# 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
Regarding the results, **(37)** had a significant effect (EC\({}_{50}\) 108.9 \(\pm\) 6.7 \(\upmu\)M, E\({}_{\text{max}}\) 96.4 \(\pm\) 4.2%) compared to the other two PCTs: **(38)** showed an EC\({}_{50}\) equal to 145.9 \(\pm\) 6.7 \(\upmu\)M, and an E\({}_{\text{max}}\) of 99.5 \(\pm\) 5.3% while **(39)** had values of 63.2 \(\pm\) 5.8 \(\upmu\)M and 27.5 \(\pm\) 1.9% for EC\({}_{50}\) and E\({}_{\text{max}}\), respectively. It is important to note that **(37)** and **(38)** had a higher E\({}_{\text{max}}\) than the positive control while **(39)** showed an EC\({}_{50}\) closer to the positive control than the other two PCTs [43]. Although the biological activities of PCTs have been essentially evaluated with microorganisms or mammals, plants have been considered too. In this way, [PERSON] and collaborators carried out trials investigating the effects of six PCTs from _Sebastiania__adenophora_ on the root growth of amaranth (_Amaranthus hypochromdiacus_ [PERSON]), tomato (_Lycopersicon esculentum_ Mill. var. [PERSON]), and barnyard grass (_Echinochla crus-galli_ [PERSON]) [44]. The isolated compounds were 3-_epi_-\(\beta\)-amyrin (**40**), \(\beta\)-amyrinone (**41**), 3-_epi_-lupeol **(27**)**, lupenone **(8)**, taraxerol **(42**)**, and taraxenone **(9)**. As part of the results, it was found out that all PCTs had a negative effect on the root growth of tomato and barnyard grass when these were applied at a dose of 250 \(\mu\)g/mL. Of all the plant-PCT combinations, **(42)** had the greatest root growth inhibition effect on barnyard grass, with a 77% inhibition, which demonstrates its potential as an allelopathic substance. On the other hand, at the same dose, the tested compounds favored the root development of amaranth. Particularly, **(40)** was the strongest stimuli (55%) of root growth. In addition, the authors tested how the applied dose was related to the effects of **(42)**, **(40)**, and the mixture of the six PCTs when applied at 125, 250, and 500 \(\mu\)g/mL. In amaranth, the effect was dose dependent on all the tested compounds. However, in barnyard grass, the mixture of the six PCTs had a root-stimulating effect when the dose was 125 \(\mu\)g/mL and an inhibitory effect when the doses were higher. A similar behavior was observed in tomato with **(40)**[44]. Additionally, [PERSON] et al. indicated the presence of three nor-triterpenes in _Galphimia glauca_: Galphimidin **(38)**, galphimidin B **(43)**, and glaucacetalin E **(44)**[45]. The compounds were extracted from aerial parts using methanol as the solvent. Anxiolytic effects were detected in mice after the administration of the compounds mentioned. Galphimidin had the strongest anxiolytic effects of the three compounds, which can be quantitatively compared with those of diazepam. It was observed that the response depended on the administered dose (1, 10, and 30 mg/kg) and the extract had a sedative effect, with a value greater than diazepam [45]. There are some works in which no previously isolated compounds were evaluated in bioassays; instead, extracts containing PCTs were studied. In these cases, the presence of PCTs is known by previous reports that achieved their characterization. There are also other studies in which triterpenes were used as part of a partially purified mixture. Oleanolic **(1)** and **ursolic (14)** acids together with \(\beta\)-sitosterol and stigmasterol (sterods) as the first two fractions in a primary chromatography from an ethanolic extract of _Moussonia deppeana_ showed anti-inflammatory activity by inducing edema in the ear of Balb/C mice in two models: TPA and carrageenan [47]. In the first model, fractions were applied at a dose of 2 mg/ear and 2.5 \(\mu\)g of TPA was applied 30 min later. The positive control, indomethacin, was used at 0.5, 1, and 2 mg/ear. After 6 h, for the first fraction, the inhibition was 31.24% in males and 27.24% in females; and for the second fraction, the males showed an inhibition of 53.03% and the females showed an inhibition of 27.24%.