Assessment of Gnaphalium viscosum (Kunth) Valorization Prospects: Sustainable Recovery of Antioxidants by Different Techniques.

This work investigates the prospects for exploitation of Gnaphalium viscosum (Kunth) abundant but with limited applications till present biomass. The feasibility of traditional techniques (two-phase solvent, and the benchmark Soxhlet extraction) and supercritical extraction without/with a cosolvent at T = 40-60 °C and p = 30-50 MPa was examined to explore the possibility of recovering phytochemicals from G. viscosum leaves, flowers and stems. The efficiency of the techniques was assessed and compared based on yield, influence of solvents used, total phenolic content and antioxidant activity of the extracts. Phenolics of different complexities were identified and quantified by applying LC (LC-MS/MS, and LC-HRAM), while the fatty acid profile was determined by GC-FID. The results of this extensive study demonstrated the huge valorization potential and prospects of G. viscosum, since highly potent antioxidants such as kaempferol, kaempferol-3-O-ß-d-glucoside (astragalin), and chlorogenic acid were ascertained in considerable amounts. Furthermore, for the first time, the presence of leontopodic acid, a greatly substituted derivative of glucaric acid, was detected in the species.

A semi-targeted NMR-based chemical profiling of retail samples of Mexican gordolobo.

Mexican gordolobo (MG) is one of the most important medicinal plants in Mexico and an important source of specialized metabolites with biological activities. The species employed in Mexican traditional medicine identified with this name are very different and difficult to identify according to existent criteria. In order to contribute to the identification of these species, a semi-targeted 1H NMR-based chemometric method was developed to characterize the chemical profiling of retail samples of MG. Thus, 17 retail samples of MG flowers were successively extracted with a gradient of water:chloroform (1:4, 1:2 and 0:1) in an ultrasonic bath for 15 min each. The organic phase of the three extracts was pooled, evaporated and analyzed by 1H NMR. The NMR data were subjected to multivariate statistical analysis, revealing that flavones gnaphaliin A (1), gnaphaliin B (2), araneol (3), 3,5,7-Tri-O-methylgalangin (4) and diterpenes sclareol (5) and kaur-16-en-18-oic acid (6) can be effectively used as chemotaxonomical markers for the correct identification of the Gnaphalium spp that compose MG. The aforementioned chemotaxonomic markers may be useful in establishing therapeutic criteria.