The present study was conducted to examine the effects of sonication treatments (time intervals of 0, 15, 30, 45 and 60 min.) on phenolics and other antioxidant compounds in starfruits extracted in methanol and water. Overall, methanolic extracts exhibited significantly higher extractability, percentage inhibition of DPPH radicals, ferric reducing antioxidant property (FRAP) value, antioxidant capacity, flavonoids, total phenolics and tannins (p<0.05) compared to control (0 min) and aqueous extracts. Methanolic extract obtained after 30 min of sonication proved to be the best treatment with regard to various parameters evaluated. Results of the present study clearly indicated sonication treatments to be effective in enhancing the antioxidant compounds in starfruit extracts and could be further explored for commercial purposes to benefit the consumers.

Aim:This study was designed to evaluate the phenolic content and antioxidant activity of ethanolic extracts from T. catappa leaves obtained by different intervals of sonication.Methods:Three commonly used methods were followed to evaluate phenolic content and four in vitro methods like 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging assay, ferric reducing antioxidant potency (FRAP), and total antioxidant capacity assays for measuring the antioxidant activities. Antioxidant values of these assays were expressed in terms of milligrams vitamin C equivalent (VCE) antioxidant activities.Results:This study showed that extract obtained with 40 minutes of sonication possessed significant (P < 0.05) polyphenolic contents compared to 20 and 60 minutes sonication and control (24 hour maceration). Moreover, sonication of T. catappa leaf above 40 minutes was found to be unsuitable for extracting out phenolic contents. Even the results of antioxidant assays showed that 40 minutes of the sonicated extract exhibited significant (P < 0.05) VCE values compared to extracts obtained at different intervals of sonication and control.Conclusions:In sonication extraction method 40 minutes is an ideal time to obtain extract enriched with high polyphenolic content with good antioxidant activity from T. catappa leaves.

Studies were undertaken to evaluate the effects of drying treatments (oven and freeze drying) on polyphenols and antioxidant compounds of raw (green) and ripe papaya extracted with ethanol and distilled water. The total phenolics varied between 21.1 and 217.3 mg GAE equivalent/g (fresh weight). Freeze-dried, ripened papaya extracts exhibited significantly higher tannin (9.58 and 6.0 mg CAE/g fresh weight) and flavonoid levels (8.40 and 3.64 mg CAE/g fresh weight) in ethanolic and aqueous extracts, respectively. Additionally, freezedried, ripened papaya showed higher inhibition of DPPH (91.8 and 93.0%) and ABTS radicals (87.1 and 97.5% fresh weight) in ethanolic and aqueous extracts, respectively. Similar results were observed for total antioxidant capacity, wherein freeze-dried, ripened papaya extracts exhibited higher levels (1315 and 2167 mg AAE/g fresh weight, respectively). As enhanced antioxidant activities were observed in raw and ripened papaya on freeze drying, it can be further explored for producing papaya-based, value-added products to benefit both consumers and producers.

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