## 2 Nature and Characteristics of _A. altissima_
### Ailanthus altissima Biomass Chemical Analysis  
_A. altissima_ leaves and bark have been found to contain various extractives, mainly essential oils, that have antimicrobial and antioxidant properties. These extractives contain various chemical compounds, including sesquiterpenes, monoterpenes, and phenols, several alkaloids, including quassin, ailanthone, and ailitone [30]. These alkaloids have been found to have insecticidal and antifungal properties [31]. Especially the bark contains a variety of bioactive compounds, including alkaloids, flavonoids, and terpenoids, which may contribute to its medicinal properties. The pharmacological properties of _A. altissima_ bark, including its anti-inflammatory, analgesic, antioxidant, antimicrobial, and anticancer effects, have also been highlighted [32]. [PERSON] et al. [33] reported that the stem bark of _Ailanthus excelsa_ Roxb is rich in phenolic compounds, known for their antioxidant and anti-inflammatory properties, and may have potential as a source of natural antioxidants and as a natural preservative in food and cosmetic industries. Extracts from leaves have even greater phenolic content than the other parts of this species tree, and a positive linear correlation between antioxidant activity and total phenolic content of all the extracts has been reported [34]. Further studies are necessary to evaluate the safety and efficacy of using this species in food and cosmetic products. Ailanthone, which constitutes an extractive of this species, can be utilized for the production of various unique and valuable products (pharmacicus, herbicides, insecticides, and ecological products). Its leaves have been found to contain various flavonoids, including kaempfer and quercetin. These flavonoids have antioxidant and anti-inflammatory properties. _A. altissima_ bark has been found to contain tannins, which have astringent properties, and coumarins that demonstrate anticoagulant properties and are employed in the treatment of various medical cases [32]. [PERSON] et al. [35] described that the main extracts for analyzing the biological activities of _A. altissima_ are essentially obtained from the leaves, seeds (e.g., essential oil), and bark. However, extracts from other plant parts, such as flowers and stems, have been rarely investigated. [PERSON] et al. [36] investigated the biosynthesis pathway of the bioactive compounds of quassinoids in the invasive tree-of-heaven and confirmed their evolutionary origin from protolimonoids. This study contributed to the development of potential applications in the pharmaceutical and agricultural industries. Transcriptome sequencing and gene expression analysis were employed to identify the genes involved in the biosynthesis of quassinoids in this species. Thirty genes involved in the biosynthesis of quassinoids were identified, including several genes that are responsible for the formation of protolimonoids, which are the precursors to quassinoids. These findings could potentially lead to the production of new bioactive compounds with diverse biological activities, with applications in the pharmaceutical and agricultural industries, although further research is needed to explore these possibilities. [PERSON] [37], analyzing _Ailanthus_ species from the Caucasus region, reported 46% cellulose, 14% lignin content, and 0.9% ash content. [PERSON] [38] reported 26.6% hemicellulose content, 46.7% cellulose, 26.2% lignin, and 0.5% ash content. [PERSON] and [PERSON] [39] identified that in the wood trunk of this species, the cellulose content was 47.18%, which is suitable for pulp production, lignin 25.19%, extracts, 3.5%, and ash 1.25%, while in the branch wood, the percentages of cellulose were 44.12%, lignin 23.86%, extracts 3.2%, and ash 1.75%. Lignin was higher in the trunk compared to the branch by 5.3%. Furthermore, [PERSON] et al. [40] found the lignin content in the trunk to be 25.19%, while [PERSON] et al. [41] found 23.33%, respectively. A difference in the amount of extract content was recorded between the stem and branch by 8.6% [41].