Protective Effects of Rosmarinus officinalis and Artemisia herba-alba Against Glucose-Induced Oxidative Stress in Human Serum: An In Vitro Study

Hyperglycemia is associated with impaired redox homeostasis and enhanced oxidative stress. This study aimed to evaluate the phytochemical composition and antioxidant activity of Rosmarinus officinalis and Artemisia herba-alba extracts and to investigate their protective effects against glucose-induced oxidative stress in human serum under in vitro conditions. Total polyphenol content (TPC) was determined using the Folin–Ciocalteu method, while total flavonoid content (TFC) was assessed using the aluminum chloride colorimetric method. Antioxidant activity was evaluated using the DPPH radical-scavenging assay. The protective effects of the extracts were further investigated in human serum samples exposed to increasing glucose concentrations (1, 10, and 100 mg/mL) by measuring total antioxidant status (TAS) and catalase (CAT) activity. Phytochemical analysis revealed that Rosmarinus officinalis showed a higher TPC than Artemisia herba-alba (81.87 ± 0.20 vs. 48.36 ± 5.19 mg GAE/g, respectively), whereas the TFC values were comparable between the two plants (26.32 ± 1.78 and 28.49 ± 0.15 mg QE/g, respectively). The ethanolic extract of Artemisia herba-alba exhibited strong DPPH radical-scavenging activity (IC₅₀ = 0.71 mg/mL), while the aqueous extract of Rosmarinus officinalis also showed notable radical-scavenging activity (IC₅₀ = 0.864 ± 0.36 mg/mL). Both extracts attenuated glucose-induced oxidative disturbances, as reflected by improvements in TAS and CAT activity in human serum samples. These findings indicate that Rosmarinus officinalis and Artemisia herba-alba possess antioxidant properties and may help mitigate glucose-induced oxidative disturbances in human serum.