Bioactivities of Wood Polyphenols: Antioxidants and Biological Effects

Abstract: Date palm, oak, quibracho, banana, and pine wood contain polyphenolic compounds that could be used in the development of natural antioxidants. This study examined the phenolic compounds of old date palm (OPW), seedling date palm (SPW), oak (OW), Quibracho (QW), Banana (BW), and Pine (PW) for their chemical structures using matrix-assisted laser desorption/ionization time-of-flight (MALDI- TOF-TOF-MS/MS) mass spectrometry. The analyses of the results showed that OPW, SPW, OW, QW are rich in phenolic acids and lignin. The phenolic acids and lignin in SPW, OPW, and OW showed higher antioxidant activity compared to QW, BW, and PW. The antioxidant activity of wood extracts was studied using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging. The antioxidant activity and phenolic content of SPW wood extract showed that it was superior to other woods tested. In addition, the antioxidant capacity of soluble (SP) and insoluble-bound (IBP) phenolics of extracted woods was examined as well as their inhibitory activity against oxidation of LDL cholesterol and DNA strand breakage. The SPW exhibited much higher antioxidant potential and inhibitory activities against oxidation of LDL cholesterol and DNA strand breakage compared to other tested woods. In another study date palm and maple wood (commercial standard) were used to generate smoke. Prominent smoke volatile compounds released during the process were adsorbed using solid-phase microextraction (SPME) followed by identification by gas chromatography–mass spectrometry (GC–MS). Regardless of the wood type, volatile compounds were mainly methoxyphenols, with the highest contribution of eugenol followed by guaiacol and their corresponding derivatives. Salmon portions were subjected to smoke generated from both date palm and maple wood standard. The oxidative stability of smoked salmon was evaluated in terms of development of thiobarbituric acid reactive substances (TBARS). The results so obtained indicated that palm date wood could compete well with maple wood for effective smoke generation with desired characteristics. The presentation will provide an account of the results obtained and their discussion.

This seminar is presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy