Detection and quantification of roemerine in wild Papaver rhoeas and Papaver glaucum from Sulaymaniyah, Iraq, and comparison of their extracts' total antioxidant activity

Abstract

Objective: This study aimed to detect, tentatively identify, and quantify the aporphine alkaloid roemerine in wild Papaver rhoeas L. and Papaver glaucum Boiss. and Hausskn. from northern Iraq, and to compare the total antioxidant activity of their purified extracts.

Methods: Whole plants were collected from Sulaymaniyah in April 2023. Methanolic extracts were subjected to alkaloid purification and analysed by chemical tests, GC-MS, TLC, and HPLC. Roemerine was quantified via a validated HPLC method. The total antioxidant capacity of extracts, standardised to an equivalent roemerine content, was evaluated using the phosphomolybdenum assay.

Results: Chemical tests confirmed alkaloids in both species. GC-MS analysis tentatively identified roemerine as a major component in P. rhoeas (26.4% relative abundance) and P. glaucum (14.7%). TLC (Rf ~0.6) and HPLC supported its presence. HPLC quantification found a higher concentration of roemerine in P. rhoeas (2.25 ± 0.11 mg/g dry weight) than in P. glaucum (1.49 ± 0.09 mg/g). The phosphomolybdenum assay indicated a higher, though not statistically significant (p=0.18), antioxidant activity in P. glaucum (0.43 ± 0.05 AAE/g) compared to P. rhoeas (0.14 ± 0.03 AAE/g).

Conclusion: Roemerine was tentatively identified and quantified for the first time in wild Iraqi P. rhoeas and P. glaucum, with a higher concentration found in P. rhoeas. The differential antioxidant activity, despite standardised roemerine content, suggests a significant contribution from other phytoconstituents, particularly in P. glaucum.