Umbu Fruit Peel as Source of Antioxidant, Antimicrobial and α-Amylase Inhibitor Compounds

Abstract

Herein, the extraction of bioactive compounds from umbu fruit peel was optimized using thermal-assisted solid–liquid extraction. In parallel, antioxidant, antimicrobial, and inhibitory effects against α-amylase of optimized extract were also evaluated. The combination of operational conditions including the temperature (32–74 °C), ethanol concentration (13–97%), and solid/liquid ratio (1:10–1:60; w/v) was employed using a rotational central composite design for optimization. The extracts were evaluated for total phenolic compounds (TPC), total flavonoid compounds (TFC) and antioxidant capacity by ABTS•+, DPPH• and FRAP assays. The bioactive profile of the optimized extract was obtained by ultra-performance liquid chromatography coupled to quadrupole/time-of-flight mass spectrometry in electrospray ionization in both negative and positive modes. The statistically evaluated results showed that the optimal operational conditions for the recovery of bioactive compounds from umbu fruit peel included 74 °C, 37% ethanol, and a solid–liquid ratio of 1:38. Under these conditions, the obtained values were 1985 mg GAE/100 g, 1364 mg RE/100 g, 122 µmol TE/g, 174 µmol/TE g and 468 µmol Fe2+/g for TPC, TFC, ABTS•+, DPPH•, and FRAP assays, respectively. In addition, the optimized extract was effective against Gram-positive and Gram-negative bacteria (MBC ranged from 0.060 to 0.24 mg GAE/mL), as well as it was effective to inhibit α-amylase (IC50 value of 0.076 mg GAE/mL). The optimized extract showed to be mainly constituted by phenolic acids and flavonoids.

Antioxidants of Fruit Extracts as Antimicrobial Agents against Pathogenic Bacteria

“…Purple-fleshed pitanga had the highest scavenging activity in the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) assay, with IC 50 of 37 mg/L, and also showed the highest FRAP, followed by xavante blackberries, Cherokee blackberries, and araçá. Moreover, bioactive compounds from peel of a Brazilian native fruit, umbu fruit (Spondias tuberosa), showed total phenolic compounds (1985 mg gallic acid equivalent/100 g), total flavonoid compounds (1364 mg rutin equivalent/100 g) and antioxidant capacity by ABTS (122 µmol Trolox equivalent/g), DPPH (174 µmol/Trolox equivalent g) and FRAP assays (468 µmol Fe 2+ /g) [148]. It can be concluded that fruits rich in phenolic compounds have high antioxidant activity.…”

Bioproducts from Passiflora cincinnata Seeds: The Brazilian Caatinga Passion Fruit

“…Its linear effect was significant and positive. In this way, higher temperatures favor the solubility of phenolic compounds and decrease the viscosity of the extraction system, leading to a better extraction yield [ 16 , 30 ]. Notably, this behavior was also observed for the antioxidant capacity of the extracts regardless of the method used ( Table 1 , Figure S1 ).…”

“…The temperature was limited to 74 °C to avoid loss of solvent. The extraction of antioxidant compounds was performed by agitated solvent extraction, using 125 mL glass flasks properly covered and heated for 1 h under constant stirring of 150 rpm, conditions based on preliminary studies and literature data [ 15 , 16 ]. The experimental data were analyzed by response surface methodology using a second order polynomial equation.…”

Spondias tuberosa and Spondias mombin: Nutritional Composition, Bioactive Compounds, Biological Activity and Technological Applications

“…Moreover, several studies have documented health benefits associated with the fruit and their components. Antioxidant and antibacterial actions, acetylcholinesterase inhibition, and cancer chemopreventive activity have already been reported [20][21][22][23][24].…”

“…In the same study, the authors identified the presence of gallotannins and ellagitannins as the main tannins present in this plant species. Ribeiro et al [23] reported fifteen compounds in the optimized extract of S. tuberosa peel, which mainly comprised phenolic acids and flavonoids.…”