Co-reporter:Juan J. Araya, Gloria Montenegro, Lester A. Mitscher, and Barbara N. Timmermann
Journal of Natural Products 2010 Volume 73(Issue 9) pp:1568-1572
Publication Date(Web):August 12, 2010
DOI:10.1021/np100465h
A novel simultaneous phase-trafficking approach using spatially separated solid-supported reagents for rapid separation of neutral, basic, and acidic compounds from organic plant extracts with minimum labor is reported. Acidic and basic ion-exchange resins were physically separated into individual sacks (“tea bags”) for trapping basic and acidic compounds, respectively, leaving behind in solution neutral components of the natural mixtures. Trapped compounds were then recovered from solid phase by appropriate suspension in acidic or basic solutions. The feasibility of the proposed separation protocol was demonstrated and optimized with an “artificial mixture” of model compounds. In addition, the utility of this methodology was illustrated with the successful separation of the alkaloid skytanthine from Skytanthus acutus Meyen and the main catechins and caffeine from Camellia sinensis L. (Kuntze). This novel approach offers multiple advantages over traditional extraction methods, as it is not labor intensive, makes use of only small quantities of solvents, produces fractions in adequate quantities for biological assays, and can be easily adapted to field conditions for bioprospecting activities.
Co-reporter:Lester A. Mitscher
Journal of Natural Products 2008 Volume 71(Issue 3) pp:497-509
Publication Date(Web):February 26, 2008
DOI:10.1021/np078017j
In just 70 short years mankind has progressed from euphoria to despair over the effectiveness of antibiotics to protect and to cure mankind from morbidity and mortality from infectious diseases. Resistance due to evolutionary factors was observed shortly after antibiotics came into use and is now not only widespread but appears to be inevitable. This review is a rather personalized account of the various attempts to deal with this problem over time.