Dr. Ahmed Mahmoud Saleh

Edible sprouts are rich in flavonoids and other polyphenols, as well as proteins, minerals, and vitamins. Increasing sprout consumption necessitates improving their quality, palatability, and bioactivity. The purpose of this study was to test how KNO3 priming affects the sprouting process species on three Medicago species (Medicago indicus, Medicago interexta, and Medicago polymorpha) and their nutritional values. Targeted species of Medicago were primed with KNO3, and the levels of different primary and secondary metabolites were determined. KNO3 induced biomass accumulation in the sprouts of the three species, accompanied by an increased content of total mineral nutrients, pigments, vitamins, and essential amino acids. Besides, our results showed that KNO3 enhanced the activity of nitrate reductase (NR), glutamate dehydrogenase (GDH), and glutamine synthetase (GS) enzymes, which are involved in the nitrogen metabolism and GOGAT cycle, which, in turn, increase the nitrogen and protein production. KNO3 treatment improved the bioactive compound activities of Medicago sprouts by increasing total phenolic and flavonoid contents and enhancing the antioxidant and antidiabetic activities. Furthermore, species-specific responses toward KNO3 priming were noticeable, where Medicago interexta showed the highest antioxidant and antidiabetic activities, followed by Medicago polymorpha. Overall, this study sheds the light on the physiological and biochemical bases of growth, metabolism, and tissue quality improvement impact of KNO3 on Medicago sprouts.

Arbuscular mycorrhizal fungi (AMF) are beneficial for the plant growth under heavy metal stress. Such beneficial effect is improved by elevated CO2 (eCO2). However, the mechanisms by which eCO2 improves AMF symbiotic associations under arsenite (AsIII) toxicity are hardly studied. Herein, we compared these regulatory mechanisms in species from two agronomical important plant families – grasses (wheat) and legumes (soybean). AsIII decreased plant growth (i.e., 53.75 and 60.29% of wheat and soybean, respectively) and photosynthesis. It also increased photorespiration and oxidative injury in both species, but soybean was more sensitive to oxidative stress as indicated by higher H2O2 accumulation and oxidation of protein and lipid. eCO2 significantly improved AMF colonization by increasing auxin levels, which induced high carotenoid cleavage dioxygenase (CCDs) activity, particularly in soybean roots. The improved sugar metabolism in plant shoots by co-application of eCO2 and AsIII allocated more sugars to roots sequentially. Sugar accumulation in plant roots is further induced by AMF, resulting in more C skeletons to produce organic acids, which are effectively exudated into the soil to reduce AsIII uptake. Exposure to eCO2 reduced oxidative damage and this mitigation was stronger in soybean. This could be attributed to a greater reduction in photorespiration as well as a stronger antioxidant and detoxification defence systems. The grass/legume-specificity was supported by principal component analysis, which revealed that soybean was more affected by AsIII stress and more responsive to AMF and eCO2. This study provided a mechanistic understanding of the impact of AMF, eCO2 and their interaction on As-stressed grass and legume plants, allowing better practical strategies to mitigate AsIII phytotoxicity.

The sequestration of elevated atmospheric CO2 levels in seawater results in increasing acidification of oceans and it is unclear what the consequences of this will be on seaweed ecophysiology and ecological services they provide in the coastal ecosystem. In the present study, we examined the physiological and biochemical response of intertidal green seaweed Ulva compressa to elevated pCO2 induced acidification. The green seaweed was exposed to control (pH 8.1) and acidified (pH 7.7) conditions for 2 weeks following which net primary productivity, pigment content, oxidative status and antioxidant enzymes, primary and secondary metabolites, and mineral content were assessed. We observed an increase in primary productivity of the acidified samples, which was associated with increased levels of photosynthetic pigments. Consequently, primary metabolites levels were increased in the thalli grown under lowered pH conditions. There was also richness in various minerals and polyunsaturated fatty acids, indicating that the low pH elevated the nutritional quality of U. compressa. We found that low pH reduced malondialdehyde (MDA) content, suggesting reduced oxidative stress. Consistently we found reduced total antioxidant capacity and a general reduction in the majority of enzymatic and non-enzymatic antioxidants in the thalli grown under acidified conditions. Our results indicate that U. compressa will benefit from seawater acidification by improving productivity. Biochemical changes will affect its nutritional qualities, which may impact the food chain/food web under future acidified ocean conditions.

Mannan oligosaccharide is one of the major components of the yeast cell wall. In the present study, the production, characterization, and bioactivity of yeast mannan were investigated. Four indigenous yeast isolates were obtained from various kinds of juice collected from local markets in Al-Ahsa, KSA, and analyzed using morphological and biochemical methods. Isolate RY1 showed the highest production of mannan. RY1 was identified as Saccharomyces cerevisiae based on morphological characteristics and sequencing of the 18S rRNA gene (GenBank accession number LC479088.1). Mannan-RY1 was characterized by polymer analytical methods, 13C and 1H nuclear magnetic resonance spectroscopy (NMR), and infrared spectroscopy (IR). Interestingly, the mannan extracted from RY1 showed a significant ability to scavenge hydroxyl radicals and superoxide anions. In addition, mannan was found to have pronounced anti-tumor activity against liver (HepG2) and breast cancer (MCF7) cell lines. The results presented in this study confirm the bio-therapeutic activity of S. cerevisiae mannan, which could be used as a potential drug for cancer treatment.

Drought stress is known to threaten the growth and productivity of many economical crops. Therefore, it is necessary to establish innovative and efficient approaches for improving crop growth and productivity. In the current study, we investigated the potentials of the cell-free extract of actinobacteria (Ac) isolated from a semi-arid habitat (Al-Jouf region, Saudi Arabia) to recover the reduction in maize growth and improve the physiology stress induced by drought. Three Ac isolates screened for production of secondary metabolites, antioxidant and antimicrobial activities, the isolate Ac3 revealed the highest levels of flavonoids, antioxidant and antimicrobial activities beside its abilities to produce siderophores and phytohormones. Based on seed germination experiment, the selected bioactive fraction of Ac3 cell-free extract (F2.7), increased the growth and photosynthesis rate under drought stress. Moreover, F2.7 application significantly alleviated drought stress-induced increases in H2O2, lipid peroxidation (MDA) and proteins oxidation (Protein carbonyls). It also increased total antioxidant power and molecular antioxidants levels (total ascorbate, glutathione and tocopherols). F2.7 improved the primary metabolism of stressed maize plants, for instances it increased several individuals of sugars, amino acids, organic acid and fatty acids. Interestingly, to reduce stress impact, it accumulated some compatible solutes, such as total soluble sugars, sucrose and proline. Hence, this comprehensive assessment recommends the potentials of actinobacterial cell-free extract as an alternative ecofriendly approach to improve the growth and the quality of crops under water deficit conditions.

Abstract: This study was conducted to investigate the potential use of arbuscular mycorrhizal fungi (AMF), Rhizophagus irregularis, as an innovative cultivation procedure to improve the production and quality of two medicinal plants, pennyroyal (Mentha pulegium), and parsley (Petroselinum hortense). We elucidated the impact of AMF on soil properties and growth and metabolic profiling of pennyroyal and parsley. AMF treatment improved the availability of essential elements and phenols in the rhizospheric soil. Plant biomass production and photosynthetic rate were improved. We also recorded improved primary and secondary metabolism, where the levels of most of the detected soluble and insoluble sugars, organic acids, essential (isoleucine and valine), and non-essential (glutamine, alanine, and cysteine) amino acids, fatty acids (especially unsaturated fatty acids), phenolic acids, and flavonoids were increased. Overall, this study supports the use of AMF in the artificial cultivation, as an alternative to the chemical fertilizers, for the production of high-quality medicinal plants with enhanced levels of bioactive compounds. Graphic abstract: [Figure not available: see fulltext.]

Balanites aegyptiaca L. is a multipurpose tree distributed in Africa and Middle East. Several parts of B. aegyptiaca have been suggested to have medicinal uses. So far the effect of ecological origin on the nutritional values and biological activities of B. aegyptiaca genotypes is rarely investigated. Further, metabolic profiling and assessment of the functional food value of B. aegyptiaca leaves are far from complete. In this study, biological activities and profiling of primary and secondary metabolites were investigated in the leaves of five B. aegyptiaca provenances collected from Egypt, Sudan, Saudi Arabia, and Yemen. Interestingly, all provenances showed notable antidiabetic, antioxidant, antiprotozoal, antibacterial, antifungal, and anticancer activities. Hierarchical clustering analysis revealed significant variability in the concentrations of individual sugars, organic acids, amino acids, fatty acids, vitamins, phenolics, and minerals among the provenances and these variations were provenance dependent. Medina provenance showed the heights diphenylpicrylhydrazyl (DPPH) scavenging and antifungal activities and was the most powerful against embryonic kidney adenocarcinoma and urinary bladder carcinoma cells. The highest inhibition against Escherichia coli and colon carcinoma cells was observed by Sudan and Cairo provenances. El-Kharga and Yemen provenances showed the greatest activity against Trypanosoma cruzi and hepatocellular and urinary bladder carcinoma. Therefore, leaves of B. aegyptiaca possess good nutritive and biological capacities and might have potential applications in the food and medical industries. However, the strength of such activities is significantly affected by the provenance. Practical applications: According to the national Research Council (NRC) of United States, Balanites aegyptiaca L. is recognized among the 24 priority lost crops of Africa. B. aegyptiaca leaves contain considerable amounts of primary metabolites (e.g., sugars, EAAs, USFAs) and secondary (e.g., phenolic acids and flavonoids) metabolites, vitamins, and macro and microelements. The obvious existence of these nutritionally and medicinally related compounds supports the functional food value of B. aegyptiaca leaves. Moreover, the present results revealed that B. aegyptiaca is not only a foliage dietary plant, but also could be considered as a valuable source for neutraceuticals, which support its pharmacological value. So far, this is the first report to explore, in detail, the functional food value of B. aegyptiaca leaves by presenting a clear image about its metabolic profiling and biological activities, and how the provenance factor could affect these values.