Análisis por HPLC y capacidad antioxidante in vitro del extracto acuoso de Desmodium molliculum (Kunth) DC de Ayacucho

Background Desmodium molliculum is an Andean medicinal plant traditionally used for various ailments, whose chemical composition and antioxidant activity require investigation. To determine the phytochemical profile using high-performance liquid chromatography with diode array detection (HPLC-DAD) and to evaluate the antioxidant activity of the aqueous extract of D. molliculum from Ayacucho, Peru. Methods Plant material was collected in Pansa, Ayacucho (2,524 m above sea level). The aqueous extract was obtained by decoction and concentration. Phytochemical characterization was performed by HPLC-DAD using a C18 column; antioxidant activity was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay (25–500 μg/mL), using Trolox as a reference standard, and was complemented with the ferric reducing antioxidant power (FRAP) assay. Results HPLC-DAD analysis identified nine phenolic compounds (107.8 ± 3.7 mg/g of extract), with rutin (24.7 mg/g) and chlorogenic acid (18.6 mg/g) as the predominant constituents. Flavonoids accounted for 61.8% of the total quantified compounds. Antioxidant activity showed IC₅₀ values of 98.45 μg/mL (ABTS) and 125.60 μg/mL (DPPH), with excellent dose–response correlation (r 2 > 0.99) and results consistent when compared with the Trolox standard. The FRAP assay confirmed a high reducing capacity. A significant correlation was observed between phenolic compounds and antioxidant activity (r = 0.967; 95% CI: 0.934–0.985; p < 0.001). Principal component analysis explained 87.3% of the total variance, identifying two distinct chemical groups. Conclusions D. molliculum exhibits a phytochemical profile rich in glycosylated flavonoids and phenolic acids with strong antioxidant activity.