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This study evaluates the antioxidant activity of Ranunculus muricatus and isolation and structure elucidation of the active constituents. The aerial parts of the plants were shade dried at room temperature and powdered and extracted with methanol. The free radical scavenging activity was evaluated by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay. The percentage scavenging activity was determined based on the percentage of DPPH radical scavenged. Column chromatography was used in order to isolate the active compounds. Spectral techniques UV, IR, 1 H NMR, 13 CNMR and HREI-MS were used for the structure elucidation of the isolated compounds. Two isolated compounds, A (caffeoyl-β-D-glucopyranoside) and B (1,3-dihydroxy-2-tetracosanoylamino-4-(E)-nonadecene), exibited a significant antioxidant activity as showed by DPPH radical scavenging method. Percentage inhibition for compound A (at 0.5 mM) was 82.67 ± 0.19 with IC 50 of 93.25 ± 0.12 (μM), and for compound B (at 0.5 mM) was 69.23 ± 0.19 with IC 50 of 183.34 ± 0.13 (μM). Quercetin was used as standard control. It was conclued from the present study that caffeoyl-β-D-glucopyranoside and 1,3-dihydroxy-2-tetracosanoylamino-4-(E)-nonadecene isolated from methanol extract of aerial parts of Ranunculus muricatus posses antioxidant activity.

The basic substances of life include various amino acids and sugars. To search such molecules is the precondition to understand the essential nature. Here we reported four unprecedented hybrids of γ-amino acids and sugars from the roots of Ranunculus ternatus, which possess potential tail to tail ether-connected (6,6-ether-connected) modes in the sugar moiety. The structures of these hybrids were elucidated by extensive analyses of spectra and calculated electronic circular dichroism (ECD) method.