Phytochemical Profiles and Anti-Glioma Activity of Bearberry Arctostaphylos uva-ursi (L.) Spreng. Leaf Extracts

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 ursolic 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 µL/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.