## 5 Chemical Characterization  
Plants of the _Ailanthus_ genus are photochemically characterised by being rich in alkaloids, terpenoids, sterols, flavonoids, and other compounds. These compounds nowadays are widely studied since they are responsible for several pharmacological activities [12]. The bark of _A. altissima_ has always been used in traditional medicine and, nowadays, it is known for being very rich in several compounds. It contains oleoresin, resin, acryl alcohol, ailanthin, isoquercetin, tannins, ceryl palmitate, and saponins [7]. Two hundred and twenty-one compounds have been isolated and identified from the dry bark, such as alkaloids, quassinoids, phenylpropanoids, triterpenoids, and volatile oils. The main active compounds of dry bark are alkaloids (Figure 2), 32 of which have already been isolated. Quassinoids (Figure 3) are also one of the characteristic compounds of dry bark, with 40 isolated to date [22]. As reported by [PERSON] [12], the root bark essentially has alkaloids and terpenoids. Some ligands, coumarins, phenylpropanoids, and new terpenoids have also been identified and isolated [12; 23; 24; 25]. The leaves of this species are characterised by having some percentage of tannins, quercetin, isoquercetin, alkaloids, and mainly flavonoids. These were widely used in traditional Indian medicine to treat seborrhoea and scabies [7; 12]. Regarding the fruits of _A. altissima_, not much is known about its constituents, but they was widely used in China as a medicine for bleeding and as an antibacterial. On the other hand, in India it was used as an emmenagogue and to treat eye diseases [12; 26]. [PERSON] et al. [27] mentioned that previous studies have shown that only four quasi-noid glycosides and several stigmasterols (Figure 4) [28] were identified from fruits. However, they elucidated the structure and isolated four new compounds: two phenylpropinamides, piperidine, and a phenolic derivative. In addition to these new compounds, 13 phenols, 10 flavonoids, and a phenylpropinamide were also isolated. According to [PERSON] and [PERSON] [29], the composition of _A. glandulosa_ (syn. of _A. altissima_) extraloral nectar diverge according to the nectery type. These authors also declared that the three essential nectars' sugars are sucrose, fructose, and glucose in the leaf nectaries. It is the high amount of fructose that characterizes this species. Furthermore, bound lipids (monogalactosyldiaz-cylglycerol) and oleic, palmitic, and linoleic acids have been isolated in the secretion of glandular trichomes in cataphylls and in young stems [7; 29]. Figure 2: Some examples of alkaloids identified in _A. altissima_: (**a**) Canthin-6-one; (**b**) 1-Hydroxyanthin-6-one; (**c**) 1-Methoxyanthin-6-one; (**d**) 4-methoxy-1-vinyl-\(\beta\)-carboline; (**e**) \(\beta\)-carboline-1-propionic acid; (**f**) 1-Acetyl-4-methoxy-\(\beta\)-carboline. The quassinoids class has been the main target of many studies due to their bioactivities and phytotoxic impacts. The most widely studied active compound in this group of terpenoids is ailanthone. This has been identified as an effective phytotoxic agent, capable of being used as a herbicide [7; 30]. In addition to ailanthone, other derivatives have been isolated and studied (such as ailanthione, ailanthinol B, and chaparrin). There is  
Figure 4: Some examples of steroids identified in _A. altissima_: (**a**) 5\(\alpha\)-Stigmastane-3,6-dione; (**b**) Stigmast-5-ene-3,7\(\alpha\)-diol; (**c**) Stigmast-4-ene-3,6-dione. Figure 3: Some examples of the main _A. altissima_ quassinoids identified: (**a**) Ailanthone; (**b**) Ailantinol A; (**c**) Chaparrinone; (**d**) Chaparrin; (**e**) Shinjudilactone; (**f**) Shinjulactone A.  
an increasing demand for the isolation of new quasasinoid derivatives to investigate their potential applications, mainly in pharmacology [31; 32; 33]. Table 1 summarises the main compounds by classes of compounds and which parts of the plants were used to identify the chemical compounds.