Abstract
Lentinula edodes is an edible mushroom grown and marketed for centuries due to its nutritional and medicinal properties. Rich in protein, fiber, minerals and low in calories, Shiitake has mainly antimicrobial, antioxidant, anti-inflammatory, hypoglycemic and anticancer activities. Few studies have been done considering the influence of Shiitake growing conditions on biological activities. Our work focused on the comparison of the antioxidant and anti-inflammatory properties of Shiitake cultivated by different producers (from the French region Occitanie), i.e., A and C non-organic and B organic mushroom professionals, using an identical strain of Shiitake (Mycelia-3782). A sequential extraction under sonication (cyclohexane, chloroform, ethanol and water) was carried out on the fungal materials. The antioxidant capacity of the four extracts was evaluated using DPPH and ORAC. The anti-inflammatory activity of the ethanolic and aqueous extracts of all the producers was evaluated in vitro on a model of J774.A1 inflammatory macrophages. The results show that at 1 mg/ml, all the extracts have a quantifiable but moderate antioxidant activity with a more pronounced antioxidant potential in the aqueous extracts, whereas the polyphenol content assayed by the Folin Ciocalteu reagent was greater in cyclohexane extracts. At 50 μg/ml, the ethanolic extracts of the three producers strongly inhibit the production of the NO in a dose-dependent manner (29.66%, 31.30% and 27.56% for the producers A, B and C, respectively) when the cells are pre-treated for 4 hours with a LPS / IFNγ stimulation time of 24 hours without affecting cell viability. On the other hand, the inhibition observed for the aqueous extracts is very low. This activity was not due to a NO scavenging activity of the extracts. The results also showed that TNFα secreted in cell supernatants of macrophages pretreated with ethanolic extracts of Shiitake was inhibited in a concentration-dependent manner, in contrast to aqueous extracts which do not have an inhibitory effect on the molecule. This preliminary study shows that the growing conditions of Shiitake (organic and non-organic) do not influence its antioxidant and anti-inflammatory potentials in vitro.