Knotwood and Branchwood Polyphenolic Extractives of Silver Fir, Spruce and Douglas Fir and Their Antioxidant, Antifungal and Antibacterial Properties

Abstract

The extractive contents of three softwood species largely used in the wood industry, namely Abies alba (Silver fir), Picea abies (spruce) and Pseudotsuga menziesii (Douglas fir), have been determined quantitatively for knots and at different points chosen along their branches, before analysis using high-performance liquid chromatography coupled with Mass Spectrometry (HPLC-MS). The results indicated that branchwood samples located in close proximity to the stem present high contents of extractives similar to those recorded for the knots. HPLC analysis showed quite similar chemical compositions, indicating that first cm of the branches could be considered as an additional source of knotwood. The antibacterial, antifungal and antioxidant activities of knot’s extractives have been investigated with the dual objective of better understanding the role of high levels of secondary metabolites present in the knot and evaluating their potential for biorefinery applications. The antioxidant activity study showed that crude extracts of Douglas fir knotwood presented higher radical scavenging activity levels than the extracts of Silver fir and spruce, which presented more or less the same activities. Silver fir and spruce knotwood extracts presented higher antibacterial activity levels than the Douglas fir knotwood extracts did, while Douglas fir knotwood extracts presented more fungal growth inhibition than the spruce and fir knotwood extracts did. The structure–activity relationships indicate that radical scavenging and antifungal activities are associated with a higher relative quantity of flavonoids in the crude extracts, while higher relative quantities of lignans are associated with antibacterial activity.

Phytochemical Characterization, Antioxidant, and Antimicrobial Activity of the Vegetative Buds from Romanian Spruce, Picea abies (L.) H. Karst.

“…A single method of analysis, however, may not provide a comprehensive understanding of the antioxidant activity of the extract we studied. For a more precise approach, it is necessary to use other assays in the future to capture the full spectrum of antioxidant activity [10,11,14,63].…”

“…Spruce is traditionally used for its anti-inflammatory and antiseptic action, in respiratory and skin diseases as different pharmaceutical preparations: syrup, tea, creams, ointments, and baths [4]. Recent clinical studies have shown antibacterial and antifungal properties [11,12], wound healing [13], immunological, anti-inflammatory and antioxidant effects [14][15][16] and even antitumoral action [17][18][19] for the spruce, due to its bioactive compounds.…”

Phytochemical Study, FTIR and GC-MS Characterization and Evaluation of the Antioxidant Activity of Letestua durissima Extracts

“…Phytochemical screening highlighted the presence of several families of extractives such as flavonoids, tannins and polyphenols, which are reported in the literature to possess strong antioxidant properties [38,39,47,48]. In addition, GC-MS analysis indicated different phenolic compounds such as catechin, 3,4-dihydroxybenzaldehyde, 4-hydroxybenzoic acid, isovanillic acid or protocatechuic acid, which may be also responsible for antioxidant activity.…”

“…Polyphenols such as lignans have antifungal and antioxidant properties. They are studied for pharmaceutical and nutraceutical applications [38,39]. Saponins have many applications in the food and cosmetic industry due to their foaming properties.…”