Evaluación de la actividad antioxidante y antiinflamatoria del extracto de Desmodium molliculum

Abstract

Desmodium molliculum, in Ecuador, “Hierba del infante”, is an Andean plant traditionally used to treat inflammatory processes. This study was established to investigate the antioxidant activity of its extrats using the in vitro techniques: Folin-Ciocalteu, ABTS, DPPH and FRAP, the anti-inflammatory activity in vivo using the croton oil-induced ear edema assay and the granuloma induced by cotton pellet assay, the toxicity in the Artemia salina model and molecular characterization of D. molliculum and D. adscendens with the barcodes: trnH-psbA, rbcL, matK, ITS1 and ITS2. There was no significant difference (p < 0.05) between the polyphenol content of the crude extract of D. molliculum (DMC) and the defatted extract (DMD) (30.1 ± 1.1 mg AG/g dry plant). Both extracts contained caffeic acid according to the TLC. DMD showed the highest antioxidant activity in the ABTS (1.16 ± 0.001 mg TE/mg) and FRAP (0.39 ± 0.01 mg TE/mg) assays and D. adscendens showed the lower activity. Of all the extracts, DMD (250 mg/kg) had the highest percentage of inhibition (34.5 ± 6.3%) in the ear edema assay, and repeated administration (6 days) of the same inhibited 35.43 ± 6.9% of inflammation by cotton pellet, and was not different (p < 0.05) from dexamethasone (36.77 ± 5.9%). DMD was shown to be nontoxic (LC50= 5980.39 µg/mL) in the Artemia salina model. The defatted extract had the highest antioxidant and anti-inflammatory activity among the extracts tested, possibly because it had a less complex matrix that facilitated polyphenols activity and had a greater impact on the subchronic model of inflammation, probably due to the periodicity of the test. Caffeic acid may have contributed to the activity of the extract. Finally, molecular analysis confirmed that the species analyzed were different. The trnH-psbA, matK and ITS1 markers were the most apt to discriminate at the species level between the accessions used considering the bootstrap value.