Antiglioma activity from Aloysia virgata (Ruíz & Pavón) Juss

Introduction

Aloysia virgata is a plant native from southern Brazil, belonging to the Verbenaceae family and popularly known as “lixeira” due to its rough leaves. Medicinally, this plant is used for the treatment of diseases which affect the digestive system, and some studies regarding its neuroactive activity have been reported.

Aim of the study

The aim of this study was to structurally characterize secondary metabolites found in the leaves of A. virgata, a medicinal plant. Additionally, we evaluated the antitumor potential of extracts and fractions obtained from the leaves of the plant against glioma cell lines.

Materials and methods

Dried and crushe leaves were subjected to aqueous (AC) and ethanolic extraction (EC). A liquid-liquid partitioning with different solvents in increasing order of polarity was performed to reduce the complexity of the extracts and facilitate their analysis. Thus, both extracts were solubilized in water and the following solvents were added in increasing order of polarity: chloroform, ethyl acetate, and butanol for EC, and ethyl acetate and butanol for AC. The partitioning process resulted in 4 fractions for EC, named ECH, EEA, EB, and EA and 3 fractions for AC, named AEA, AB, and AA. After obtaining the extracts and fractions, they were tested to assess their effect on cell viability. Cells from human glioma cell line U251 and rat cell line C6 were treated with all the extracts and fractions obtained at concentrations of 1, 5, and 10 mg/mL for 24, 48, and 72 hours, followed by the MTT assay. To simulate the treatment cycle used in the clinic, which consists of 5 days of treatment followed by 23 days without treatment, U251 cells were plated and exposed to treatments with AEA, ECH, and EEA for 5 days. After this period, the cells were maintained for additional 23 days without treatment.

Results

After characterization analyses, the presence of 28 major compounds were identified for both extracts and their respective fractions, of which only 5 had been previously described for this plant, with the majority belonging to the class of flavonoids. Cell viability tests revealed that treatments AEA, ECH, and EEA exhibited the highest rates of decrease in glioma cell viability and population doubling.

Conclusions

This study characterized metabolites present in the plant A. virgata. It was demonstrated for the first time that this extract exhibited cytotoxic effects on glioma cell lines, indicating potential to be further explored through additional studies for future application as a treatment for tumors.