Determination of total phenolic content and antioxidant activity in vitro of Chelidonium majus L. raw material

Introduction. Chelidonium majus L. (C. majus), commonly known as greater celandine, is a perennial herbaceous plant belonging to the Papaveraceae family. It has a long history of use in traditional medicine, particularly for its antimicrobial, antiviral, and anti-inflammatory properties. The plant is rich in secondary metabolites, including alkaloids, flavonoids, and phenolic compounds, which contribute to its pharmacological effects. Recent studies have highlighted the potential antioxidant activity of C. majus, making it a valuable subject for further phytochemical and biomedical research [1]. The aim of the study was to determine the content of phenolic compounds in C. majus raw material and to evaluate their antioxidant activity. Materials and methods. Raw material (stems, leaves, and flowers) of C. majus was collected in Lithuania between June and August. The total phenolic content was determined using the Folin–Ciocâlteu assay, while antioxidant activity in vitro was evaluated using ABTS, FRAP, and CUPRAC methods. Results and their discussion. The highest total phenolic content in C. majus raw material (27.25 GAE mg/g DW) was recorded in June, while the lowest (19.50 GAE mg/g DW) was observed in August. The strongest antioxidant activity, as determined by the CUPRAC and ABTS assays, was observed in July ‒ 188.88 µmol TE/g and 177.53 µmol TE/g, respectively. However, according to the FRAP method, the highest antioxidant activity (58.63 µmol TE/g) was found in the raw material collected in August. The lowest antioxidant activity of C. majus extracts, as measured by the CUPRAC and ABTS assays, was recorded in June ‒ 111.15 µmol TE/g and 84.51 µmol TE/g, respectively. However, according to the FRAP method, the raw material collected in July showed the highest antioxidant activity, reaching 27.24 µmol TE/g. When compared to previous studies, the results of this research show both similarities and unique seasonal trends in phenolic content and antioxidant activity in C. majus. For instance, Wojdyło et al. (2007) reported total phenolic content ranging from 18.5 to 29.8 GAE mg/g DW in C. majus extracts, depending on the plant part and extraction method, which corresponds well with the highest value observed in this study (27.25 GAE mg/g DW in June) [2]. Similarly, Koczka et al. (2013) found that antioxidant activity assessed by CUPRAC and ABTS assays in various medicinal plants, including C. majus, ranged between 100 and 180 µmol TE/g, supporting the July peak values in our results ‒ 188.88 µmol TE/g (CUPRAC) and 177.53 µmol TE/g (ABTS) [3]. In contrast, the FRAP values observed in this study (ranging from 27.24 to 58.63 µmol TE/g) were slightly higher than those reported by Ivanova et al. (2005), who noted FRAP activity around 20–30 µmol TE/g in C. majus aerial parts [4]. These comparisons emphasize the influence of seasonal factors, plant maturity, and assay specificity on the measured antioxidant potential. The variations observed in this study underline the importance of selecting optimal harvesting times to maximize the desired phytochemical properties in C. majus. The results of this study demonstrate that the total phenolic content and antioxidant activity in vitro of C. majus raw material vary significantly depending on the harvest time. The highest total phenolic content was determined in June, while the strongest antioxidant activity (CUPRAC and ABTS) was observed in July. Interestingly, FRAP results peaked in August, indicating that different antioxidant mechanisms may be active at different growth stages. These findings highlight the importance of selecting the appropriate harvest period to maximize the bioactive potential of C. majus.