Lo. Orafidiya et al., SOLUTION AND COLOR STABILITY OF THE BARK EXTRACT OF BRIDELIA-FERRUGINEA BENTH, PTR. Phytotherapy research, 10(3), 1996, pp. 266-268
A solvent system consisting of water: propylene glycol: ethanol (2:2:1
) was found suitable for diluting the ethanol bark extract and for rec
onstituting the freeze-dried extract of Bridelia ferruginea Benth for
preparation of a gargle formulation. Such solutions remained clear whe
n subjected to high storage temperatures and eight freeze-thaw cycles.
The wine colour of Bridelia bark extract solution darkened on storage
. Darkening was accelerated by heat while light had minimal effect. In
clusion of certain antioxidants-sodium metabisulphite, ascorbic acid a
nd citric acid, reduced the colour change. Heating the freeze-dried ex
tract at 115 degrees C for 4 h and at 130 degrees C for at least 1 h a
rrested the colour change. When lime juice was added to the solution o
f the heated powder, the colour of the resulting solution became unsta
ble implicating a pH effect on colour stability. The colour of bottle
and use of carton for storage had no appreciable effect on colour stab
ility.