Bioactive compounds and scavenging capacity of pulp, peel and seed extracts of the Amazonian fruit Quararibea cordata against ROS and RNS

Optimization of Ultrasonic-Assisted Extraction of Phenolic Compounds and Antioxidant Activity from Araticum Peel Using Response Surface Methodology

The peel represents a significant portion of the araticum fruit (about 40%), which becomes waste after its consumption or processing. Previous studies have shown that the araticum peel is rich in phenolic compounds; however, little is known about the ideal conditions for recovering these compounds. Therefore, response surface methodology, using a central composite rotatable design, was employed to optimize the extraction process to maximize the total phenolic compounds (TPCs) and enhance the Trolox equivalent antioxidant capacity (TEAC) from araticum peel. The variables optimized were ethanol concentration (EC; 20-80%, v/v), extraction time (ET; 5-45 min), and solid-solvent ratio (SSR; 10-100 mg/mL). Additionally, condensed tannins, antioxidant capacity against synthetic free radicals (TEAC and FRAP) and reactive oxygen species (ROS), and the phenolic compounds profile, were evaluated. Optimum extraction conditions were 50% (v/v) ethanol concentration, 5 min of extraction time, and 10 mg/mL solid-solvent ratio. Under these conditions, experimental TPCs and TEAC values were 70.16 mg GAE/g dw and 667.22 µmol TE/g dw, respectively, comparable with predicted models (68.47 mg GAE/g dw for TPCs and 677.04 µmol TE/g dw for TEAC). A high condensed tannins content (76.49 mg CE/g dw) was also observed and 12 phenolic compounds were identified, predominantly flavonoids (97.77%), including procyanidin B2, epicatechin, and catechin as the major compounds. Moreover, a potent antioxidant activity was observed against synthetic free radicals and ROS, especially in scavenging peroxyl and hydroxyl radicals. From this study, we obtained the ideal conditions for recovering phenolic compounds from araticum peel using a simple, fast, sustainable, and effective method, offering a promising opportunity for the management of this plant byproduct.

Scavenging Capacity of Extracts of Arrabidaea chica Leaves from the Amazonia against ROS and RNS of Physiological and Food Relevance

Arrabidaea chica, a medicinal plant found in the Amazon rainforest, is a promising source of bioactive compounds which can be used to inhibit oxidative damage in both food and biological systems. In this study, the in vitro scavenging capacity of characterized extracts of A. chica leaves, obtained with green solvents of different polarities [water, ethanol, and ethanol/water (1:1, v/v)] through ultrasound-assisted extraction, was investigated against reactive oxygen (ROS) and nitrogen (RNS) species, namely superoxide anion radicals (O2•-), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), and peroxynitrite anion (ONOO-). The extract obtained with ethanol-water presented about three times more phenolic compound contents (11.8 mg/g) than ethanol and water extracts (3.8 and 3.6 mg/g, respectively), with scutellarein being the major compound (6.76 mg/g). All extracts showed high scavenging efficiency against the tested ROS and RNS, in a concentration-dependent manner with low IC50 values, and the ethanol-water extract was the most effective one. In addition, all the extracts were five times more efficient against ROO• than Trolox. Therefore, the extracts from A. chica leaves exhibited high promising antioxidant potential to be used against oxidative damage in food and physiological systems.

Protective Effect of Ultrasound-Processed Amazonian Sapota-do-Solimões (Quararibea cordata) Juice on Artemia salina Nauplii

Juice processing by non-thermal technology has been extensively studied, aiming at microbial inactivation and quality improvement. However, the knowledge about the possible toxic effects that those technologies can produce in foodstuffs due to the production of reactive oxygen species is still unknown. In this study, sapota-do-Solimões juice processed by ultrasound (2, 6, and 10 min) was evaluated by a toxicity test and protective effect through stress biomarkers (catalase, superoxide dismutase, and lipid peroxidation) using Artemia salina nauplii. The non-thermal processed juice was nontoxic to A. salina. However, the juice fibers imparted some damage to the animal’s body. The ultrasound-processed juice (2 and 6 min) decreased the A. salina mortality to 30% compared to the control assay with H2O2 where mortality was 80% after 48 h of exposure. However, after 72 h of exposure, the A. salina was entirely degraded by H2O2-induced toxicity. Furthermore, the catalase and superoxide dismutase presented the highest activity after A. salina was exposed to the unprocessed juice. Thus, sapota-do-Solimões juice processed by the ultrasound could promote a protective effect on A. salina, revealing this technology’s potential to enhance juice features without toxicity.

Antrocaryon amazonicum: An unexploited Amazonian fruit with high potential of scavenging reactive oxygen and nitrogen species

Antrocaryon amazonicum fruits are unexploited sources of bioactive compounds found in the Amazonia region of Brazil. In this study, for the first time, the carotenoid and phenolic compound profiles of the pulp and peel of A. amazonicum fruits, from two varieties at two harvest periods, were determined by LC-MS. Additionally, the potential of the peel and pulp extracts to scavenge physiologically relevant reactive oxygen species (ROS) and reactive nitrogen species (RNS) was assessed. The major carotenoids in both parts of the fruits were lutein, accounting for ≈42% of the identified carotenoids in the peel and ≈25% in the pulp, whereas catechin and hydroxybenzoic acid derivatives were the major phenolics in both parts. The peel extract, which presented the highest bioactive compound contents, was more efficient to scavenge ROS than the pulp. The peel extract showed high scavenging efficiency (IC₅₀ ) for singlet oxygen (¹ O₂ ; 16 µg/ml), hypochlorous acid (HOCl; 20 µg/ml), peroxynitrite (ONOO^- ; 38 µg/ml), and superoxide radical (O₂ ^•- ; 47 µg/ml), whereas the pulp extract exhibited high efficiency for ONOO^- (13 µg/ml), followed by HOCl (30 µg/ml), ¹O₂ (76 µg/ml), and less efficient for O₂ ^•- (44 µg/ml). Therefore, A. amazonicum fruits can be seen as an expressive source of bioactive compounds with high antioxidant potential to be further investigated to inhibit or delay oxidative processes both in food and physiological systems triggered by ROS and RNS. PRACTICAL APPLICATION: Bioactive compound extracts of Antrocaryon amazonicum fruits have high potential to be exploited for inhibiting or delaying oxidative processes and increase food stability.

A study of the bioactive potential of seven neglected and underutilized leaves consumed in Brazil

This study investigated the vitamin C content, total phenolic compounds (TPC), and the potential bioactivities (antioxidant, antiproliferative, antibacterial activities, and inhibition capacity against N-nitrosation) of seven neglected and underutilized species (NUS): culantro (Eryngium foetidum), false roselle (Hibiscus acetosella), roselle (Hibiscus sabdariffa), tree basil (Ocimum gratissimum), Barbados Gooseberry (Pereskia aculeata), purslane (Portulaca oleracea), and tannia (Xanthosoma sagittifolium). Phenolic-rich extracts were obtained by a sequential optimization strategy (Plackett-Burman and Central Composite Design). O. gratissimum presented the highest TPC and X. sagittifolium the greater total vitamin C content. Overall, the plant extracts presented promising bioactive capacities, as scavenging capacity against HOCl, H₂O₂ and ROO^• induced oxidation. P. oleracea demonstrated the highest cytostatic effect against ovarian and kidney tumor cells. O. gratissimum effectively inhibited S. Choleraesuis growth. Maximum inhibition on n-nitrosation was showed by O. gratissimum and E. foetidum. These results highlight the studied NUS as sources of potential health-promoting compounds.

Phenolic profile and potential beneficial effects of underutilized Brazilian native fruits on scavenging of ROS and RNS and anti-inflammatory and antimicrobial properties

Brazilian native fruits (BNF) have aroused interest of researchers and consumers for their great human health benefits. In this study, five BNF (Byrsonima lancifolia, Campomanesia phaea, Jacaratia spinosa, Solanum alternatopinnatum and Acnistus arborescens) were tested for their polyphenolic compounds by LC-ESI-MS/MS, reactive species deactivation (ROO˙, O2˙-, HOCl and NO˙), anti-inflammatory properties in vivo, and in vitro antimicrobial activity - with determination of putative mechanism(s) of action. Eighty-one polyphenols were identified, which exhibited a significant capacity to deactivate both ROS and RNS. C. phaea extract had the highest capacity to scavenge ROO˙ (68.94 μmol TE per g), O2˙- (IC50: 575.36 μg mL-1) and NO˙ (IC50: 16.96 μg mL-1), which may be attributed to the presence of ellagitanins. B. lancifolia decreased neutrophil influx into the peritoneal cavity of mice by 50% as compared to carrageenan and reduced Candida albicans biofilm viability by 3 log10 possibly due to complexation with cell membrane ergosterol. In summary, the BNF presented herein are good sources of bioactive compounds with positive effects on deactivation of biological reactive species, as well as with anti-inflammatory and antimicrobial activities, which can be altogether highly beneficial to human health.

Melatonin delays leaf senescence of postharvest Chinese flowering cabbage through ROS homeostasis

Reactive oxygen species (ROS) trigger and accelerate leaf senescence. Melatonin, a low molecular compound with several biological functions in plants, is known to delay leaf senescence in different species, including Chinese flowering cabbage. However, the mechanism(s) underpinning melatonin-delayed leaf senescence remains unclear. Here, we found that melatonin lowered the expression of chlorophyll catabolic genes (BrPAO and BrSGR1) and senescence-associated genes (BrSAG12 and BrSEN4), decreased chlorophyll loss, minimized the alteration in Fv/Fm ratio and remarkably delayed senescence of Chinese flowering cabbage after harvest. Moreover, the over-accumulation of O₂^•-, hydrogen peroxide (H₂O₂) and malondialdehyde contents and the expression of respiratory burst oxidase homologues (RBOH) genes (BrRbohB, BrRbohC, BrRbohD, BrRbohD2 and BrRbohE) were significantly inhibited by melatonin treatment. Melatonin-treated cabbages also showed higher O₂^•-, OH^• and DPPH radical scavenging capacity and enhanced activities of peroxidase (POD), superoxide dismutase (SOD) and their gene expressions. Up-regulation of key components of ascorbate-glutathione (AsA-GSH) cycle, the metabolic pathway that detoxify H₂O₂, was also observed in melatonin-treated cabbages. These findings suggest that melatonin-delayed postharvest leaf senescence of postharvest Chinese flowering cabbage may be mediated, at least in part, by maintaining ROS homeostasis through restraining RBOHs-catalyzed ROS production and enhancing the activity of ROS-scavenging system including major antioxidant enzymes and AsA-GSH cycle.

Chlorinated phosphorus flame retardants exert oxidative damage to SMMC-7721 human hepatocarcinoma cells

Chlorinated phosphorus flame retardants are organic pollutants widely distributed in the environment. However, there is still a lack of understanding of the toxicity mechanism of chlorinated phosphorus flame retardants at the molecular level. Tris (1, 3-dichloroisopropyl) phosphate (TDCPP), tris (2-chloropropyl) phosphate (TCPP) and tris (2-chloroethyl) phosphate (TCEP) were used as typical representatives of chlorinated phosphorus flame retardants to evaluate their cytotoxicity as well as changes in the expression of the enzymes lactate dehydrogenase (LDH), superoxide dismutase (SOD), and catalase (CAT), which will be meaningful for an in-depth study of the toxicity mechanism of TDCPP, TCPP and TCEP. The results showed that the three chemicals reduced cell viability over a period of 24 h. The exposure increased extracellular levels of lactate dehydrogenase and decreased intracellular levels of superoxide dismutase and catalase in a concentration-dependent manner. Expression of the SOD and CAT genes were down-regulated indicating that the SMMC-7721 human hepatocarcinoma cells may experience oxidative damage as a result of exposure to the three chemicals. The expression of the Bax apoptosis protein was up-regulated and the Bcl-2 apoptosis protein was down-regulated, suggesting that the three chemicals may cause functional defects, damage the cell structure and promote apoptosis. The results from this study should provide the basis for a detailed investigation of the ecological toxicity of chlorinated phosphorus flame retardants.

Extracts of Peels and Seeds of Five Varieties of Brazilian Jabuticaba Present High Capacity to Deactivate Reactive Species of Oxygen and Nitrogen

Jabuticaba has a high concentration of phenolic compounds, which have a significant antioxidant capacity. Methodologies have been developed to evaluate the ability of plant extracts to fight free radicals such as H₂O₂, O₂^•-, HOCl, ONOO- and ROO^•. Thus, the capacity of deactivation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in peel and seed extracts of five varieties of jabuticaba was evaluated. Sabará peel (SFP) deactivated HOCl with IC₅₀ 9.24 μg. mL^-1; Paulista seed (PF) deactivated O₂^•- with IC₅₀ 16.15 μg. mL^-1; Coroada seed (CFP) deactivated ONOO- with IC₅₀ 3.84 μg. mL^-1; the peel of CFP deactivated ONOO- with IC₅₀ 5.88 μg. mL^-1; the peel of SFP deactivated the ROO^• at 918.16 μmol TE. g^-1; and Sabará seed deactivated H₂O₂ with 49.11% inhibition at a concentration of 125 μg. mL^-1 of extract. These results demonstrate the high antioxidant potential of this fruit, indicating that it could be extremely beneficial to human health.