## 4 Health-Promoting Effects of Avocado and Its Bioactives
### Benefits against Neurodegenerative Disorders  
In the reviewed literature, many studies and clinical trials exhibited a connection between avocado fruit and neuroprotection. By an in-silico approach, [PERSON] et al. evaluated the positive health effects of avocado against Cadmium-induced toxicity. Cadmium interferes with the proper functioning of cells by disrupting cellular redox balance, causing apoptosis, and leading to hepatocellular damage, neurotoxicity, pulmonary edema, cancer, and cardiac and neurodegenerative diseases. It was observed that avocado juice treatment successfully reduced Cd accumulation and lipid peroxidation in the liver, kidney, and hippocampal tissues, while it beneficially upregulated the expression of the genes for important antioxidant enzymes, such as the SOD (Superoxide Dismutase), CAT (Catalase), and GPx (Glutathione Peroxidase), and it also showed considerable active potential for improving memory and learning. These results suggest that a diet containing papaya and avocado can help treat the lethal effects caused by Cd due to the beneficial effects of their biouctics that can improve health at the cellular and molecular levels [121]. Moreover, an in vivo study of the neuroprotective effects of _P. americana_ extracts based on a _D. melanogaster_ model was followed by [PERSON] et al. [122]. The flies after a rotenone-induced neurotoxicity had their survival rate evaluated. It was found that seed extracts, in comparison with peel extracts, had a much more significant result in preventing neurodegenerative diseases. In conclusion, introducing a flavonoid- and polyketides-rich diet through avocado extracts showed both a preventive and a therapeutic role, while the preventive approach exhibited a better survival rate. To continue, the effects of P. Americana in rats with AlCl\({}_{3}\)-induced Alzheimer's were thoroughly examined [123]. Many parameters were tested, and it was found that avocado can treat neurological damage. In more detail, xanthophylls and flavonoids, constituents of avocado, are proposed to possess antioxidant and DNA-protective capabilities. In addition to that, ellagic acid is a tannin that can protect the membrane of the cell by binding into it and preventing cell death, apoptosis, DNA fragmentation, and oxidative stress. Another mechanism of neuroprotection was tested by a decrease in caspase 3 levels that induce apoptosis and upregulation of dopamine, an important parameter of the pathologicalysis of Alzheimer's, by omega-3 fatty acids [123]. At the same time, in a recently published in vitro study, neuroprotective and antioxidant activities of avocados were also suggested. In this case, a rich-in-phenolics extract derived by a pressurized liquid extraction process with an environmental-friendly practice exhibited a strong antioxidant capacity of 3350 umol Trolox equivalent/g dry extract and 0.14 ug/mL in both ABTS and ORAC assay procedures, respectively, which also suggested antioxidant neuroprotection [124]. Prior to that, a clinical trial on adults who were introduced to an avocado diet showed no correlation between avocado consumption and cognitive function except an increase in serum lutein concentration in the order of 33% after testing in comparison to the control group which was given daily avocado intake for 12 weeks. In the end, the increased lutein is uncorrelated with cognitive ability [81]. One group of researchers, [PERSON] et al. [125], proposed that avocado oil could protect neuro cells that are damaged by oxidative stress. This protective effect is attributed to PUFA like omega-3, which can decrease risk factors in neurodegenerative disorders. This in vitro experiment examined oxidative and apoptotic markers while focusing on the toxic effect of hydrocortisone in neuroblastoma cells (SH-SYSY). The antioxidant effect of the avocado oil (AO) increased BDNF (Brain-Derived Neurotrophic Factor) by 28% in the 5 \(\upmu\)g/mL dosage, which is important for brain development.