1,720,990 research outputs found
Vesicles and micelles: two versatile vectors for the delivery of natural products
No full textNatural plant-based extracts and isolated constituents have been widely used around the world since ancient times for both treatment and prevention of human diseases. Currently, the importance of natural products in clinical practice is highlighted by the number of herbal medicinal products on the market. However, formulation development of many active constituents of plant extracts is often hampered by their limited bioavailability due to several issues among which low water solubility, poor absorption and degradation are the most frequent. To overcome these issues, several research studies proposed to combine herbal medicinal products with nanocarriers widely used as drug delivery systems. The nanotechnology approach is especially attractive because colloidal carriers can modify the payload pharmacokinetic and biodistribution, as well as increase solubility, stability, and efficacy. Moreover, nanoencapsulation may decrease toxicity and modulate drug release. In recent years, delivery systems such as micelles and vesicles, obtained by the self-assembly of biocompatible surfactants, have attracted increasing attention as carriers for various herbal products. Thus, the aim of this paper is to review the main investigations developed by Italian research groups on formulations of natural products, including isolated compounds, extracts and essential oils, using micelles and vesicles as carrier
Liposomes as carriers for verbascoside: stability and skin permeation studies
No full textIn this study the influence of liposomal incorporation on both the stability and the in vitro (trans) dermal delivery of verbascoside was evaluated. The effect of drug entrapment into vesicles on its radical scavenging activity was also studied. Liposomes were obtained from soy phosphatidylcholine and cholesterol according to the film hydration method. Stability of verbascoside-loaded vesicles was studied over 6 months. Results showed that verbascoside can be incorporated in liposomes (E% = 57-66%), preventing its degradation. Stability studies (dynamic lager light scattering [DLLS] measurements and transmission electron microscopy [TEM] visualization) pointed out that vesicles were stable for 90 days and neither verbascoside leakage nor vesicle size alteration occurred during this period. The effects of vesicular incorporation on verbascoside diffusion through skin were investigated in vitro using newborn pig skin. Results showed that liposomes promoted drug accumulation into the stratum corneum but they did not give rise to any significant transdermal verbascoside delivery. Finally, results obtained from a 1, 1-diphenyl-2-pierylhydrazyl (DPPH) radical assay demonstrated that liposomes did not interfere with the radical scavenging activity of verbascoside
Preliminary chemical and pharmacological study of crude extracts from Caulerpa taxifolia.
No full textAntiplasmodial Effects of a few Selected Natural Flavonoids and their Modulation of Artemisinin Activity
No full textStudies on the interactions between some flavonols and cyclodextrins
No full textThe interactions of some natural flavonols with alpha, beta- and gamma-Cds have been investigated. Guest molecules were galangin, kaempferol and quercetin. Inclusion complexes were prepared by kneading and freeze-drying. The complexes were characterized using different physico-chemical methods based on differential scanning calorimetry (DSC), infrared spectroscopy (IR) and NMR spectroscopy. In the proton and carbon spectra the effects of complexation on the chemical shifts of the internal and external protons of Us in the presence of each flavonoid were observed. Moreover, the water-solubility of the flavonols in the presence of Us was also evaluated. The increased solubility of quercetin and kaempferol in the presence beta-Cd was evidenced. For all three guests, multidimensional NMR experiments in DMSO and water are consistent with dynamic binding processes, dominated by insertion of the B ring into the wider rim of the Cd cavity
Preliminary results of crude extracts from caulerpa taxifolia (VAHAL) C.AGARDH on guinea-pig ileum activity
No full text
- …
