الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Nanoparticles (NPs) are defined as a varied class of small-scale (<100 nm) materials designed by molecular-level engineering to attain unique mechanical, photosensitive, electrical, and magnetic properties (Tsuji et al., 2005). Although humans have been exposed to airborne nanoparticles during their evolutionary periods, this exposure has increased intensely over the last century as a result of anthropogenic sources (Oberdörster et al., 2005). There are many different forms of nanomaterials (ex. carbon-based materials, metals, metal oxides, and biopolymers ( Sharma et al., 2012). Zinc oxide nanoparticles (ZnO NPs) are one of the most abundantly used nanomaterials, they are used in cosmetics (sunscreens, foot care, ointments, and topical products) as they efficiently absorb UV light and also do not scatter visible light(Vandebriel and De Jong 2012). In the food industry, they are increasingly used as additives, moreover, in packaging due to their antimicrobial properties (Zahra et al., 2017). Nowadays, ZnO NPs are widely explored in biomedical fields for their anticancer activity, as well as in the pharmaceutical industries (Srivastav et al., 2017; Upadhyaya et al., 2018). However, the increase in the production and consumption of ZnO NPs enhances the chance of exposure in occupational and environmental settings (Vandebriel and De Jong 2012).
Despite their increasing usage in consumer products, there is still a lack of information about the safety exposure of ZnO NPs regarding their possible toxicity (Scherzad et al., 2017). It’s well-known that zinc deficiency in the human body can result in nutrition problems, chronic hepatic or kidney disease, malignancy, and other chronic illnesses, on the other hand, large amounts of Zn in the body has been reported to lead to pathologies, such as copper deficiency (Shen et al., 2013). This can be related to the competitive relationship between zinc and copper ions for absorption within enterocytes, moreover the preference of metallothioneins (MTs) for binding to copper with a higher affinity than zinc (Plum et al., 2010). Moringa oleifera (MO) is fast growing a widely cultivated tree considered as a multi-purpose plant that has been used as a food crop, a source of vegetable oil, and as a coagulant and adsorbent in water treatment (Silva et al., 2014). In a traditional way, it is used with folk medicine mainly in Pakistan, India, Afghanistan, and Bangladesh also around the world due to empiric observations. (Castillo et al., 2013). Historically, ancient Romans, Greeks, and Egyptians utilized all parts of the MO plant for human consumption other than Asian communities have been made now (Ferreira et al., 2014). Furthermore, the MO tree has been cultivated for different purposes such as medicine, vegetable, spice, cooking, and cosmetic oil (Okechukwu et al., 2013). Mainly all the parts of the MO plant (leaves, bark, seeds, flowers, and seed oil ) have been used for the treatment of health problems such as inflammation and
infectious diseases along with cardiovascular, gastrointestinal, and nervous disorders ( Goyal et al., 2007; Ferreira et al., 2014). The aqueous and ethanolic extracts of MO seeds have been tested for various pharmacological properties and have been found to possess anti-oxidative and hepatoprotective effects (Silva et al. 2014). Additionally, the hydro-alcoholic seed extract shows prophylactic and curative hepatoprotective efficiency against CCl4 liver injury in rats (Nanjappaiah and Hugar, 2012). Due to the many experimental challenges and issues faced when assessing the toxicity of nanomaterials, and despite the numerous researches done in this field; knowledge about the interactions of nanoparticles with biological systems is still in its early stages (Scherzad et al., 2017; Inoue et al., 2018).