# State-of-the-Art and Opportunities for Bioactive Pentacyclic Triterpenes from Native Mexican Plants
## 2 Pentacyclic Triterpenes from Mexican Plants
### Biological Activity Survey of PCTs Found in Mexican Plants
Compound **(25)** led to a mean reduction of 25.9 \(\pm\) 6.1%. In a comparable way, in alloxan-induced hyperglymic mice, the highest decrement in glucose levels was shown after 3 and 4.5 h of administration [38]. The genus Bursera is composed of trees and shrubs and 80 species are distributed widely in Mexico [39]. The resin of _Bursera copallifera_, known as \"copal\", yielded six PCTs. Anti-inflammatory in vivo tests were carried out in mice through the induction of edema by applying phorol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) at a dose of 1, 0.75, 0.50, 0.25, and 0.125 mg/ear, using indomethacin as a positive control at the same doses, and acetone as a negative control [39]. At a dose of 1 mg/ear, the highest inhibition effect was observed with \(\alpha\)-amyrin acetate **(26)** (69.45 \(\pm\) 1.8%), followed by 3-epiluppel **(27)** (66.39 \(\pm\) 4.38%), 3-epilupel formiate **(28)** (62.16 \(\pm\) 1.8%), lupenone **(8)** (57.25 \(\pm\) 1.36%), 3-epilupel acetate **(29)** (49.35 \(\pm\) 3.6%), and, lastly, \(\alpha\)-amyrin **(16)** (25 \(\pm\) 1.81%). The previously mentioned compounds had an ID\({}_{50}\) of 1.17, 0.83, 0.96, 1.052, >2.13, and >2.34 mmol/ear, respectively. Additionally, the authors measured the effect of the compounds on nitric oxide (NO) production in macrophages (RAW 264.7 cell line). For this purpose, the macrophages were cultured with the tested compounds at 4.37, 8.75, 17.5, 35, and 70 mM, and dimethyl sulfoxide (DMSO) at 0.5% _v/v_ or indomethacin at 30 ug/mL were used as the negative and positive controls, respectively. Lipopolysaccharides (LPSs) (10 ug/mL) were added to the macrophages in the presence or absence of the mentioned compounds to incubate the cells and stimulate NO production. Among all the tested compounds, **(28)** had the greatest NO IC\({}_{50}\) (43.31 \(\pm\) 2.60 mM), followed by **(29)** (31.13 \(\pm\) 1.25 mM), (26) (22.47 \(\pm\) 1.19 mM), **(8)** (20.8 \(\pm\) 1.07 mM), **(27)** (15.50 \(\pm\) 1.14), and, lastly, **(16)** (8.98 \(\pm\) 1.73 mM). In this study, indomethacin showed an IC50 of 54.69 \(\pm\) 10.34 mM [39]. [PERSON] and collaborators extracted \(\alpha\)-amyrin **(16)**, moronic **(30)**, and ursolic acids **(14)** (Figure 4) from _Bursera cuneata_ (Schldl.). Engl aerial parts with dichloromethane [40]. The identified compounds showed significant edema inhibition activity in comparison with indomethacin (positive control) in the ears of a mouse model. For the assay, TPA was applied at a dose of 2.5 ug/ear and a concentration of 0.1 mg of compound/ear. Then, they calculated the edema inhibition percentage by comparing the ear weight before the addition of only TPA versus the addition of TPA plus the treatment. In this part of the study, they identified that **(16)**, **(30)**, and **(14)** showed relevant anemia inhibition (44.9 \(\pm\) 1.2, 68.1 \(\pm\) 1.3, and 55.6 \(\pm\) 2.1%, respectively), in comparison with indomethacin (41.5 \(\pm\) 0.8% at the same dose), an inhibition percentage lower than the three pentacyclic triterpenes studied. These edema inhibition percentages correlated with the histamine inhibition results, with **(30)** being the compound with the major activity (73.3 \(\pm\) 1.1%). It is important to mention that the anti-inflammatory effect **(30)** was dose dependent, evaluating doses of 0.03, 0.1, 0.3, and 0.5 mg/ear. Additionally, the authors studied the effect of **(30)** on macrophage viability using RAW 264.7 cells at a concentration ranging from 0.3 to 60 ug/mL or with the control etoposide at 20 \(\upmu\)M for 24 h. As result, at 60 \(\upmu\)g/mL, the viability of the macrophages was reduced by 43% [40]. In a similar way, another research group identified four PCTs in the organic extract of _Sapium lateriflorum_ and analyzed their anti-inflammatory and cytotoxic activities [41]. For the latter, the team used six human tumor cell lines: U251 (glioblastoma), PC-3 (prostate), K562 (leukemia), HCT-15 (colon), MCF-7 (breast), and SKLU-1 (lung) at doses of 50 \(\upmu\)g/mL using etoposide as the positive control.