt. The EOs from the leaves of guava varieties were extracted by hydro-distillation and analyzed with GC-MS. The EOs were categorized in a holistic manner using chemometric tools. The hydro-distillation of the samples yielded 0.11–0.48% of the EO (v/w). The GC-MS analysis of the extracted EOs showed the presence of 38 identified compounds from the six varieties. The sesquiterpene compounds were recorded as main compounds of E, EQ, ESEG, RI, and WI varieties, while the RM variety attained the highest content of monoterpenes (56.87%). The sesquiterpenes, β-caryophyllene (11.21–43.20%), and globulol (76.17–26.42%) were detected as the major compounds of all studied guava varieties, while trans-nerolidol (0.53–10.14) was reported as a plentiful compound in all of the varieties except for the RM variety. A high concentration of D-limonene was detected in the EOs of the RM (33.96%), WI (27.04%), and ESEG (9.10%) varieties. These major compounds were consistent with those reported for other genotypes from different countries. Overall, the EOs’ composition and the chemometric analysis revealed substantial variations among the studied varieties that might be ascribed to genetic variability, considering the stability of the cultivation and climate conditions. Therefore, this chemical polymorphism of the studied varieties supports that these varieties could be considered as genotypes of P. guajava. It is worth mentioning here that the EOs, derived from leaves considered to be agricultural waste, of the studied varieties showed that they are rich in biologically active compounds, particularly β-caryophyllene, trans-nerolidol, globulol, and D-limonene. These could be considered as added value for pharmacological and industrial applications. Further study is recommended to confirm the chemical variations of the studied varieties at a molecular level, as well as their possible medicinal and industrial uses

Essential Oil of <i>Ipomoea carnea</i>: Chemical Profile, Chemometric Analysis, Free Radical Scavenging, and Antibacterial Activities

Essential oils (EOs) have been reported as a promising group of naturally extracted compounds due to their various reported biological activities. Ipomoea carnea is a widely distributed plant with many traditional uses worldwide. However, although the EOs of various Ipomea species have been reported, I. carnea remains poorly studied. Therefore, the present investigation aimed to characterize the chemical profile of the EO of I. carnea growing in Egypt via gas chromatography/mass spectroscopy (GC-MS) and correlate its profile with other reported species via chemometric analysis using agglomerative hierarchical clustering (AHC) and principal component analysis (PCA). In addition, the aim was to determine the antioxidant and antibacterial activities of the extracted EO. Depending on the GC-MS analysis, 31 compounds were identified, mainly terpenes (94.82), with traces of carotenoid and apocarotenoid-derived compounds. The major compounds were tau-cadinol (35.68%), α-cadinol (26.76%), spathulenol (8.11%), and caryophyllene oxide (6.56%), which were assigned as major compounds. The chemometric studies showed that the Egyptian ecospecies of I. carnea differs in chemical profile from those growing in Brazil, as well as those reported for other Ipomea species. The EO showed significant DPPH and ABTS radical scavenging abilities, with IC50 values of 33.69 and 40.86 mg L−1, respectively. Additionally, the I. carnea EO displayed significant inhibition against the growth of all tested bacterial strains, where it showed an MIC range of 82–1442 mg mL−1. Based on the current results, the I. carnea EO, particularly the major identified compounds, could be used as a potential eco-friendly green resource for antioxidant and antimicrobial activities. Therefore, further study is recommended to evaluate the biological significance of the main compounds, either individually or in combination, as well as assess their modes of action and safety

Essential Oil of Ipomoea carnea: Chemical Profile, Chemometric Analysis, Free Radical Scavenging, and Antibacterial Activities

Essential oils (EOs) have been reported as a promising group of naturally extracted compounds due to their various reported biological activities. Ipomoea carnea is a widely distributed plant with many traditional uses worldwide. However, although the EOs of various Ipomea species have been reported, I. carnea remains poorly studied. Therefore, the present investigation aimed to characterize the chemical profile of the EO of I. carnea growing in Egypt via gas chromatography/mass spectroscopy (GC-MS) and correlate its profile with other reported species via chemometric analysis using agglomerative hierarchical clustering (AHC) and principal component analysis (PCA). In addition, the aim was to determine the antioxidant and antibacterial activities of the extracted EO. Depending on the GC-MS analysis, 31 compounds were identified, mainly terpenes (94.82), with traces of carotenoid and apocarotenoid-derived compounds. The major compounds were tau-cadinol (35.68%), &alpha;-cadinol (26.76%), spathulenol (8.11%), and caryophyllene oxide (6.56%), which were assigned as major compounds. The chemometric studies showed that the Egyptian ecospecies of I. carnea differs in chemical profile from those growing in Brazil, as well as those reported for other Ipomea species. The EO showed significant DPPH and ABTS radical scavenging abilities, with IC50 values of 33.69 and 40.86 mg L&minus;1, respectively. Additionally, the I. carnea EO displayed significant inhibition against the growth of all tested bacterial strains, where it showed an MIC range of 82&ndash;1442 mg mL&minus;1. Based on the current results, the I. carnea EO, particularly the major identified compounds, could be used as a potential eco-friendly green resource for antioxidant and antimicrobial activities. Therefore, further study is recommended to evaluate the biological significance of the main compounds, either individually or in combination, as well as assess their modes of action and safety

Antiviral Potentialities of Chemical Characterized Essential Oils of Acacia nilotica Bark and Fruits against Hepatitis A and Herpes Simplex Viruses: In Vitro, In Silico, and Molecular Dynamics Studies

Acacia nilotica (synonym: Vachellia nilotica (L.) P.J.H.Hurter and Mabb.) is considered an important plant of the family Fabaceae that is used in traditional medicine in many countries all over the world. In this work, the antiviral potentialities of the chemically characterized essential oils (EOs) obtained from the bark and fruits of A. nilotica were assessed in vitro against HAV, HSV1, and HSV2. Additionally, the in silico evaluation of the main compounds in both EOs was carried out against the two proteins, 3C protease of HAV and thymidine kinase (TK) of HSV. The chemical profiling of the bark EOs revealed the identification of 32 compounds with an abundance of di- (54.60%) and sesquiterpenes (39.81%). Stachene (48.34%), caryophyllene oxide (19.11%), and spathulenol (4.74%) represented the main identified constituents of bark EO. However, 26 components from fruit EO were assigned, with the majority of mono- (63.32%) and sesquiterpenes (34.91%), where trans-caryophyllene (36.95%), Z-anethole (22.87%), and &gamma;-terpinene (7.35%) represented the majors. The maximum non-toxic concentration (MNTC) of the bark and fruits EOs was found at 500 and 1000 &micro;g/mL, respectively. Using the MTT assay, the bark EO exhibited moderate antiviral activity with effects of 47.26% and 35.98% and a selectivity index (SI) of 2.3 and 1.6 against HAV and HSV1, respectively. However, weak activity was observed via the fruits EO with respective SI values of 3.8, 5.7, and 1.6 against HAV, HSV1, and HSV2. The in silico results exhibited that caryophyllene oxide and spathulenol (the main bark EO constituents) showed the best affinities (&Delta;G = &minus;5.62, &minus;5.33, &minus;6.90, and &minus;6.76 kcal/mol) for 3C protease and TK, respectively. While caryophyllene (the major fruit EO component) revealed promising binding capabilities against both proteins (&Delta;G = &minus;5.31, &minus;6.58 kcal/mol, respectively). The molecular dynamics simulation results revealed that caryophyllene oxide has the most positive van der Waals energy interaction with 3C protease and TK with significant binding free energies. Although these findings supported the antiviral potentialities of the EOs, especially bark EO, the in vivo assessment should be tested in the intraoral examination for these EOs and/or their main constituents

Exogenous Application of Proline and Salicylic Acid can Mitigate the Injurious Impacts of Drought Stress on Barley Plants Associated with Physiological and Histological Characters

Barley is a very important crop worldwide and has good impact in preserving food security. The impacts of 10 mM proline and 0.5 mM salicylic acid were evaluated on water stressed barley plants (Hordeum vulgare L. Giza126). Salicylic acid and proline treatments led to increased stem length, plant dry weights, chlorophyll concentration, relative water content, activity of antioxidant enzymes, and grain yield under drought stress. Nevertheless, lipid peroxidation, electrolyte leakage (EL), superoxide (O2&middot;&minus;), and hydrogen peroxide (H2O2) significantly decreased in treated barley plants with proline and salicylic acid in both growing seasons as compared with drought treatment only, which caused significant decrease in stem length, plant dry weights, chlorophyll concentration, activity of antioxidant enzymes, as well as biological and grain yield. These results demonstrated the importance of salicylic acid and proline as tolerance inducers of drought stress in barley plants