ABSTRACT
Leaf exudates from Aloe species, such as the Southern African Aloe ferox, are used in traditional medicines for both humans and livestock. This includes aloesin, a skin bleaching product that inhibits the synthesis of melanin. Aloesin, (a C-glycoside-5-methylchromone) can be released from aloeresin A, an ester of aloesin, through hydrolysis. The objective of the current study was to identify an enzymatic hydrolysis method for converting aloeresin A to aloesin, resulting in increased concentrations of aloesin in the aloe bitters extract. More than 70 commercially available hydrolytic enzymes were screened for the conversion of aloeresin A. An esterase (ESL001-02) from Diversa, a lipase (Novozym 388) and a protease (Aspergillus oryzae) preparation were identified during screening as being capable of providing conversion of pure aloeresin A, with the protease giving the best conversion (~100%). It was found that a contaminating enzyme in Novo 388 was responsible for the conversion of aloeresin A to aloesin. This contaminating enzyme, possibly a protease, was able to give almost complete conversion using crude aloe bitters extract, doubling the concentration of aloesin in aloe bitters extract via the hydrolysis of aloeresin A.
Subject(s)
Aloe/chemistry , Biocatalysis , Chromones/isolation & purification , Chromones/metabolism , Glucosides/isolation & purification , Glucosides/metabolism , Skin Lightening Preparations/isolation & purification , Africa, Southern , Aloe/enzymology , Aspergillus oryzae/enzymology , Chromones/chemistry , Esterases/metabolism , Glucosides/chemistry , Hydrolysis , Lipase/metabolism , Peptide Hydrolases/metabolism , Plant Extracts/chemistry , Plant Leaves/chemistry , Plant Leaves/enzymology , Skin Lightening Preparations/chemistry , Skin Lightening Preparations/metabolismABSTRACT
The 1997 World Cancer Research Fund and the American Institute for Cancer Research (WCRF/AICR) report, Food, Nutrition and the Prevention of Cancer: a global perspective, has become the most authoritative statement on the topic. WCRF International has begun the process of producing its second global report on food, nutrition, physical activity, and the prevention of cancer. The process is in three stages. The first begins with the development of a suitable methodology as advised by a task force of experts. The second stage will involve the systematic collection and display of the evidence by independent review teams. The final stage will be the assessment and judgment of that evidence by an independent panel of experts responsible for the content of the report, including its conclusions and recommendations. Two major differences between this report and previous reports on the prevention of chronic diseases are that a portfolio approach to the evidence is being used in which all types of study are weighed and the process of collecting and displaying the evidence is being clearly separated from assessment and judgment. This paper outlines the methodological procedures and their development that will be applied for the second WCRF International report.
Subject(s)
Advisory Committees/standards , Exercise , Food , Neoplasms/prevention & control , Nutritional Physiological Phenomena , Advisory Committees/organization & administration , HumansABSTRACT
The development of a real-time 2D-3D duplex ultrasonic scanner offers faster diagnostic imaging.
