Avaliação morfoanatômica, fitoquímica, atividade antioxidante e potencial prebiótico de Eriobotrya japonica (Thunb.) Lindl. visando investigar sua capacidade terapêutica no tratamento da dermatite atópica

Abstract

Eriobotrya japonica (Rosaceae) is a plant that, due to its secondary metabolites such as phenolics and flavonoids, may have therapeutic effects on diseases like atopic dermatitis (AD), which mainly involves dysbiosis of the cutaneous microbiome, alterations in the epidermal barrier, exacerbated inflammatory processes, and oxidative stress. Therefore, this study aimed to characterize morphoanatomically and histochemically the leaves and seeds of E. japonica, a genus with 35 species, and to extract phenolics and flavonoids using different solvents (ethyl acetate, acetone, and methanol) and methods (ultrasonic bath and maceration). The antioxidant (ABTS•+ and FRAP) and prebiotic potential (Staphylococcus epidermidis ATCC 12228) were also evaluated. The results were associated with qualitative analysis performed via highperformance liquid chromatography coupled to a diode array detector (HPLC-DAD). The leaves have pinnate venation, with a glabrescent surface on the adaxial side and a lanuginous surface on the abaxial side, and anomocytic stomata restricted to the abaxial side. Epidermal cells have straight anticlinal walls, and the mesophyll is dorsiventral. Cuticular striations perpendicular to the stomata may constitute diagnostic markers. Neutral lipophilic compoundswere observed in the cuticle, in addition to mucilage and phenolic compounds in the palisade parenchyma. The Lugol's solution test confirmed the presence of starch. The midrib is planoconvex, with lateral vascular bundles, and the petiole exhibits a similar vascular organization. The exalbuminous seeds vary from globose to oblong and contain phenolics, proteins, and starch, the latter being their main reserve compound. After quantifying the levels of total phenolics and flavonoids, the leaf sample obtained by maceration with acetone (FMacAcet) stood out, presenting a high content of phenolic compounds (175.086 ± 1.413 mg GAE.mL-1) mostly hydroxycinnamic phenolic acids, directly correlated to the total antioxidant capacity (TAC) of the extracts (IC50 = 0.008 mg.mL-1 ), which showed performance only 9.8 times lower than quercetin in the ABTS•+ assay. A similar result was observed in the FRAP (0.143 ± 0.029 µmol TE.g-1 ). It is suggested that the neutralization of free radicals is the main antioxidant mechanism of the species. Kinetic analysis of microbial growth demonstrated a high prebiotic potential of the FMacAcet sample against S. epidermidis, with results statistically similar to the positive controls (1% glucose and inulin) (p > 0.05). Furthermore, the flavonoids in the pulp showed bactericidal and bacteriostatic activity. Therefore, this information offers relevant support for the quality control of the species, especially if it is to be used in pharmaceutical formulations. In addition, the findings reinforce the potential of E. japonica as a source of bioactive phenolic compounds with antioxidant and prebiotic activity, making it a promising alternative for the management of dermatological conditions associated with cutaneous dysbiosis and oxidative stress, such as atopic dermatitis.