###### Abstract  
The use of diversified raw materials and various extractant types is justified because the varied chemical composition of extracts obtained via extraction determines their biological activity. Therefore, the objective of this study was (i) to characterize the chemical profile of two types of bearberry extracts (70% ethanolic and water) and (ii) to investigate the biological activity of the analyzed extracts through an assessment of their possible proapoptotic effects on glioma cell lines. The HPLC-UV analysis of individual compounds was performed for the determination of the phytochemical profile of the bearberry extracts, and their total phenolic content (TPC) and total flavonoid content (TFC) were determined spectrophotometrically. The induction of apoptosis, autophagy, and necrosis in anaplastic astrocytoma MOGGCCM and human glioblastoma LN229 cell lines were investigated. The results indicated that the ethanolic (Et) and aqueous (Aq) extracts had different chemical profiles. The TPC in the Et was ca. 60% higher than in the Aq. Similarly, the TFC and methylarbutin (mARB) concentrations were significantly higher in the Et. On the other hand, the concentration of hydroquinone (HQ) was ca. 70% and that of corilagin (COR) was ca. 100% higher in the Aq. In turn, the presence of unsolic acid (UA) and oleanolic acid (OA) was confirmed solely in the Et. In contrast to Aq, Et demonstrated high proapoptotic activity. At the concentration of 2 uL/mL, the level of apoptosis varied between 14.7% and 26% in the case of the MOGGCCM cells and between 12.3% and 33.3% in the case of the LN229 cell line. The knowledge and information obtained in this study indicate a need for further research on the anticancer effect of the studied bearberry phytochemicals on the MOGGCCM and LN229 cell lines and for the elucidation of their molecular anticancer mechanisms. Arctostaphylos uva-ursi; chemical compounds; anaplastic astrocytoma MOGGCCM cell line; human glioblastoma LN229 cell line 2024 202  
interactions with environmental factors [1; 2]. In recent decades, medicinal plants and their molecules have gained considerable attention due to their potent biological activities [3; 4; 5; 6]. Many of them are used as pharmaceuticals, nutraceuticals, food additives, and natural agents against pathogens [5]. Natural products provide a sustainable source with considerable efficacy to treat and overcome several disorders and fatal diseases [6]. Medicinal plants and their bioactive compounds also have potential as anticancer agents [4; 5; 6; 7; 8] and are one of the main sources of drugs [3; 4; 9]. Almost half of them are either natural compounds or directly derived therefrom [3; 4]. Alternative treatments and therapies based on medicinal plants offer a wide range of benefits, especially for patients who are looking for options with fewer side effects compared to conventional medications [10]. _Arctostayhylos uwa-ursi_ (L.) Spreng., commonly known as bearberry, represents plants containing very interesting phytochemicals. For many years, the leaves of this plant have been used in traditional medicine [11]. The raw material is obtained through both wild harvesting and cultivation [12]. Due to the excessive pressure exerted by the collection of the raw material, many populations and habitats of bearberry have been destroyed; hence, the species is subject to strict protection and its collection is controlled in several countries [13; 14]. This wild perennial shrub is widely distributed in the circumboreal area of Europe, North America, and Asia, and is a source of raw material for the pharmaceutical and herbal medicine sectors [12; 15; 16]. Its leaves contain several active compounds, including arbutin, hydroquinone, tannins, and flavonoids, which contribute to its therapeutic effects [16; 17]. Arbutin, one of its active components, is metabolized into hydroquinone, which has antiseptic and antiadhesion properties in the urinary tract [18].