Advanced Extraction Techniques Combined with Natural Deep Eutectic Solvents for Extracting Phenolic Compounds from Pomegranate (Punica granatum L.) Peels.

Pomegranate (Punica granatum L.) peel is a potential source of bioactive phenolic compounds such as ellagic acid and α- and ß-punicalagin. This work explores the efficiency of natural deep eutectic solvents combined with ultrasound-assisted extraction (UAE) and pressurized liquid extraction (PLE) for their extraction. Five NaDESs were evaluated by employing UAE (25 °C, for 50 min) to determine their total phenolic content (Folin-Ciocalteu assay) and ellagic acid and α- and ß-punicalagin contents (high-performance liquid chromatography (HPLC-DAD)). The NaDES composed of choline chloride (ChCl) and glycerol (Gly) (1:2, molar ratio) was the most efficient in the UAE when compared with the rest of the NaDESs and water extracts. Therefore, ChCl:Gly was further evaluated using PLE at different temperatures (40, 80, 120 and 160 °C). The PLE-NaDES extract obtained at 80 °C for 20 min at 1500 psi exhibited the highest contents of ellagic acid and α- and ß-punicalagin compared to the rest of the temperatures and PLE-water extracts obtained under the same extraction conditions. Combining UAE or PLE with a NaDES emerges as a sustainable alternative for extracting ellagic acid and α- and ß-punicalagin from pomegranate peel.

Evaluation of the acute toxicity of ellagic acid and gallic acid incorporated in Poloxamer407® gel, in Zophobas morio larvae.

Gallic acid (GA) has antioxidant, anti-inflammatory and antimicrobial properties, while ellagic acid (EA) demonstrates anticancer, antiviral and photoprotective activity. In this study, the combination of these substances incorporated into a poloxamer gel was tested to verify the individual effect of the substances, in addition to taking advantage of a probable complementary effect, aiming to provide additional therapeutic benefits. As a result of the incorporation, formulations containing GA, EA and GA + EA were obtained, which were evaluated for the effects of the Freeze-thaw cycle on pH, which revealed a significant decrease (p < 0.05) in most samples, including the vehicle (without drug) and the gel containing both drugs. No sample showed variation outside the normal pH range for the skin, with values ranging from 4.8 to 6.0. Regarding conductivity, the GA, EA and GA + EA formulations showed a reduction (p < 0.05) after the freeze-thaw cycle. The drug content in the formulations ranged from 95.86% to 101.35% initially to 91.30% to 101.51% after the freeze-thaw cycle. Regarding the drug release, the results revealed the following cumulative percentages: GA-3% - 92.58% after 1.5 h; AE-3% - 51.60% after 6 h; GA + EA (1.5% = 1.5%) - 99.91% after 2 h; GA + EA- (1.5% = 1.5%) released 57.06%, after 6 h. Regarding toxicity, it was observed that the group treated with GA showed a lower survival rate of the larvae (40%) at the dose 3000 mg/Kg in the formulation. Following the same trend, in the acute lethal concentration (ALC50) test performed using Zophobas morio larvae, an ALC50 of 2191.51 mg/Kg was observed for GA at 48 h. Melanin analysis showed a decrease in concentrations of 30 mg/Kg in the GA group, 3 mg/Kg of EA and 3, 300, 3000 mg/Kg of GA + EA, of the pure drugs. In the groups with the drugs incorporated into the gel, there was a significant decrease (P < 0.05) in melanin in the vehicle (gel), at concentrations of 300 and 3000 mg/Kg of GA and EA. On the other hand, in the combination of GA + EA, a reduction was observed at concentrations of 3 and 30 mg/Kg when compared to the control group. Thus, the gel showed good quality as a pharmaceutical formulation for topical use and low toxicity, making it promising for use in skin therapies.

Ellagic Acid-Cyclodextrin Complexes for the Treatment of Oral Candidiasis.

The increase in the prevalence of fungal infections worldwide and the rise in the occurrence of antifungal resistance suggest that new research to discover antifungal molecules is needed. The aim of this study was to evaluate the potential use of ellagic acid-cyclodextrin complexes (EA/HP-ß-CD) for the treatment of oral candidiasis. First, the effect of EA/HP-ß-CD on C. albicans planktonic cells and biofilms was evaluated. Then, the cytotoxicity of the effective concentration was studied to ensure safety of in vivo testing. Finally, the in vivo effectiveness was determined by using a murine model of induced oral candidiasis. Data was statistically analyzed. The minimal inhibitory concentration of EA/HP-ß-CD was 25 µg/mL and a concentration of 10 times MIC (250 µg/mL) showed an inhibitory effect on C. albicans 48 h-biofilms. The complex at concentration 250 µg/mL was classified as slightly cytotoxic. In vivo experiments showed a reduction in fungal epithelial invasion after treatment with EA/HP-ß-CD for 24 h and 96 h when compared to the negative control. In conclusion, the results demonstrated that EA/HP-ß-CD has antifungal and anti-inflammatory effects, reducing the invasive capacity of C. albicans, which suggests that EA/HP-ß-CD may be a promising alternative for the treatment of oral candidiasis.

Is it possible to obtain nanodispersions with jaboticaba peel's extract using low energy methods and absence of any high cost equipment?

Jaboticaba (Myrciaria cauliflora) is considered a "super fruit" due to its remarkable phenolic content and antioxidant capacity. Despite the great potential of its peels, to our knowledge the investigation of novel nanostructured systems with this natural raw material, still considered an industrial residue, is scarce. The present study aimed to obtain nanodispersions with its peel's extract through a low energy method. Antioxidant assays were performed, showing positive results for DPPH (IC50 = 0.89 µg/mL) and FRAP (225.53 µmol equivalent ferrous sulphate/g). The chemical characterization in terms of flavonoids (2.56%) and total monomeric anthocyanins (0.80%) contents were also performed. Overall, the nanodispersion prepared with the non-ionic surfactant polysorbate 85 and the hydroalcoholic extract standardized in ellagic acid (129 µg/mL) presented the best properties regarding particle size distribution and zeta potential. Thus, it opens perspectives for the generation of novel food-grade nanodispersions through an ecofriendly approach that is in accordance to sustainable concepts.

Flavonols and ellagic acid derivatives in peels of different species of jabuticaba (Plinia spp.) identified by HPLC-DAD-ESI/MSn.

Extracts of jabuticaba peels show complex chromatographic profiles at 360 nm, with some peaks presenting UV-Vis spectra resembling those of flavonol glycosides and others resembling that of ellagic acid. The presence and tentative identification of these phenolic compounds were comprehensively studied in four species of Brazilian jabuticaba fruit - Plinia trunciflora, variety 'jabuticaba de cabinho'; P. caulifora, varieties 'jabuticaba paulista' and 'jabuticaba canaã-açu'; P. jaboticaba, variety 'jabuticaba sabará'; and P. phitrantha, variety 'jabuticaba branca-vinho' - using HPLC-DAD-ESI-MSn. Seventeen flavonols derived from quercetin and three from myricetin and eighteen derivatives of ellagic acid and eleven of methyl ellagic acid were detected. Most of them were newly described and mainly occurred in glycosylated and acylglycosylated forms. Some compounds were missing in one variety, such as the absence of methyl ellagic acid derivatives in 'jabuticaba branca-vinho', and others only appeared in one variety, thus suggesting potential capacity for varietal differentiation.

Jaboticaba (Plinia peruviana) extract nanoemulsions: development, stability, and in vitro antioxidant activity.

OBJECTIVE: The aim of this work is to develop and characterize nanoemulsions containing jaboticaba extract (Plinia peruviana) aiming pharmaceutical and cosmetic applications. METHODS: Nanoemulsions were prepared by high-pressure homogenization method using different concentrations of components (oil, surfactant, and extract) and homogenization pressures, in order to optimize the preparation conditions. Both unloaded and extract-loaded nanoemulsions were characterized according to their size, polydispersity, zeta potential, pH, morphology, and physical stability. Total phenolic and flavonoid contents in free jaboticaba extract and jaboticaba-loaded nanoemulsions were determined spectrophotometrically, while ellagic acid content was determined by high-performance liquid chromatography (HPLC) analysis. In vitro antioxidant activity was investigated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. RESULTS: Colloidal dispersions exhibited a mean particle size around 200 nm, with monodisperse size distribution (PdI <0.3), and spherical shape. Stability studies showed that nanoemulsions were stable over 120 d of storage at room temperature. Jaboticaba nanoemulsions showed significant concentrations of phenolics, flavonoids, and ellagic acid, with encapsulation efficiency values higher than 90%. Antioxidant properties of jaboticaba nanoemulsions were demonstrated by its remarkable ability to scavenge DPPH free radicals and to reduce ferric-tripyridyltriazine complex, which can be attributed to their phenolic and flavonoid contents. CONCLUSIONS: The results suggest that nanoemulsions containing jaboticaba extract can be considered a promising candidate as a new antioxidant agent.

Ellagitannins: Bioavailability, Purification and Biotechnological Degradation.

The ellagitannins are a group of phenolic compounds with biological activities. Ellagic acid is the product obtained from hydrolysis of ellagitannins. Information related to the biosynthesis of ellagitannins still been scarce and confused. The ellagitannins are obtained from plants and their purification process implies mainly the use of chromatographic techniques. The ellagitannin acyl hydrolase (EAH) also known as ellagitannase is an enzyme capable of hydrolyzing the ester bonds of ellagitannins and the consequent releasing of ellagic acid. Information about the EAH is not clear because the enzyme had showed different activities due to the low purity or complexity of substrates and there is no available information about the biochemical, physicochemical and molecular characteristics of EAH. The present review describes information related to the sources, biosynthesis and the purification of ellagitannins and a current assessment on the production of ellagitannase.

Targeted Metabolomic Analysis of Polyphenols with Antioxidant Activity in Sour Guava (Psidium friedrichsthalianum Nied.) Fruit.

Psidium is a genus of tropical bushes belonging to the Myrtaceae family distributed in Central and South America. The polar extract of Psidium friedrichsthalianum Nied. was partitioned with ethyl ether, ethyl acetate, and n-butanol, and the total phenolic content and antioxidant activity were measured by Folin-Ciocalteu and ABTS assays, respectively. The ethyl acetate fraction exhibited both the highest phenolic content and antioxidant activity. Due to the complexity of this fraction, an analytical method for the comprehensive profiling of phenolic compounds was done by UPLC-ESI/QqQ in MRM (multiple reaction monitoring) mode. In this targeted analysis, 22 phenolic compounds were identified, among which several hydroxybenzoic, phenylacetic, and hydroxycinnamic acid derivatives were found. This is the first time that (+)-catechin, procyanidin B1, procyanidin B2, and (-)-epicatechin have been reported as constituents of sour guava. A fractionation by exclusion size, C18-column chromatography, and preparative RRLC (rapid resolution liquid chromatography) allowed us to confirm the presence of ellagic acid and isomeric procyanidins B, well-known bioactive compounds. The content of phenolic compounds in this fruit shows its potential for the development of functional foods.

Ricinine and other constituents of Aparisthmium cordatum (Euphorbiaceae).

The chemical study of Aparisthmium cordatum (Euphorbiaceae) led to the isolation of tannins, together with the alkaloid ricinine and other common compounds. The composition of A. cordatum is similar to most of the Alchornea species, from the same subtribe, except for the occurrence of ricinine. This study rectifies the first investigations published for A. cordatum that were conducted with Croton palanostigma.

Variations in antioxidant properties of strawberries grown in Brazilian savannah and harvested in different seasons.

BACKGROUND: Strawberries are nutritive fruits and a source of antioxidants. We evaluated antioxidant properties of 'Camino Real' strawberries grown in the Brazilian savannah, harvested in different seasons. Analytical and meteorological data were analyzed by partial least squares regression. RESULTS: Fruits from May showed the lowest contents of total phenolics (1789.78 mg kg⁻¹ fresh weight (FW)), catechin (21.37 mg kg⁻¹ FW), quercetins (4.89 mg kg⁻¹ FW) and total ellagic acid (208.68 mg kg⁻¹ FW) and the lowest antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) (11.39 mg Butylated hydroxytoluene (BHT) eq. g⁻¹ FW) and ferric reducing antioxidant power (FRAP) (22.01 mg ferrous sulfate eq. g⁻¹ FW) assays. Strawberries harvested in July presented the lowest concentrations of total (190.61 mg kg⁻¹ FW) and individual anthocyanins (73.88 mg kg⁻¹ FW and 5.96 mg kg⁻¹ FW for pelargonidin-3-glucoside and cyanidin-3-glucoside, respectively), but the highest contents of vitamin C (685.47 mg kg⁻¹ FW), DPPH (18.87 mg BHT eq. g⁻¹ FW) and FRAP (39.30 mg ferrous sulfate eq. g⁻¹ FW). The highest contents of free ellagic acid (26.11 mg kg⁻¹ FW), pelargonidin-3-glucoside (291.82 mg kg⁻¹ FW) and cyanidin-3-glucoside (11.84 mg kg⁻¹ FW) were found in strawberries from September. Rain in the previous 30 days to harvest influenced negatively many phenolics and antioxidant activity of strawberries harvested in May. In July, longer photoperiod and lower temperature at 30 days previous to harvest probably led to higher antioxidant activity and vitamin C. Increased photoperiod and temperature at the final stage of maturation seem to raise pigments and free ellagic acid in strawberries. CONCLUSION: It was possible to observe significant relationships among meteorological and antioxidant variables for strawberries grown in the Brazilian savannah.

Isolation and characterization of ellagic acid derivatives isolated from Casearia sylvestris SW aqueous extract with anti-PLA(2) activity.

The Casearia sylvestris SW (Flacourtiaceae) is utilized in folk medicine (Brazil and all Latin American) to treat several pathologic processes as inflammation, cancer, microbial infection and snake bites. Studies showed that C. sylvestris aqueous extract can inhibit many toxic effects caused by snake venoms (or caused by phospholipase A(2) isolated) from different species, mainly of Bothrops genus. Inhibition of enzymatic and myotoxic activities, decrease of edema formation and increase of the survival rate of rats injected with lethal doses of bothropic venoms are some toxic effects inhibited by C. sylvestris. In this study, four ellagic acid derivatives from aqueous extracts of C. sylvestris were isolated, characterized, and tested against effects from both total venom and PLA(2) (Asp 49 BthTX-II) from the venom of Bothrops jararacussu. The isolated compounds were as follows: ellagic acid (A), 3'-O-methyl ellagic acid (B), 3,3'-di-O-methyl ellagic acid (C), 3-O-methyl-3',4'-methylenedioxy ellagic acid (D). The inhibition constant values (Ki) for enzymatic activity, as well the IC(50) values found in the edematogenic and myotoxic activities, indicate that the ellagic acid is the best inhibitor of these activities, while compounds C and D are the substances with lowest capacity on inhibiting these same effects. Our results show that the presence of hydroxyls at position 3 or 3' (compounds A and B) increases the capacity of these derivatives on inhibiting these toxic effects. However, the presence of methoxyl groups at position 3 or 3' reduced, but did not completely inhibit the capacity of compounds C and D on inhibiting all the toxic effects studied.

Ellagic acid production by Aspergillus niger in solid state fermentation of pomegranate residues.

Two Aspergillus niger strains (GH1 and PSH) previously isolated from a semiarid region of Mexico were characterized for their effectiveness in converting pomegranate ellagitannins (ET) into ellagic acid (EA) in a solid state fermentation (SSF). Pomegranate seeds and husk were used as support for the SSF. Released EA was evaluated by liquid chromatography. Yields of 6.3 and 4.6 mg of EA per gram of dried pomegranate husk were obtained with A. niger GH1 and PSH, respectively. Total hydrolyzable polyphenols of pomegranate husk were degraded during the first 72 h of culture (71 and 61%, by GH1 and PSH strains, respectively). Tannin acyl hydrolase activity was not clearly associated with EA production. EA that accumulated in cultures of A. niger GH1 was remarkably pure after a simple extraction process. Pomegranate husk is a good support, and at the same time an excellent substrate in the production of high commercial interest metabolites like EA due the degradation of its ET content.

Phenolic compounds from Miconia myriantha inhibiting Candida aspartic proteases.

Assay-guided fractionation of the ethanol extract of the twigs and leaves of Miconia myriantha yielded two new compounds, mattucinol-7-O-[4' ',6' '-O-(S)-hexahydroxydiphenoyl]-beta-D-glucopyranoside (1) and mattucinol-7-O-[4' ',6' '-di-O-galloyl]-beta-D-glucopyranoside (2), along with mattucinol-7-O-beta-D-glucopyranoside (3), ellagic acid (4), 3,3'-di-O-methyl ellagic acid-4-O-beta-D-xylopyranoside, and gallic acid. Complete (1)H and (13)C NMR assignments of compound 1, which possesses a hexahydroxydiphenoyl unit, were achieved using the HMBC technique optimized for small couplings to enhance the four-bond and two-bond H/C correlations. Compounds 1 and 4 showed inhibitory effects against Candida albicans secreted aspartic proteases, with IC(50) of 8.4 and 10.5 microM, respectively.

Constituents of Coriaria ruscifolia fruits.

Corianin (1) and ellagic acid 3,3'-dimethylether (2) were obtained from the methanol extract of powdered fruits of Coriaria ruscifolia. Biological screening of both compounds and of the methanol extract revealed slight antibacterial activity and cytotoxicity.