RESUMO
II-V semiconductor nanocrystals such as Cd3P2 and Zn3P2 have enormous potential as materials in next-generation optoelectronic devices requiring active optical properties across the visible and infrared range. To date, this potential has been unfulfilled due to their inherent instability with respect to air and moisture. Core-shell system Cd3P2/Zn3P2 is synthesized and studied from structural (morphology, crystallinity, shell diameter), chemical (composition of core, shell, and ligand sphere), and optical perspectives (absorbance, emission-steady state and time resolved, quantum yield, and air stability). The improvements achieved by coating with Zn3P2 are likely due to its identical crystal structure to Cd3P2 (tetragonal), highlighting the key role crystallographic concerns play in creating cutting edge core-shell NCs.
RESUMO
Currently, oxidative stress is one of the major problems that threatens human health. It is at the root of many diseases such as cancer. Despite the enormous efforts provided to combat this scourge, oxidative stress is still relevant and hence comes the need for research of new remedies especially from natural origin. For this purpose, the study of the antioxidant activity of extracts of Cistus monspeliensis from Morocco is a principal research objective. The phenolic extracts were obtained by maceration of the plant in a water/acetone mixture and then separated by liquid/liquid extraction with solvents of increasing polarity. The first phytochemical tests carried out on these extracts showed the existence of different families of phenolic compounds, such as flavonoids, tannins, and others. Assays for total polyphenols, flavonoids, hydrolysable, and condensed tannins were carried out by known colorimetric methods. The results of these assays have shown that the studied extracts are rich in phenolic compounds present in the plant in the form of flavonoids (69.81 ± 0.22 mg EQ/g DM), hydrolysable tannins (61.86 ± 0.89 mg ETA/g DM), and condensed tannins (70.05 ± 1.61 mg EC/g DM). The evaluation of the antioxidant activity is carried out by two different methods: the DPPH test (2,2-DiPhenyl-1-Picryl-Hydrazyl) and the FRAP test (Ferric Reducing Antioxidant Power). The results obtained show that the extracts of Cistus monspeliensis are active and have interesting antioxidant powers. In particular, the water/acetone (WAE) (IC50 = 0.079 mg/mL) and butanolic (BUE) (IC0.5 = 0.099 mg/mL) extracts are the most active with values comparable to that of ascorbic acid. The interesting results obtained in this study clearly show that Cistus monspeliensis originating from Morocco can be considered as a source of natural antioxidants. Therefore, the extracts of this plant deserve to be tested in the medicinal field, against cancer and cardiovascular diseases, and in food field as an additive and preservative.