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

Abstract

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. <i>Rheum officinale</i>, 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 <i>Rheum officinale</i> 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 <i>P</i>. <i>aeruginosa, S</i>. <i>aureus, E</i>. <i>coli, E. faecalis, and C</i>. <i>albicans</i> was confirmed <i>via</i> 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, <i>Rheum officinale</i> presents promising opportunities for therapeutic product development, supporting the pharmaceutical industry.