A comparative analysis of antioxidant activity in ultrasound-assisted extractions of Artemisia annua L. and Artemisia vulgaris L. utilizing diverse excipients

Abstract

Background. Flavonoids, exemplified by apigenin and luteolin, represent bioactive compounds renowned for their pronounced anti-inflammatory, antioxidant, and anticancer properties. Such compounds, alongside other polyphenols, coumarins and tannins, are prevalent within the Artemisia species. The inclusion of specific excipients in the extraction process has been posited to enhance polyphenol yield and antioxidant activity. Aim. The study aimed to investigate the influence of excipient utilization in ultrasound-assisted extractions on Artemisia annua L. and Artemisia vulgaris L. and to evaluate its influence on the antioxidant activity of the extracted compounds. Methods. The extracts of Artemisia annua L. and Artemisia vulgaris L. were prepared using 80% (V/V) ethanol as the solvent. Ultrasound-assisted extraction was employed with diverse excipients, including β-cyclodextrin, L-glutathione, titanium dioxide, propylene glycol, and a control group. The analytes were subjected to analysis via high-performance liquid chromatography (HPLC), and antioxidant activity was assessed using the HPLC-ABTS (2.2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) post-column assay. Results. The extracts prepared with the incorporation of excipients exhibited notable results compared to those without. L-Glutathione yielded the most favourable chemical profiles, indicating that Artemisia annua L. contained 7.268 ± 0.363 μg/g of apigenin and 1.246 ± 0.062 mg/g of luteolin, while Artemisia vulgaris L. contained 5.054 ± 0.253 μg/g of apigenin and 773.995 ± 38.699 μg/g of luteolin. In contrast, extracts prepared using the conventional method without excipients resulted in lower concentrations: Artemisia annua L. exhibited 4.495 ± 0.225 μg/g of apigenin and 775.679 ± 38.784 μg/g of luteolin, while Artemisia vulgaris L. contained 3.175 ± 0.159 μg/g of apigenin and 530.285 ± 26.514 μg/g of luteolin. Chlorogenic acid, neochlorogenic acid, caffeic acid and luteolin displayed heightened antioxidant activity. Artemisia annua L. extracts prepared with titanium dioxide demonstrated heightened statistically significant antioxidant activity, exemplified by luteolin at 152.520 ± 7.626 μg TE/g and chlorogenic acid at 251.575 ± 12.579 μg TE/g. Correspondingly, Artemisia vulgaris L. extracts prepared with titanium dioxide exhibited increased statistically significant antioxidant activity, including neochlorogenic acid at 29.089 ± 1.454 μg TE/g and luteolin at 90.196 ± 4.509 μg TE/g. Conclusion. The study reveals that extracts from both Artemisia annua L. and Artemisia vulgaris L., when prepared with titanium dioxide, displayed superior antioxidant activity. Notably, Artemisia annua L. extracts demonstrated heightened antioxidant activity compared to Artemisia vulgaris L. extracts.