99 Acta Poloniae Pharmaceutica – Drug Research, Vol. 80 No. 1 pp. 99-107, 2023 DOI: 10.32383/appdr/161588 Received 18 October 2022, Received in revised form 13 February 2023, Accepted 23 February 2023 NATURAL DRUGS PROTECTIVE EFFECT OF BETULIN AGAINST ALUMINIUM-INDUCED ALZHEIMER-LIKE NEURODEGENERATION AGNIESZKA ZAKRZESKA , PAWEŁ KITLAS , ALEXIEJ SHLYAHTUN , RYSZARD JABŁOŃSKI , MIKOŁAJ TOMULEWICZ , and NATALIA SZYMAŃSKA University of Medical Science in Bialystok, ul. Krakowska 9, 15-875 Białystok, Poland Abstract: The purpose of this study was to show the preventive properties of betulin (Bet) and its combi- nation with cyclodextrin in a model of neurodegenerative disease like Alzheimer’s disease (AD) in rats. Betulin was obtained from birch bark using standard methodology. The AD model was induced by ad- ministering aluminum chloride AlCl 3 (200 mg/kg/day) to animals for 120 days. All animals were divided into 4 groups: the control group (sham operation), the second - the AD model (Alz) without prevention with betulin, the third - the Alz+Bet receiving betulin (100 mg/kg/day, i.g., during the last 50% of the ex- perimental days), and the Alz+Bet Complex receiving betulin in complex with cyclodextrin (100 mg/kg/ day, i.g., during the last 50% of the experimental days). We showed that betulin in complex with cyclo- dextrin improved spatial memory and lowered levels of the TNF-α, APLP2, and β-amyloid in rats with AlCl 3 -induced AD. We conclude that betulin has neuroprotective properties which may form the basis for the development of a new pharmaceutical that is effective in both the prevention and treatment of Al- zheimer’s disease. Keywords: Alzheimer’s disease, betulin, pentacyclic triterpene. * Corresponding author: e-mail: a.zakrzeska@wsmed.pl In recent years, natural biologically active com- pounds of plant origin and the study of their pre- ventive and therapeutic properties have increased attention from chemists, biologists, pharmacists, and physicians (1, 2). Among them, lupeol, betulin- ic acid and betulin (derivatives of pentacyclic trit- erpene compounds) show strong biological activity (3, 4) (Figure 1). Betulin (Bet), a biologically active substance isolated from the bark of the bearded birch tree (Betula verrucosa) by sublimation by Lovitz in 1778 in birch water and later in birch tar, is a widely studied triterpenoid. The pure substance was frst ob- tained by extraction of birch bark with organic sol- vents of different polarities, in particular ethanol (5). Betulin is a resinous substance that flls the cell cavities of the cork tissue of white birch (Betula) species, e.g. B. verrucosa, B. pendula, B. pubes- cens, B. alba, and gives them a white color. It is an organic compound of the lupane-type pentacy- clic triterpenes group and has the chemical formula C 30 H 50 O 2 (Figure 2). According to various sources, birch bark con- tains up to 35% betulin and up to 5-10% lupeol (6). H H HO HO HO H H OH OH C B A O H H H H H H H H Figure 1. Chemical structure of botulin (A), betulinic acid (B) and lupeol (C). ISSN 2353-5288 Polish Pharmaceutical Society