Fungal chitosan is a polymer that has been discussed and studied since 1859 in the world with great advances occurring over the years. Due to its global importance, this review aims to expose the history of the production and application of fungal chitosan in Brazil. Data collection was done at the Scielo, Sciencedirect and Pubmed databases, considering the period of the last 50 years. The inclusion criteria were articles on pure or associated chitosan and, in particular, fungal chitosan produced or applied by Brazilian research groups. At the end of the review, it was noticed a fungal chitosan very studied in different continents, and in Brazil is still used in specific and small groups. With the present work, it is expected that the diffusion of the studies will be accelerated and that potential research groups for fungal chitosan may grow through interaction with the existing ones.

A 12.4 kDa laminarin (LM) composed of β(1→3)-glucan with β(1→6)-branches was extracted from brown seaweed Lobophora variegata and modified via carboxylation using dielectric barrier discharge (LMC), conjugation with gallic acid (LMG), and sulfation (LMS). Analyses of the chemical composition of LMC, LMG, and LMS yielded 11.7% carboxyl groups, 1.5% gallic acid, and 1.4% sulfate content, respectively. Antioxidant activities of native and modified laminarins were assessed using six different in vitro methods. Sulfation stopped the antioxidant activities of LM. On the other hand, carboxylation improved cooper chelation (1.2 times). LMG was found to be a more efficient antioxidant agent than LM in terms of copper chelation (1.3 times), reducing power (1.3 times), and total antioxidant capacity (80 times). Gallic acid conjugation was further confirmed using Fourier transform infrared spectroscopy (FT-IR) and one- and two-dimensional NMR spectroscopy analyses. LMG also did not induce cell death or affect the cell cycle of Madin–Darby canine kidney (MDCK) cells. On the contrary, LMG protected MDCK cells from H2O2-induced oxidative damage. Taken together, these results show that LMG has the potent antioxidant capacity, and, therefore, potential applications in pharmacological and functional food products.

RESUMO:O uso indiscriminado de antibióticos no tratamento de mastite ocasiona a seleção da microbiota resistente, dificultando o tratamento da doença. Esse trabalho teve como objetivo, testar a atividade antimicrobiana do extrato hidroalcoólico da casca de Jucá (Libidibia ferrea (Mart. ex Tul.) L. P. Queiroz) em diferentes concentrações contra micro-organismos causadores de mastite em caprinos. Foram isoladas 18 estirpes bacterianas de cabras com mastite crescidas em meio ágar sangue as quais foram transferidas para caldo BHI e após o crescimento, foi feito o teste antimicrobiano pela técnica de difusão em discos, usando os seguintes antibióticos: Ampicilina, Cefalexina, Gentamicina, Penicilina G e Oxacilina. Foram testadas também três concentrações de extrato hidroalcoólico de L. ferrea (extrato bruto, extrato 70% (v/v) e extrato 50% (v/v)). Os microorganismos isolados apresentaram alta resistência a ampicilina, penicilina G e oxacilina, apresentando resistência de 88, 83 e 77%, respectivamente. O extrato bruto apresentou uma eficiência de 61,1% na inibição dos micro-organismos em teste. O extrato hidroalcoólico bruto da casca de L. ferrea tem potencial como antimicrobiano natural contra micro-organismos causadores de mastite caprina. Palavras-chave antibióticos; leite caprino; sensibilidade ABSTRACT: Dairy goat production is of great importance for the economy of the Northeast. Inadequate handling of goats causes a number of diseases that affect the production, among them, mastitis, an inflammation of the mammary glands, caused by a broad spectrum of microorganisms. The indiscriminate use of antibiotics in the treatment of mastitis causes the process of microbial resistance, which makes treating the disease. This study aims to test the antimicrobial activity of hydroalcoholic extract of the bark of Juca (Libidibia ferrea (Mart. ex Tul.) L.P.Queiroz) against microorganisms causing mastitis in goats. We isolated 18 bacterial strains grown on blood agar medium were transferred to BHI and after growth, antimicrobial testing was done by disc diffusion technique, using the following antibiotics: ampicillin, cephalexin, gentamicin, penicillin G and oxacillin. Three concentrations were tested extract of L. Ferrea (crude extract, extract 70% and extract 50%). The results show that micro-organisms has high resistance to ampicillin, penicillin G, oxacillin, with resistor 88, 83 and 77% respectively. The crude extract showed an efficiency of 61.1% in the inhibition of microorganisms. The results showed that the hydroalcoholic extract of the bark of L ferrea iron as natural antimicrobial is effective against microorganisms causing mastitis goats.

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Oxidative stress is the cause of numerous diseases in humans; therefore, there has been a continuous search for novel antioxidant molecules. Fungal chitosan is an attractive molecule that has several applications (antifungal, antibacterial, anticancer and antiparasitic action) owing to its unique characteristics; however, it exhibits low antioxidant activity. The aim of this study was to obtain fungal chitosan (Chit-F) from the fungus Rhizopus arrhizus and synthesize its derivative, fungal chitosan-gallic acid (Chit-FGal), as a novel antioxidant chitosan derivative for biomedical use. A low molecular weight Chi-F (~3.0 kDa) with a degree of deacetylation of 86% was obtained from this fungus. Chit-FGal (3.0 kDa) was synthesized by an efficient free radical-mediated method using hydrogen peroxide (H2O2) and ascorbic acid. Both Chit-F and Chit-FGal showed similar copper chelating activities; however, Chit-FGal was more efficient as an antioxidant, exhibiting twice the total antioxidant capacity than Chi-F (p < 0.05). Furthermore, H2O2 (0.06 M) promoted a 50% decrease in the viabilities of the 3T3 fibroblast cells. However, this effect was abolished in the presence of Chit-FGal (0.05–0.25 mg/mL), indicating that Chit-FGal protected the cells from oxidative damage. These results suggest that Chit-FGal may be a promising agent to combat oxidative stress.

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To investigate the simultaneous influence of different non-nutritional factors in production and physical-chemical characteristics of chitosan obtained by Syncephalastrum racemosum we used individually agroindustrial wastes as the only nutritional sources for fungus growth. The growth conditions were evaluated according to Factorial Design, 2 4 with three central points in order to determine the mainly factors for maximum production of microbiological chitosan in submerged culture. Syncephalastrum racemosum grown in corn steep liquor and yield up to 7.8 g chitosan/kg of substrate in the best condition by factorial design. The microbiological chitosan obtained has deacetilation degree 88.14%, crystallinity rate of 55.96%, mass decomposition process at 304.43 ºC, and low molecular weight. To fast production we performed a kinetic study and confirmed that at 36 h the chitosan production is higher and the physical-chemical characteristics were maintained. This research describes, for the first time, the factorial study of chitosan production by Syncephalastrum racemosum in agroindustrial wastes and its economic potential for commercialization.

Animal chitosan (Chit-A) is gaining more acceptance in daily activities. It is used in a range of products from food supplements for weight loss to even raw materials for producing nanoparticles and hydrogel drug carriers; however, it has low antioxidant activity. Fungal oligochitosan (OChit-F) was identified as a potential substitute for Chit-A. Cunninghamella elegans is a fungus found in the Brazilian savanna (Caatinga) that produces OligoChit-F, which is a relatively poorly studied compound. In this study, 4 kDa OChit-F with a 76% deacetylation degree was extracted from C. elegans. OChit-F showed antioxidant activity similar to that of Chit-A in only one in vitro test (copper chelation) but exhibited higher activity than that of Chit-A in three other tests (reducing power, hydroxyl radical scavenging, and iron chelation). These results indicate that OChit-F is a better antioxidant than Chit-A. In addition, Chit-A significantly increased the formation of calcium oxalate crystals in vitro, particularly those of the monohydrate (COM) type; however, OChit-F had no effect on this process in vitro. In summary, OChit-F had higher antioxidant activity than Chit-A and did not induce the formation of CaOx crystals. Thus, OChit-F can be used as a Chit-A substitute in applications affected by oxidative stress.