High-performance thin-layer chromatographic analysis of antioxidants present in different parts of Saraca asoca (Roxb.) de Wilde

Objective

Gallic acid, ellagic acid and quercetin are the important antioxidant compounds of Saraca asoca (Roxb.) de Wilde (Caesalpiniaceae). This report describes the determination of free radical scavenging activity in different plant parts (of S. asoca) by DPPH assay with correlation, and quantification of gallic acid, ellagic acid and quercetin in different plant parts by a simple, sensitive and validated HPTLC method.

Methodology

Methanolic extracts of bark, leaf and flowers of S. asoca were investigated for their antioxidant potential with the aid of DPPH assay followed by HPTLC analysis for quantitative evaluation of antioxidants (gallic acid, ellagic acid, and quercetin) in different plant parts.

Results

HPTLC analysis exhibited high amount of gallic acid and quercetin in flower (0.320% and 0.11% w/w respectively) and high amount of ellagic acid in bark (0.4805% w/w) which corresponds to low IC50 values of 6.83 ± 0.07 μg/ml and 6.6 ± 0.10 μg/ml respectively, indicating the remarkable antioxidant activity of these two plant parts whereas moderate amount of gallic acid (0.164 %w/w) and very low amount of quercetin (0.0445% w/w) and ellagic acid (0.04% w/w) correlate high IC50 value of 28.6 ± 0.62 μg/ml representing its poor antioxidant potential.

Conclusion

Consumption of bark and flower of S. asoca could be beneficial by virtue of its high antioxidant activity. The flower and bark may be considered as a source of gallic acid and ellagic acid respectively. The presence of moderate amount of gallic acid in leaf can be an alternative source.