Identification and quantification of polyphenolic compounds in underutilized fruits (Star fruit and Egg fruit) using HPLC

The study was aimed to investigate the antioxidant capacity, total phenolics, total flavonoids and polyphenolic compounds of two common underutilized fruits namely, star fruit and egg fruit. Results showed that, the star fruit extract had higher total phenolics content (161.56±9.24 mg GAE/100 gm FWB) and DPPH radical scavenging ability (91.77±8.68 mg ascorbic acid equivalent antioxidant activity (AAEAA) /100 gm fresh weight basis (FWB) with low IC50 value = 0.6 mg/ml compared to egg fruit extract which had a low phenolics content (152.45±8.75 mg gallic acid equivalent (GAE) /100 gm FWB) as well as lesser DPPH radical scavenging activity (87.21±6.32 mg AAEAA/100 gm FWB) with the IC50 value = 0.88 mg/ml. Total flavonoids content was 72±2.69 and 109.73±5.91 mg quercetin equivalent (QE) /100 gm FWB for star fruit and egg fruit, respectively. Polyphenolic compounds were identified and quantified using HPLC and the data revealed the abundance of gallic acid; quercetin; ferulic acid and epi-catechin in star fruit and egg fruit extracts as well. Overall, the higher potency of star fruit in terms of radical scavenging effects is due to higher content of total phenolics that of egg fruit. In conclusion, the results obtained from our study indicates the star fruit and egg fruit are a good source of phytochemical properties, which are nutritionally prominent for their antioxidant activities and defensive functions against diseases caused by oxidative stress, therefore can be used in functional food formulations.