Isolation, phytochemical and antioxidant screening of roemerine obtained from Papaver dubium and Papaver macrostomum grown in Iraq

Purpose: To isolate roemerine from Papaver dubium and Papaver macrostumum, two plants widely grown in Northern Iraq and to evaluate its antioxidant properties. Methods: Aerial parts of the plants were harvested and extracted using methanol. Roemerine (alkaloid) was isolated from the methanol extracts, followed by identification and quantification using Gas Chromatography-Mass Spectrometry (GC-MS), Thin-layer Chromatography (TLC) and High-Performance Liquid Chromatography (HPLC) analysis. Determination of antioxidant potential of varying concentrations of roemerine (50, 100, 200, 300, and 400 μg/mL) in dimethyl sulphoxide (DMSO) was performed using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and ferric reducing antioxidant power (FRAP) assays and results were compared against those of standard ascorbic acid (vitamin C). Results: Roemerine was present in the extracts of both Papaver species. However, a higher concentration of the alkaloid was found in P. dubuim extract (2.67 mg/g) compared to P. macrostomum extract (1.92 mg/g; p < 0.05). The free radical scavenging activity of DPPH revealed that roemerine possessed weak antioxidant activity with an IC50 value almost two times higher than that of ascorbic acid. Furthermore, the scavenging activity of roemerine at the highest concentration was 50 % lower than that of ascorbic acid (33 vs 67 %, respectively). There was also no significant increase (p > 0.05) in the reducing power of roemerine at all concentrations assayed compared to vitamin C. Conclusion: Roemerine has been isolated from P. dubium and P. macrostomum. A higher concentration of the alkaloid is seen in P. dubium compared to P. macrostomum. This report presents the first evidence of roemerine availability in Papaver dubium and Papaver macrostomum in Iraq.