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Dark pericarp disease (DPD), a physiological disorder induced by excess Manganese (Mn) in litchi, severely impacts the appearance and its economic value. To elucidate the underlying mechanisms of DPD, this study investigated the variations of phenolic compound, antioxidant defense system, subcellular structure, and transcriptome profiles in both normal fruit and dark pericarp fruit (DPF) at three developmental stages (green, turning, and maturity) of 'Guiwei' litchi. The results reveal that excess Mn in DPF pericarp resulted in a significant increase in reactive oxygen species, especially H 2 O 2, and subsequent alterations in antioxidant enzyme activities. Notably, SOD (EC 1.15.1.1) activity at the green stage, along with POD (EC 1.11.1.7) and APX (EC 1.11.1.11) activities at the turning and the maturity stages, and GST (EC 2.5.1.18) activity during fruit development, were markedly higher in DPF. Cell injury was observed in pericarp, facilitating the formation of dark materials in DPF. Transcriptome profiling further reveals that genes involved in flavonoid and anthocyanin synthesis were up-regulated during the green stage but down-regulated during the turning and maturity stages. In contrast, PAL (EC 4.3.1.24), C4H (EC 1.14.14.91), 4CL (EC 6.2.1.12), CAD (EC 1.1.1.195), and particularly POD, were up-regulated, leading to reduced flavonoid and anthocyanin accumulation and increased lignin content in DPF pericarp. The above suggests that the antioxidant system and phenolic metabolism jointly resisted the oxidative stress induced by Mn stress. We speculate that phenols, terpenes, or their complexes might be the substrates of the dark substances in DPF pericarp, but more investigations are needed to identify them., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lixian Yao reports financial support was provided by China Agriculture Research System of MOF and MARA., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Suitable drying method is critical for the preservation of physicochemical and pharmacological quality of lychee pulp polysaccharides (LPPs). In current work, the effects of five drying methods, i.e. air drying (A), infrared drying (I), heat pump drying (H), vacuum freeze drying (F) and freeze vacuum drying combined with heat pump drying (FH) on the physicochemical characterizations, antioxidant activities and hypoglycemic activities of LPPs were explored. Results showed all five drying methods led to thermal aggregation of LPPs and the stronger the thermal effect induced by drying, the more serious the aggregations were. Additionally, the thermal aggregation significantly affected the composition, structure and biological activity of LPPs. Less thermal aggregation was observed in LPPF and LPPFH, which exhibited stronger oxygen, DPPH and ABTS radical scavenging activities, higher ferric-reducing power and better α-glycosidase and α-amylase inhibition activities, resulting from their higher contents of neutral sugar, protein and uronic acid and lower molecular weight than LPPA and LPPI. Besides, FH consumed about half drying time and one fifth energy of F. Therefore, from industrial perspective, FH is a promising alternative to F for producing LPPs by comprehensively considering physicochemical characterizations, bioactivity as well as energy consumption., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Obesity continues to be a global public health challenge. Litchi chinensis seed is rich in bioactive ingredients with pharmacological effects, such as hypoglycemic activity and anti-oxidation. This study aimed to assess the potential anti-obesity effects of L. chinensis seed and the changes of gut microbiota and mycobiota compositions in obese zebrafish induced by a high-fat diet. The anti-obesity effects were supplemented and validated in high-fat diet-induced obese mice. In this study, various chemical components of L. chinensis seed water and ethanol extracts were detected using UHPLC-QE-MS, and both extracts showed strong in vitro antioxidant activities. Network pharmacology analysis showed the potential of the extracts to improve obesity. Litchi chinensis seed powder, water and ethanol extracts decreased the weight of obese zebrafish, improved lipid accumulation and lipid metabolism, regulated appetite, and inhibited cell apoptosis and inflammation of the liver and intestine. They showed similar effects in obese mice, and also reduced the weight of fat tissues, regulated insulin resistance and glucose metabolism, and improved the intestinal barrier. Additionally, L. chinensis seed modulated the compositions of gut microbiota and mycobiota in zebrafish, with the regulation of the proportion of bacteria that produce short-chain fatty acids or affect intestine health, including Cetobacterium , Trichococcus , Aeromonas , Staphylococcus , and Micrococcaceae, and the proportion of fungi that produce mycotoxins or have special metabolic capacities, including Penicillium , Candida , Rhodotorula , and Trichoderma . Spearman's correlation analysis revealed the potential link between zebrafish obesity parameters, gut bacteria and fungi. Overall, these findings indicated that L. chinensis seed effectively improved obesity.

Litchi grown in the upper Yangtze River region have the advantage of being late-maturing owing to the geographical location. This study aimed to evaluate the physical characteristics, nutritional values, phenolic composition and antioxidant activities of 16 litchi cultivars grown in the upper Yangtze River region. Litchi grown in this region had total soluble solid and ascorbic acid contents comparable with those of cultivars grown in other locations. The total polyphenol contents were determined using the Folin-Ciocalteu assay, and the phenolic profiles were determined using UPLC-QqQ-MS/MS. Nine phenolic compounds were identified and quantified in this study. Naringin, rutin and p-coumaric acid were the major phenolic compounds in all the litchi cultivars. Statistical analysis of all the physiochemical results was performed using principal component analysis. Our results indicated that litchi grown in the upper Yangtze River region not only showed the late-maturity characteristic but were also good dietary sources of phenolic compounds and antioxidants. In particular, 'Fei Zi Xiao' and 'Jing Gang Hong Nuo', characterized by high polyphenol contents and high antioxidant capacities, were of superior comprehensive quality. This study provides important information for the development of late-maturing litchi industry., (© 2021 Wiley-VHCA AG, Zurich, Switzerland.)

Context: The study was carried out to evaluate the effect of the aqueous fruit pericarp extract of Litchi chinensis (APLC) on parameters which leads to diabetic cataractogenesis and retinopathy in the streptozotocin-induced diabetic rats., Objective: The objective of the study is to evaluate the APLC for in vivo antioxidant activity and its role in inhibiting the polyol pathway and formation of advanced glycation end products (AGEs)., Materials and Methods: The diabetic animals were treated with L. chinensis for a period of 12 weeks. At the end of 12 weeks, the animals were killed and the biochemical pathways involved in the pathogenesis of cataract such as oxidative stress by protein content, superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and polyolpathway by aldose reductase (AR) in lens homogenates, alterations in protein carbonyl content (PCO) and AGEs in both serum and lens the APLC-treated diabetic rats were compared against diabetic control rats. Cataract progression due to hyperglycemia was monitored by slit lamp bio microscope and classified into four stages. Fundoscope test and retinal histopathology were done for assessing retinopathy., Results: Statistically significant reduction in glucose, and elevation of protein content, SOD, CAT, and GSH levels and decreased levels of AR and PCO in lens homogenate and significant reduction in AGEs serum and lens homogenate were observed. Slit lamp examination, fundoscope, and histopathology showed improvement in retinal changes in APLC-treated rats compared to diabetic control animals., Conclusion: The treatment with APLC found to delay the progression of diabetic cataractogenesis and retinopathy, which might be due to its antioxidant activity, because of the presence of active phytochemicals in APLC.

'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 28days of storage and were excluded from the study. Fruit-stored under CA7-combination (1% O2+5% CO2) showed reduced weight loss, pericarp browning, membrane leakage and malondialdehyde contents. Soluble solid contents, titratable acidity and ascorbic acid contents were higher in CA7-stored fruit. Activities of catalase and superoxide dismutase enzymes, levels of total anthocyanins, DPPH radical-scavenging-activity and phenolic contents were significantly higher in CA7-stored litchi fruit. In contrast, activities of polyphenol oxidase and peroxidase enzymes were substantially lower in fruit kept under CA7-combination. Fruit subjected to CA7-conditions also maintained higher organoleptic quality. In conclusion, 1% O2+5% CO2 CA-conditions delayed pericarp browning, maintained antioxidative activities and biochemical characteristics along with better organoleptic quality of litchi fruit for 35days., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Environmental conditions, including shading, generally influence the physical and chemical qualities of coffee beans. The present study assessed the changes in some phenolic compounds, antioxidant activity and agronomic characters of coffee beans (Coffea arabica L. cv. Catimor) as affected by different shading conditions including full sun, three artificial shading conditions using a saran covering (50% shade, 60% shade, and 70% shade) and lychee shade., Results: Bean weight and bean size increased significantly (P < 0.05) when the shade level was progressively increased. The coffee beans grown under lychee shade exhibited superior bean yield, 1000-bean weight, total phenolic content and antioxidant activity compared to all other beans. Chlorogenic acid was the most predominant phenolic acid in all samples studied, being the highest in the beans grown under lychee shade, followed by 60% shade, 70% shade, 50% shade and full sun, respectively. In contrast, bean grown under full sun had the highest amount of vanillic acid and caffeic acid., Conclusions: Antioxidant activity was highly positively associated with chlorogenic acid content. The content of total sugar (fructose, glucose and sucrose) was found highest in coffee beans grown in 60% shade, with fructose the predominant sugar. Under climatic conditions similar to this experiment, it is advisable that growers provide shade to the coffee crop to reduce heat from direct sunlight and promote yield as well as obtain good quality coffee beans., (Copyright © 2012 Society of Chemical Industry.)

Polyphenols called procyanidins can be extracted from agro-industrial waste like litchi peel and coffee pulp. However, their efficacy is limited due to instability, which hinders both the bioavailability and preservation of their activity. This study aims to establish the ideal encapsulation conditions required to preserve the procyanidin properties found in extracts taken from litchi peel and coffee pulp. To attain the maximum procyanidin encapsulation efficacy (EE), the Taguchi method was utilized to streamline the spray-drying conditions for different wall materials—maltodextrin (MD), whey protein (WP), citrus pectin (CP), and skim milk (SM). The optimized conditions consisted of feed flow (3, 4.5, and 6 mL/min), temperature (125, 150, and 175 °C), and airflow (30, 35, and 40 m3/h). The microcapsules were characterized using ABTS, DPPH, lipoperoxidation, and scanning electron microscopy. Objective evaluations revealed that MD was the most effective encapsulation material for the litchi extract, whereas WP was the optimal option for the coffee extract. Of all the factors considered in the spray-drying process, feed flow had the strongest impact. The spray-drying process for the litchi peel extracts achieved high procyanidin encapsulation efficiencies at a feed flow rate of 4.5 mL/min, a temperature of 150 °C, and an airflow rate of 35 m3/h. Meanwhile, the coffee extract spray drying achieved similar results at a feed flow rate of 4.5 mL/min, a temperature of 175 °C, and an airflow rate of 40 m3/h. Encapsulation efficiencies of 98.1% and 93.6% were observed for the litchi and coffee extracts, respectively, under the mentioned optimal conditions. The microencapsulation process was successful in preserving the antioxidant properties of procyanidins. The microcapsules' size ranged from 2.6 to 3.2 micrometers. The results imply that the phenolic compounds present in the extracts function as effective antioxidant agents. [ABSTRACT FROM AUTHOR]

Lychee seeds (LS) and longan seeds (LoS) are excellent sources of phenolic compounds (PCs) with strong antioxidant activity (AOA). The aim of this study was to optimize the extraction conditions regarding extraction yield (EY), extractable phenolic compound (EPC), and AOA from LS and LoS using surface response methodology (RSM). Solvent concentration, extraction temperature, time, and solid to liquid ratio were optimized using RSM. Increasing the solid to solvent ratio from 1:05 to 1:40 (w/v), increased EY for LoS, however, EY did not change from 1:20 to 1:40 for LS. Solid–liquid ratio 1:20 was chosen for this study. Increasing the quantity of solvent leads to higher EPC and FRAP. The results showed that LoS exhibited higher AOA than LS measured as DPPH, ABTS, and FRAP, respectively. Ethanol concentrations and temperatures significantly (p < 0.05) affect EY, EPC, and AOA. The results (R2 > 0.85) demonstrated a good fit to the suggested models and a strong correlation between the extraction conditions and the phenolic antioxidant responses. The ethanol concentrations of 41 and 53%, temperatures of 51 and 58 °C, and the corresponding times of 139 and 220 min were the optimal conditions that maximized the EY, EPC, and AOA from LS and LoS. [ABSTRACT FROM AUTHOR]

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The agri-food industry generates substantial waste, leading to significant environmental impacts. Lychee (Litchi chinensis Sonnerat), which is rich in bioactive compounds in its peel, pulp, and seeds, offers an opportunity for waste use. This study aimed to evaluate the effects of supplementing a high-carbohydrate diet with varying levels of lychee peel flour on lipid metabolism biomarkers and oxidative stress in a zebrafish (Danio rerio) model. A total of 225 zebrafish, approximately four months old, were divided into five groups: control, high-carbohydrate (HC), HC2%, HC4%, and HC6%. The study did not find significant differences in the growth performance of zebrafish in any group. However, the HC6% group exhibited a significant decrease in glucose and triglyceride levels compared with the HC group. Furthermore, this group showed enhanced activities of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD), along with reduced levels of malondialdehyde (MDA). Increased antioxidant activity was also evidenced by DPPH−, ABTS+, and β-carotene/Linoleic acid assays in the HC6% group. A positive correlation was identified between SOD/CAT activity and in vitro antioxidant assays. These findings suggest that dietary supplementation with 6% lychee peel flour can significantly modulate glucose homeostasis, lipid metabolism, and antioxidant activity in zebrafish. [Display omitted] • o -Coumaric Acid and Resveratrol were the most abundant bioactive compounds in lychee peel flour. • The evaluation of antioxidant activity using the ABTS+ and DPPH− assays was effective in zebrafish. • The addition of 6% lychee peel flour to the diet reduced blood glucose. • The addition of 6% lychee peel flour increased CAT and SOD activity. • The addition of 4 and 6% lychee peel flour reduced lipid peroxidation. [ABSTRACT FROM AUTHOR]

Background: Diabetes mellitus, an endocrine disease, is a major health concern all over the world. Litchi chinensis Gaertn. and Glycine max (L.) Merr have been traditionally used in Chinese medicines for the treatment of various disorders. The present study was carried out to explore the antioxidant and antihyperglycemic potential of ethyl acetate and hydroethanolic extracts of L. chinensis fruit pericarp and G. max seed coats. Methods: Phytoconstituents of ethyl acetate and hydroethanolic extracts of L. chinensis fruit pericarp and G. max seed coat were investigated using preliminary qualitative techniques. In vitro and in vivo antioxidant potential of ethyl acetate and hydroethanolic extracts was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2) free radical scavenging, reducing power assays, total phenol content, glutathione (GSH), superoxide dismutase (SOD), and thiobarbituric acid reactive substances (TBARS). In vivo antihyperglycemic activity was assessed using alloxan-induced diabetic rats. Blood glucose levels were evaluated on 0, 7th, 14th, and 28th day of the study. Results: Hydroethanolic extracts of both plants exhibited superior antioxidant activity to ethyl acetate extract. A marked increase in levels of serum glucose was observed in diabetic rats. Ethyl acetate and hydroalcoholic extract treatment for 28 days accounted for decreased blood glucose levels in hyperglycemic rats. Conclusions: The present study suggests that ethyl acetate and hydroethanolic extracts of L. chinensis fruit pericarp and G. max seed coats possess potent antioxidant antihyperglycemic activities and have potential as a therapeutic agent in diabetes. [ABSTRACT FROM AUTHOR]

Summary: Water‐soluble polysaccharides (LCPs) were extracted from litchi, wherein LPS, LPH, LPP and LPM were extracted by ultrasound, hot water, ultra‐high pressure and microwave methods, respectively. The physicochemical properties, components, structures and in vitro antioxidant activities of four LCPs were investigated. LPP was the highest in yield and purity, and most physicochemical properties of four LCPs were similar. FTIR showed that LPP, LPS and LPH had ɑ‐dominating configuration in pyranose rings. SEM showed that four LCPs were different, and LPH and LPP had relatively smooth and compact surfaces. The Mw of LPS, LPH, LPP and LPM were 79 538, 320 213, 192 891 and 200 198 Da, respectively. All four LCPs consisted of fucose, galactose, glucose and rhamnose. Except for LPS, the other three LCPs contained mannose. Based on the results of in vitro antioxidant activity, 5 mg mL−1 LPP presented the highest in DPPH and hydroxyl scavenging activity, while it ranked secondly in reducing power. [ABSTRACT FROM AUTHOR]

Changes of phenolic profiles and antioxidant activity of litchi pericarp during storage at 4 °C for seven days and at room temperature (RT) for 72 h were evaluated in this study. The contents of total phenolic and procyanidin decreased by 20.2% and 24.2% at 4 °C and by 37.8% and 47.8% at RT, respectively. Interestingly, the corresponding reductions of anthocyanins were 41.3% and 73%, respectively. Four phenolic compounds, including epicatechin, procyanidin A2, procyanidin B2, and quercetin-3-O-rutinoside-7-O-α-l-rhamnosidase were detected in litchi pericarp. Their contents after storage at 4 °C and at RT were decreased by 22.1-49.7% and 27.6-48.7%, respectively. The oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) of litchi pericarp decreased by 17.6% and 58.7% at 4 °C, and by 23.4% and 66.0% at RT, respectively. The results indicated that storage at 4 °C preserved more phenolics and retained higher antioxidant activity in litchi pericarp compared to storage at RT, suggesting that storage at 4 °C should be considered as a more effective method for slowing down the degradation of litchi pericarp phenolics. [ABSTRACT FROM AUTHOR]

Litchi (Litchi chinensis Sonn.) fruit is known for its rich source of phenolics. Litchi pericarp contains high levels of epicatechin that may form oligomers of various lengths. Except for several A or B type epicatechin dimers, other soluble oligomers have rarely been identified in the pericarp. Here, bioassay-guided column fractionation was applied to isolate bioactive phenolics from aqueous pericarp extract. A fraction (S3) was obtained by two rounds of Sephadex LH-20 column chromatography, and showed higher antioxidant activity and inhibition on the proliferation of human lung cancer cells (A549) than Litchi anthocyanins. S3 was further separated to isolate fractions P1-P4, which all showed higher antioxidant activity than vitamin C. P3 showed 32.9% inhibition on A549 cells at 30 μg/mL, higher than other fractions and cis-Dichlorodiamineplatinum (DDP, 0.5 μg/mL), but not as high as the combination of the four fractions. Using HPLC-Q-TOF-MS/MS, one B-type and complex A/B type epicatechin trimers were identified in P3; another B-type and two A/B-type trimers were identified in P4. P1 and P2, containing epicatechin and proanthocyanidin B2, respectively, showed no cell inhibition at 30 μg/mL. It is the first time that the two B type trimers of epicatechins (Litchitannin B1 and B2), have been found in Litchi species. The identified proanthocyanidins were detected in the pericarp of the young fruit, and the levels of the compounds decreased as the fruit developed, correlating to the decreasing patterns of the expression of LcLAR and LcANR, two key genes in the catechin biosynthesis pathway. [ABSTRACT FROM AUTHOR]

Effect of air drying and freeze drying on polysaccharides of lychee with three cultivars was determined in terms of polysaccharides yield, antioxidant capacity and hypoglycemic action. The results show that Guiwei lychee pulp had the highest crude polysaccharide yield among three lychees. However, Feizixiao lychee had the lowest EC50 concentration and the highest FRAP (Ferric reducing antioxidant power) value. Moreover, Guiwei lychees dried by air drying had the best effect for improving glucose tolerance of normal mice and diabetic mice. Three freeze dried lychees had no significant effect. The effect of air dried Guiwei samples on decreasing TG was the best and it was even better than dapagliflozin group. Only freeze-dried Guiwei lychee could significant decrease the TC content in blood among all lychee samples. In a word, Feizixiao lychees had the best antioxidant capacity and Guiwei lychees had the best hypoglycemic effect. Air drying was better drying method for lychee polysaccharides than freeze drying in this study. [ABSTRACT FROM AUTHOR]

To establish optimal ultra-high-pressure (UHP)-assisted extraction conditions for procyanidins from lychee pericarp, a response surface analysis method with four factors and three levels was adopted. The optimum conditions were as follows: 295 MPa pressure, 13 min pressure holding time, 16.0 mL/g liquid-to-solid ratio, and 70% ethanol concentration. Compared with conventional ethanol extraction and ultrasonic-assisted extraction methods, the yields of the total procyanidins, flavonoids, and phenolics extracted using the UHP process were significantly increased; consequently, the oxygen radical absorbance capacity and cellular antioxidant activity of UHP-assisted lychee pericarp extracts were substantially enhanced. LC-MS/MS and high-performance liquid chromatography quantification results for individual phenolic compounds revealed that the yield of procyanidin compounds, including epicatechin, procyanidin A2, and procyanidin B2, from lychee pericarp could be significantly improved by the UHP-assisted extraction process. This UHP-assisted extraction process is thus a practical method for the extraction of procyanidins from lychee pericarp. The ORAC and CAA antioxidant activities of lychee pericarp procyanidins were improved by ultra-high-pressure (UHP)-assisted processing. [ABSTRACT FROM PUBLISHER]

The total phenolic content (TPC) and antioxidant activity (AA) of commercially available fruit juices (kiwi, mango, guava, litchi, apple and pineapple) from Himachal Pradesh, an Indian state in the North Western Himalayas was evaluated. The stability of TPC and AA was also compared between the juices using in vitro simulated digestion using pepsin and pancreatin. The TPC in all the juices ranged from 6.78 to 86.6 mg gallic acid equivalent (GAE)/L with AA ranging from 55.8 to 402 Trolox equivalent antioxidant activity (TEAC) µM/L. Under in vitro simulated digestion, the TPC and AA were significantly enhanced after each phase of digestion ( p <0.05). A strong correlation was observed for AA and TPC (R 2 =0.98) at all the stages of digestion. The principal component analysis (PCA) indicated that the increase in AA in pineapple juice was more related with the phase of digestion, with the highest increase of AA after gastric (4.5 fold) and intestinal (21.0 fold) phases. The study indicates that the antioxidant potential varies considerably among different fruit juices at different stages of digestion [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the immunomodulatory and antioxidant activities of litchi pulp polysaccharides (LP) in cyclophosphamide (Cy)-induced mice. The administration of LP (50, 100 and 200 mg/kg/d) remarkably enhanced mesenteric lymph node cells proliferation and serum IgA. Moreover, IL-6, TNF-α, IgG and IgM levels in serum were significantly improved in a dose-dependent manner with LP treatment. Dietary LP induced systemic immune responses including stimulating the proliferation of splenocytes, balancing the ratio of spleen lymphocyte subsets, up-regulating the thymus and spleen indices. Thus, we speculate litchi polysaccharides would express their systemic immunomodulatory effects by triggering the intestinal mucosal immunity. Likewise, LP also significantly increased total antioxidant capacity, as well as superoxidase dismutase and glutathione peroxidase activity, while decreasing malondialdehyde levels in the serum and liver. The immunomodulatory activity of LP was accompanied with its antioxidant activity, which might be related with its structure and prebiotic effect. This is a novel study on the relationship between the immunomodulatory and antioxidant activities of litchi polysaccharides. [ABSTRACT FROM AUTHOR]

Condensed tannin is a ubiquitous polyphenol in plants that possesses substantial antioxidant capacity. In this study, we have investigated the polyphenol extraction recovery and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of the extracted polyphenol after litchi pericarp is treated with Aspergillus awamori, Aspergillus sojae or Aspergillus oryzae. We have further explored the activity of A. awamori in the formation of condensed tannin. The treatment of A. awamori appeared to produce the highest antioxidant activity of polyphenol from litchi pericarp. Further studies suggested that the treatment of A. awamori releases the non-extractable condensed tannin from cell walls of litchi pericarp. The total extractable tannin in the litchi pericarp residue after a six-time extraction with 60% ethanol increased from 199.92 ± 14.47-318.38 ± 7.59 μg/g dry weight (DW) after the treatment of A. awamori. The ESI-TOF-MS and HPLC-MS2 analyses further revealed that treatment of A. awamori degraded B-type condensed tannin (condensed flavan-3-ol via C4-C8 linkage), but exhibited a limited capacity to degrade the condensed tannin containing A-type linkage subunits (C4-C8 coupled C2-O-C7 linkage). These results suggest that the treatment of A. awamori can significantly improve the production of condensed tannin from litchi pericarp. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the influence of oxalic acid on pericarp browning, biochemical quality, antioxidative and enzymatic changes in litchi cv. 'Gola' fruit under extended cold storage, which has not been studied extensively. Postharvest application of 2 mM oxalic acid reduced fruit weight loss and delayed pericarp browning by maintaining higher anthocyanin contents, as compared with control. Activities of polyphenol oxidase and peroxidase enzymes in litchi peel as well as pulp tissues were reduced in fruit treated with 2 mM oxalic acid during 28 days of cold storage. Activities of antioxidative enzymes (superoxide dismutase and catalase) and level of total phenolic contents and total antioxidants in litchi peel as well as pulp tissues were significantly higher in 2 mM oxalic acid-treated fruit. In conclusion, postharvest application of 2 mM oxalic acid significantly delayed pericarp browning and maintained better quality of litchi cv. 'Gola' fruit during cold storage. Practical Applications Pericarp browning of litchi fruit is associated with postharvest oxidative stress, which deteriorates its quality, long-term storability and commercial value. Postharvest application of oxalic acid has been found to be a useful strategy to overcome the issue of pericarp browning and enhance antioxidative potential of litchi under low temperature storage; thereby, applicable to commercial supply chains for domestic and export markets. Furthermore, this study may facilitate in understanding the changes in antioxidative potential and enzymatic activities during cold storage with gradual browning in pulp as well as peel tissues of litchi. [ABSTRACT FROM AUTHOR]

Litchi leaf is a good resource for phenolics, which are good candidates for medicines. In this work, three phenolics were isolated from litchi leaf by column chromatography. Their structures were identified by electrospray ionization–mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy as secoisolariciresinol 9′- O - β - D- xyloside ( 1 ), 4,7,7′,8′,9,9′-hexahydroxy-3,3′-dimethoxy-8,4′-oxyneolignan ( 2 ), and cinnamtannin B1 ( 3 ). Cinnamtannin B1 showed better extra- and intracellular antioxidant activities than Compounds 1 and 2 . The intracellular antioxidant activity of cinnamtannin B1 was related to the upregulation of endogenous antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase), and inhibition of ROS generation. Furthermore, cinnamtannin B1 exhibited strong antiproliferative effects against HepG 2 and Siha cell lines with no significant cytotoxicities. In the case of the HepG 2 cell line, cell cycle arrest and apoptosis induction were the underlying anticancer mechanisms of cinnamtannin B1. The results indicated that cinnamtannin B1 was a potent cancer cell proliferation inhibitor and a good intracellular antioxidant. [ABSTRACT FROM AUTHOR]

The antioxidative properties of lychee seed water extract (LSWE) in raw meat paste during a storage period of 0–15 days at 4 °C were evaluated. The cytotoxic effects and the anti-obese effects of LSWE were evaluated using an in vitro 3T3-L1 preadipocyte cell model. The sensory properties of the cooked meat paste supplemented with different amount of LSWE were also evaluated. Results showed that LSWE was non-toxic and effective in inhibiting preadipocyte differentiation. These effects were attributable to down-regulation of several adipogenesis-specific genes, i.e., PPAR γ, C/EBP α, C/EBP β, C/EBP δ, and KLF9. Supplementation with LSWE was also effective in retarding lipid oxidation of meat paste. Sensory evaluation indicated that LSWE did not adversely affect the sensory properties of the meat paste. On the contrary, LSWE significantly improved the sensory properties of the meat paste during the late stage of the storage period. Based on the results, LSWE was determined to be effective in inhibiting adipogenesis and retarding lipid oxidation, which can improve the safety and quality of meat products. [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]

Litchi is known for its delicious taste and reddish pericarp colour. However, pericarp browning limits the postharvest life of litchi fruit with reduced fruit quality. Therefore, present study was conducted to investigate the influence of harvest location (Lahore and Haripur) as well as cultivar ('Gola' and 'Serai') on pericarp browning, changes in the biochemical quality attributes and enzymatic activities in litchi fruit. Fruit harvested from Lahore exhibited significantly higher pericarp browning index (3.99), weight loss (12.7%), ascorbic acid contents (48.9 mg 100 g-1) and activities of enzymes responsible for browning (peroxidase and polyphenol oxidase) as compared to Haripur. Moreover, fruit harvested from Lahore exhibited less SSC: TA ratio (105.3), total phenolic contents (187.35 mg GAE 100 g-1), total antioxidants (45.27%) and activity of superoxide dismutase enzyme (40.86 U mg-1 protein) than that of Haripur. On the other hand, 'Serai' fruit exhibited higher weight loss (12.86%), SSC (19.58oBrix), TA (0.24%), activities of peroxidase (35.81 U mg-1 protein) and polyphenol oxidase (25.22 U mg-1 protein) enzymes. Moreover, lower level of TPC (202.9 mg GAE 100 g-1), total antioxidants (50.2%), activities of superoxide dismutase (39.85 U mg-1 protein) and catalase (22.32 U mg-1 protein) enzymes were observed in 'Serai' than 'Gola' fruit. Results suggested that fruit harvested from Haripur exhibited better fruit quality characteristics and browning index than fruit harvested from Lahore. Cultivar 'Gola' showed better quality with less pericarp browning than 'Serai'. [ABSTRACT FROM AUTHOR]

Content of total proanthocyanidins as well as total phenolics, flavonoids, antioxidant activities were evaluated for litchi (Litchi chinensis Sonn.) pulp of 32 cultivars. One cultivar, Hemaoli, showed the highest total proanthocyanidins and total phenolics, and DPPH or ABTS radical scavenging activities. ESI-MS and NMR analysis of the Hemaoli pulp crude extracts (HPCE) showed that procyandins composed of (epi)catechin unites with degree of polymerization (DP) of 2–6 were dominant proanthocyanidins in HPCE. After the HPCE was fractionated by a Sephadex LH-20 column, 32 procyanidins were identified by LC-ESI-Q-TOF-MS in litchi pulp for the first time. Quantification of individual procyanidin in HPCE indicated that epicatechin, procyanidin B2, procyanidin C1 and A-type procyanidin trimer were the main procyanidins. The radical scavenging activities of different fractions of HPCE as well as six procyanidins standards were evaluated by both DPPH and ABTS assays. HPCE fractions showed similar antioxidant activities with those of Vc and six individual procyanidins, the IC50 of which ranged from 1.88 ± 0.01 to 2.82 ± 0.10 μg/ml for DPPH assay, and from 1.52 ± 0.17 to 2.71 ± 0.15 μg/ml for ABTS assay. Such results indicate that litchi cultivars rich in proanthocyanidins are good resources of dietary antioxidants and have the potential to contribute to human health. [ABSTRACT FROM AUTHOR]

Objectives L itchi chinensis has been traditionally used in folk medicine to treat several ailments. In this study, we investigated the chemical composition, antioxidant and antinociceptive activity of L . chinensis leaves. Methods The antioxidant capacity of the extract, fraction and compounds was evaluated using the 1,1-diphenyl-picrylhydrazyl ( DPPH) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) ( ABTS) assays, and the liposome model with peroxyl radicals generated by 2,2′-azobis (2-amidinopropane) dihydrochloride radical. The pharmacological models of acute nociception used in mice were: writhing test with acetic acid ( AA), hotplate ( HP), glutamate ( GLU), capsaicin ( CP) and formalin ( FM) tests. Key findings The main compounds isolated were procyanidin A2 ( PA2), procyanidin B2 ( PB2) and (-)-epicatechin. The biochemical features of the crude extracts and their ethyl acetate fraction ( EtOAcFR) presented high antioxidant activity, and the antioxidant activity of PA2 and PB2 was remarkably high, with DPPH and ABTS. The crude methanol extract ( MeOHEXTR), EtOAcFR and PB2 were effective in reducing nociception in FM and HP models. MeOHEXTR and EtOAcFR treatments also reduced pain induced by GLU and AA. In the CP model, only EtOAcFR and PB2 were effective. Conclusions The results demonstrate the antinociceptive and antioxidant of MeOHEXTR, EtOAcFR and PB2. [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]

The optimal extraction of bioactive compounds from lychee fruits using commercial Pectinex® Ultra SP-L pectinase hydrolysis of the fruit pulp homogenate was evaluated. The lychee fruit pulp was treated with the pectinase at volume per mass ratios between 0.5 and 2.5 % for 0.5-5 h. The degree of hydrolysis (DH), monitored as the level of released reducing sugar, increased with the increase of enzyme volume per mass ratio and time up to 2 % and 4 h, respectively, to give a maximum DH of 19 %. The antioxidant activity in lychee pulp hydrolysates increased with increasing DH, with the highest DH of 19 % displaying an EC50 of 0.25 µg of fresh mass (FM) per pg of diphenyl-(2,4,6-trinitrophenyl)-iminoazanium and 53.17 µM of Trolox equivalents per g of FM. The lychee hydrolysate with the DH of 19 % had the highest level of total phenolic acids (165.8 mg of gallic acid equivalents per 100 g of FM) and flavonoids (70.8 mg of catechin equivalents per 100 g of FM), and the highest prebiotic activity score of 1.68 and 0.82 of Bifidobacterium lactis Bbl2 and Lactobacillus acidophilus La5, respectively. In accordance with the level of phenolic acids and flavonoids, the lychee hydrolysate with the DH of 19 % revealed a reasonably good level (72-77 %) of lipid peroxidation inhibition in soya bean, lard and olive oil. The lychee hydrolysate with the DH of 19 % increased the number of detected volatile compounds to 37, with 11 new compounds that were not found in the lychee hydrolysate with the DH of 0 %. Moreover, the particle size and insoluble fibre level were reduced with a concomitant increase in the soluble fibre level. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nitric oxide donor, sodium nitroprusside (SNP) treatment reduced pericarp browning and extended shelf life of litchi fruit, during storage at ambient condition. [•] Fruits treated with SNP (2.0mM) maintained 42% higher anthocyanin content and preserved bioactive compounds like phenolics, ascorbic acid and antioxidant capacity, compared to control. [•] SNP treatment minimized weight loss, decay percentage, and malondialdehyde content in fruit. [•] TSS and titratable acidity also maintained higher in SNP treated fruits. [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: The effects of scavenging 2, 2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radicals and inhibiting low-density lipoprotein (LDL) oxidation, and phenolic quantities were used for the activity-guided separation to identify the effective components of litchi flower. The acetone extract of the flower with notable antioxidant capacities was suspended in water and sequentially partitioned with n-hexane, ethyl acetate (EA) and n-butanol. The EA partition with the highest phenolic levels and antioxidant capacities was subjected to silica gel column chromatography. Thirteen fractions (Fr. 1–13) were collected; Fr. 10–12 with higher phenolic levels and antioxidant effects were applied to Sephadex LH-20 column chromatography. Each fraction was further separated into three sub-fractions and the second ones (Fr. 10-II, 11-II, and 12-II) were the best, which two major compounds could be isolated by semi-preparative high performance liquid chromatography (HPLC). Through Mass (MS) and Nuclear Magnetic Resonance (NMR) measurements, they could be identified as (-)-epicatechin and proanthocyanidin A2. Their contents in the litchi flower were 5.52 and 11.12mg/g of dry weight, respectively. The study was the first time to reveal the effective antioxidant components of litchi flower. [Copyright &y& Elsevier]

Background: Litchi (Litchi chinensis Sonn.) pericarp is a major byproduct which contains a significant amount of polyphenol. This study was designed to biotransformation litchi pericarp extract (LPE) by Aspergillus awamori to produce more bioactive compounds with stronger antioxidant activities. Results: The study exhibited that the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities significantly (p < 0.05) increased from 15.53% to 18.23% in the water-extracted fraction and from 25.41% to 36.82% in the ethyl acetate-extracted fraction. Application of DNA cleavage assay further demonstrated the enhanced protection effect of the fermented phenolics on DNA damage. It is also noted that the water-extracted fraction of the fermented LPE possessed a much stronger capacity than the ethyl acetate-extracted fraction to prevent from damage of supercoiled DNA. Interestingly, it was found that some new compounds such as catechin and quercetin appeared after of A. awamori fermentation of LPE, which could account for the enhanced antioxidant activity. Conclusion: The DPPH radical scavenging activity and DNA protection effect of LPE were increased by Aspergillus awamori bioconversion while some compounds responsible for the enhanced antioxidant activity were identified. This study provided an effective way of utilizing fruit pericarp as a readily accessible source of the natural antioxidants in food industry and, thus, extended the application area such as fruit by-products. [ABSTRACT FROM AUTHOR]

Abstract: The effects of pure oxygen on pericarp browning, reactive oxygen species (ROS) metabolism, antioxidant enzyme and antioxidant activity of harvested litchi fruit were investigated. Application of pure oxygen significantly prevented pericarp browning and delayed the increase in membrane permeability of litchi fruit during storage. Litchi fruit exposed to pure oxygen showed a lower level of lipid peroxides, compared to control fruit, with the delay in the increases of both H2O2 content and superoxide production rate. Furthermore, it was found that the treatment with pure oxygen induced the activities of superoxide dismutase (SOD), ascorbated peroxidase (APX) and catalase (CAT), which could be beneficial in scavenging of H2O2 and superoxide and alleviating lipid peroxidation. In addition, antioxidant ability (reducing power and free-radical scavenging activity against DPPH radical, superoxide anions and hydroxyl radical) of methanol extracts from litchi fruit pericarp declined gradually, with decreasing contents of anthocyanins and phenolic compounds, as storage time of the fruit progressed. There was a linear relationship between the contents of either anthocyanins or phenolic compounds and antioxidant ability or free radical scavenging activity. Treatment with pure oxygen markedly increased antioxidant ability, which was related to higher levels of anthocyanins and phenolic compounds, compared with those of control fruit. It is suggested that enhanced antioxidant activity and antioxidant enzyme induced by pure oxygen may contribute to alleviating lipid peroxidation and maintenance of membrane integrity, which reduced decompartmentation of enzymes and substrates, resulting in enzymatic browning. [Copyright &y& Elsevier]

Abstract: The pericarps of 10 litchi cultivars from two production seasons were studied for their phenolic concentrations and composition and activities of anti-oxidation. The total phenolic concentrations in dried litchi pericarp ranged from 51 to 102gkg−1. Different cultivars varied considerably in phenolic concentration and composition. Cultivars ‘Nuomici’ exhibited significantly higher concentrations of proanthocyanidins, flavonoids, phenolic acids and therefore total soluble phenolics than the other cultivars, while ‘Lanzhu’ and ‘Guiwei’ had minor values in phenolics. The extracts of litchi pericarp exhibited considerably high ferric reducing antioxidant power (FRAP) and strong activities of 1,1-diphenyl-2-picryhydrazyl (DPPH) scavenging, lipid peroxidation inhibiting, and oxidative DNA damage protection. The crude ethanol extracts of pericarp displayed significantly higher FRAP and stronger DPPH scavenging capacity than butylated hydroxylytoluene (BHT) and catechin. Among the tested cultivars, concentrations of major phenolics had significant linear correlations with FRAP and DPPH scavenging activities. These results indicated that litchi pericarp is rich in natural antioxidant phenolic compounds and different litchi cultivars differed considerably in phenolic concentration and antioxidant activities. [Copyright &y& Elsevier]