Abstract Background: Steviol glycosides (SGs) from Stevia rebaudiana are known for their natural sweetness and potential health benefits. However, extraction efficiency and biological activity vary across genotypes and depend on the extraction conditions. Aims and Objectives: This study aimed to evaluate the effect of an optimized extraction method on yield, total polyphenol content, and the in vitro antioxidant and anti-inflammatory activities of steviol glycosides obtained from six S. rebaudiana genotypes. Materials and Methods: Steviol glycosides were extracted using an optimized protocol. Extraction yield was quantified, and total polyphenol content was determined by the Folin–Ciocalteu method. Antioxidant activity was evaluated by the 2,2 diphenyl 1 picrylhydrazyl (DPPH) radical scavenging and reducing power assays, while anti-inflammatory potential was assessed by the protein denaturation inhibition method. Gallic acid, ascorbic acid and diclofenac sodium served as reference compounds. Results: The optimized method significantly enhanced extraction efficiency, reaching 149.00 ± 1.76 mg/g and 142.20 ± 1.62 mg/g for genotypes P7 and V9 7/7, respectively. Genotypes P7, V9, and P7 7/7 exhibited the highest total polyphenol content (0.1 mg/mL). The most potent antioxidant activity was recorded for P7 7/7 and Q1 (DPPH IC 50 = 0.11 mg/mL), comparable to ascorbic acid (0.10 mg/mL). These genotypes also demonstrated the strongest anti-inflammatory activity (IC 50 = 53.77 and 66.06 µg/mL), close to diclofenac sodium (66.02 µg/mL). Conclusion: The optimized extraction process substantially improves the yield and bioactivity of Stevia -derived compounds. Genotype P7 is notable for its high yield and polyphenol content, while P7 7/7 and Q1 show superior antioxidant and anti-inflammatory potential.
Ouriagli et al. (Wed,) studied this question.