## 3 Results and Discussion
### Composition of Seed lipophilic Extract  
In the next part of our research, we focused on lipophilic seed extract, which is still a little-explored \"piece of knowledge\". The yield of the non-polar extract of Canadian hemlock seeds was 35%. This is a high value compared to the yield of extracts obtained from the seeds of other conifer species and published by us earlier: _Abies alba_ had the highest total lipophilic extract content (41.1%), followed by the _A. cephalonica_ (32.0%), _Pica pungens_ (21.5%), _Abies concolor_ (19.8%), _Picea abies_ (16.8%), _Abies koreana_ (16.3%), and _Pica orientalis_ (9.8%) [10]. Our analysis of the _T. canadensis_ seed extract revealed a diverse composition of fatty acids, tocopherols, and phytosterols (Table 2). The most abundant fatty acid (FA) in the extract was linoleic acid (C18:2; 9; 12; n-6), constituting 0.408% \(w/w\) of the identified fatty acids, followed sciedonic (C20:3; 5,11,14; n-6; _cis_) at 0.541% \(w/w\), and oleic acid (C18:1; n-9) at 0.089% \(w/w\). These results are in agreement with our previous study focused on fatty acids (FAs) content in seeds of chosen conifers [10]. As was found in the literature, linoleic acid is almost always, except in a few cases, the most prominent of total fatty acids, ranging from 40 to 60%. The second habitual is oleic acid, which accounts for from 12 to 30% [19; 20]. In our study, the content of this acid is lower. Polyunsaturated fats play crucial roles in cellular functions and have been associated with antioxidant and anti-inflammatory activities [21]. The presence of these fatty acids in the plant extracts suggests the antioxidant potential of this plant. Interestingly, the fatty acid composition of the seeds of coniferous trees of the _Abies, Tsuga, Pseudotsuga, Larix, Picea, Pinus_, and _Cedrus_ species are rich in unusual unsaturated fatty acids with the first site of unsaturation at the fifth carbon atom (\(\Delta\)5-FAs) and _cis_ (Z) configuration, such as: _cis_-5,9-octadecadienoic (taxoleic), _cis_-5,9,12-octadecatrienoic (pinolenic), _cis_-5,11-octadecadienoic (ephedronic), _cis_-5,11-eicosadienoic (keteleeronic), _cis_-5,11,14-eicosatrienoic (sciadonic), _cis_-5,9,12,15-eicosatetraenoic (coniferonic), and _cis_-5,11,14,17-eicosatetraenoic (juniperonic) acids. The proportions of these acids have been documented in a few studies, based on the seeds of popular coniferous species [19; 20]. The highest level of total \(\Delta\)5-FAs was 30-31% of all FAs for _P. sylvestris_. Our GC-MS analysis of lipophilic seed extract from the _Tsuga canadensis_ allowed us to identify pinolenic and sciadonic acid from the \(\Delta\)5-FAs group (1.56 mg/g). The proportions of acids, including \(\Delta\)5 FAs, differ within species. They are probably a chemotaxonomic determinant. According to literature data, the acid composition of the _Tsuga_ species is more similar to Picea _Pinus_ than to _Abies_[19]. From our observations, the shape and size of _Tsuga_ seeds are also closer to sprues than to firs. Fatty acids constitute a large proportion of the lipophilic extract from _Tsuga canadensis_ seeds, with monounsaturated and polyunsaturated fatty acids being the dominant ones. In recent decades, intensive research has been conducted on the properties of unsaturated fatty acids and their action in the human body. Fatty acid micelles scavenged superoxide in an unsaturation-dependent manner, where long-chain polyunsaturated acids, especially those of n-3 series, have the strongest antioxidant properties [22; 23]. Tocopherols are common lipophilic antioxidants abundant in many plant oils and nuts, but their presence in Canadian hemlock seeds provides vitamin E activity and antioxidant potential as well. A study based on antioxidant potential was conducted on Norway spruce cones and eastern hemlock cones found that these cones possess high antioxidant properties [5]. The findings of this study align with the present study findings and further support the antioxidant potential of _T. canadensis_ seed extract.