Phytochemical contents, in vitro and in vivo antioxidant and anticancer activities of avocado (Persea americana Mill.) seed extract against MCF-۷ and HMVII cancer cells

Background and aims: Avocados are unique in Nigeria for their taste and medicinal uses. This study was performed to determine the phytochemicals and evaluate the antioxidant and cytotoxic effects of avocado seed extracts (ASEs). Methods: The phytochemicals were analyzed using the gas chromatography-mass spectrometry (GC-MS) apparatus. The total phenolic and flavonoid contents and in vitro antioxidant activity were evaluated using standard methods. In contrast, in vivo, antioxidants were used in a group of thirty healthy Wistar rats randomly grouped into five groups of six, with cytotoxicity activity by benchtop and MTT (۳-[۴,۵-dimethylthiazol-۲-yl]-۲,۵ diphenyl tetrazolium bromide) assays and apoptosis by assessing caspase-۳-like activity. Results: The GC-MS revealed polyphenols and fatty acids. Phenolic and flavonoid contents were ۱۱۷۸.۶۷ mg gallic acid equivalent per gram (GAE/g) and ۸۶.۲۴ mg rutin equivalent per gram (RE/g), respectively. High radical scavenging toward ۲,۲-diphenyl-۱-picrylhydrazyl (DPPH), ABTS, and ferric reducing antioxidant power (FRAP) reducing power with IC۵۰ values of ۲۵.۲۵±۱.۰۱ µg/mL, ۳۸.۲۲±۲.۰۱ µg/mL, and ۴۳.۹۹ mM Fe (II) equivalent, respectively, in vitro antioxidation as well as dose-dependent in vivo antioxidant activities with reduced malondialdehyde (MDA), total superoxide dismutase (TSOD), and catalase (CAT) and increased glutathione peroxidase (GSH-Px) contents in vital organs were obtained. Cytotoxic effects on MCF-۷ and HMVII cells were detected, with IC۵۰ values of ۱۶.۵۱±۰.۰۲ µg/mL and ۳۱.۷۱±۲.۰۳ µg/mL, respectively, which was statistically significant (P=۰.۰۰۱) when compared to doxorubicin standard drug and a higher selective index on breast cancer (BC). Conclusion: The findings revealed that avocado seed possessed antioxidant and anticancer activities on human MCF-۷ and HMVII cancer cell lines.