Investigação da atividade antiglioma de extratos provenientes de Aloysia Virgata (Ruíz & Pavón) Juss

Abstract

Gliomas are the most common primary tumors of the central nervous system, accounting for 70% of all primary brain tumors. The treatment used for this type of tumor has had little effect, where the rate of recurrence, progression, and mortality of the disease are high. Thus, the search for a more effective treatment is constant. With the increasing discovery of compounds of plant origin associated with benefits to human health, many researchers have begun to test the antitumor potential of these compounds. Among the botanical families with specimens with medicinal potential, the Verbenaceae stands out, a family with species widely used in popular medicine and with few studies related to their chemical composition. In this context is the species Aloysia virgata, popularly known as trash, widespread in South America to treat symptoms of diseases related mainly to the digestive system, and some studies concerning its neuroactive activity. Thus, the objective of this work was to verify the antitumor potential of aqueous and hydroalcoholic extracts from the leaves of the medicinal plant Aloysia virgata in glioma cell lines. Initially, the plant was collected and the leaves and stalks were extracted with distilled water and ethanol in order to isolate and identify the main chemical constituents present in different extraction forms. In order to separate high molecular weight compounds from those of low weight, the crude extracts were precipitated with chilled ethyl alcohol, resulting in ethanol soluble fractions containing the secondary metabolites, named ET for the ethanolic extract and AQ for the aqueous extract, and later, these same crude extracts were fractionated in liquid-liquid partitioning, generating seven more different treatments with their own characteristics, namely: AA, AE, BA, BE, ACA, ACE and CE. To verify cell viability after treatment with the extracts and fractions, C6 and U251 strains were treated at concentrations of 1, 5 and 10 mg/mL for 24, 48 and 72 hours. After the treatment time for each partitioning, cell viability was measured using the MTT assay, where it was found that ACA, ACE, and CE demonstrated higher rates of decrease in cell viability, causing a decline of at least 50% in relation to the control (100%), for both cell lines used. To simulate the treatment cycle used in the clinic, which corresponds to 5 days of treatment and 23 days without treatment, U251 cells were plated and exposed to the treatments that showed the best results in the MTT assay for 5 days. After this period, the cells were kept for another 23 days without treatment. At the end of 28 days, the treatments used showed high cytotoxicity power, preventing the cells from restoring to their initial number, which may mean that the plant has chances to not only aid in the treatment of gliomas, but also act in the reduction of the cells.