On damage of conifer trees, oleoresin is exuded onto the tree stem. The oleoresin is typically composed of monoterpenes and resin acids. It serves to protect the tree from dehydration and microbial attack. Callus resin, in the traditional German term “Überwallungsharz”, is a resin exuded from the callus tissue formed as the wound is closed by annual growth. These resins can usually be found as nodules or lumps on the rim of the closing wound. Both types of resin, collected from Picea abies, Pinus sylvestris, Larix decidua and Pseudotsuga menziesii, were analyzed separately by GC/GC-MS. Expectedly, the oleoresin samples were composed of resin acids. However, the callus resins were of a completely different composition as they are composed primarily of lignans and hydroxycinnamic acid derivatives. In addition, the L. decidua sample contained significant amounts of abietol and abietadiene. The P. abies and L. decidua callus resins were found to be essentially resin acid-free. The components identified in the callus resin samples have previously been identified as minor components in oleoresin and bark samples. The potential for the inadvertent inclusion of callus resin in previously analyzed samples of oleoresin, bark and ingrown (dead) knots is highlighted.

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Aims: The aim of this study was to examine the antimicrobial properties of novel aqueous natural rapeseed oil/saline emulsions containing different soluble components of spruce resin. Methods and Results: The composition of aqueous resin emulsions was analysed by GC-MS and their antimicrobial properties were studied with challenge tests and with turbidometric assays. The emulsions were strongly antimicrobial against common Gram-positive and Gram-negative bacteria (including MRSA) as well as common yeasts. Furthermore, they inhibited the biofilm formation and eradicated the microbial biofilms on tested microbes. Characteristic for the emulsions was the presence of oxidized resin acids. Other main components present in emulsions, such as lignans and coumaric acids, were not antimicrobial, when tested separately. Conclusions:The results indicated that the oxidized resin acids were the antimicrobial components in the emulsions. Also, there appears to be a stoichiometric relationship between the number of resin acid molecules and the number microbe cells in the antimicrobial action. Significance and Impact of the Study: The fact that these solutions do not contain abietic acid, which is the main allergenic compound in resins, suggests that these solutions would be suitable, well-tolerated antimicrobials for various medical applications. The aqueous formulation will also allow the expansion of the use of these emulsions in from medical applications to the food preservatives and disinfectants. IntroductionCreams or salves based on natural resins collected from trunks ("callus" resin) of Norway spruce (Picea abies), have been used as home-made remedies for skin wounds and infections for hundreds of years (Cowan 1999;Kalemba and Kunicka 2003;Mahady 2005;Rautio et al. 2007;Sipponen 2013). The water-insoluble main resin acids (e.g. abietic acids or dehydroabietic acid) in coniferous resins have been shown to be antimicrobial and antifungal in several previous studies (S€ oderberg et al. 1990;Savluchinske Feio et al. 1999;Rautio et al. 2007Rautio et al. , 2012Sipponen and Laitinen 2011). However, the poor solubility in water limits their applicability as microbicidal agents, or as modern liquid antiseptics (Peng and Roberts 2000;Keeling and Bohlmann 2006).A novel method to disperse the partially soluble components of natural coniferous resins into water makes the manufacturing of aqueous resin emulsions possible. However, this might lead to the loss antimicrobial properties due to the exclusion of resin acids. In this study, we examined the retained antimicrobial activities of two 136

Biocompatible aqueous solutions of ILs rich in 7-hydroxymatairesinol (HMR) can be safely used in cosmetic and nutraceutical applications.