• Natural Product Sciences
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• v.27 no.2
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• pp.78-85
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• 2021

Through bio-guided isolation, two natural iron chelators were isolated from Mangifera indica L. leaves, identified as mangiferin (1) and iriflophenone-3-C-𝛽-D-glucoside (2). Their iron-chelating activity was compared to that of Desferal^® using bipyridyl assay and EDTA as a standard. Mangiferin showed the highest activity with IC₅₀ value of 0.385 mM (162.85 ㎍/mL). Furthermore, two combinations of mangiferin with Desferal^® (M-D) and iriflophenone-3-C-𝛽-D-glucoside (M-I) were evaluated. The results showed that mangiferin potentiated the iron chelation activity of Desferal^® about 46%, also that M-I combination is a promising candidate formula for iron chelation therapy. In addition, mangiferin and Desferal-iron complexes were prepared and characterized by IR, UV, and Mass spectra to compare their mode of chelation to iron. Their structural stability was studied by DFT calculations. Furthermore, they displayed increased ABTS antioxidant activity when bound to iron as compared to their free form, which enhances their pharmacological importance.

• Archives of Pharmacal Research
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• v.29 no.3
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• pp.249-255
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• 2006

Ability of iron acquisition of pathogenic microorganisms functions as a virulence factor. Candida albicans, a fungal pathogen that requires iron for growth, is susceptible to growth retardation by high-affinity iron binding proteins such as transferrin. Recently, we reported that C. albicans could utilize the heme as a part of heme-containing proteins dissociated by heme oxygenase, CaHMX1. In search of another pathway that C. albicans can use to bypass the growth regulation produced by iron limitation, this present study examined utilization of non-candidal siderophores such as Desferal and rhodotorulic acid (RA) for acquisition of inorganic iron by the fungus. C. albicans secreting no siderophores was cultured in iron-free (pretreated with apotransferrin for 24 h) (culture medium). Once growth of the yeast reached stasis from iron starvation, a siderophore was added to the culture media. Results showed that cultures containing apotransferrin within a dialysis membrane recovered growth to the level of untreated controls, whereas C. albicans yeast cells in direct contact with soluble iron-free (apo) transferrin recovered growth only partially. When static growth from iron limitation was reached, the addition of siderophore-apotransferrin complex to culture medium also permitted the yeast to recover growth from apotransferrin growth regulation. All the data show that C. albicans can utilize the non-candidal siderophores for iron acquisition under transferrin regulation as can pathogenic bacteria.