ANTIMICROBIAL AND ANTIOXIDANT ACTIVITIES OF JUGLANS AUSTRALIS WALNUT SHELL EXTRACT

ORCE INGRID; GABRIELA FURQUE; LENCINA SIBILA; LORENZO EMILIA; ALBERTO MARIA ROSA; GOMEZ PATRICIA; ARENA MARIO

Jornada; XXXIX JORNADAS CIENTÍFICAS; 2022

In Argentina occurs a native walnut, Juglans australis. The bioactive molecules were investigated in the commercial walnut J. regia, and no research has been reported on native walnut. This work analyzed the antimicrobial and antioxidant properties of native walnuts shells extracts compared to their commercial counterpart. Samples of shell walnuts were collected in Ancasti, Catamarca. The shells were cleaned and ground into small particles. Solvent extraction was performed using methanol, hexane, and ethyl acetate. The total phenolic content (TPC) and the extracts´ antioxidant activity were analyzed using the DPPH and FRAP tests to measure the antiradical and reducing power, respectively. In addition, the antibacterial activity was evaluated against Gram-positive and Gram-negative phytopathogenic bacteria (Erwinia amylovora and Clavibacter sp.), and the minimum inhibitory concentration (MIC) was carried out using the broth microdilution method. The best performance in phenolic content and the higher reducer activity were observed in the methanolic extract of J. australis with 121 mg of gallic acid equivalent (GAE) g-1 dry shell and 58.6mmol Trolox 100 g-1 dry shell, respectively. However, the best antiradical activity was observed in the methanolic extract of J. regia (11.5 mM Trolox 100 g-1 dry shell). The MIC was 10 mg mL-1 for both specie for methanolic and ethyl acetate extracts and were able to inhibit the growth of Gram-positive and negative phytopathogen. The observed results denote a difference in the profile of the phenolic compounds between both species, which can be analyzed with specific analytical techniques.