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Litchi (Litchi chinensis Sonn.) is a tropical fruit with various health benefits. The objective of this study is to present a thorough analysis of the cancer preventive and anticancer therapeutic properties of litchi constituents and phytocompounds. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis criteria were followed in this work. Various litchi extracts and constituents were studied for their anticancer effects. In vitro studies showed that litchi-derived components reduced cell proliferation, induced cytotoxicity, and promoted autophagy via increased cell cycle arrest and apoptosis. Based on in vivo studies, litchi flavonoids and other extracted constituents significantly reduced tumor size, number, volume, and metastasis. Major signaling pathways impacted by litchi constituents were shown to stimulate proapoptotic, antiproliferative, and antimetastatic activities. Despite promising antineoplastic activities, additional research, especially in vivo and clinical studies, is necessary before litchi-derived products and phytochemicals can be used for human cancer prevention and intervention. • Litchi (Litchi chinensis Sonn.) is a tropical fruit with various health benefits • We have evaluated the preventive and anticancer properties of litchi constituents • Litchi-derived components exert antiproliferative and proapoptotic activities • They also reduced tumor growth and metastasis in animal tumor models • Various litchi components target a plethora of cell signaling pathways [ABSTRACT FROM AUTHOR]

Lactobacillus strains have emerged as promising probiotics for enhancing the bioactivities of plant-based foods associated with flavonoid biotransformation. Employing microbial fermentation and mass spectrometry, we explored flavonoid metabolism in lychee pulp fermented separately by Lactiplantibacillus plantarum and Limosilactobacillus fermentum. Two novel metabolites, 3,5,7-trihydroxychromone and catechol, were exclusively identified in L. plantarum -fermented pulp. Concomitant with consumption of catechin and quercetin glycosides, dihydroquercetin glycosides, 2,4-dihydroxybenzoic acid and p -hydroxyphenyllactic acid were synthesized by two strains through hydrogenation and fission of C-ring. Quantitative analysis revealed that bound phenolics were primarily located in water-insoluble polysaccharides in lychee pulp. Quercetin 3- O -rutinoside was partially liberated from water-insoluble polysaccharides and migrated to water-soluble polysaccharides during fermentation. Meanwhile, substantial accumulations in short-chain fatty acids (increased 1.45 to 3.08-fold) and viable strains (increased by 1.97 to 2.00 Log 10 CFU/mL) were observed in fermentative pulp. These findings provide broader insight into microbial biotransformation of phenolics and possible guidance for personalized nutrition. [Display omitted] • Lactiplantibacillus plantarum converted flavonoids into chromone and phenolic acids • C-ring of quercetin 3- O -rutinoside (QR) was hydrogenated by Lactobacillus strains • QR and gallic acid were identified as the dominant bound phenolics in lychee pulp • Lactobacillus altered distribution of bound phenolics among various polysaccharides • Accumulation of phenolic metabolites enhanced quality of fermentative lychee pulp [ABSTRACT FROM AUTHOR]

Previous studies have indicated that hydrogen-rich water (HW) treatment can delay fruit ripening and senescence. However, little is known about the HW-delaying pulp breakdown. In this study, eight physiological characteristics revealed that HW treatment delayed both pericarp browning and pulp breakdown of litchi fruit. To gain a comprehensive understanding of the changes in litchi pulp, a combination of multiple metabolomics and gene expression analyses was conducted, assessing 67 primary metabolites, 103 volatiles, 31 amino acids, and 13 crucial metabolite-related genes. Results showed that HW treatment promoted starch degradation, decelerated cell wall degradation and glycolysis, and maintained the flavor and quality of litchi fruit. Furthermore, HW treatment stimulated the production of volatile alcohols, aldehydes, ketones, olefins, and amino acids, which might play a vital role in HW-delaying pulp breakdown. This study sheds light on the mechanism by which HW delayed pulp breakdown by investigating small molecule metabolites and metabolic pathways. • Hydrogen-rich water (HW) treatment delayed pulp breakdown of litchi fruit. • HW accelerated starch degradation, TCA cycle, lipid synthesis, ester synthesis and amino acids synthesis. • HW slowed down cell wall degradation, glycolysis, and sesquiterpene synthesis. • HW treatment induced volatile alcohols and olefins at early stage of storage. • Aldehydes, ketones and amino acids play vital role in HW-delaying pulp breakdown. [ABSTRACT FROM AUTHOR]

This study presents the contents of α-methylenecyclopropylglycine, a potentially toxic amino acid, in the peel, pulp and seed fractions of two well-known litchi varieties, namely Shahi and China, over a span of three harvest-seasons. For analysing α-methylenecyclopropylglycine, an LC-MS/MS-based method was validated. The method-accuracies fell within 75–110 % (RSD, <15 %) at 0.1 mg/kg (LOQ) and higher levels. A comparative evaluation of the results in peel, pulp and seed at 30 days before harvest (DBH), 15-DBH, and edible-ripe stage revealed that α-methylenecyclopropylglycine content increased as the litchi seeds grew towards maturity, regardless of the cultivar. In arils, at maturity, the concentration of α-methylenecyclopropylglycine ranged from not-detected to 11.7 μg/g dry weight. The Shahi cultivar showed slightly higher α-methylenecyclopropylglycine content in comparison to China litchi. This paper presents the first known analysis of combined seasonal data on different fruit components at various growth stages for the two chosen litchi cultivars grown in India. • An LC-MS/MS method optimised for estimation of α-methylenecyclopropylglycine in litchi • MCPG was quantified in peel, seed and aril of China and Shahi litchi at 3 growth stages • MCPG in litchi aril ranged between 0 and 11.7 μg/g DW • Shahi litchi showed slightly higher MCPG content over China cultivar • Ripe arils showed higher MCPG over unripe in Shahi cultivar [ABSTRACT FROM AUTHOR]

[Display omitted] • Two polysaccharides were obtained from unprocessed and Lactobacillus fermented litchi pulp (named LP and LPF, respectively). • LPF was more readily utilized by bacteria than LP. • LPF enhanced the levels of short-chain fatty acids than LP. • LPF increased the growth of Bifidobacterium , Prevotella , and Bacteroides than LP. • Structure-prebiotic activity relationship of litchi polysaccharides was elaborated. In this study, litchi polysaccharides were obtained from unfermented or fermented pulp by Lactobacillus fermentum (denoted as LP and LPF, respectively). The differences between LP and LPF in the colonic fermentation characteristics and modulatory of gut microbiota growth and metabolism were investigated with an in vitro fecal fermentation model. Results revealed that the strategies of gut bacteria metabolizing LP and LPF were different and LPF with lower molecular weight (Mw) was readily utilized by bacteria. The monosaccharide utilization sequence of each polysaccharide was Ara > Gla > GalA > GlcA ≈ Glu ≈ Man. Moreover, LPF promoted stronger proliferation of Bifidobacterium , Megamonas , Prevotella , and Bacteroides and higher SCFAs production (especially acetic and butyric acids) than LP. Correlation analysis further revealed that Mw could represent an essential structural feature of polysaccharides associated with its microbiota-regulating effect. Overall, Lactobacillus fermentation pre-treatment of litchi pulp promoted the fermentation characteristics and prebiotic activities of its polysaccharide. [ABSTRACT FROM AUTHOR]

[Display omitted] • Investigating metabolic signature of Quercetin 3- O -rutinose-7- O - α - l - rhamnoside (QRR). • 7- O -hydroxyethyl-isorhamnetin was identified in microbial metabolism of QRR. • Bacteroides and Akkermansia were enriched by QRR but not Quercetin 3- O -rutinose (QR). • QRR exerted a weaker release to aglycone than QR due to varying microbial response. Quercetin 3- O -rutinose-7- O - α - l - rhamnoside (QRR), a characteristic lychee pulp flavonoid, has been linked to diverse bioactivities involving microbial metabolism. By integrating colonic fermentation and mass spectrometry, the catabolites including 7- O -hydroxyethyl-isorhamnetin and 3′-amino-4′- O- methyl-7- O -hydroxyethyl-isorhamnetin were unprecedently identified and unique to QRR metabolism, relative to the structural analog quercetin 3- O -rutinoside (QR) metabolism. These above-described metabolites highlighted a special biotransformation hydroxyethylation in QRR catabolism. QRR was partially deglycosylated into quercetin 3- O -glucoside-7- O - α - l - rhamnoside potentially catalyzed by Bacteroides. QR was more directly degradable to aglycone during colonic fermentation than are QRR. Unlike with QR fermentation, equivalent QRR effectively upregulated concentrations of propionic and butyric acids that were highly relevant with Faecalibacterium and Coprococcus. After fermentation, the relative abundances of Bacteroides uniformis (0.03%) and Akkermansia muciniphila (0.13%) were only upregulated by QRR among all fermentation groups, leading to the enrichments of the corresponding genera. These results further reveal the relationship between flavonoid structures and metabolic characteristics. [ABSTRACT FROM AUTHOR]

Highlights • About 60% of extracted litchi pericarp polyphenols corresponded to procyanidins. • A first molecular structure of the oxidized procyanidins in litchi was achieved. • Five oxidation markers of procyanidins were clearly identified. • Thioglycolysis–HPLC–ESI–MS is a useful method to characterize oxidized procyanidins. Abstract 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. [ABSTRACT FROM AUTHOR]

Highlights • Eight phenolic compounds in litchi pulp were isolated and identified. • Molecular Networking was applied to characterize the phenolic compounds in plants. • Six phenolic compounds were discovered for the first time in litchi pulp. • Quercetin-3- O -rutinoside-(1 → 2)- O -rhamnoside had considerable α-glucosidase inhibitory activity. Abstract Phenolic compounds are a large class of plant secondary metabolites with various health-promoting effects, and are known for their structural diversity. Therefore, high efficiency characterization of phenolic profiles is of key importance in identifying their potential bioactivity. In the present study, Global Natural Products Social (GNPS) Molecular Networking was applied to trace the phenolic compounds in plants, which allowed the characterization of 9 procyanidins and 11 flavonoid glycosides (di-, tri-, or tetra-saccharides of kaempferol, quercetin, isorhamnetin and myricetin) in litchi pulp extracts. Six compounds were reported for the first time in litchi pulp. In addition, quercetin-3- O -rutinoside-(1 → 2)- O -rhamnoside, the most abundant flavonoid glycoside in litchi pulp, was proved to have considerable α-glucosidase inhibitory activity, illustrating the anti-diabetic potential of phenolic-rich litchi pulp extracts. [ABSTRACT FROM AUTHOR]

Highlights • Sodium para -aminosalicylate (PAS-Na) reduced pericarp browning of harvested litchi fruit. • PAS-Na inhibited expressions of senescence/apoptosis-related genes. • PAS-Na reduced oxidative stress in harvested litchi fruit. • PAS-Na maintained membrane integrity of litchi pericarp. • The mechanism of PAS-Na reducing browning index of harvested litchi fruit was elucidated partially. Abstract The effect of sodium para -aminosalicylate (PAS-Na) on litchi pericarp browning and the potential regulating mechanism was investigated in this study. Results showed that 0.3 g L−1 PAS-Na significantly inhibited the development of pericarp browning and reduced respiration rate of litchi fruit. PAS-Na inhibited the production of reactive oxygen species (ROS) and decreased the expression level of senescence-related genes. Additionally, PAS-Na treatment enhanced the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), which might contribute to the scavenging of ROS. Meanwhile, PAS-Na treatment maintained membrane integrity as indicated by reduced relative membrane leakage rate and malondialdehyde (MDA) content, as well as lower activities of membrane lipids-degrading enzymes: lipase and lipoxygenase (LOX). Amino acids, especially GABA, Glu, Met contents were also significantly affected by PAS-Na treatment. Taken together, we postulated that PAS-Na treatment might be a promising method for controlling postharvest browning and prolonging shelf-life of harvested litchi fruit. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of a novel chitosan formulation (Kadozan) treatment on disease development, response of disease resistance, metabolism of reactive oxygen species (ROS) in Peronophthora litchii -inoculated “Wuye” litchis. Compared with P. litchii -inoculated litchis, Kadozan-treated P. litchii -inoculated litchis exhibited lower fruit disease index, higher lignin content, higher activities of disease resistance-related enzymes (CHI, GLU and PAL), lower O 2 − generating rate and malondialdehyde content, higher activities of ROS scavenging enzymes (SOD, CAT and APX), higher contents of ascorbic acid and glutathione, and higher levels of reducing power and DPPH radical scavenging activity. These results suggest that Kadozan can be used to inhibit the growth of P. litchii in harvested litchis owning to the enhancement of disease resistance and ROS scavenging capacity, and decreases in O 2 − accumulation and membrane lipid peroxidation. Kadozan treatment can be used as a facile and novel method for suppressing postharvest pathogenic disease of litchis. [ABSTRACT FROM AUTHOR]

Methylenecyclcopropylglycine (MCPG) and hypoglycin A (HGA) are naturally occurring amino acids found in various soapberry ( Sapindaceae ) fruits. These toxins have been linked to illnesses worldwide and were recently implicated in Asian outbreaks of acute hypoglycemic encephalopathy. In a previous joint agricultural and public health investigation, we developed an analytical method capable of evaluating MCPG and HGA concentrations in soapberry fruit arils as well as a clinical method for the urinary metabolites of the toxins. Since the initial soapberry method only analyzed the aril portion of the fruit, we present here the extension of the method to include the fruit seed matrix. This work is the first method to quantitate both MCPG and HGA concentrations in the seeds of soapberry fruit, including those collected during a public health investigation. Further, this is the first quantitation of HGA in litchi seeds as well as both toxins in mamoncillo and longan seeds. [ABSTRACT FROM AUTHOR]

Starch was isolated from the kernels of jackfruit, longan, loquat, litchi, and mango fruits, which contained approximately 56, 59, 71, 53, and 64% starch, respectively, indicating that these fruit kernels are good starch sources. The structural and functional properties of these isolated starches were investigated and compared. The starches had irregular, truncated, spherical, and elliptical shapes with central hila and exhibited different sizes, with mango starch being the largest and jackfruit and longan starches being the smallest. The five starches had similar amylose contents but exhibited significantly different crystalline properties including crystalline type, relative crystallinity, short-range ordered structure, and lamellar intensity. Among the five starches, the jackfruit and loquat starches had the highest and lowest gelatinization temperature and enthalpy, respectively, and the litchi and mango starches had the highest and lowest pasting viscosity, respectively. The longan and loquat starches were more susceptible to enzyme hydrolysis than the other starches. [ABSTRACT FROM AUTHOR]

The effects of Kadozan (a novel chitosan formulation) treatment on physiological attribute, nutritional quality and storage behavior of harvested “Wuye” litchi fruit were studied. Compared with control litchis, Kadozan treatment significantly decreased fruit respiration rate, retarded the increase of pericarp cell membrane permeability, maintained higher contents of anthocyanins and flavonoids and higher values of L ∗ , a ∗ and b ∗ in litchi pericarp, and reduced the decreases of titratable acidity, total soluble solids, total soluble sugars, and vitamin C contents in litchi pulp, maintaining better quality of litchis. Furthermore, Kadozan treatment decreased browning index and disease index of litchis, kept higher rate of commercially acceptable fruit, and reduced fruit weight loss, showing better storage behavior of litchis under ambient temperature. The optimal Kadozan treatment for litchis was the 1:100 (V Kadozan : V Kadozan + Water ) dilution, which might be a promising method for keeping quality and prolonging shelf-life of harvested “Wuye” litchi fruit. [ABSTRACT FROM AUTHOR]

A novel method for simultaneous determination of pyrethroids residues in Litchi fruit has been developed by HPLC-UV detection using microwave-assisted extraction (MAE) coupled with ultrasonic-assisted dispersive liquid-liquid microextraction (UADLLME). Extraction conditions of MAE and UADLLME were respectively investigated by single-factor experiments and response surface methodology. Optimized experimental conditions included 310 μL of chlorobenzene as extraction solvent, 1.3 mL of ethanol as dispersive solvent and 3 min of extraction time for UADLLME. In the case of MAE, extraction temperature of 70 °C, extraction time of 4 min and solvent-to-materials ratio of 40:1 were adopted. Results demonstrated that the proposed method had good performance with linearity of 0.0050–4.98 mg/L, recovery of 83.3–91.5%, RSDs below 5.6% and detection limit (LOD) of 1.15–2.46 μg/L for six pyrethroids, offering higher extraction efficiency and larger enrichment factor. MAE-UADLLME provided a sensitive and efficient alternative to determination of trace amounts of pesticides residues in food samples. [ABSTRACT FROM AUTHOR]

• Rapid water loss together with pericarp browning occurred at water deficit atmospheres. • VLC fatty acids, primary alcohols, and n -alkanes changed mostly following water loss. • Biosynthesis of VLC waxes was modified following water loss and pericarp browning. • Cuticular wax metabolism altered in response to both water loss and browning in litchi. Litchi fruit is susceptible to pericarp browning, which is largely due to the oxidation of phenols in pericarp. However, the response of cuticular waxes to water loss of litchi after harvest is less mentioned. In this study, litchi fruits were stored under ambient, dry, water-sufficient, and packing conditions, while rapid pericarp browning and water loss from the pericarp were observed under the water-deficient conditions. The coverage of cuticular waxes on the fruit surface increased following the development of pericarp browning, during which quantities of very-long-chain (VLC) fatty acids, primary alcohols, and n -alkanes changed significantly. Genes involved in the metabolism of such compounds were upregulated, including LcLACS2 , LcKCS1 , LcKCR1 , LcHACD, and LcECR for elongation of fatty acids, LcCER1 and LcWAX2 for n- alkanes, and LcCER4 for primary alcohols. These findings reveal that cuticular wax metabolism may take part in the response of litchi to water-deficient and pericarp browning during storage. [ABSTRACT FROM AUTHOR]

• Magnetic Nanometer combined with Microwave Thawing (MN-MT) is a rapid thawing treatment. • The release of phenolic compounds in frozen lychee was promoted by MN-MT. • MN-MT protected thermally unstable compound procyanidin B2 from degradation. Magnetic nanometer combined with microwave thawing (MN-MT) could become a novel solution to challenges uneven and overheating of microwave thawing (MT), while retaining high thawing efficiency, compared to conventional water immersion thawing (WT). In this study, MN-MT was applied to thaw fruit (lychee as an example) for the first time, and was evaluated by comparison with WT, MT and water immersion combined with microwave thawing (WI-MT). Results showed that MN-MT could significantly shorten the thawing time of frozen lychee by 80.67%, 25.86% and 18.83% compared to WT, MT and WI-MT, respectively. Compared to WT, MN-MT was the only thawing treatment which significantly enhanced the release of quercetin-3- O -rutinose-7- O -α- l -rhamnoside, according to HPLC-DAD. Meanwhile, thermal-sensitive procyanidin B2, phenylpropionic acid and protocatechuic acid were found to be protected from degradations only by MN-MT based on UPLC-ESI-QTOF-MS/MS results. In summary, MN-MT is a potential novel treatment for rapid thawing and quality maintenance of frozen fruits. [ABSTRACT FROM AUTHOR]

• Oligomeric procyanidins in litchi fruitlet was about 3 times of mature pericarp. • >60% oligomeric procyanidins in litchi fruitlet are A-type. • The levels of total phenols and procyanidins in Huaizhi cultivar were the highest. • The bioactivity of LF was positively related to A-type procyanidin trimer content. Characterization and bioactivity of A-type procyanidins was investigated in litchi fruitlet (LF) at different stages and mature pericarp (MP) of 5 litchi cultivars. The content of total phenols in LFs was higher than that of MP and showed good antioxidant activity. Eleven procyanidins were identified in samples, including procyanidin A 2 , procyanidin A 4 , and 1 dimer, 2 trimers, and 1 tetramer of A-type procyanidin. Also, A-type procyanidin could stably exist in LFs stage, but declined substantially after maturity, which was about 1.45 – 3.56 times than mature pericarp. In addition, the second stage of LFs showed strong anti-inflammatory and anti-proliferative activities, in which monomer and A-type procyanidin trimers in LFs were significantly correlated with antioxidant (r > 0.72; p < 0.01) and anti-inflammatory (r = 0.53; p < 0.05) activities, respectively. Therefore, litchi in LF stage could be a good source of A-type oligomer procyanidins which had good application value. [ABSTRACT FROM AUTHOR]

• Carbon dots (CDs) with fluorescent and antioxidant properties were synthesized. • Chitosan enhances the coating's antibacterial and mechanical properties. • Multifunctional coating was prepared with egg albumin, chitosan and CDs. • The composite coatings exhibited UV blocking and strong antioxidant activity. • Albumin bio-nanocomposite coating reduced postharvest losses of fresh litchi fruit. Green synthesis of a bio-nanocomposite coating containing egg albumin, chitosan, and carbon dots (CDs) was achieved. Physical, chemical and biological properties of the coating and its application in quality maintenance of litchi were explored. The results demonstrated that the coating prepared with egg albumin, chitosan and CDs in a volume ratio of 5:5:1 had good flexibility, antibacterial, antioxidant and UV barrier properties. Compared to control litchi, during storage, the litchi coated with bio-nanocomposite displayed a lower pericarp browning index, a lower percentage of weight loss, and a lower content of reducing sugar, but retained high contents of vitamin C, total sugar, and sucrose, higher levels of chromaticity a∗, b∗ , and L∗ values. These results indicated that the novel multifunctional bio-nanocomposite coating based on egg albumin, chitosan, and CDs could be a safe and eco-friendly method to maintain the quality and reduce postharvest losses of fresh litchi during storage. [ABSTRACT FROM AUTHOR]

• Salicylic acid (SA) content was altered by P. litchii infection. • LcmiR159- LcGAMYB and LcmiR828- LcTT2 modules participated in litchi downy blight through regulating fruit senescence. • LcmiR160- LcARF18 and LcmiR167- LcARF8 modules was involved in litchi downy blight by regulating SA-mediated defense response. Litchi downy blight, caused by Peronophythora litchii , results in decline of market value of litchi fruit. In this study, roles of microRNAs (miRNAs) in regulating litchi fruit response to P. litchii infection was investigated. Results showed that P. litchii infection decreased anthocyanin content while accelerating fruit senescence. Salicylic acid (SA) content was also altered by P. litchii infection. Meanwhile, expression levels of LcmiR159, LcmiR828, LcmiR160 and LcmiR167 were investigated using stem-loop real-time quantitative PCR (RT-qPCR). Then, we identified LcGAMYB , LcTT2, LcARF18 and LcARF8 as their target genes, respectively, based on RNA Ligase-Mediated (RLM)-5′-RACE, transient co-expression assay in Nicotiana benthamiana as well as expression change of target genes. Our results suggested that LcmiR159- LcGAMYB and LcmiR828- LcTT2 modules participated in litchi downy blight possibly through regulating fruit senescence while LcmiR160- LcARF18 and LcmiR167- LcARF8 through SA-mediated defense response. This study provides new knowledge on deployment of miRNAs to increase litchi fruit resistance against fungal disease. [ABSTRACT FROM AUTHOR]

• ATP, ADP, and AMP levels declined with increasing pulp autolysis index. • Arabinogalactan was the main component of WSP in litchi pulp. • Storage induced WSP depolymerization but did not change its structure. • Except for some LcPME , LcPL, LcGAL and LcPME were downregulated. Water-soluble polysaccharides (WSP) were extracted from the pulp of litchi. Its main component was identified as arabinogalactan. The dominant monosaccharide constituents were arabinose and galactose. Galactose and mannose accumulated at the end of storage. ATP, ADP and AMP levels declined with increasing pulp breakdown index. WSP depolymerized which was characterized by a decrease in its content and molecular weight, while its structure remained stable during storage. Polygalacturonase and pectate lyase (PL) were active at the early storage time, and β-galactosidase (GAL) and α- l -arabinofuranosidase followed thereafter. Except for some pectin methylesterase (LcPME), LcPL, LcGAL and LcPME gene expression was downregulated. It was deduced that depolymerization of polysaccharides was mainly caused by the rupture of the branched side chain and glacturonic acid backbone to smaller repeating units, and both cell wall-degrading enzymes and nonenzymatic factors, such as energy level, participated in the degradation of polysaccharides, and consequently pulp breakdown of litchi. [ABSTRACT FROM AUTHOR]

In this study, Toxicodendron vernicifluum fisetin chelated silver nanoparticles (FT-AgNPs) with outstanding antioxidant and antimicrobial activities were constructed via self-assembly. To surprise, 0.6 wt% FT-AgNPs was compatibly dispersed into the 1:1 chitosan/pullulan (CS/PUL, CP) matrix. The hydrogen bonding and electrostatic interaction between FT-AgNPs and CP, slightly increased the CP thermal stability, and greatly enhanced the tensile strength to 61.2 MPa, water vapor permeability below 20 kg/m 2 •d. Furthermore, after treated with the composite hydrocolloid film (FT-AgNPs/CP), the reactive oxygen species level of the treated Aspergillus niger cells was significantly increased, and the membrane permeability was enhanced. It effectively slowed down the decay of litchi fruit induced by microbial infection under the storage at 25 °C (15 d of the 0.6 % FT-AgNPs/CP treatment vs 9 d of the control). In addition, 0.024 μg/kg Ag + residual in lichi pulp verified the qualified safety of the application of the 0.6 % FT-AgNPs/CP., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

‘Gola’ litchi fruits were stored under ten different CA-combinations at 5 ± 1 °C to investigate its effects on pericarp browning, biochemical quality and antioxidative activities. Control fruit turned completely brown after 28 days of storage and were excluded from the study. Fruit-stored under CA 7 -combination (1% O 2 + 5% CO 2 ) showed reduced weight loss, pericarp browning, membrane leakage and malondialdehyde contents. Soluble solid contents, titratable acidity and ascorbic acid contents were higher in CA 7 -stored fruit. Activities of catalase and superoxide dismutase enzymes, levels of total anthocyanins, DPPH radical-scavenging-activity and phenolic contents were significantly higher in CA 7 -stored litchi fruit. In contrast, activities of polyphenol oxidase and peroxidase enzymes were substantially lower in fruit kept under CA 7 -combination. Fruit subjected to CA 7 -conditions also maintained higher organoleptic quality. In conclusion, 1% O 2 + 5% CO 2 CA-conditions delayed pericarp browning, maintained antioxidative activities and biochemical characteristics along with better organoleptic quality of litchi fruit for 35 days. [ABSTRACT FROM AUTHOR]

This work examined for the first time the impact of malolactic fermentation (MLF) on the chemical constituents of lychee wine. Oenococcus oeni Viniflora® Oenos (MLF inducer) and Saccharomyces cerevisiae MERIT.ferm were co-inoculated into lychee juice to induce simultaneous alcoholic fermentation (AF) and MLF. MLF did not affect sugar utilisation and ethanol production statistically (8.54% v/v for MLF and 9.27% v/v for AF). However, MLF resulted in dramatic degradation of malic and citric acids with concomitant increases of lactic acid, ethyl lactate and pH. The final concentrations of acetic and succinic acids between AF and MLF wines had no significant difference. The MLF wine contained significantly higher amounts of amino acids than the AF wine. More importantly, MLF significantly elevated the levels of potent aroma-active compounds including isoamyl acetate, linalool, geraniol and cis -rose oxide (to levels above or near respective detection thresholds), suggesting that MLF is an effective way of retaining the original lychee flavour. [ABSTRACT FROM AUTHOR]

‘Guiwei’ litchi fruit were treated with 5 g a.i. L −1 apple polyphenols (APP) and then stored at 25 °C to investigate the effects on pericarp browning. APP treatment effectively reduced pericarp browning and retarded the loss of red colour. APP-treated fruit exhibited higher levels of anthocyanins and cyanidin-3-rutinoside, which correlated with suppressed anthocyanase activity. APP treatment also maintained membrane integrity and reduced oxidative damage, as indicated by a lower relative leakage rate, malondialdehyde content, and reactive oxygen species (ROS) generation. The data suggest that decompartmentalisation of peroxidase and polyphenoloxidase and respective browning substrates was reduced. In addition, APP treatment enhanced the activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase), as well as non-enzymatic antioxidant capacity (DPPH radical-scavenging activity and reducing power), which might be beneficial in scavenging ROS. We propose that APP treatment is a promising safe strategy for controlling postharvest browning of litchi fruit. [ABSTRACT FROM AUTHOR]

Highlights: [•] Major contributors to the antioxidant activity of lychee pulp are isolated. [•] We use cellular antioxidant activity and ORAC assays. [•] A new major phenolic compound is identified by NMR and ESI-MS. [•] The major bioactive component is quercetin 3-O-rut-7-O-α-l-rha. [ABSTRACT FROM AUTHOR]

Highlights: [•] It is the first report on dehydroxylated effect of polyphenols caused by Aspergillus awamori fermentation. [•] A. awamori fermentation increased significantly the antioxidant activity from litchi pericarp. [•] Production of quercetin, kaempferol and their glycosidic derivatives was from litchi pericarp caused by A. awamori. [ABSTRACT FROM AUTHOR]

• Maillard reaction of LcTLP and fructose was simulated during litchi drying. • The structure of Maillard reaction products was analyzed by using SAXS. • Molecular weight, Rg and secondary structure of conjugates were changed. • Maillard reaction process of LcTLP and fructose could be divided two stages. • Maillard reaction reduced the pro-inflammation activity of LcTLP. The structural characteristics and inflammatory activity of Maillard reaction products (MRPs) from fructose (Fru) and litchi thaumatin-like protein (LcTLP) with a pro-inflammatory activity were investigated. The structural changes of LcTLP-Fru MRPs were divided into two stages during the Maillard reaction. In 0–6 h, the unfolding and degradation of the LcTLP were dominant, resulting in a looser structure; the increase of β -sheets was 13.02%; the decrease of α -helices was 9.21%; and both the molecular weight and gyration radius R g decreased. After 6 h, the enhanced glycosylation caused the molecular weight to increase, while R g remained low, implying that the molecular structure became more compact. In addition, LcTLP-Fru MRPs reduced the inflammation response by significantly reducing the gene and protein expressions of tumor necrosis factor- α , interleukin-1 β , and interleukin-6 compared with the LcTLP group in RAW264.7 macrophages. The findings provided a theoretical foundation for addressing the inflammatory response caused by litchi products consumption. [ABSTRACT FROM AUTHOR]

Abstract: The phenolic profiles and antioxidant activity of litchi pulp of 13 varieties were investigated. The free, bound and total phenolic contents were 66.17–226.03, 11.18–40.54, and 101.51–259.18mg of gallic acid equivalents/100g, respectively. The free, bound and total flavonoid contents were 16.68–110.33, 10.48–22.75, and 39.43–129.86mg of catechin equivalents/100g, respectively. Free phenolics and flavonoids contributed averagely 80.1% and 75% to their total contents, respectively. Six individual phenolics (gallic acid, chlorogenic acid, (+)-catechin, caffeic acid, (−)-epicatechin, and rutin) were detected in litchi pulp by HPLC. The contents of each compound in free and bound fractions were determined. Significant varietal discrepancy in antioxidant activity was also found by FRAP and DPPH scavenging capacity methods. Antioxidant activity was significantly correlated with phenolic and flavonoid contents. Thus, phenolics and flavonoids exist mainly in the free form in litchi pulp. There were significant varietal differences in phytochemical contents and antioxidant activity of litchi pulp. [Copyright &y& Elsevier]

Abstract: Litchi, being a highly juicy and nutritious fruit, has very short life at ambient temperature, mainly due to microbial spoilage. The fruit soon loses its appeal because of pericarp browning due to anthocyanin degradation and enzymatic oxidation of phenolics. A sequential dip treatment, including sodium hypochlorite (0.2%, 4min, 52°C), potassium metabisulfite (3%, 30min, 26°C), and hydrochloric acid (0.25N) containing ascorbic acid (2%, 10min, 26°C), followed by gamma irradiation, helped in overcoming this problem confronting trade. Dip treatment reduced polyphenol oxidase activity by ∼85%, retained major anthocyanins, cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside by ⩾82% and 97%, respectively, and reduced microbial load to below detectable limits. Shelf life of processed ‘Shahi’ and ‘China’ varieties, at 4°C, was found to be 45 and 30days, respectively, whereas, unprocessed fruits spoiled within 15days. Processing helped in maintaining overall quality attributes and can expand market access of the fruit in non-producing regions. [Copyright &y& Elsevier]

Abstract: Cardiovascular disease (CVD) is the major cause of death in the developed countries. Litchi-flower-water-extract (LFWE) contains plenty of phytochemicals, i.e. phenols, flavonoids, tannins which may own cardio-protection. Ten male hamsters per group were assigned randomly to one of the following dietary groups: chow diet and normal distilled water (LFCD/NDW); high-fat/cholesterol diet and normal distilled water (HFCD/NDW); HFCD and 2.5% litchi-flower-water-extract (HFCD/2.5% LFWE); HFCD and 5% LFWE (HFCD/5% LFWE). Serum lipids, cardiac index, and hepatic lipids were lowered (p <0.05) in high-fat/cholesterol-dietary hamsters by drinking 2.5% and 5% LFWE which may result from higher (p <0.05) LDL receptor and peroxisome proliferator-activated receptor-alpha (PPAR-α) gene expressions and lower (p <0.05) fatty acid synthase (FAS) gene expression, as well as increased (p <0.05) faecal lipid and bile acid excretions. Drinking LFWE also lowered (p <0.05) serum malondialdehyde (MDA) contents in high-fat/cholesterol-dietary hamsters, and even showed the same (p >0.05) serum MDA contents as the LFCD/NDW group’s which could be due to increased (p <0.05) serum trolox equivalent antioxidant capacity (TEAC). Therefore, this study indicated that LFWE indeed characterises a protective effect on cardiovascular health in vivo. [Copyright &y& Elsevier]

Abstract: The experiments were performed to extract and purify substrates for polyphenol oxidase (PPO) from pericarp tissue of postharvest litchi fruit. Two purified PPO substrates were identified as (−)-epicatechin and procyanidin A2. The antioxidant properties of two PPO substrates were further evaluated in the present study. Variation in the content of the major substrate (−)-epicatechin of litchi fruit during storage at 25°C was analysed using the HPLC-UV method. The results showed that (−)-epicatechin exhibited stronger antioxidant capability than procyanidin A2, in terms of reducing power and scavenging activities of DPPH radical, hydroxyl radical and superoxide radical. Furthermore, (−)-epicatechin content in pericarp tissue tended to decrease with increasing skin browning index of litchi fruit during storage at 25°C. Thus, these two compounds can be used as potential antioxidants in litchi waste and the fresh pericarp tissue of litchi fruit exhibited a better utilisation value. [Copyright &y& Elsevier]

Abstract: The degradation of flavanols had been studied both in the litchi pericarp during the storage and in the model system containing PPO and flavanols of litchi pericarp. The results showed that (−)-epicatechin was the optimal endogenous substrate of litchi pericarp PPO, and the procyanidins of litchi pericarp were oxidised very slowly when incubated alone with PPO. However, (−)-epicatechin could accelerate the oxidation of the other flavanols in litchi pericarp through a coupled oxidation pathway. The results obtained allowed us to draw a conclusion that the oxidation of (−)-epicatechin was a precursor of litchi pericarp browning. A pathway of enzymatic browning of litchi pericarp was proposed as follows: with the loss of cellular compartmentation, the litchi pericarp PPO and flavanols mixed and, then, (−)-epicatechin was oxidised by the PPO and o-quinones formed. The o-quinones reacted with other flavanols and anthocyanins, accelerating the oxidation of other polyphenols. Finally, the oxidation of (−)-epicatechin and other polyphenols led to the formation of the brown-coloured compounds, resulting in the enzymatic browning of litchi pericarp. [Copyright &y& Elsevier]

Abstract: The impact of energy level on antioxidant properties in relation to pericarp browning and loss of disease resistance of litchi fruit was investigated. Litchi fruits were vacuum-infiltrated with distiled water (control), 1mM adenosine triphosphate (ATP) and 0.5mM 2,4-dinitrophenol (DNP) under 75kPa for 3min before being inoculated with Peronophythora litchi or not. ATP-treated fruits presented higher activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX). Higher activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, reducing power and contents of phenolic compounds were also observed in ATP-treated fruit during storage. In contrast, DNP treatment lowered the enzymes activities, scavenging ability and the contents of phenolic compounds. Higher levels of antioxidant enzymatic system and non-enzymatic system were observed in P. litchii-inoculated fruits than those in non-inoculated fruits. Application of ATP and DNP exhibited a similar change patterns and effects in inoculated fruits. When related to previously reported ATP levels, the results suggested that ATP levels could regulate the antioxidant system. Sufficient available energy is crucial for inhibiting browning and preventing the loss of disease resistance in harvested litchi fruit. [Copyright &y& Elsevier]

Abstract: Litchi (Litchi chinensis Sonn.) is one of the most desirable subtropical fruits with high commercial values, which is significantly affected by its skin colour due to the embedded anthocyanin pigments. This work was conducted with a view to explaining the unexpected observation that litchi polyphenol oxidase (PPO) did not oxidise directly anthocyanins. Litchi fruit were stored for 4days at 25°C and 80–90% relative humidity. Browning index and H2O2 and OH contents of pericarp tissues of litchi fruit during storage were determined. The browning index of litchi fruit rapidly increased while H2O2 and OH contents decreased and then increased markedly, as storage time progressed. The obvious pericarp browning was associated with the rapid increases in H2O2 and OH contents of litchi fruit after 4days of storage. Furthermore, litchi anthocyanins were purified by column chromatography and then H2O2 and hydroxyl radical were used to examine their degradation roles in the purified anthocyanin. It was found that the purified litchi anthocyanin was degraded markedly in the presence of H2O2 or hydroxyl radical. Increasing concentration of H2O2 or hydroxyl radical enhanced the anthocyanin degradation, of which the latter exhibited a greater effect on the anthocyanin degradation although no peak of litchi anthocyanin appeared after the treatment with 0.1% H2O2 for 10min. This study can account for the pericarp browning of postharvest litchi fruit during storage based on the oxidative degradation of anthocyanin caused by PPO. [Copyright &y& Elsevier]

Abstract: Antioxidant and antitryrosinase compounds from Litchi sinensis Sonn. seeds were extracted with five different types of polar solvents. The five extracts, namely ethanol extract (EE), 50% ethanol extract (50% EE), methanol extract (ME), 50% methanol extract (50% ME), and water extract (WE), were used for the evaluations of total phenolic content, antioxidant capabilities and antityrosinase activity. The 50% EE showed the highest total antioxidant capacity, scavenging the 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical and inhibitory activity against lipid peroxidation, and it was comparable to the activity of the synthetic antioxidant, butylated hydroxyl toluene. Fifty percent EE showed a better antityrosinase activity compared to the other extracts. After application of reverse phase high performance liquid chromatography, coupled to a diode array detector and electrospray ionisation mass spectra, five phenolic compounds, namely, gallic acid, procyanidin B2, (−)-gallocatechin, (−)-epicatechin and (−)-epicatechin-3-gallate were identified from 50% EE. This study suggests that litchi seed can potentially be used as a readily accessible source of natural antioxidants. [Copyright &y& Elsevier]

Abstract: The degradation of anthocyanins and/or the oxidation of phenolics caused by polyphenol oxidase (PPO) results in an enzymatic browning reaction of fruits and vegetables. This work was conducted with a view to explaining the unexpected observation that litchi (Litchi chinensis Sonn.) PPO did not directly oxidise litchi anthocyanins. PPO and anthocyanin from litchi fruit pericarp were extracted and purified, respectively, and then the anthocyanin degradation by PPO in the presence of (−)-epicatechin (endogenous PPO substrate), and catechol and gallic acid (exogenous PPO substrates) were analysed comparatively. The results showed that catechol was the most effective in litchi anthocyanin degradation, followed by (−)-epicatechin and gallic acid, but no significant differences existed between catechol and (−)-epicatechin. The study suggested that litchi PPO directly oxidised (−)-epicatechin; then oxidative products of (−)-epicatechin in turn catalysed litchi anthocyanin degradation, and finally resulted in the browning reaction, which can account for pericarp browning of postharvest litchi fruit. [Copyright &y& Elsevier]

Abstract: The main oligomeric procyanidins from litchi pericarp (Litchi chinensis) were isolated and identified. Complete assignment of epicatechin-(4β→8, 2β→O→7)-epicatechin-(4β→8)-epicatechin structure was obtained using CD, NMR and ESI-MS techniques. The known (−)-epicatechin and procyanidin A2 were also isolated from litchi pericarp. The effects of oligomeric procyanidins, A2 and epicatechin-(4β→8, 2β→O→7)-epicatechin-(4β→8)-epicatechin from litchi pericarp on free radical-scavenging were determined by using a chemiluminescent method. The results showed that all of them had a strong scavenging effect on OH, and the IC50 values were 2.60μg/ml, 1.75μg/ml and 1.65μg/ml for oligomeric procyanidins, A2 and the trimeric procyanidins, respectively. The antioxidant activities of A-type dimeric and trimeric procyanidins seemed to be related to the number of hydroxyls in their molecular structures. [Copyright &y& Elsevier]

Abstract: Large amount of polyphenolic compounds with strong antioxidant activity was present in the pericarp of harvested lychee fruits. Flavonoids were extracted with 85% ethanol:15% HCl from lychee fruit pericarp tissues. Most of the lychee flavonoids were partitioned into the ethyl acetate fraction. Three major components of the ethyl acetate fraction were obtained by reverse phase high-performance liquid chromatography and determined to be flavanol by their ultraviolet/visible spectra. Furthermore, these three components were identified as proanthocyanidin B4, proanthocyanidin B2 and epicatechin by nuclear magnetic resonance and mass spectrometry. The ethyl acetate fraction, proanthocyanidin B4, proanthocyanidin B2 and epicatechin exhibited a good antioxidant capability. The hydroxyl radical and superoxide anion scavenging activities of proanthocyanidin B2 was greater than those of proanthocyanidin B4 and epicatechin, while the epicatechin had the highest DPPH scavenging activity [Copyright &y& Elsevier]