Abstract

Salvadora persica and Juglans regia L. are traditionally used for the treatment of oral infections. The anticandidal; antibacterial and antioxidant activities of diluted acetone extract of S. persica (dry stems) and ethyl acetate extract of Tunisian Juglans regia L. bark were tested. The chemical composition of the volatile oil of the stems of S. persica was also investigated. The essential oil of S. persica stems was rich on benzyl isothiocyanate (52.5%) and benzyl nitrile (38.3%). Comparatively to the diluted acetone extract of S. persica, ethyl acetate extract of walnut’s bark was more effective against Gram positive and Gram negative bacteria and the different species of Candida tested in the present work. Similarly, the walnut extract was rich on phenols (34.833 mg GAE.g^-1 DW) and tannins (16.167 mg EC.g^-1 DW) comparatively to the arak extract (0.443 mg GAE.g^-1DW and 0.39 mg EC.g^-1 DW, respectively). The walnut extract displayed the highest DPPH scavenging ability with the lowest IC₅₀ value (IC₅₀, 3 µg/ml), a high capacity to quench superoxide (IC₅₀: 70 mg.ml^-1), the greater reducing power and bleaching of β-carotene (EC₅₀, 99 mg.ml^-1 and IC₅₀, 280 µg.ml^-1, respectively) as compared to S. persica extract. These findings support the interest of S. persica and especially walnut bark and their possible use in the developing countries due to their inexpensive cost in order to maintain oral hygiene and as a source of new antioxidant compounds.

Key words: Salvadora persica, Juglans regia L., antibacterial activity, antioxidant activities.