Ochna serrulata (Ochnaceae) is an ornamental plant introduced into Brazil from Asia and Africa. Species of the Ochna genus are rich in phenolic compounds, mainly flavonoids. The biological screening of extracts and fractions showed that this plant exhibited a significant antioxidant activity, when evaluated by the DPPH and reducing potential assays. Ochna serrulata also demonstrated slight toxic activity against Artemia salina and a potential inhibitory allelopathic activity, when evaluated using the Lactuca sativa seed germination test. The ethyl acetate fraction, the most active one, was partitioned on a silica gel column to obtain epicatechin, which showed potential antioxidant activity.