Identification of polyphenoilc compounds within fruit extracts and their role in the treatment of glioma

Abstract

Glioblastoma multiforme (GBM) is the most common and malignant primary brain tumour in adults. Despite current treatment options, including surgery followed by radiation and chemotherapy with temozolomide (TMZ) and cisplatin, the median survival rate remains below 16 months. Epidemiological studies have shown a positive correlation between consumption of fruits and vegetables in the reduced risk and prevention of cancers, resulting in improved mortality rates. This is due to various fruits encompassing differing antioxidant abilities, which are derived from their phytochemical components. Research has emphasised the importance of antioxidants and their ability to neutralise reactive oxygen species (ROS) which cause oxidative damage to lipids, proteins and nucleic acids. This study examined the presence of polyphenolic compounds within five fruits: cranberry, strawberry, goji berry, maqui berry and acai berry, and their effect on cell viability. Through High Performance Liquid Chromatography, it was possible to identify the potential of all fruits to contain antioxidants; specifically, gallic acid, punicalagin, cyanidin-3-glucoside and malvidin. Subsequently, flavonoid and phenolic assays quantified the levels of antioxidants present within the fruits whereby, cranberry had the highest total flavonoid content (670.93 ±45.30 µg/CE/serving) and strawberry had the highest total phenolic content (2835.11± 26.48 µg/GAE/serving). Also, the DPPH· radical scavenging assay quantified antioxidant activity of fruits and phytochemical compounds showing punicalagin to have the highest antioxidant activity (6522.74 ± 59.30 µM TROLOX equivalents). The results presented a significant difference in each assay, between all fruits samples (p<0.001). This identified cranberry to contain the highest antioxidant activity when compared to the other fruits. This study examined the effect of the fruit extracts and antioxidant compounds in comparison to cisplatin and determined effects on cell viability. Cyanidin-3-glucoside and maqui berry significantly reduced the viability of U87-MG cells. These results suggest a potential for antioxidants as chemotherapeutic agents in the treatment of glioblastoma multiforme.