In vitro hematotoxicity of Vernonanthura polyanthes leaf aqueous extract and its fractions.

Vernonanthura polyanthes , popularly known as 'assa-peixe', is widely used in Brazil for therapeutic purpose mainly to treat respiratory tract problems. However, few studies investigated its chemical safety. In this way, we first obtained the V. polyanthes leaf aqueous extract ( Vp LAE) and three fractions (aqueous; n-butanol, n-BF; and ethyl acetate), and we chemically characterized this material. Then, the cytogenotoxic potential of the Vp LAE and its fractions was investigated against human erythrocytes and lymphocytes using Trypan blue exclusion test of cell viability and CometChip. The phytochemical screening of V. polyanthes leaf revealed the presence of total phenolic compounds, flavonoids, tannins, coumarins, terpenic compounds, and cardioactive heterosides. n-BF presented the highest total phenolic, flavonoids, and tannins contents and, consequently, the highest antioxidant activity, according to the DPPH free radical scavenging method. Although the Vp LAE and its fractions did not cause death of erythrocytes, the cells acquired an echinocytic form. Regarding lymphocytes, Vp LAE and its fractions presented cytotoxicity and genotoxicity. When Vp LAE or its fractions were co-treated with doxorubicin (DXR), a recognized cytotoxic drug, we observed an enhancement of DXR cytotoxicity against lymphocytes, but the DXR genotoxicity decreased around 15%. Since the Vp LAE and its fractions increased the DXR cytotoxicity and decreased its genotoxicity, further studies should be conducted for the development of an adjuvant drug from this extract to reduce the side effects of chemotherapy. Moreover, the indiscriminate use of 'assa-peixe' by local people should be discouraged.