MICROSCOPIC CHARACTERISTICS, ANTIOXIDANT ACTIVITIES, AND CHEMICAL COMPOSITIONS OF OCHNA INTEGERRIMA LEAVES AND STEMS

Tóm tắt

Ochna integerrima is a typical and precious plant for spring in Vietnam. The plant has been used traditionally for treatments of various ailments. The microscopic transverse section of its leaf and stem reveals the presence of phloem arcs from the leaf midrib. The upper and lower arcs are continuous and separated. The sclerenchyma contains two rings with a continuous outer and an interrupted inner in the stem. The MeOH extracts of the leaf and stem possess significant total phenolic contents of 114.11 ± 2.1 and 127.6 ± 3.45 mg GAE/g, respectively. These results corresponded to IC₅₀ values of 17.2 ± 0.15 and 11.9 ± 0.37 µg/ml for DPPH inhibitory activity, respectively. These results corresponded to the remarkable DPPH-scavenging activity with IC₅₀ values of 17.2 ± 0.15 and 11.9 ± 0.37 µg/ml, respectively. Methanol stem extract displayed higher antioxidant activity than methanol leaf extract. Chromatographic separation of MeOH extract of stems led to the isolation of four compounds, including 6˗γ,γ˗dimethyl-allylkaempferol 7˗O˗β˗ᴅ˗glucopyranoside (1), 6˗γ,γ˗dimethylallyldihydrokaempferol 7˗O˗β˗ᴅ˗glucoside (2), iriskumaonin-3¢-methyl ether (3), calodenone (4). The results from this study suggest that O. integerrima and its isolates could be good candidates for further investigation of antioxidant bioactivities.