From the aerial parts of Decatropis bicolor, heraclenin (1), seselin (2), psoralen (3), imperatorin (4), skimmianine (5), and heraclenol (6), were isolated. This is the first time that coumarin-like compounds are isolated from Decatropis genus. The anti-inflammatory properties of compounds 1-6 were examined against the ear edema in mice produced by TPA. The results suggest that the anti-inflammatory activity of each compound depends of its individual substitution on the aromatic ring rather than the coumarin skeleton itself.

So far, several studies have focused on the synthesis of metallic nanoparticles making use of extracts from the fruit of the plants from the genus Capsicum. However, as the fruit is the edible, and highly commercial, part of the plant, in this work we focused on the leaves, a part of the plant that is considered agro-industrial waste. The biological synthesis of gold (AuNPs) and silver (AgNPs) nanoparticles using aqueous extracts of root, stem and leaf of Capsicum chinense was evaluated, obtaining the best results with the leaf extract. Gold and silver nanoparticles synthesized using leaf extract (AuNPs-leaf and AgNPs-leaf, respectively) were characterized by UV-visible spectrophotometry (UV-Vis), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), X-ray Photoelectron Spectroscopy (XPS), Ultra Hight Resolution Scanning Electron Microscopy coupled to Energy-Dispersive X-ray spectroscopy (UHR-SEM-EDX) and Transmission Electron Microscopy (TEM), and tested for their antioxidant and antimicrobial activities. In addition, different metabolites involved in the synthesis of nanoparticles were analyzed. We found that by the use of extracts derived from the leaf, we could generate stable and easy to synthesize AuNPs and AgNPs. The AuNPs-leaf were synthesized using microwave radiation, while the AgNPs-leaf were synthesized using UV light radiation. The antioxidant activity of the extract, determined by ABTS, showed a decrease of 44.7% and 60.7% after the synthesis of the AuNPs-leaf and AgNPs-leaf, respectively. After the AgNPs-leaf synthesis, the concentration of polyphenols, reducing sugars and amino acids decreased by 15.4%, 38.7% and 46.8% in the leaf extract, respectively, while after the AuNPs-leaf synthesis only reducing sugars decreased by 67.7%. These results suggest that these groups of molecules are implicated in the reduction/stabilization of the nanoparticles. Although the contribution of these compounds in the synthesis of the AuNPs-leaf and the AgNPs-leaf was different. Finally, the AgNPs-leaf inhibited the growth of S. aureus, E. coli, S. marcescens and E. faecalis. All of them are bacterial strains of clinical importance due to their fast antibiotic resistance development.

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The use of selenium nanoparticles (SeNPs) in the biomedical area has been increasing as an alternative to the growing bacterial resistance to antibiotics. In this research, SeNPs were synthesized by green synthesis using ascorbic acid (AsAc) as a reducing agent and methanolic extract of Calendula officinalis L. flowers as a stabilizer. Characterization of SeNPs was performed by UV-vis spectrophotometry, infrared spectrophotometry (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques. SeNPs of 40–60 nm and spherical morphologies were obtained. The antibacterial activity of marigold extracts and fractions was evaluated by disk diffusion methodology. The evaluation of SeNPs at different incubation times was performed through the colony-forming unit (CFU) count, in both cases against Serratia marcescens, Enterobacter cloacae, and Alcaligenes faecalis bacteria. Partial antibacterial activity was observed with methanolic extracts of marigold leaves and flowers and total inhibition with SeNPs from 2 h for S. marcescens, 1 h for E. cloacae, and 30 min for A. faecalis. In addition, SeNPs were found to exhibit antioxidant activity. The results indicate that SeNPs present a potentiated effect of both antimicrobial and antioxidant activity compared to the individual use of marigold extracts or sodium selenite (Na2SeO3). Their application emerges as an alternative for the control of clinical pathogens.

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