Influence of calcium nanoparticles (CaNPs) on nutritional qualities, radical scavenging attributes of Moringa oleifera and risk assessments on human health

This study investigated stimulatory potentials of zero-charged calcium nanoparticles (CaNPs) on nutritional contents and free radical scavenging abilities of Moringa oleifera. M. oleifera seeds were planted on soil wetted with water (control: group A), 100 mgL(-1) Ca(NO3)(2), 100, 75 and 50 mgL(-1) CaNPs as groups B, C, D and E respectively. Elemental compositions were determined with inductively coupled plasma optical emission spectrometer (ICP-OES). CaNPs beneficially improved crude fibre, ash, K and Ca by 124.82, 152.5, 10.66 and 28.91% respectively in M. oleifera. There were significant declines in concentrations of Na, Ni, Pb, Cd and Cr in M. oleifera planted on CaNPs amended soil. CaNPs significantly improved free radical scavenging ability from 43.85 to 74.06%, phenolic contents from 248.82 to 555.88 mg quercetin/g and flavonoid contents from 120.75 to 148.08 mg quercetin/g. Reduction in oxidative stress biomarker (MDA) from 1.83 to 1.54 mmolg(-1) in M. oleifera planted on CaNPs amended soil was also recorded. Strong correlations among essential mineral pairs indicate M. oleifera is a source of multiple mineral nutrients and a poor source of toxic heavy metals. Results of estimated daily intake of mineral nutrients and toxic hazard quotients of heavy metals suggest M. oleifera planted on CaNPs as the safest for consumption with respect to heavy metal toxicity. Lifetime risk assessment reveals a 50% reduction in cancer risk from consumption of M. oleifera planted on CaNPs soil. Thus, it is evidently clear from results of this study that CaNPs enhanced nutritional quality of M. oleifera.