Rheum officinale Baill.: chemical characterization and in-vitro biological activities

Medicinal plants constitute a valuable natural resource of bioactive phytochemicals, which are increasingly studied for their therapeutic potential and broad applications in the pharmaceutical, nutraceutical, and cosmetic fields. Rheum officinale, a medicinal rhubarb species, is appreciated for the presence of biologically active compounds with therapeutic relevance. This work analyses the chemical composition, including the phytochemical profile, and pharmacological activities of Rheum officinale Baill. stems in Algeria. The plant extract was analyzed for its notable antioxidant capacity using various assays, including DPPH, ABTS, β-carotene bleaching, ferric and also cupric reducing power, and metal chelation. The inhibitory potential against cholinesterase and α-amylase was assessed through specific enzymatic assays. LC-ESI-MS/MS assessment highlighted the phytochemical profile within the extract, with quinic acid identified as the major component. Antimicrobial potential against P. aeruginosa, S. aureus, E. coli, E. faecalis, and C. albicans was confirmed via agar diffusion and inhibition zone (C) tests. The extract demonstrated potent antioxidant activity, with radical scavenging IC₅₀ values less potent than reference antioxidants such as BHT and α-tocopherol (IC₅₀ = 0.42 ± 1.43 μg/mL). Total phenol and flavonoid content were quantified using Folin-Ciocalteu and AlCl₃ methods, yielding high values (373.10 ± 0.055 mg GAE/g and 38.012 ± 0.05 mg QE/g, respectively). Enzyme inhibition assays demonstrated significant activity against key enzymes related to Alzheimer's disease (IC₅₀: 28.14 ± 2.22; 73.71 ± 1.48 μg/m) and diabetes (IC₅₀: 36.21 ± 0.56 μg/m). The extract also exhibited antimicrobial effects. Given its bioactive potential, Rheum officinale presents promising opportunities for therapeutic product development, supporting the pharmaceutical industry.