PP86. CAN FRUIT JUICE PHYTOCHEMICALS HAVE A CHEMOTHERAPEUTIC EFFECT IN THE TREATMENT OF GLIOMA?

Abstract

INTRODUCTION: 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 low (<16 months). Combined with increasing drug resistance and the inability of some compounds to cross the blood brain barrier (BBB), novel compounds are being sought for the treatment of this disease. 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. Phytochemicals are bioactive non-nutrient plant compounds which have particular roles within plants including contributing to reproduction and growth, defence mechanisms against pathogens and parasites, as well as providing colour and fragrance to the plant. Various fruits encompass 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. Phytochemicals can be classified into five main categories; phenolics, carotenoids, nitrogen-containing compounds, organosulfur compounds and alkaloids, of which phenolics (polyphenols) are the most common and widely distributed. With their ability to combat reactive oxygen species and cross the blood brain barrier, polyphenols have the potential to improve current treatment options and outcomes of GBM. METHODS: Gold standard end-point assays were used to determine the total phenolic, total flavonoid and total antioxidant capacity of five freeze-dried fruit samples (acai berry, maqui berry, goji berry, strawberry and cranberry). Using the most common polyphenol reference standards, high performance liquid chromatography (HPLC) was then undertaken to identify and measure individual polyphenols present in each fruit sample. RESULTS: Strawberry was found to have the highest flavonoid content (2.45 +/- 0.292 mg/ml catechin) and antioxidant capacity (7.30 +/- 0.01mM TROLOX equivalence) of the fruit samples tested. Subsequent HPLC analysis indicated high levels of punicalagin in comparison to the other fruits (which ranged from 4.44mM to 0.03mM TROLOX equivalence). CONCLUSIONS: This data suggests that the high flavonoid levels, and in particular punicalagin, found in strawberry, contributes to the antioxidant capacity of this fruit juice. Current studies are underway to test this compound in vitro using the established cell lines of U87 MG (Grade IV human glioblastoma) and SVG-p12 (human foetal astroglia) in conditions of normoxia (95% air/5% CO2) and hypoxia (1% O2 / 5% CO2) to mimic the tumour environment.