Synthesis, characterisation and biological activities of homoisoflavonoids.
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Date
2012
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Abstract
Fifteen homoisoflavonoids (3-17) were synthesised using the base-catalysed aldol
condensation, thirteen of which were of the 3-benzylidene-4-chromanone type and the
remaining two of the 3-benzyl-4-chromanone type. The substitution patterns of the
homoisoflavonoids were varied by keeping the A-ring unsubstituted whilst changing the
substituent’s on the 3' and 4' positions of the B-ring. Methoxy, hydroxy, chloro, fluoro and
nitro groups were inserted on the B-ring of the homoisoflavonoids. All homoisoflavonoids
were characterised by NMR (1D and 2D), IR, UV spectroscopy and GC-MS. The crystal
structures were obtained for seven of the homoisoflavonoids. The homoisoflavonoids (3-17)
were tested for their antibacterial activity against ten gram-positive and six gram-negative
bacterial strains using the method of disc diffusion. Five compounds showed moderate
antibacterial activity whilst compound 14 showed good antibacterial activity against the gram
positive bacteria. The hydroxylated compounds were tested for their antioxidant activity
using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method as well as the
FRAP (ferric reducing antioxidant power) method. Compound 15 showed good antioxidant
activity, comparable to that of ascorbic acid, due to the presence of a catechol system within
the molecule.
Description
M. Sc. University of KwaZulu-Natal, Durban, 2012.
Keywords
Flavonoids--Synthesis., Flavonoids., Theses--Chemistry.