Centre for the Research and Technology of Agro-Environmental and Biological Sciences

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Antimicrobial, Antibiofilm, and Antioxidant Properties of Boletus edulis and Neoboletus luridiformis Against Multidrug-Resistant ESKAPE Pathogens

Publication . Garcia, Juliana; Rodrigues, Francisca; Castro, Flávia; Aires, Alfredo; Marques, Guilhermina; Saavedra, Maria José

Multidrug-resistant ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) has become the most recurrent global cause of skin and soft-tissue infections, belonging to the WHO priority pathogens list. Successful therapy remains challenging and entails the assessment of novel and successful antibiotics. In this study, mushrooms are considered a valuable and unique source of natural antimicrobial compounds. Therefore, this study aimed to evaluate the antimicrobial and antibiofilm properties of Boletus edulis (B. edulis) and Neoboletus luridiformis (N. luridiformis) aqueous and methanolic extracts against ESKAPE isolates from clinical wound infections. Disk diffusion and microdilution methods were used to assess the antimicrobial activity. Phytochemical characterization was achieved by analysis of total phenols, orthodiphenols content, and antioxidant activity as well as by high-performance liquid chromatography-diode array detector (HPLC-DAD). Human foreskin fibroblasts-1 (HFF-1) cell viability was performed by the MTT assay. Aqueous and methanolic extracts of B. edulis and N. luridiformis showed antimicrobial and antibiofilm properties against multidrug-resistant bacteria, although with different efficacy rates. The results showed that there is a convincing relation between the content of phenolic compounds, antioxidant activity, and antimicrobial activity suggesting that the presence of phenolic compounds may explain the biological effects. HPLC analysis revealed high levels of protocatechuic acid, homogentisic acid, pyrogallol, gallic acid, p-catechin, and dihydroxybenzoic acid in the aqueous extract of B. edulis, explaining the highest antimicrobial and antibiofilm properties. Importantly, the mushrooms extracts were non-cytotoxic at all the tested concentrations. Overall, the tested mushrooms extracts are good candidates to further explore its use in the prevention of wound infection, particularly by multidrug-resistant pathogens

2022-02-24Journal article

Open access

Bioactive polysaccharides from medicinal mushrooms: A review on their isolation, structural characteristics and antitumor activity

Publication . Garcia, Juliana; Rodrigues, Francisca; Saavedra, Maria José; Nunes, Fernando M.; Marques, Guilhermina

Mushrooms either alone or in combination with conventional cancer treatment have been enhanced the efficacy of chemotherapy and radiotherapy improving the patients' quality of life. These therapy effects have been attributed to polysaccharides; the most potent compounds found in the fungi kingdom. Due to their wide range of biological activity and the backbone of glucose residues linked by β-(1 → 3)-glycosidic bonds, often with attached side-chain glucose residues joined by β-(1 → 6) linkages, the mushroom's polysaccharides, particularly the β-glucans, are the most versatile metabolites. Lentinan, D-fraction, and schizophyllan from Lentinula edodes, Grifola frondosa, and Schizophyllum commune, respectively are well-known β-glucans, however, the precise immunomodulation and anticancer mechanisms of action remain to be uncovered. According to several studies, β-glucan can interact with certain receptors on macrophages and dendritic cells, such as dectin-1 and TLRs, producing different cytokines and, in turn, indirectly activating other immune cells including T and B cells. Moreover, recent findings have proved that β-glucans have a direct cytotoxic effect on cancer cells suppressing proliferation and enhancing apoptosis possibly via multiple pathways such as PI3K/Akt/mTOR, NF-κB-, ERK-, ERα-, caspase- and p53-dependent pathways. Indeed, this study intends to provide information on the lentinan, D-fraction, and schizophyllan by examining the extraction procedures, chemical composition, and immunostimulatory and antitumoral biological activities. Future research directions should be directed toward improving the validity and reliability of randomized trials to confirm the potential role of β-glucans on the immune system and as anticancer therapy.

2022Journal article

Restricted access