In vitro antioxidant activity and qualitative phytochemical analysis of two Vismia (Hypericaceae) species collected in Los Andes, Venezuela
Vismia genus is distributed mainly in tropical and subtropical regions of Central, South America and some areas of Africa. According to previous investigations, antioxidant potential of Vismia species might be related to anthrones, anthraquinones, flavonoids and phenol derivatives biosynthesized by these plants. The aim of present study is to evaluate the free radical scavenging capacity, total phenolic and flavonoids content as well as the qualitative phytochemical screening of methanol extracts obtained from Vismia macrophylla (VM) and Vismia baccifera (VB) collected in Táchira and Mérida state, Venezuela. Phytochemical screening of VB and VM methanolic extracts carried out using various chemical assays revealed an abundant presence of anthraquinones in both species analyzed. Glycosides were also present while flavones and dehydroflavones were observed abundantly in VB but moderated in VM. Triterpenes were also detected and steroids showed to be abundant in VM but moderate in VB. On the other hand, antioxidant capacity measured by the DPPH radical scavenging assay showed that VM possesses a stronger antioxidant activity than VB with IC50 5.50 µg/mL. Phenol and flavonoid assays also revealed that methanol extracts of both VM and VB contain high concentrations of these metabolites. A relationship between the antioxidant activity, total phenol and flavonoids content of the extracts analyzed was demonstrated in present investigation since those samples with higher phenolic concentrations showed likewise higher antioxidant activity.