Picea abies and Larix decidua were subjected to GC/MS analyses, and antimicrobial (fungi and bacteria) assays of their stem wood and bark extracts were investigated. L. decidua bark extract exhibited the highest antifungal and antibacterial activities against the microorganisms that were screened. The microbes Penecillium ochrochloron and Aspergillus ochraceus were the most sensitive to the extracts, whereas Candida albicans was the most resistant fungus. L. decidua wood and bark did not exhibit much variation in their antibacterial activities, except against Micrococcus flavus and Pseudomonas aeruginosa. The bacterium most sensitive to the extracts was Escherichia coli, whereas the most resistant was M. flavus. 13-epimanool and α-cedrol were the main components of P. abies wood extract. The main components in its bark were abietic acid, astringin, dehydroabietic acid, and α-terpineol. The main chemical compounds in L. decidua wood extract were abietic acid, oleanolic acid, duvatrienediol, and larixol. The main chemical compounds in its bark were (-)-2,9-dihydroxyverrucosane and larixol. The study revealed that P. abies and L. decidua stem wood and bark extracts contain several compounds that have antimicrobial activities towards diverse human pathogenic, food, and agricultural microbes. These results might guide in future searches for novel natural products with chemotherapeutic uses. (El-Shatby), Alexandria University, Alexandria, Egypt; b: Molecular Biology Laboratory, Floriculture, Ornamental Horticulture and Garden Design Department, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria, Egypt; c: Department of Botany, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt; d: Department of Wood Processing, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic; e: Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; f: Department of Timber Trees Research, Sabahia Horticulture Research Station, Horticulture Research Institute, Agriculture Research Center, Alexandria, Egypt; g: Department of Environmental Sciences, University of South Africa, Florida campus, Florida 1710, South Africa; * Corresponding author: zidan_forest@yahoo.com; mohamed-salim@alexu.edu.eg
Keywords: Picea abies; Larix decidua; Antifungal activity; Antibacterial activity; GC/MS
Contact information: a: Department of Forestry and Wood Technology, Faculty of Agriculture
INTRODUCTIONForestry residues such as tree barks and branches are important but underexplored supplies of biologically or pharmaceutically active compounds (Liimatainen et al. 2012;Si et al. 2012;Patinha et al. 2013). Tree bark, for example, provides not only a physical protective barrier for plants, but also an important chemical defense mediated through the secondary compounds they produce (Horsfall 1980;Merrill 1992;Alfredsen et al. 2008). Numerous studies recently conducted on bark extracts focus on tropical tree spec...