Comparative Evaluation of Antioxidant Potential in Natural Plants, In Vitro Regenerants, and Callus Cultures of Ungernia victoris and U. sewerzowii

Ungernia victoris and U. sewerzowii (Amaryllidaceae J.St.-Hil.) are rare medicinal species of Central Asia known as sources of biologically active alkaloids, including galantamine. In this study, antioxidant activity was comparatively evaluated across different types of plant material, including natural populations, botanical garden specimens, in vitro regenerants, callus cultures, in vitro obtained bulbs, and seeds. Micropropagation systems based on direct and indirect organogenesis were developed using Murasige and Skoog and Vollosovich et al. media with various plant growth regulator combinations. Antioxidant activity was determined with the use of DPPH and ABTS assays and expressed as IC50 values. Significant variability was observed depending on population origin, type of biological material, and in vitro cultivation conditions. U. sewerzowii demonstrated higher antioxidant activity than U. victoris in natural populations. The highest activity was recorded in callus cultures, whereas in vitro-derived bulbs showed relatively low activity. A strong positive correlation between DPPH and ABTS assays confirmed the reliability of the results and indicated the contribution of multiple types of secondary metabolites. These findings highlight the potential of Ungernia callus cultures as a promising biotechnological platform for the production of antioxidant-active compounds and support sustainable utilization strategies.