Author(s):
Malmir, Maryam ; Lima, Katelene ; Camões, Sérgio Póvoas ; Manageiro, Vera ; Duarte, Maria Paula ; Miranda, Joana Paiva ; Serrano, Rita ; da Silva, Isabel Moreira ; Lima, Beatriz Silva ; Caniça, Manuela ; Silva, Olga
Date: 2023
Persistent ID: http://hdl.handle.net/10362/158329
Origin: Repositório Institucional da UNL
Subject(s): anthracene derivatives; antimicrobial activity; Asphodelus bento-rainhae; Asphodelus macrocarpus; root tubers; toxicity; Molecular Medicine; Pharmaceutical Science; Drug Discovery
Description
Funding Information: This research was funded by the Foundation for Science and Technology/MCTES (FCT, Portugal) through national funds to iMed.ULisboa (UIDP/04138/2020, UIDB/04138/2020), to CECA (UIDB/00211/2020) and to MEtRICs (UIDP/04077/2020, UIDB/04077/2020) research projects, as well as a doctoral scholarship (SFRH/BD/125310/2016) granted to the first author. Publisher Copyright: © 2023 by the authors.
Root tubers of Asphodelus bento-rainhae subsp. bento-rainhae (AbR), a vulnerable endemic species, and Asphodelus macrocarpus subsp. macrocarpus (AmR) have traditionally been used in Portugal to treat inflammatory and infectious skin disorders. The present study aims to evaluate the in vitro antimicrobial activity of crude 70% and 96% hydroethanolic extracts of both medicinal plants, specifically against multidrug-resistant skin-related pathogens, to identify the involved marker secondary metabolites and also to assess the pre-clinical toxicity of these medicinal plant extracts. Bioguided fractionation of the 70% hydroethanolic extracts of both species using solvents of increasing polarity, namely diethyl ether (DEE: AbR-1, AmR-1), ethyl acetate (AbR-2, AmR-2) and aqueous (AbR-3, AmR-3) fractions, enabled the identification of the DEE fractions as the most active against all the tested Gram-positive microorganisms (MIC: 16 to 1000 µg/mL). Furthermore, phytochemical analyses using TLC and LC-UV/DAD-ESI/MS techniques revealed the presence of anthracene derivatives as the main constituents of DEE fractions, and five known compounds, namely 7′-(chrysophanol-4-yl)-chrysophanol-10’-C-beta-D-xylopyranosyl-anthrone (p), 10,7′-bichrysophanol (q), chrysophanol (r), 10-(chrysophanol-7′-yl)-10-hydroxychrysophanol-9-anthrone (s) and asphodelin (t), were identified as the main marker compounds. All these compounds showed high antimicrobial activity, particularly against Staphylococcus epidermidis (MIC: 3.2 to 100 µg/mL). Importantly, no cytotoxicity against HepG2 and HaCaT cells (up to 125 µg/mL) for crude extracts of both species and genotoxicity (up to 5000 µg/mL, with and without metabolic activation) for AbR 96% hydroethanolic extract was detected using the MTT and Ames tests, respectively. Overall, the obtained results contribute to the concrete validation of the use of these medicinal plants as potential sources of antimicrobial agents in the treatment of skin diseases.
