o:30820 From Aloe vera Leaf Waste to the Extracts with Biological Potential: Optimization of the Extractions, Physicochemical Characterization, and Biological Activities en ABSTRACT In the study, the optimization of the extraction from Aloe vera leaf waste was performed via varying solid-to-solvent ratio, solvent type, extraction time, and technique (maceration, heat-,ultrasound-, and microwave-assisted extractions—HAE, UAE, and MAE, respectively). The optimal extraction conditions for achieving the highest polyphenol content are a 1:30 ratio, 70% ethanol, and 30 min of HAE. Total flavonoid and protein contents were significantly higher in the extract from MAE, while total condensed tannin content was the highest in HAE. LC-MS analysis quantified 13 anthraquinone and chromone compounds. The variations in the FT-IR spectra of the extracts obtained by different extraction procedures are minor. The influence of extraction conditions on the antioxidant ability of the extracts depended on applied antioxidant assays. The extracts possessed medium inhibition properties against Staphylococcus aureus and weak inhibitory activity against Enterococcus feacalis. The extracts had stimulative effect on HaCaT cell viability. Regarding the extraction yield, there was a significant difference between the used extraction techniques (MAE > HAE > maceration and UAE). The presented study is an initial step in the production of polyphenol- rich extracts from A. vera leaf waste aimed to be used for the potential preparation of pharmaceutical and cosmetic formulations for the skin. Aloe vera; biological potential; extraction; optimization; polyphenols 1552099 10.3390/plants12142744 2023-09-15T10:10:54.746Z 44 yes 46 Muna Rajab Elferjane Faculty of Nursing and Health Sciences, University of Misurata, Libya Aleksandra A. Jovanović University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor nauka-tehnološko inženjerstvo-biotehnologija person 0000-0001-5394-0125 Violeta Milutinović Faculty of Pharmacy, University of Belgrade, Serbia person Natalija Čutović Institute for Medicinal Plant Research “Dr Josif Pančić”, Belgrade, Serbia person Milica Jovanović Krivokuća University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor bioloških nauka person 0000-0001-8292-4853 Aleksandar Marinković Faculty of Technology and Metallurgy, University of Belgrade, Serbia person application/pdf 2334639 https://phaidrabg.bg.ac.rs/o:30820 no yes 16 70 92000001 11A29 11A13 11A41 Plants 12 MDPI 2023