Advancements in Litchi chinensis Peel Processing: A Scientific Review of Drying, Extraction, and Isolation of Its Bioactive Compounds.

This article systematically reviews the advancements in processing litchi peel (Litchi chinensis), emphasizing drying, extraction, purification methods, and the potential of bioactive compounds obtained from litchi peel. This work also highlights the impact of various drying techniques on phytochemical profiles, focusing on how methods such as hot air and freeze-drying affect the preservation of bioactive compounds. The study delves into extraction methods, detailing how different solvents and techniques influence the efficiency of extracting bioactive compounds from litchi peel. Furthermore, the purification and characterization of active compounds, showcasing the role of chromatographic techniques in isolating specific bioactive molecules, is discussed. Biological properties and mechanisms of action, such as antioxidant, antihyperglycemic, cardioprotective, hepatoprotective, anti-atherosclerotic, and anticancer activities, are reviewed, providing insight into the potential health benefits of litchi peel compounds. This review highlights the importance of optimizing and selecting accurate drying and extraction methods to maximize the therapeutic effects of litchi peel and its bioactive compounds. This review also reveals the broad pharmacological potential of the isolated compounds, underscoring the need for further research to discover their specific actions and health benefits.

Procyanidins: From Agro-Industrial Waste to Food as Bioactive Molecules.

Procyanidins are an important group of bioactive molecules known for their benefits to human health. These compounds are promising in the treatment of chronic metabolic diseases such as cancer, diabetes, and cardiovascular disease, as they prevent cell damage related to oxidative stress. It is necessary to study effective extraction methods for the recovery of these components. In this review, advances in the recovery of procyanidins from agro-industrial wastes are presented, which are obtained through ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, pressurized fluid extraction and subcritical water extraction. Current trends focus on the extraction of procyanidins from seeds, peels, pomaces, leaves and bark in agro-industrial wastes, which are extracted by ultrasound. Some techniques have been coupled with environmentally friendly techniques. There are few studies focused on the extraction and evaluation of biological activities of procyanidins. The identification and quantification of these compounds are the result of the study of the polyphenolic profile of plant sources. Antioxidant, antibiotic, and anti-inflammatory activity are presented as the biological properties of greatest interest. Agro-industrial wastes can be an economical and easily accessible source for the extraction of procyanidins.

Structural characterization of native and oxidized procyanidins (condensed tannins) from coffee pulp (Coffea arabica) using phloroglucinolysis and thioglycolysis-HPLC-ESI-MS.

Procyanidins from coffee pulp are responsible from the limited valorization of this by-product. Information about procyanidin structure is still scarce and imprecise. The aim of this work was to study the native and oxidized procyanidins from coffee pulp with respect to composition and structure. An aqueous acetone extract from coffee pulp was purified using Sephadex LH-20. Butanolysis, phloroglucinolysis and thioglycolysis coupled to HLPC-ESI-MS were applied for the characterization of the native and oxidized procyanidins. The purification allowed to recovery three fractions (aqueous, ethanolic and acetonic) and only acetone fraction showed a high concentration of procyanidins (98%, w/w). HPLC-ESI-MS of procyanidins-rich fraction without any reaction resulted in a UV-Vis chromatogram unresolved typical of the presence of procyanidins. The extracted ion chromatogram and MS2 analysis revealed the presence from dimers to pentamers of native procyanidins. Interestingly, by first time an A-type trimeric procyanidin (m/z of 863) was observed in coffee pulp. In our study, (-)-epicatechin was the constitutive unit of procyanidins with an aDP of 6.8 (oligomeric native procyanidins) according to the phloroglucinolysis assay. Two oxidation markers useful to characterization of oxidized procyanidins were observed in the procyanidins-rich fraction after thioglycolysis, a dimer A2-ext and a molecule that corresponds to a linkage between an extension and a terminal unit. Coffee pulp procyanidins were presented with only a minor class of oxidized procyanidins. As far as we know, this is the first study about characterization of the oxidized procyanidins from coffee pulp.

Characterization by HPLC-ESI-MS2 of native and oxidized procyanidins from litchi (Litchi chinensis) pericarp.

Procyanidins (PCs) are polyphenols highly accumulated in litchi fruit (Litchi chinensis). Despite their bioactivity, the molecular composition of native and oxidized procyanidins is little understood. In this paper, polyphenols from litchi pericarp were extracted using two solvents (methanol and acetone). The mean degree of polymerization (mDP) of native and identification of oxidized PCs were carried out by phloroglucinolysis- and thioglycolysis-HPLC-ESI-MS/MS, respectively. About 60% of extracted polyphenols corresponded to procyanidins from litchi pericarp. Native PCs were mainly oligomeric procyanidins (mDP 4). Only (-)-epicatechin was detected as terminal and extension units in PCs. Thioglycolysis-HPLC-ESI-MS identified five oxidation markers of PCs with [M-H]-m/z 575, 593, 609, 679 and 863. Intra- and intermolecular modifications of A and B-type procyanidins were identified. The method used for the characterization of PCs from litchi pericarp allowed understanding of the structural composition of its native and oxidized tannins.

On-line monitoring of Aspergillus niger GH1 growth in a bioprocess for the production of ellagic acid and ellagitannase by solid-state fermentation.

The present work describes the monitoring of CO2 production by Aspergillus niger GH1 in a bioprocess for the production of ellagitannase (EAH) and ellagic acid by solid state fermentation. Pomegranate ellagitannins, mainly punicalagin, were used as carbon source and EAH inducer. A second condition, using ellagitannins and maltose as growth promoting carbon source, was tested. The ellagic acid production was quantified and the EAH activity was assayed. The accumulated metabolites were identified by HPLC-ESI-MS/MS. Higher CO2 production (7.79mg/grams of dry material) was reached in media supplemented with maltose. Short-time lag phase (7.79h) and exponential phase (10.42h) were obtained using only ellagitannins, despite its lower CO2 production (3.79mg/grams of dry material). Without the use of maltose lower ellagic acid (11.85mg/L/h) and EAH (21.80U/L/h) productivities were reached. The use of maltose enhances the productivity of EA (33.18mg/L/h) and EAH (33.70U/L/h). Besides of punicalin and ellagic acid, two unknown compounds with mass weight of 702 and 290g/mol (ions 701 and 289m/z in negative mode, respectively) were identified and characterized by HPLC-ESI-MS/MS analysis.

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.

Characterisation of Pomegranate-Husk Polyphenols and Semi-Preparative Fractionation of Punicalagin.

INTRODUCTION: Pomegranate-husk is the main by-product generated from the pomegranate industry. It is a potential source of compounds highly appreciated by different costumers. Punicalagin is the main compound present in pomegranate-husk. OBJECTIVE: To characterise the pomegranate-husk total polyphenols by HPLC-ESI-MS and to establish a method for the recovery of punicalagin using a medium pressure liquid chromatography (MPLC) system. MATERIALS AND METHODS: The characterisation of total pomegranate-husk polyphenols was carried out using liquid chromatography coupled to mass spectrometry. Thus, 200 mg of pomegranate-husk polyphenols were fractionated by MPLC. The isolated punicalagin was characterised by HPLC-MS and was tested as standard reagent for the measurement of its scavenging capacity reducing DPPH and ABTS radicals. RESULTS: Twenty peaks were identified by analytical HPLC-MS analysis from the pomegranate-husk polyphenols. The main compounds were the punicalagin anomers, punicalin and ellagic acid. The MPLC method allowed three fractions to be obtained. In fraction three 39.40 ± 8.06 mg of punicalagin anomers (purity > 97.9%) were recovered. The scavenging capacity of punicalagin showed an IC50 of 109.53 and 151.50 µg/mL for DPPH and ABTS radicals, respectively. CONCLUSION: The MPLC system was an excellent tool for the separation of the main ellagitannins from pomegranate husk and for the isolation of punicalagin anomers. Fraction three was rich in high purity punicalagin anomers. The IC50 was obtained for DPPH and ABTS radicals. Copyright © 2017 John Wiley & Sons, Ltd.

Gallic acid production under anaerobic submerged fermentation by two bacilli strains.

BACKGROUND: Tannase is an enzyme that catalyses the breakdown of ester bonds in gallotannins such as tannic acid. In recent years, the interest on bacterial tannases has increased because of its wide applications. The lactic acid bacteria (LAB) plays an important role in food tannin biotransformation, it has the ability of hydrolyse tannins in ruminants intestine. The finding of tannin hydrolysis by LAB has sparked their use as tannase producer. RESULTS: The bacterial strains used in the present work were identified as Bacillus subtilis AM1 and Lactobacillus plantarum CIR1. The maximal tannase production levels were 1400 and 1239 U/L after 32 and 36 h of fermentation respectively, for B. subtilis AM1 and L. plantarum CIR1. Maximum gallic acid release was 24.16 g/L for B. subtilis AM1 and 23.73 g/L for L. plantarum CIR1. HPLC analysis showed the formation of another peaks in the retention time range of 9-14 min, which could be attributed to the formation of di or tri-galloyl glucose. CONCLUSIONS: According to database, the strains were identified as Bacillus subtilis AM1 and Lactobacillus plantarum CIR1. In conclusion, both strains had the capability to produce good titres of extracellular tannase and release gallic acid.

Total phenolic content, in vitro antioxidant activity and chemical composition of plant extracts from semiarid Mexican region.

OBJECTIVE: To determine the extraction suitable conditions of total phenolic content (TPC) by heat-reflux system, antioxidant activities and HPLC characterization of the aqueous-ethanolic extracts of Jatropha dioica (J. dioica) (Dragon's blood), Flourensia cernua (F. cernua) (Tar bush), Eucalyptus camaldulensis (E. camaldulensis) (Eucalyptus) and Turnera diffusa (T. diffusa) (Damiana). METHODS: TPC was evaluated by the well-known colorimetric assay using Folin-Ciocalteu reagent. The antioxidant activities were assayed by three methods based on scavenging of DPPH, ABTS and by lipid oxidation inhibition. The chemical composition of the extracts obtained was subject to HPLC analysis. RESULTS: TPC in the plant extracts ranged from 2.3 to 14.12 mg gallic acid equivalents/g for J. dioica and E. camaldulensis, respectively. The plant extracts of F. cernua, E. camaldulensis and T. diffusa showed similar strong antioxidant activities on scavenging of DPPH and lipid oxidation inhibition. In contrast, J. dioica extracts had lowest potential antioxidant in three assays used. HPLC assay showed the presence of several phenolic compounds in the extracts used. CONCLUSIONS: The results obtained suggest that F. cernua, E. camaldulensis and T. diffusa are potential sources to obtain bioactive phenolic compounds with high antioxidant properties which can be used in the factories as antioxidant agents or for treatments in diseases.

Ultrasound-assisted extraction of polyphenols from native plants in the Mexican desert.

Several plants that are rich in polyphenolic compounds and exhibit biological properties are grown in the desert region of Mexico under extreme climate conditions. These compounds have been recovered by classic methodologies in these plants using organic solvents. However, little information is available regarding the use of alternative extraction technologies, such as ultrasound. In this paper, ultrasound-assisted extraction (UAE) parameters, such as the liquid:solid ratio, solvent concentration and extraction time, were studied using response surface methodology (RSM) for the extraction of polyphenols from desert plants including Jatrophadioica,Flourensiacernua, Turneradiffusa and Eucalyptuscamaldulensis. Key process variables (i.e., liquid:solid ratio and ethanol concentration) exert the greatest influence on the extraction of all of the phenolic compounds (TPC) in the studied plants. The best conditions for the extraction of TPC involved an extraction time of 40min, an ethanol concentration of 35% and a liquid:solid ratio ranging from 8 to 12mlg(-1) depending on the plant. The highest antioxidant activity was obtained in the E. camaldulensis extracts. The results indicated the ability of UAE to obtain polyphenolic antioxidant preparations from desert plants.

Microplate quantification of total phenolic content from plant extracts obtained by conventional and ultrasound methods.

INTRODUCTION: There is increasing interest in phenolic compounds around the world because of their potential positive impact on human health. Phenolic compounds are largely found in fruits and vegetables. Extraction of phenolic compounds is a very important step in their recovery. The newly developed technique of ultrasound-assisted extraction (UAE) appears to be an advantageous alternative compared with conventional techniques, because it is simple and environmental friendly. The potential of UAE needs to be evaluated in each plant in order to demonstrate its efficiency. OBJECTIVE: The objective of the present study was to compare a conventional method and UAE on the extraction efficiency of phenolic compounds from Jatropha dioica, Fluorensia cernua, Turnera diffusa and Eucalyptus camaldulensis plants and evaluate the in vitro anti-oxidant potential. METHODS: Validation of the new method was carried out using mixed-model methodology and regression analysis. Feasibility of this new method was shown and applied using several plants extracts obtained by different extraction methods from semi-arid Mexican plants, which were characterised by high levels of polyphenols. Additionally, the anti-oxidant potential of these extracts was determined by 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. RESULTS: Results showed that the new microplate method can be used to determine total phenolic content in plant extracts. Additionally, an alternative extraction method by ultrasound was less efficient compared with the conventional method. CONCLUSION: The tested plants are good candidates to obtain nutraceuticals and functional food ingredients.

Ultrasound-assisted extraction of phenolic compounds from Laurus nobilis L. and their antioxidant activity.

Bay leaves (BL) (Laurus nobilis L., Family: Laureceae) are traditionally used to treat some symptoms of gastrointestinal problems, such as epigastric bloating, impaired digestion, eructing and flatulence. These biological properties are mainly attributed to its phenolic compounds. In this paper, ultrasound-assisted extraction of phenolic compounds from Laurus nobilis L. (Laureceae) was studied. Effects of several experimental factors, such as sonication time, solid/liquid ratio and concentration of solvent on extraction of phenolic compounds were evaluated through a randomized complete block design with factorial treatment arrangement (3(3)). The best extraction conditions were: 1g plant sample with 12 mL of 35% ethanol, for 40 min, obtaining a yield of phenolic compounds of 17.32±1.52 mg g(-1) of plant. In addition, free radical-scavenging potential of DPPH and lipid oxidation inhibition, by linoleic acid peroxidation of the selected extract was measured in order to evidence their antioxidant properties. Results indicated that high amounts of phenolic compounds can be extracted from L. nobilis by ultrasound-assisted extraction technology.