Green Biogenic of Silver Nanoparticles Using Polyphenolic Extract of Olive Leaf Wastes with Focus on Their Anticancer and Antimicrobial Activities.

Agro-industrial wastes are rich in polyphenols and other bioactive compounds, and valorizing these wastes is a crucial worldwide concern for saving health and the environment. In this work, olive leaf waste was valorized by silver nitrate to produce silver nanoparticles (OLAgNPs), which exhibited various biological, antioxidant, anticancer activities against three cancer cell lines, and antimicrobial activity against multi-drug resistant (MDR) bacteria and fungi. The obtained OLAgNPs were spherical, with an average size of 28 nm, negatively charged at -21 mV, and surrounded by various active groups more than the parent extract based on FTIR spectra. The total phenolic and total flavonoid contents significantly increased in OLAgNPs by 42 and 50% over the olive leaf waste extract (OLWE); consequently, the antioxidant activity of OLAgNPs increased by 12% over OLWE, recording an SC50 of OLAgNPs of 5 µg/mL compared to 30 µg/mL in the extract. The phenolic compound profile detected by HPLC showed that gallic acid, chlorogenic acid, rutin, naringenin, catechin, and propyl gallate were the main compounds in the HPLC profile of OLAgNPs and OLWE; the content of these compounds was higher in OLAgNPs than OLWE by 16-fold. The higher phenolic compounds in OLAgNPs are attributable to the significant increase in biological activities of OLAgNPs than that of OLWE. OLAgNPs successfully inhibited the proliferation of three cancer cell lines, MCF-7, HeLa, and HT-29, by 79-82% compared to 55-67% in OLWE and 75-79% in doxorubicin (DOX). The preliminary worldwide problem is multi-drug resistant microorganisms (MDR) because of the random use of antibiotics. Therefore, in this study, we may find the solution in OLAgNPs with concentrations of 2.5-20 µg/mL, which significantly inhibited the growth of six MDR bacteria L. monocytogenes, B. cereus, S. aureus, Y. enterocolitica, C. jejuni, and E. coli with inhibition zone diameters of 25-37 mm and six pathogenic fungi in the range of 26-35 mm compared to antibiotics. OLAgNPs in this study may be applied safely in new medicine to mitigate free radicals, cancer, and MDR pathogens.

Potential use of a novel actinobacterial species to ameliorate tungsten nanoparticles induced oxidative damage in cereal crops.

Tungsten nanoparticles (WNPs) could induce hazard impact on plant growth and development; however, no study investigated their phytotoxicity. On the other hand, plant growth-promoting bacteria (PGPB) can effectively reduce WNPs toxicity. To this end, Nocardiopsis sp. was isolated and employed to mitigate the phytotoxic effect of WNPs on three crops (wheat, barley, and oat). Soil contamination with WPNs induced the W accumulation in all tested crops, inhibited both growth and photosynthesis and induced oxidative damage. On the other hand, pre-inoculation with Nocardiopsis sp. significantly reduced W level in treated plants. Concomitantly, Nocardiopsis sp. strikingly mitigated the inhibitory effect of WNPs by augmenting both growth and reactive oxygen species (ROS) homeostasis. To cope with heavy metal stress, all the tested species orchestrated their antioxidant homeostasis through enhancing the production of antioxidant metabolites (e.g., phenolics, flavonoids and tocopherols) and elevated the activities of ROS-scavenging enzymes (e.g., APX, POX, CAT, as well as the enzymes involved in AsA/GSH cycle). Moreover, pre-inoculation with Nocardiopsis sp. improved the detoxification metabolism by enhancing the accumulation of phytochelatins (PCs), metallothionein (MTC) and glutathione-S-transferase (GST) in grasses grown in WNPs-contaminated soils. Overall, restrained ROS homeostasis and improved WNPs detoxification systems were the bases underlie the WNPs stress mitigating impact of Nocardiopsis sp treatment.

Soil Amendment Using Biochar and Application of K-Humate Enhance the Growth, Productivity, and Nutritional Value of Onion (Allium cepa L.) under Deficit Irrigation Conditions.

Water scarcity, due to physical shortage or inadequate access, is a major global challenge that severely affects agricultural productivity and sustainability. Deficit irrigation is a promising strategy to overcome water scarcity, particularly in arid and semiarid regions with limited freshwater resources. However, precise application of deficit irrigation requires a better understanding of the plant response to water/drought stress. In the current study, we investigated the potential impacts of biochar-based soil amendment and foliar potassium-humate application (separately or their combination) on the growth, productivity, and nutritional value of onion (Allium cepa L.) under deficient irrigation conditions in two separate field trials during the 2018/2019 and 2019/2020 seasons. Our findings showed that deficit irrigation negatively affected onion resilience to drought stress. However, these harmful effects were diminished after soil amendment using biochar, K-humate foliar application, or their combination. Briefly, integrated biochar and K-humate application increased onion growth, boosted the content of the photosynthetic pigments, enhanced the water relations, and increased the yield traits of deficient irrigation onion plants. Moreover, it improved the biochemical response, enhanced the activities of antioxidant enzymes, and enriched the nutrient value of deficiently irrigated onion plants. Collectively, these findings highlight the potential utilization of biochar and K-humate as sustainable eco-friendly strategies to improve onion resilience to deficit irrigation.

An In Vitro and In Silico Study of the Enhanced Antiproliferative and Pro-Oxidant Potential of Olea europaea L. cv. Arbosana Leaf Extract via Elastic Nanovesicles (Spanlastics).

The olive tree is a venerable Mediterranean plant and often used in traditional medicine. The main aim of the present study was to evaluate the effect of Olea europaea L. cv. Arbosana leaf extract (OLE) and its encapsulation within a spanlastic dosage form on the improvement of its pro-oxidant and antiproliferative activity against HepG-2, MCF-7, and Caco-2 human cancer cell lines. The LC-HRESIMS-assisted metabolomic profile of OLE putatively annotated 20 major metabolites and showed considerable in vitro antiproliferative activity against HepG-2, MCF-7, and Caco-2 cell lines with IC50 values of 9.2 ± 0.8, 7.1 ± 0.9, and 6.5 ± 0.7 µg/mL, respectively. The encapsulation of OLE within a (spanlastic) nanocarrier system, using a spraying method and Span 40 and Tween 80 (4:1 molar ratio), was successfully carried out (size 41 ± 2.4 nm, zeta potential 13.6 ± 2.5, and EE 61.43 ± 2.03%). OLE showed enhanced thermal stability, and an improved in vitro antiproliferative effect against HepG-2, MCF-7, and Caco-2 (IC50 3.6 ± 0.2, 2.3 ± 0.1, and 1.8 ± 0.1 µg/mL, respectively) in comparison to the unprocessed extract. Both preparations were found to exhibit pro-oxidant potential inside the cancer cells, through the potential inhibitory activity of OLE against glutathione reductase and superoxide dismutase (IC50 1.18 ± 0.12 and 2.33 ± 0.19 µg/mL, respectively). These inhibitory activities were proposed via a comprehensive in silico study to be linked to the presence of certain compounds in OLE. Consequently, we assume that formulating such a herbal extract within a suitable nanocarrier would be a promising improvement of its therapeutic potential.

Improved Mineral Acquisition, Sugars Metabolism and Redox Status after Mycorrhizal Inoculation Are the Basis for Tolerance to Vanadium Stress in C3 and C4 Grasses.

Vanadium (V) can be beneficial or toxic to plant growth and the interaction between arbuscular mycorrhizal fungi (AMF) and V stress was rarely investigated at physiological and biochemical levels of plant groups (C3 and C4) and organs (roots and shoots). We tested the potential of AMF to alleviate the negative effects of V (350 mg V/Kg soil) on shoots and roots of rye and sorghum. Relative to sorghum (C4), rye (C3) showed higher levels of V and lower levels of key elements under V stress conditions. V inhibited growth, photosynthesis, and induced photorespiration (increased HDR & GO activities) and oxidative damage in both plants. AMF colonization reduced V stress by differently mitigating the oxidative stress in rye and sorghum. This mitigation was accompanied with increases in acid and alkaline phosphatase activities in plant roots and increased organic acids and polyphenols exudation into the soil, thus reduced V accumulation (29% and 58% in rye and sorghum shoot, respectively) and improved absorption of mineral nutrients including Ca, Mg and P. AMF colonization improved photosynthesis and increased the sugar accumulation and metabolism. Sugars also acted as a supplier of C skeletons for producing of antioxidants metabolite such as ascorbate. At the antioxidant level, rye was more responsive to the mitigating impact of AMF. Higher antioxidants and detoxification defence system (MTC, GST, phenolics, tocopherols and activities of CAT, SOD and POX) was recorded for rye, while sorghum (C4) improved its GR activity. The C3/C4-specificity was supported by principal component analysis. Together, this study provided both fundamental and applied insights into practical strategies to mitigate the phytotoxicity hazards of V in C3 and C4 grasses. Moreover, our results emphasize the importance of AMF as an environment-friendly factor to alleviate stress effects on plants and to improve growth and yield of unstressed plants.

Incorporated Biochar-Based Soil Amendment and Exogenous Glycine Betaine Foliar Application Ameliorate Rice (Oryza sativa L.) Tolerance and Resilience to Osmotic Stress.

Osmotic stress is a major physiologic dysfunction that alters the water movement across the cell membrane. Soil salinity and water stress are major causal factors of osmotic stress that severely affect agricultural productivity and sustainability. Herein, we suggested and evaluated the impact of integrated biochar-based soil amendment and exogenous glycine betaine application on the growth, physiology, productivity, grain quality, and osmotic stress tolerance of rice (Oryza sativa L., cv. Sakha 105) grown in salt-affected soil under three irrigation intervals (6, 9, or 12 days), as well as soil properties and nutrient uptake under field conditions during the 2019 and 2020 seasons. Our findings showed that dual application of biochar and glycine betaine (biochar + glycine betaine) reduced the soil pH, electrical conductivity, and exchangeable sodium percentage. However, it enhanced the K+ uptake which increased in the leaves of treated-rice plants. Additionally, biochar and glycine betaine supplementation enhanced the photosynthetic pigments (chlorophyll a, b, and carotenoids) and physiological attributes (net photosynthetic rate, stomatal conductance, relative water content, and electrolyte leakage) of osmotic-stressed rice plants. Biochar + glycine betaine altered the activity of antioxidant-related enzymes (catalase, ascorbate peroxide, and peroxidase). Moreover, it improved the yield components, biological yield, and harvest index, as well as the nutrient value of rice grains of osmotic-stressed rice plants. Collectively, these findings underline the potential application of biochar and glycine betaine as a sustainable eco-friendly strategy to improve plant resilience, not only rice, but other plant species in general and other cereal crops in particular, to abiotic stress, particularly those growing in salt-affected soil.

Antiulcer Potential of Olea europea L. cv. Arbequina Leaf Extract Supported by Metabolic Profiling and Molecular Docking.

Gastric ulceration is among the most serious humanpublic health problems. Olea europea L. cv. Arbequina is one of the numerous olive varieties which have scarcely been studied. The reported antioxidant and anti-inflammatory potential of the olive plant make it a potential prophylactic natural product against gastric ulcers. Consequently, the main goal of this study is to investigate the gastroprotective effect of Olea europea L. cv. Arbequina leaf extract. LC-HRMS-based metabolic profiling of the alcoholic extract of Olea europea L. cv. Arbequina led to the dereplication of 18 putative compounds (1-18). In vivo indomethacin-induced gastric ulcer in a rat model was established and the Olea europea extract was tested at a dose of 300 mg kg-1 compared to cimetidine (100 mg kg-1). The assessment of gastric mucosal lesions and histopathology of gastric tissue was done. It has been proved that Olea europea significantly decreased the ulcer index and protected the mucosa from lesions. The antioxidant potential of the extract was evaluated using three in vitro assays, H2O2 scavenging, xanthine oxidase inhibitory, and superoxide radical scavenging activities and showed promising activities. Moreover, an in silico based study was performed on the putatively dereplicated compounds, which highlighted that 3-hydroxy tyrosol (4) and oleacein (18) can target the 5-lipoxygenase enzyme (5-LOX) as a protective mechanism against the pathogenesis of ulceration. Upon experimental validation, both compounds 3-hydroxy tyrosol (HT) and oleacein (OC) (4 and 18, respectively) exhibited a significant in vitro 5-LOX inhibitory activity with IC50 values of 8.6 and 5.8 µg/mL, respectively. The present study suggested a possible implication of O. europea leaves as a potential candidate having gastroprotective, antioxidant, and 5-LOX inhibitory activity for the management of gastric ulcers.