ABSTRACT
The Indian system of medicine (ISM) consists of several major components such as Ayurveda, Siddha, Unani and homeopathy. All these components provide the major healthcare for a large part of the population in India and have been flourishing in this country for many centuries. Medicinal plants constitute a major part in all of these traditional systems. Several regulations and controls on the use of medicinal plants in traditional medicine have evolved. On the one hand, such regulations will help to cure different aliments through Indian indigenous resources and, on the other hand, they will help in the screening and evaluation of natural resources through the development of potential lead components in order to provide better healthcare through ISM. Several lead molecules have been developed from ISM. This review aims at highlighting aspects of drug development from Indian medicinal plants through the use of ethnobotany, ethnopharmacology and systems biology, with different approaches using metabolomics and allied fields.
ABSTRACT
Nicotianamine (NA) occurs in all plants and chelates metal cations, including FeII, but reportedly not FeIII. However, a comparison of the FeII and ZnII affinity constants of NA and various FeIII-chelating aminocarboxylates suggested that NA should chelate FeIII. High-voltage electrophoresis of the FeNA complex formed in the presence of FeIII showed that the complex had a net charge of 0, consistent with the hexadentate chelation of FeIII. Measurement of the affinity constant for FeIII yielded a value of 10(20.6), which is greater than that for the association of NA with FeII (10(12.8)). However, capillary electrophoresis showed that in the presence of FeII and FeIII, NA preferentially chelates FeII, indicating that the FeIINA complex is kinetically stable under aerobic conditions. Furthermore, Fe complexes of NA are relatively poor Fenton reagents, as measured by their ability to mediate H2O2-dependent oxidation of deoxyribose. This suggests that NA will have an important role in scavenging Fe and protecting the cell from oxidative damage. The pH dependence of metal ion chelation by NA and a typical phytosiderophore, 2'-deoxymugineic acid, indicated that although both have the ability to chelate Fe, when both are present, 2'-deoxymugineic acid dominates the chelation process at acidic pH values, whereas NA dominates at alkaline pH values. The consequences for the role of NA in the long-distance transport of metals in the xylem and phloem are discussed.
