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Leptocarpha rivularis, commonly known as “palo negro”, is a species of the Astereaceae family, endemic in the forests of Southern Chile. The extracts of this plant have medicinal properties attributable to its secondary metabolites, mainly identified as flavonoids and terpenes. Among them, leptocarpine has gained importance as a powerful anticarcinogen. The aim of this study was the in vitro establishment of L. rivularis to develop future alternatives to obtain biomass for medicinal purposes. Young shoots obtained from plants in growth chambers were treated with Captan™ (2.5% (w/v)), subjected to disinfection method with ethanol, commercial chlorine, and antioxidants and tested in different Murashige & Skoog based media to establish in vitro culture. The most effective growth was observed with half strength Murashige & Skoog medium supplemented with 20 g L−1 sucrose and 3.2 g L−1 gelrite (MGS medium) with 95% survival at 30-d and shooting reaching 82% of the explants when Plant Preservative Mixture™ is added to the medium. The addition of 1 mg L−1 of indole-3-butyric acid to the MSG medium was necessary for inducing roots and obtaining well-rooted plants that were acclimatized and successfully established in the greenhouse. Our study represents the first report describing the in vitro culture of L. rivularis, allowing the sustainable use of this plant.

A series of ten chalcones (7a–j) and five new dihydrochromane–chalcone hybrids (7k–o) were synthesized and identified using spectroscopic techniques (IR, NMR, and MS). All compounds were evaluated in vitro against the B. cinerea and M. fructicola phytopathogens that affect a wide range of crops of commercial interest. All compounds were tested against both phytopathogens using the mycelial growth inhibition test, and it was found that two and five compounds had similar activity to that of the positive control for B. cinerea (7a = 43.9, 7c = 45.5, and Captan®= 24.8 µg/mL) and M. fructicola (7a = 48.5, 7d = 78.2, 7e = 56.1, 7f = 51.8, 7n = 63.2, and Mystic®= 21.6 µg/mL), respectively. To understand the key chalcone structural features for the antifungal activity on B. cinerea and M. fructicola, we developed structure–activity models with good statistical values (r2 and q2 higher than 0.8). For B. cinerea, the hydrogen bonding donor and acceptor and the atomic charge on C5 modulate the mycelial growth inhibition activity. In contrast, dipole moment and atomic charge on C1′ and the carbonyl carbon modify the inhibition activity for M. fructicola. These results allow the design of other compounds with activities superior to those of the compounds obtained in this study.

Chalcones are a group of molecules with a broad spectrum of biological activities, being especially appealing for their antiproliferative effects on several cancer cell lines. For this reason, we synthesized 23 chalcones with good to excellent yields and assessed their effect on the viability of the SH-SY5Y neuroblastoma cell line and on primary human fibroblasts. The results indicated that 18 of these compounds were more active than 5-fluorouracil in the cancer cell line and one of them was more selective than this reference drug. To identify structural features related to the antiproliferative activity of these compounds, as well as, the selectivity on the cancer cell line, a 2D-QSAR analysis was performed. The QSAR model (q2 = 0.803; r2 = 0.836) showed that lipophilicity (CLogP) is the most important factor to increase their cytotoxicity on the cancer cell line. On the other hand, the selectivity QSAR model (q2 = 0.917; r2 = 0.916) showed that changes in the Mulliken’s charge of the carbonyl group and at the C4’ position in the chalcone core can increase the selectivity for SH-SY5Y cell line compared to normal fibroblasts.

Chalcones are bioactive compounds obtained from either natural sources or synthetic procedures and widely used due to their several biological properties. The most common experimental methodology in obtaining these compounds is Claisen–Schmidt reaction, which is a particular type of aldolic condensation. In this work, we have synthesized 23 chalcones and by density functional theory (DFT) calculation, we have studied the difference in reactivity of the several benzaldehydes and their effects on the yield of this reaction. From molecular orbital descriptors were obtained two quantitative structure–reactivity relationship (QSRR) models based on Hansch’s analysis. The results of this study showed that, for the most benzaldehydes (15 of 23 compounds), their reactivity was correlated with LUMO energy and global Electrophilicity Index (ω) values, which are determined in the first step of Claisen–Schmidt condensation mechanism (nucleophilic addition). Likewise, for the smallest group of benzaldehydes, their reactivity was related to their HOMO and ΔL − H (LUMO − HOMO) energies, which were determined in the second step of the mechanism (trans-elimination). This is the first report of a QSRR model analyzing the yield of chalcone synthesis based on DFT methodology.

Background Ephedra chilensis K Presl, known locally as pingo–pingo, is a Chilean endemic plant used in traditional medicine as an anti-inflammatory and used in other treatments. However, unlike for the other Ephedra species, there have been no reports on the antioxidant and cytotoxic effects of this plant. The present study aims to explore the potential applications of E. chilensis extract as a cytotoxic agent against in vitro cancer cell lines and to explore the relationship between this extract and antioxidant activity. Methods Total anthraquinone, flavonoid, and phenolic contents, as well as antioxidant activity (DPPH, FRAP, and TRAP assays) and cytotoxic effect on several cancer cell lines (MCF-7, PC-3, DU-145, and HT-29) were measured for the hexane, dichloromethane and ethanol extracts of E. chilensis. In addition, several correlations among the phytochemical content, antioxidant activity, and cytotoxic effect were evaluated. Finally, GC-MS analyses of the most active extracts were carried out to identify their major components and to relate these components to the cytotoxic effect. Results Antioxidant activity was found in the EtOH extracts of Ephedra, and the results were correlated with the phenolic content. For the cytotoxic activity, the non-polar extracts of E. chilensis had the highest antiproliferative effect for the MCF-7 and PC-3 cancer lines; the extract was shown to be up to three times more selective than doxorubicin. However, the cytotoxic effect was not correlated with the antioxidant activity. Lastly, the GC-MS analysis showed a high concentration of saturated fatty acids (mainly n-hexadecanoic acid) and terpenoids (mainly 4-(hydroxy-ethyl)-γ-butanolactone). Conclusion The cytotoxic activity and selectivity of the non-polar extracts of E. chilensis for the MCF-7 and PC-3 cell lines could be related to the terpenic compounds and fatty acids of the extracts or to the synergistic effect of all of the compounds in the extracts. These non-polar extracts can be used for the development of new drugs against breast and prostate cancer.

Sorption experiments for copper removal were carried out using two different parts of the brown seaweed Lessonia nigrescens (L. nigrescens) as biosorbent. The effect of initial pH, contact time, mass–volume-ratio (M/V) and initial metal concentration was evaluated. The best adsorption capacities were obtained at pH = 3.2 ± 0.2, and to reach equilibrium, 7 days of contact time were necessary for both sections of the seaweed. The maximum experimental uptake achieved was 54.5 mg Cu g−1 by the blades of the alga and 58.5 mg Cu g−1 by the stipes. Both Langmuir and Freundlich models described the equilibrium sorption isotherms very well when using stipes as biosorbent, but the fitting was poor with both models when blades were used as biosorbent. The Ho and McKay pseudo-second order model described the sorption kinetics for stipes and blades satisfactorily.