Datura stramonium Flowers as a Potential Natural Resource of Bioactive Molecules: Identification of Anti-Inflammatory Agents and Molecular Docking Analysis.

The present study investigated the antioxidant, antibacterial, antiviral and anti-inflammatory activities of different aerial parts (flowers, leaves and seeds) of Datura stramonium. The plant material was extracted with 80% methanol for about 24 h. The sensitivity to microorganisms analysis was performed by the microdilution technique. Antioxidant tests were performed by scavenging the DPPH and ABTS radicals, and by FRAP assay. Anti-inflammatory activity was evaluated through the inhibition of nitric oxide production in activated macrophage RAW 264.7 cells. Cell viability was assessed with an MTT assay. Results show that the flower extract revealed a powerful antimicrobial capacity against Gram-positive bacteria and strong antioxidant and anti-inflammatory activities. No significant cytotoxicity to activated macrophages was recorded. High resolution electrospray ionization mass spectrometry and nuclear magnetic resonance analysis identified two molecules with important anti-inflammatory effects: 12α-hydroxydaturametelin B and daturametelin B. Molecular docking analysis with both pro-inflammatory agents tumor necrosis factor alpha and interleukin-6 revealed that both compounds showed good binding features with the selected target proteins. Our results suggest that D. stramonium flower is a promising source of compounds with potential antioxidant, antibacterial, and anti-inflammatory activities. Isolated withanolide steroidal lactones from D. stramonium flower extract with promising anti-inflammatory activity have therapeutic potential against inflammatory disorders.

Do we need aerobiological air monitoring in desert climates? The Qatar experience.

Knowledge about diurnal, seasonal, and annual fluctuations in airborne pollen and fungal spores in any geographical area is essential for effective diagnosis and treatment of allergies. Aerobiological analysis enables the detection of airborne pollen and spores, thus providing information on plant phenology, plant distribution, related diseases, and the risks for some species in terms of allergies. Although pollen and fungal spores have been widely studied as aeroallergens throughout the world, not much is known about the biological aerosols in countries with a desert environment; and these could be present in much higher concentrations than expected. Arid desert regions (including the region surrounding the Arab Gulf), characterized by hot weather, poor soils, and low biological productivity, have typically been neglected when building ambitious biomonitoring networks for the large-scale monitoring of biological particles; however, few studies in Kuwait, Saudi Arabia, and recently Qatar have aimed to delineate the various botanical families that contribute to inhalant allergens in this region. Understanding the aerobiological features of countries with hot and desert climates may better prepare healthcare providers to assist patients with allergic rhinitis. It may be argued that one of the reasons why aerobiologists have only recently turned their attention to the state of Qatar investigating how pollen and fungal spore records could contribute to evaluating the correlation between different pollen conditions and allergy symptoms. The first aerobiological network of Qatar was monitoring (2017-2020) the atmospheric pollen concentrations of Doha and Al Khor to determine the association between the possible risk of respiratory allergies and the distribution of certain species throughout the region. In the Qatari database, more than 25 native taxa have been recorded, up to 50% of which can be considered allergenic. This includes Amaranthaceae and Poaceae pollen among the major aeroallergens causing allergy symptoms in Qatar. Our study has confirmed a statistically significant association between Amaranthaceae and asthma and allergic rhinitis. To summarize, it is worth considering aerobiological monitoring in desert climate regions when assessing the effectiveness of pollen allergy therapy and planning prevention methods for patients.

Antifungal mechanism of the combination of Cinnamomum verum and Pelargonium graveolens essential oils with fluconazole against pathogenic Candida strains.

The present study aimed to investigate the anti-Candida activity of ten essential oils (EOs) and to evaluate their potential synergism with conventional drugs. The effect on secreted aspartic protease (SAP) activity and the mechanism of action were also explored. The antifungal properties of essential oils were investigated using standard micro-broth dilution assay. Only Cinnamomum verum, Thymus capitatus, Syzygium aromaticum, and Pelargonium graveolens exhibited a broad spectrum of activity against a variety of pathogenic Candida strains. Chemical composition of active essential oils was performed by gas chromatography-mass spectrometry (GC-MS). Synergistic effect was observed with the combinations C. verum/fluconazole and P. graveolens/fluconazole, with FIC value 0.37. Investigation of the mechanism of action revealed that C. verum EO reduced the quantity of ergosterol to 83%. A total inhibition was observed for the combination C. verum/fluconazole. However, P. graveolens EO may disturb the permeability barrier of the fungal cell wall. An increase of MIC values of P. graveolens EO and the combination with fluconazole was observed with osmoprotectants (sorbitol and PEG6000). Furthermore, the combination with fluconazole may affect ergosterol biosynthesis and disturb fatty acid homeostasis in C. albicans cells as the quantity of ergosterol and oleic acid was reduced to 52.33 and 72%, respectively. The combination of P. graveolens and C. verum EOs with fluconazole inhibited 78.31 and 64.72% SAP activity, respectively. To our knowledge, this is the first report underlying the mechanism of action and the inhibitory effect of SAP activity of essential oils in synergy with fluconazole. Naturally occurring phytochemicals C. verum and P. graveolens could be effective candidate to enhance the efficacy of fluconazole-based therapy of C. albicans infections.

Myrtus communis leaf compounds as novel inhibitors of quorum sensing-regulated virulence factors and biofilm formation: In vitro and in silico investigations.

Antibiotic resistance of the Gram-negative bacterium Pseudomonas aeruginosa and its ability to form biofilm through the Quorum Sensing (QS) mechanism are important challenges in the control of infections caused by this pathogen. The extract of Myrtus communis (myrtle) showed strong anti-QS effect on C hromobacterium . violaceum 6267 by inhibiting 80 % of the production of violacein pigment at a sub-MIC concentration of 1/8 (31.25 µg/mL). In addition, the extract exhibited an inhibitory effect on virulence factors of P. aeruginosa PAO1 at half MIC (125 µg/mL), significantly reducing the formation of biofilms (72.02 %), the swarming activity (75 %), and the production of protease (61.83 %) and pyocyanin (97 %). The active fraction also downregulated the expression of selected regulatory genes involved in the biofilm formation and QS in the P. aeruginosa PAO1 strain. These genes included the autoinducer synthase genes (lasI and rhlI), the genes involved in the expression of their corresponding receptors (lasR and rhlR), and the pqsA genes. The analysis of the active fraction by HPLC/UV/MS and NMR allowed the identification of three phenolic compounds, 3,5-di-O-galloylquinic acid, myricetin 3-O-α-l-rhamnopyranoside (myricitrin), and myricetin 3-O-(2″-O-galloyl)-ß-d-galactopyranoside. In silico studies showed that 3,5-di-O-galloylquinic acid, with an affinity score of -9.20 kcal/mol, had the highest affinity to the active site of the CviR protein (3QP8), a QS receptor from C. violaceum. Additionally, myricetin 3-O-α-l-rhamnopyranoside (myricitrin) and myricetin 3-O-(2″-O-galloyl)-ß-d-galactopyranoside interact to a lesser extent with 3QP8. In conclusion, this study contributed significantly to the discovery of new QS inhibitors from M. communis leaves against resistant Gram-negative pathogens.

Identification of an anti-herpetic compound isolated from Pistacia vera L. male floral buds.

Due to the numerous side effects of conventional drugs against herpetic infections and the growing phenomenon of resistance, the researchers turned to natural compounds as a source of new drugs because they are less toxic than the synthetic molecules. This study aimed to analyse the activity of Pistacia vera L. male floral bud extracts, against the replication of herpes simplex virus type 2, as well as to investigate their mode of action, isolate, and identify the active compound. Cell viability and anti-herpes virus activity were performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and the plaque reduction assay, respectively. Three extracts (ethanolic, aqueous and polysaccharide extracts) were tested, only aqueous and polysaccharide extracts had anti-herpetic activity with a selectivity index of 29.12 and 20.25, respectively. Investigation about the mechanism of action indicated that the two active extracts inhibited the virus replication by direct contact with virucidal selectivity indexes of 39.15 and 32.09, respectively. An active compound was isolated from the aqueous extract using TLC bio-guided assay: it was identified as gallic acid by high-performance liquid chromatography-diode array detection coupled with electrospray ionization mass spectrometry (HPLC-DAD-ESI-MSn). The antiviral activity of Pistacia vera L. has been previously shown. The selectivity index of gallic acid is much lower than that of the active extract from which it has been isolated. Therefore, we can consider the aqueous extract prepared from Pistacia vera L. male floral buds as a promising natural product for treating herpetic diseases.

The correlation between middle schoolchildren allergic symptoms and airborne particle season: A cross-sectional study.

ABSTRACT: Limited studies correlate allergic symptoms and associated outdoor biological particle exposure among schoolchildren globally.This study aimed to investigate the relationship between the seasonality of symptoms of allergic diseases among middle schoolchildren and the annual variation of airborne pollen and fungal spore in a hot and humid geographical region (Qatar).During November 2017 to January 2018, a self-reported study of middle schoolchildren living in the Doha capital city of Qatar was conducted, and data gathered were evaluated in relation to the collected monthly pollen and fungal spores. Participants' data were collected by conducting a survey based on a modified questionnaire adopted from the International Study of Asthma and Allergy in Childhood (ISAAC). The airborne pollen and fungal spore in Doha's atmosphere were extracted from the Doha aerobiology project (2017-2020).Among the 1000 distributed questionnaires, 100 were excluded due to significant missing data and 644 middle schoolchildren living in Doha city responded and were included in the final analysis. The symptoms of allergic rhinitis (AR) pattern among the responders with positive symptoms were strongly linked with the higher airborne fungal spore incidence during the month of November. Out of 331 students with positive symptoms, the prevalence of AR, lifetime wheeze, and eczema was 62.8%, 28.1%, and 26.6%, respectively. Asthma was significantly higher in Qatari (39.8%) compared to non-Qatari (26.7%) middle schoolchildren (P = .02).Outdoor aeroallergen may be a contributing factor in addition to other environmental and genetic predisposing factors for childhood atopic diseases in the prevalence rate of allergic symptoms among middle schoolchildren in the peninsula of Qatar.

Aerobiological monitoring in a desert type ecosystem: Two sampling stations of two cities (2017-2020) in Qatar.

BACKGROUND: The increasing number of aerobiological stations empower comparative studies to determine the relationship between pollen concentrations in different localities and the appropriate distance, which should be established between sampling stations. In Qatar, this is basically the first aerobiological study for a continuous monitoring interval. OBJECTIVES: The study aimed to assess the abundance and seasonality of the most prevalent pollen types, plus identify potential differences between two sites within the country. METHODS: Airborne pollen data were collected during 2017-2020 by using Hirst-type volumetric samplers in Doha capital city and Al Khor city in Qatar, placed 50 km apart. RESULTS: Higher total pollen indexes were recorded in the Al Khor station (2931 pollen * day/m3) compared to the Doha station (1618 pollen * day/m3). Comparing the pollen spectrum between the sampling stations revealed that ten pollen types were found in common. Amaranthaceae and Poaceae airborne pollen constituted 73.5% and 70.9% of the total amount of pollen detected at the samplers of Al Khor station and Doha station. In both sampling sites, a very pronounced seasonality was shown; August-October appeared as the period with the most intense incidence of atmospheric herbaceous pollen, with 71% and 51% of the annual total counts in Al Khor and Doha stations, respectively. August (Al Khor, 21%; Doha, 9%), September (Al Khor, 33%; Doha, 26%), October (Al Khor, 17%; Doha, 16%) were the months in which the herbs pollen concentrations were highest. Significant statistical differences between the two stations were observed in specific pollen types with local distribution in each trap's vicinity. CONCLUSIONS: Comparison of data obtained by the two samplers running at a distance of 50 Km indicated that potential inter-site differences could be attributed to the vegetation surrounding the city having a decisive influence on data collected.

The association between airborne pollen monitoring and sensitization in the hot desert climate.

BACKGROUND: Pollen is a major cause of allergic respiratory diseases. In Qatar, data on the presence and prevalence of allergenic airborne types of pollen is quite limited. METHODS: The study aimed to determine and correlate the most frequently implicated airborne pollen detected by aerobiological monitoring samplers in respiratory allergy symptoms. An aerobiological survey was started on May 8, 2017. Airborne pollen was collected using two Hirst type seven-day recorder volumetric traps. Skin prick test in patients attending allergy clinics in Doha using commercial extracts was conducted. RESULTS: Twenty-five pollen types representing the native, as well as the introduced plants, with a relatively low daily mean concentration were observed from May 2017 to May 2019. The highest pollen concentrations were reached by Amaranthaceae (58.9%), followed by Poaceae (21.7%). SPT revealed a comparatively higher degree of sensitization to pollen. Among 940 patients, 204 were sensitized to pollen (54% female) with 135 (66.2%) and 114 (55.8%) to Amaranthaceae and Poaceae, respectively. Some patients had polysensitization. There was a statistically significant association between Amaranthaceae, and asthma (r = 0.169, P = 0.016) and allergic rhinitis (r = 0.177, P = 0.012). CONCLUSIONS: This is the first study to monitor airborne pollen in the state of Qatar. The main pollen detected were Amaranthaceae and Poaceae. Pollen may represent a possible exacerbating factor in adult patients with allergic diseases such as asthma and allergic rhinitis.

Utilization of Grape Seed Flour for Antimicrobial Lipopeptide Production by Bacillus amyloliquefaciens C5 Strain.

An endophytic Bacillus amyloliquefaciens strain called C5, able to produce biosurfactant lipopeptides with a broad antibacterial activity spectrum, has been isolated from the roots of olive tree. Optimization of antibacterial activity was undertaken using grape seed flour (GSF) substrate at 0.02, 0.2, and 2% (w/v) in M9 medium. Strain C5 exhibited optimal growth and antimicrobial activity (MIC value of 60 µg/ml) when incubated in the presence of 0.2% GSF while lipopeptide production culminated at 2% GSF. Thin layer chromatography analysis of lipopeptide extract revealed the presence of at least three active spots at Rf 0.35, 0.59, and 0.72 at 0.2% GSF. Data were similar to those obtained in LB-rich medium. MALDI-TOF/MS analysis of lipopeptide extract obtained from 0.2% GSF substrate revealed the presence of surfactin and bacillomycin D. These results show that GSF could be used as a low-cost culture medium supplement for optimizing the production of biosurfactants by strain C5.

Enhancement of Exochitinase Production by Bacillus licheniformis AT6 Strain and Improvement of N-Acetylglucosamine Production.

A strain producing chitinase, isolated from potato stem tissue, was identified as Bacillus licheniformis by biochemical properties and 16S RNA sequence analysis. Statistical experimental designs were used to optimize nine independent variables for chitinase production by B. licheniformis AT6 strain in submerged fermentation. Using Plackett-Burman design, (NH4)2SO4, MgSO4.7H2O, colloidal chitin, MnCl2 2H2O, and temperature were found to influence chitinase production significantly. According to Box-Behnken response surface methodology, the optimal fermentation conditions allowing maximum chitinase production were (in gram per liter): (NH4)2SO4, 7; K2HPO4, 1; NaCl, 1; MgSO4.7H2O, 0.1; yeast extract, 0.5; colloidal chitin, 7.5; MnCl2.2H2O, 0.2; temperature 35 °C; pH medium 7. The optimization strategy led to a 10-fold increase in chitinase activity (505.26 ± 22.223 mU/mL versus 50.35 ± 19.62 mU/mL for control basal medium). A major protein band with a molecular weight of 61.9 kDa corresponding to chitinase activity was clearly detected under optimized conditions. Chitinase activity produced in optimized medium mainly releases N-acetyl glucosamine (GlcNAc) monomer from colloidal chitin. This enzyme also acts as an exochitinase with ß-N-acetylglucosaminidase. These results suggest that B. licheniformis AT6 secreting exochitinase is highly efficient in GlcNAc production which could in turn be envisaged as a therapeutic agent or as a conservator against the alteration of several ailments.

Isolation of a chitinolytic Bacillus licheniformis S213 strain exerting a biological control against Phoma medicaginis infection.

Among nine chitinase-producing strains isolated from Tunisian soil, one isolate called S213 exhibited a potent chitinolytic activity. S213 strain was identified as Bacillus licheniformis by API 50CH system and sequence analysis of its partial 16S ribosomal DNA. Chitinolytic activity was induced either by colloidal chitin or fungal cell walls, and the highest chitinase activity reached at the late stationary phase exhibiting optimal temperature and pH of 50-60 °C and pH 6.0, respectively. SDS-PAGE analysis of the secreted colloidal chitin-induced proteins showed a major protein of about 65 kDa. This protein was identified as chitinase on the basis of its peptide sequences which displayed high homology with chitinase sequence of B. licheniformis ATCC 14580. Moreover, chitinolytic activity containing supernatant inhibited the growth of several phytopathogenic fungi including Phoma medicaginis. Interestingly, S213 strain reduced efficiently the damping-off disease caused by P. medicaginis in Medicago truncatula and should be envisaged in enzyme-based biopesticides against phytopathogen application.

Antioxidative and DNA protective effects of bacillomycin D-like lipopeptides produced by b38 strain.

In the present study, we evaluated the antioxidant and the scavenging ability of C14, C15 and C16 bacillomycin D-like lipopeptides produced by B38 strain. They all displayed strong reducing power activity, hydroxyl and superoxide anion radicals scavenging activities and inhibition of lipid peroxidation. In addition, they were found to protect plasmid DNA damage from hydroxyl radical oxidation. Data suggested that their antioxidant potency can be attributed to the hydrophobic and aromatic side-chain groups of their amino acids as well as to the aliphatic chain of their beta amino fatty acids. Note that the hydrocarbon chain length did not interfere with the antioxidant power. Overall, such bacillomycin D lipopeptides which exhibit antioxidant and radical scavenging activities may be useful for cosmetic, therapeutic or pharmaceutical purposes in order to delay or prevent oxidative deterioration of manufactured products.