Chemical profile, antioxidant potential and toxicity of Smilax brasiliensis Sprengel (Smilacaceae) stems

Abstract

Smilax brasiliensis Sprengel is a monocotyledon of the Smilacaceae family, native to the Brazilian Cerrado, popularly known as "salsaparrilha" or "japecanga". In this study, the ethanol extract (EE) and the hexane (HEXF), dichloromethane (DCMF), ethyl acetate (ACF), and hydroethanol (HEF) fractions of the stems were obtained. The chemical composition was determined, the contents of phenolic compounds and flavonoids were quantified, and the antioxidant potential and the cytotoxic effect on Artemia salina were evaluated. Fatty acid esters, hydrocarbons, and phytosterols were identified in the HEXF analyzed by gas chromatography - mass spectrometry (GC-MS). The EE and DCMF, ACF, and HEF were analyzed by liquid chromatography coupled to a diode array detector and mass spectrometer (LC-DAD-MS), and the identified constituents included glycosylated (rutin, 3-O-β-galactopyranosyl quercetin, 3-O-β-glucopyranosyl quercetin, O-deoxyhexosyl-hexosyl quercetin, O-deoxyhexosyl-hexosyl kaempferol, O-deoxyhexosyl-hexosyl O-methyl quercetin, and others), and non-glycosylated (quercetin) flavonoids, phenylpropanoids (3-O-E-caffeoyl quinic acid, 5-O-E-caffeoyl quinic acid, O-caffeoyl shikimic acid, and others), neolignan, steroidal saponin (dioscin), and N-feruloyltyramine. The EE, DCMF, and ACF showed high total contents of phenolic compounds (112.99, 175.71, and 524.02 µg of GAE/mg, respectively), and in the ACF and DCMF a great content of flavonoids was also quantified (50.08 and 31.49 µg of QE/mg, respectively). The EE, DCMF, ACF, and HEF exhibited great antioxidant potential by DPPH (IC₅₀ 1.71 - 32.83 µg/mL) and FRAP (IC₅₀ 0.63 - 6,71 µg/mL) assays. A maximum cytotoxic activity on A. salina of 60% was observed for the DCMF (LC₅₀ = 856.17 µg/mL). This study contributes to the phytochemical study of S. brasiliensis since these compounds were identified for the first time in the stems of this species. The S. brasiliensis stems demonstrated to be a rich source of polyphenols compounds and exhibited high antioxidant potential without toxicity. Thus, extract and fractions obtained from the S. brasiliensis stems can be used in food supplements or as natural antioxidants in the food industry.

Keywords: Artemia salina; DPPH; FRAP; Flavonoids; Phenolic compounds; Salsaparrilha.