Identification and quantification of polyphenolic compounds in Longan (Euphoria longana Lam.) fruit

Changes in phenolic compounds of Phyllanthus emblica juice during different storage temperature and pH conditions

The aim of this experiment was to investigate the effect of storage temperature and pH on phenolic compounds of Phyllanthus emblica juice. Juice was stored at different temperatures and pH for 15 days and sampled on 2-day intervals. The browning index (BI, ABS420 nm), pH, centrifugal precipitation rate (CPR), and phenolic compounds were evaluated. The results showed 4°C and pH 2.5 could effectively inhibit browning and slow down pH drop of P. emblica juice. The result of orthogonal partial least square-discriminant analysis showed P. emblica juice stored at 4°C and pH 2.5 still had a similar phenolic composition, but at 20°C, 37°C, and pH 3.5, the score plots were concentrated only in the first 3 days. Additionally, gallic acid (GA) and ellagic acid (EA) were screened out to be the differential compounds for browning of P. emblica juice. The contents of GA, epigallocatechin (EGC), corilagin (CL), gallocatechin gallate (GCG), chebulagic acid (CA), 1,2,3,4,6-O-galloyl-d-glucose (PGG), and EA were more stable at 4°C and pH 2.5. Overall, during storage at 4°C and pH 2.5, it could inhibit the increase of GA and EA and decrease of CL, GCG, CA, and PGG, whereas EGC did not show significant difference between storage conditions. The CPR was higher at 4°C, while pH 2.5 could reduce the CPR. In conclusion, in order to maintain stability of phenolic compounds and extended storage period, the P. emblica juice could be stored at low temperature and adjust the pH to increase the stability of juice system.

A Review of Medicinal Plants and Phytochemicals for the Management of Gout

Gout, characterized by elevated uric acid levels, is a common inflammatory joint disease associated with pain, joint swelling, and bone erosion. Existing treatments for gout often result in undesirable side effects, highlighting the need for new, safe, and cost-effective anti-gout drugs. Natural products, including medicinal plants and phytochemicals, have gained attention as potential sources of anti-gout compounds. In this review, we examined articles from 2000 to 2020 using PubMed and Google Scholar, focusing on the effectiveness of medicinal plants and phyto-chemicals in managing gout. Our findings identified 14 plants and nine phytochemicals with anti-gout properties. Notably, Teucrium polium, Prunus avium, Smilax riparia, Rhus coriaria, Foenic-ulum vulgare, Allium cepa, Camellia japonica, and Helianthus annuus exhibited the highest xa-thine oxidase inhibitory activity, attributed to their unique natural bioactive compounds such as phenolics, tannins, coumarins, terpenoids, and alkaloids. Herbal plants and their phytochemicals have demonstrated promising effects in reducing serum urate and inhibiting xanthine. This review aims to report recent studies on plants/phytochemicals derived from herbs beneficial in gout and their different mechanisms.

Optimization of Ethanolic Extraction of Phenolic Antioxidants from Lychee and Longan Seeds Using Response Surface Methodology

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.

Biochemical characterization of Dimocarpus longan polyphenol oxidase provides insights into its catalytic efficiency

The "dragon-eye" fruits produced by the tropical longan tree are rich in nutrients and antioxidants. They suffer from post-harvest enzymatic browning, a process for which mainly the polyphenol oxidase (PPO) family of enzymes is responsible. In this study, two cDNAs encoding the PPO have been cloned from leaves of Dimocarpus longan (Dl), heterologously expressed in Escherichia coli and purified by affinity chromatography. The prepro-DlPPO1 contains two signal peptides at its N-terminal end that facilitate transportation of the protein into the chloroplast stroma and to the thylakoid lumen. Removal of the two signal peptides from prepro-DlPPO1 yields pro-DlPPO1. The prepro-DlPPO1 exhibited higher thermal tolerance than pro-DlPPO1 (unfolding at 65 °C vs. 40 °C), suggesting that the signal peptide may stabilize the fold of DlPPO1. DlPPO1 can be classified as a tyrosinase because it accepts both monophenolic and diphenolic substrates. The pro-DlPPO1 exhibited the highest specificity towards the natural diphenol (-)-epicatechin (k_cat/K_M of 800 ± 120 s^-1 mM^-1), which is higher than for 4-methylcatechol (590 ± 99 s^-1 mM^-1), pyrogallol (70 ± 9.7 s^-1 mM^-1) and caffeic acid (4.3 ± 0.72 s^-1 mM^-1). The kinetic efficiencies of prepro-DlPPO1 are 23, 36, 1.7 and 4.7-fold lower, respectively, than those observed with pro-DlPPO1 for the four aforementioned diphenolic substrates. Additionally, docking studies showed that (-)-epicatechin has a lower binding energy than any other investigated substrate. Both kinetic and in-silico studies strongly suggest that (-)-epicatechin is a good substrate of DlPPO1 and ascertain the affinity of PPOs towards specific flavonoid compounds.

Characterization of the SWEET Gene Family in Longan (Dimocarpus longan) and the Role of DlSWEET1 in Cold Tolerance

Sugars will eventually be exported transporters (SWEET), a group of relatively novel sugar transporters, that play important roles in phloem loading, seed and fruit development, pollen development, and stress response in plants. Longan (Dimocarpus longan), a subtropic fruit tree with high economic value, is sensitive to cold. However, whether the SWEET gene family plays a role in conferring cold tolerance upon longan remains unknown. Here, a total of 20 longan SWEET (DlSWEET) genes were identified, and their phylogenetic relationships, gene structures, cis-acting elements, and tissue-specific expression patterns were systematically analyzed. This family is divided into four clades. Gene structures and motifs analyses indicated that the majority of DlSWEETs in each clade shared similar exon–intron organization and conserved motifs. Tissue-specific gene expression suggested diverse possible functions for DlSWEET genes. Cis-elements analysis and quantitative real-time PCR (qRT-PCR) analysis revealed that DlSWEET1 responded to cold stress. Notably, the overexpression of DlSWEET1 improved cold tolerance in transgenic Arabidopsis, suggesting that DlSWEET1 might play a positive role in D. longan’s responses to cold stress. Together, these results contribute to a better understanding of SWEET genes, which could serve as a foundation for the further functional identification of these genes.

Corilagin induces apoptosis and inhibits HMBG1/PI3K/AKT signaling pathways in a rat model of gastric carcinogenesis induced by methylnitronitrosoguanidine

Gastric cancer, invasive cancer of the gastrointestinal tract, found in developing countries. Chemotherapy to patients with advanced gastric cancer, exhibits greater drug resistance to standard chemotherapy drugs. Therefore, important to establish anti-cancer drugs that are successful for cancer therapy. Corilagin is a natural ellagitannin (ET) with profound pharmacological properties has been used for the study to assess its anticancer effects against N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) stimulated gastric cancer rats. Biochemical studies showed Thiobarbituric acid reactive substances (TBARS) and enzymatic and non-enzymatic antioxidants increased in corilagin treated animals compared with controls. Histopathologic evaluation revealed corilagin treated rats showed cell morphology similar that control showing its ameliorating effects. In corillagen treament mRNA protein expression levels of HIF-1α, AKT, PI3K, CT4, CD147 and HMGB1 were drastically lowered transcription factors triggering gastric cancer. In Western blot analysis showed released higher apoptotic marker of caspase-3, -9, Bax while Bcl-2 levels were significantly reduced confirming that corilagin triggers apoptosis in gastric cancer.

Anticancer potential of corilagin on T24 and TSGH 8301 bladder cancer cells via the activation of apoptosis by the suppression of NF-κB-induced P13K/Akt signaling pathway

Bladder cancer (BC) is a primary source of malignancy-associated death, and the mortality rate is high due to its prevalence of metastasis. Corilagin (CLG), a bioactive constituent of numerous medicinal plants, exerts assorted pharmacological actions comprising anti-cancer, apoptotic, anti-inflammatory, and hepatoprotective. CLG possesses a substantial anti-tumor prospective and less noxiousness in normal cells in vitro. However, the molecular mechanisms of CLG on BC cells are not studied well. The current research explored the molecular process intricate in the anticancer and anti-proliferative actions of CLG on the relocation of BC cells T24 and TSGH 8301. The cytotoxicity, apoptosis, adhesion, and migration of CLG on BC cells T24 and TSGH 8301 were evaluated by MTT assay, DAPI, Rh-123, cell adhesion, and cell migration assay. The results point out that CLG inhibits the viability, adhesion, movement, incursion, and inflammation, whereas persuades BC cells apoptosis in a concentration-dependent mode. Besides, CLG treated with T24 and TSGH-8301 cells subdue inflammatory and PI3K/Akt signaling pathways. CLG is accomplished of impeding BC cell migration, invasion, and metastasis through the repression of the NF-κB mediated P13K/Akt signaling. Our findings offer a unique vision into the demonstration of the anti-cancer potential of CLG on BC cells.

Newly generated and increased bound phenolic in lychee pulp during heat-pump drying detected by UPLC-ESI-triple-TOF-MS/MS

BACKGROUND

During the thermal processing of fruit, it has been observed for phenolic compounds to either degrade, polymerize, or transfer into macromolecules. In this study, the bound and free phenolic compound composition, content, and phenolic-related enzyme activity of lychee pulp were investigated to determine whether the free phenolic had converted to bound phenolic during heat-pump drying (HPD).

RESULTS

It was found that after HPD, when compared with the fresh lychee pulp (control), the content of bound phenolics of dried lychee pulp had increased by 62.69%, whereas the content of free phenolics of dried lychee pulp decreased by 22.26%. It was also found that the antioxidant activity of bound phenolics had also increased after drying. With the use of high-performance liquid chromatography-tandem mass spectrometry, it was identified that (+)-gallocatechin, protocatechuic aldehyde, isorhamnetin-3-O-rutoside, 3,4-dihydroxybenzeneacetic acid, and 4-hydroxybenzoic acid were newly generated during HPD, when compared with the control sample. After drying, the contents of gallic acid, catechin, 4-hydroxybenzoic acid, vanillin, syringic acid, and quercetin in bound phenolics had also increased, and polyphenol oxidase and peroxidase still showed enzyme activity, which could be related to the conversion of free phenolics to bound phenolics.

CONCLUSION

Overall, during the thermal processing of lychee pulp, the free phenolics weres found to be converted into bound phenolics, new substances were generated, and antioxidant activity was increased. Hence, it was concluded that HPD improved the bound phenolics content of lychee pulp, thus providing theoretical support for the lychee processing industry. © 2021 Society of Chemical Industry.

Natural products can be used in therapeutic management of COVID-19: Probable mechanistic insights

The unexpected emergence of the new Coronavirus disease (COVID-19) has affected more than three hundred million individuals and resulted in more than five million deaths worldwide. The ongoing pandemic has underscored the urgent need for effective preventive and therapeutic measures to develop anti-viral therapy. The natural compounds possess various pharmaceutical properties and are reported as effective anti-virals. The interest to develop an anti-viral drug against the novel severe acute respiratory syndrome Coronavirus (SARS-CoV-2) from natural compounds has increased globally. Here, we investigated the anti-viral potential of selected promising natural products. Sources of data for this paper are current literature published in the context of therapeutic uses of phytoconstituents and their mechanism of action published in various reputed peer-reviewed journals. An extensive literature survey was done and data were critically analyzed to get deeper insights into the mechanism of action of a few important phytoconstituents. The consumption of natural products such as thymoquinone, quercetin, caffeic acid, ursolic acid, ellagic acid, vanillin, thymol, and rosmarinic acid could improve our immune response and thus possesses excellent therapeutic potential. This review focuses on the anti-viral functions of various phytoconstituent and alkaloids and their potential therapeutic implications against SARS-CoV-2. Our comprehensive analysis provides mechanistic insights into phytoconstituents to restrain viral infection and provide a better solution through natural, therapeutically active agents.

Comparative Analysis of the MADS-Box Genes Revealed Their Potential Functions for Flower and Fruit Development in Longan (Dimocarpus longan)

Longan (Dimocarpus longan Lour.) is an important economic crop widely planted in tropical and subtropical regions, and flower and fruit development play decisive effects on the longan yield and fruit quality formation. MCM1, AGAMOUS, DEFICIENS, Serum Response Factor (MADS)-box transcription factor family plays important roles for the flowering time, floral organ identity, and fruit development in plants. However, there is no systematic information of MADS-box family in longan. In this study, 114 MADS-box genes were identified from the longan genome, phylogenetic analysis divided them into type I (Mα, Mβ, Mγ) and type II (MIKC*, MIKC ^C ) groups, and MIKC ^C genes were further clustered into 12 subfamilies. Comparative genomic analysis of 12 representative plant species revealed the conservation of type II in Sapindaceae and analysis of cis-elements revealed that Dof transcription factors might directly regulate the MIKC ^C genes. An ABCDE model was proposed for longan based on the phylogenetic analysis and expression patterns of MADS-box genes. Transcriptome analysis revealed that MIKC ^C genes showed wide expression spectrums, particularly in reproductive organs. From 35 days after KClO₃ treatment, 11 MIKC genes were up-regulated, suggesting a crucial role in off-season flower induction, while DlFLC, DlSOC1, DlSVP, and DlSVP-LIKE may act as the inhibitors. The gene expression patterns of longan fruit development indicated that DlSTK, DlSEP1/2, and DlMADS53 could be involved in fruit growth and ripening. This paper carried out the whole genome identification and analysis of the longan MADS-box family for the first time, which provides new insights for further understanding its function in flowers and fruit.

Genome-Wide Identification and Expression Analysis of the R2R3-MYB Transcription Factor Family Revealed Their Potential Roles in the Flowering Process in Longan (Dimocarpus longan)

Longan (Dimocarpus longan Lour.) is a productive fruit crop with high nutritional and medical value in tropical and subtropical regions. The MYB gene family is one of the most widespread plant transcription factor (TF) families participating in the flowering regulation. However, little is known about the MYB TFs involved in the flowering process in longan and its regulatory network. In this study, a total of 119 DlR2R3-MYB genes were identified in the longan genome and were phylogenetically grouped into 28 subgroups. The groupings were supported by highly conserved gene structures and motif composition of DlR2R3-MYB genes in each subgroup. Collinearity analysis demonstrated that segmental replications played a more crucial role in the expansion of the DlR2R3-MYB gene family compared to tandem duplications, and all tandem/segmental duplication gene pairs have evolved under purifying selection. Interspecies synteny analysis among longan and five representative species implied the occurrence of gene duplication events was one of the reasons contributing to functional differentiation among species. RNA-seq data from various tissues showed DlR2R3-MYB genes displayed tissue-preferential expression patterns. The pathway of flower development was enriched with six DlR2R3-MYB genes. Cis-acting element prediction revealed the putative functions of DlR2R3-MYB genes were related to the plant development, phytohormones, and environmental stresses. Notably, the orthologous counterparts between Arabidopsis and longan R2R3-MYB members tended to play conserved roles in the flowering regulation and stress responses. Transcriptome profiling on off-season flower induction (FI) by KClO₃ indicated two up-regulated and four down-regulated DlR2R3-MYB genes involved in the response to KClO₃ treatment compared with control groups. Additionally, qRT-PCR confirmed certain genes exhibited high expression in flowers/flower buds. Subcellular localization experiments revealed that three predicted flowering-associated MYB proteins were localized in the nucleus. Future functional studies on these potential candidate genes involved in the flowering development could further the understanding of the flowering regulation mechanism.

Alteration of Bioactive Compounds and Antioxidative Properties in Thermal, Ultra-High Pressure and Ultrasound Treated Maoberry (Antidesma Bunius L.) Juice during Refrigerated Storage

Maoberry (Antidesma bunius L.) is a tropical fruit locally referred to as “Mao-Luang” in Thailand. The fruit contains high amounts of ascorbic acid and phenolic compounds with antioxidative potential, which has demonstrated medicinal value in terms of anti-cancer and anti-diabetic effects. In this term, this research purposed to determine the changes of predominant bioactive phytochemicals, antioxidant capacity and microbiological quality of pasteurized (85ºC/1 min), pressurized (500 and 600 MPa/30ºC/30 min), and ultra-sonicated (20 kHz/60% and 80% amplitude/30 min) maoberry juices during storage at 4°C for 30 days. The results displayed that ascorbic acid, phenolic acids (gallic and vanillic acids), anthocyanins (cyanidin 3-o-glucoside and cyanidin 3-rutinoside), flavonoids [(+)-catechin and (˗)-epicatechin), 2,2-diphenyl-1-picryl hydrazyl hydrate (DPPH) radical inhibition and ferric reducing antioxidant power (FRAP) value in pressurized and ultra-sonicated juices displayed higher reduction rate during storage than those in pasteurized juice. Nevertheless, at the final stage of storage, both juices still contained higher levels of antioxidant compounds and properties than in thermally treated juice. All the treated samples were shown to reduce initial microbial load of fresh maoberry juice to a non-detectable amount, while maintaining their quality during prolonged refrigerated storage.

Eco-Friendly Rice Straw Paper Coated with Longan (Dimocarpus longan) Peel Extract as Bio-Based and Antibacterial Packaging

This study aimed to develop active paper from rice straw fibers with its function as antibacterial activity obtained from longan (Dimocarpus longan) peels. The morphology and mechanical properties of fibers of rice straw were examined as quality parameters for paper production. Rice straw paper (RSP) with basis weight ca 106.42 g/m², 0.34 mm thickness, 34.15% brightness, and 32.26 N·m/g tensile index was successfully prepared from fibers and pulps without chemical bleaching process. Bioactive compounds of longan peels were extracted using maceration technique with a mixture of ethanol-water, and subsequently coated onto RSP at concentration of 10%, 15% and 20% (w/v). Fourier transform infrared (FTIR) spectroscopic analysis demonstrated the functional groups of phytochemicals in the peel extract. The results of physical properties showed that the coated RSP had similar thickness and tensile index, but had lower brightness compared to control papers. Scanning electron microscopy (SEM) confirmed the significantly different of surface and cross-section structures between coated and uncoated RSP. The coated RSP had relatively greater barrier properties to prevent water absorption. In addition, the RSP coated with longan peel extracts showed significant antibacterial activity against foodborne bacteria, Staphylococcus aureus and Bacillus cereus. This study reveals the benefits of natural byproducts as potential materials for active packaging prepared by environmentally friendly processes.

Corilagin prevents SARS-CoV-2 infection by targeting RBD-ACE2 binding

BACKGROUND

The outbreak of coronavirus (SARS-CoV-2) disease caused more than 100,000,000 people get infected and over 2,200,000 people being killed worldwide. However, the current developed vaccines or drugs may be not effective in preventing the pandemic of COVID-19 due to the mutations of coronavirus and the severe side effects of the newly developed vaccines. Chinese herbal medicines and their active components play important antiviral activities. Corilagin exhibited antiviral effect on human immunodeficiency virus (HIV), hepatitis C virus (HCV) and Epstein-Barr virus (EBV). However, whether it blocks the interaction between SARS-CoV-2 RBD and hACE2 has not been elucidated.

PURPOSE

To characterize an active compound, corilagin derived from Phyllanthus urinaria as potential SARS-CoV-2 entry inhibitors for its possible preventive application in daily anti-virus hygienic products.

METHODS

Computational docking coupled with bio-layer interferometry, BLI were adopted to screen more than 1800 natural compounds for the identification of SARS-CoV-2 spike-RBD inhibitors. Corilagin was confirmed to have a strong binding affinity with SARS-CoV-2-RBD or human ACE2 (hACE2) protein by the BLI, ELISA and immunocytochemistry (ICC) assay. Furthermore, the inhibitory effect of viral infection of corilagin was assessed by in vitro pseudovirus system. Finally, the toxicity of corilagin was examined by using MTT assay and maximal tolerated dose (MTD) studies in C57BL/6 mice.

RESULTS

Corilagin preferentially binds to a pocket that contains residues Cys 336 to Phe 374 of spike-RBD with a relatively low binding energy of -9.4 kcal/mol. BLI assay further confirmed that corilagin exhibits a relatively strong binding affinity to SARS-CoV-2-RBD and hACE2 protein. In addition, corilagin dose-dependently blocks SARS-CoV-2-RBD binding and abolishes the infectious property of RBD-pseudotyped lentivirus in hACE2 overexpressing HEK293 cells, which mimicked the entry of SARS-CoV-2 virus in human host cells. Finally, in vivo studies revealed that up to 300 mg/kg/day of corilagin was safe in C57BL/6 mice. Our findings suggest that corilagin could be a safe and potential antiviral agent against the COVID-19 acting through the blockade of the fusion of SARS-CoV-2 spike-RBD to hACE2 receptors.

CONCLUSION

Corilagin could be considered as a safe and environmental friendly anti-SARS-CoV-2 agent for its potential preventive application in daily anti-virus hygienic products.

Anti-apoptotic and pro-survival effects of longan flower extracts on rat hearts with fructose-induced metabolic syndrome

The aim of this study was to investigate the effects of longan flower (LF) water extract on cardiac apoptotic and survival pathways in rat models of fructose-induced metabolic syndrome. The study findings revealed that the levels of glucose, insulin, triglyceride, and cholesterol and TUNEL-positive apoptotic cells were significantly increased in the HF group compared with the control group; whereas, the levels were decreased in the HFLF group. The expressions of Fas, FADD, and activated caspases 8 and 3, as well as the expressions of Bax, Bak, Bax/Bcl-2, Bak/Bcl-xL, cytosolic cytochrome c, and activated caspases 9 and 3 were increased in the HF group were significantly reversed in HFLF administrated group. Furthermore, LF extract increased IGF-1R, p-PI3K, p-Akt, Bcl-2, and Bcl-xL expression compared to HF group. Taken together, the present findings help identify LF as a potential cardioprotective agent that can be effectively used in treating fructose-induced metabolic syndrome.

Longan (Dimocarpus longan Lour.) Aril ameliorates cognitive impairment in AD mice induced by combination of D-gal/AlCl3 and an irregular diet via RAS/MEK/ERK signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

According to the theory of traditional Chinese medicine (TCM), Alzheimer's disease (AD) is identified as "forgetfulness" or "dementia", and it can be caused by spleen deficiency. Longan Aril (the aril of Dimocarpus longan Lour., LA) is a kind of Chinese medicine, and it can improve intelligence attributed to entering the spleen-meridian. This study aimed to explore the therapeutic effects of LA on AD mice with spleen deficiency, and to understand anti-AD mechanism of LA.

MATERIAL AND METHODS

A mouse model of AD with spleen deficiency was established by D-gal (140 mg/kg, intraperitoneal injection) and AlCl₃ (20 mg/kg, intragastrical administration) in combination with an irregular diet for 60 days, in which mice in LA group were daily given LA (0.5, 1.0 or 2.0 g/kg). The anti-AD effects of LA were evaluated by the Morris water maze, enzyme-linked immunosorbent assay (ELISA), hematoxylin and eosin (H&E), Nissl, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays. The anti-AD mechanism of LA was studied by using metabolomics, and the expressions of RAS/MEK/extracellular signal-regulated kinase (ERK) signaling pathway-related proteins were detected by Western blotting.

RESULTS

LA improved learning and memory abilities, superoxide dismutase (SOD) level, and form and number of Nissl bodies, while reduced the levels of Aβ₄₂, phosphorylated-tau (p-tau), reactive oxygen species (ROS), malondialdehyde (MDA), monoamine oxidase-B (MAO-B), histological injury, and apoptosis rate in AD group (P < 0.05, P < 0.01 or P < 0.001). The anti-AD mechanism of LA may be related to RAS/MEK/ERK and other signaling pathways, in which the expressions of RAS/MEK/ERK signaling pathway-related proteins significantly reduced (P < 0.05 or P < 0.01).

CONCLUSIONS

LA could improve the cognitive ability and reduce the pathologic impairment in AD mice, which might be partly mediated via inhibition of RAS/MEK/ERK singling pathway.

Acute and chronic oral toxicity assessment of longan sugar extracts derived from whole fruit and from fruit pulp in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Longan (Dimocarpus longan Lour.) is one of the most popular subtropical fruits. Various parts of longan, including seeds, pericarp and pulp, have long been used in traditional medicine in China, Thailand and other Asian countries. The pulp has high sugar, vitamin and mineral content as well as bioactive components. The seeds and pericarp have also been reported to contain beneficial polyphenolic compounds. Longan sugar extract from pulp (LGSP) is prepared as a conventional sugar product. Longan sugar extract from whole longan fruit (LGSW) is also offered as a health food and as a medicinal product.

AIM OF THE STUDY

The objective of this study was to identify and compare potential health hazards of both LGSW and LGSP by testing for acute and chronic oral toxicity in rats.

MATERIALS AND METHODS

In acute toxicity testing, an oral dose (20 g/kg) of either LGSW or LGSP was administered to groups of rats. Mortality and clinical signs of toxicity were observed for 24 h, and then daily for a total of 14 days. In the chronic toxicity test, either LGSW (1, 2.5 and 5 g/kg/day) or LGSP (5 g/kg/day) was administered orally for a period of 180 days. After that treatment period, the rats in the satellite groups which received the highest doses of either LGSW or LGSP were observed for an additional 28 days. The rats then underwent clinical observation, body and organ weight measurement, hematological and biochemical analyses, and histopathological examination.

RESULTS

In the acute toxicity study, the oral administration of LGSP or LGSW in either pellet or syrup formulations did not cause mortality or any pathological abnormalities. In the chronic toxicity study, neither LGSW nor LGSP resulted in death or in any changes in behavior of the rats. All hematological and serum biochemical values of both the LGSW- and LGSP-treated groups were within the normal ranges. No histopathological abnormalities of any internal organs were observed.

CONCLUSION

The safety of longan sugar extract made from whole fruit (pulp, seeds and pericarb) is comparable to that of longan sugar extract made from pulp alone.

Corilagin Represses Epithelial to Mesenchymal Transition Process Through Modulating Wnt/β-Catenin Signaling Cascade

Corilagin (CLG), a major component of several medicinal plants, can exhibit diverse pharmacological properties including those of anti-cancer, anti-inflammatory, and hepatoprotective qualities. However, there are no prior studies on its potential impact on the epithelial-to-mesenchymal transition (EMT) process. EMT can lead to dissemination of tumor cells into other organs and promote cancer progression. Hence, we aimed to investigate the effect of CLG on EMT and its mechanism(s) of action in tumor cells. We noted that CLG reduced the expression of various epithelial markers and up-regulated the expression of Occludin and E-cadherin in both basal and TGFβ-stimulated tumor cells. CLG treatment also abrogated cellular invasion and migration in colon and prostate carcinoma cells. In addition, CLG effectively attenuated the Wnt/β-catenin signaling cascade in TGFβ-stimulated cells. Overall, our study suggests that CLG may function as and effective modulator of EMT and metastasis in neoplastic cells.

Environmentally Friendly Methods for Flavonoid Extraction from Plant Material: Impact of Their Operating Conditions on Yield and Antioxidant Properties

The flavonoids are compounds synthesized by plants, and they have properties such as antioxidant, anticancer, anti-inflammatory, and antibacterial, among others. One of the most important bioactive properties of flavonoids is their antioxidant effect. Synthetic antioxidants have side toxic effects whilst natural antioxidants, such as flavonoids from natural sources, have relatively low toxicity. Therefore, it is important to incorporate flavonoids derived from natural sources in several products such as foods, cosmetics, and drugs. For this reason, there is currently a need to extract flavonoids from plant resources. In this review are described the most important parameters involved in the extraction of flavonoids by unconventional methods such as ultrasound, pressurized liquid extraction, mechanochemical, high hydrostatic pressure, supercritical fluid, negative pressure cavitation, intensification of vaporization by decompression to the vacuum, microwave, infrared, pulsed electric field, high-voltage electrical discharges, and enzyme-assisted extraction. There are no unified operation conditions to achieve high yields and purity. Notwithstanding, progress has been achieved in the development of more advanced and environmentally friendly methods of extraction. Although in literature are found important advances, a complete understanding of the extraction process in each of the unconventional techniques is needed to determine the thermodynamic and kinetic mechanisms that govern each of the techniques.

Sequential extraction and enrichment of pesticide residues in Longan fruit by ultrasonic-assisted aqueous two-phase extraction linked to vortex-assisted dispersive liquid-liquid microextraction prior to high performance liquid chromatography analysis

A simple, green and efficient method for extraction, purification and enrichment of pesticide residues of triazoles and pyrethroids in Longan fruit was developed by ultrasonic-assisted aqueous two-phase extraction (UAATPE) coupled to vortex-assisted dispersive liquid-liquid microextraction (VADLLME). Using an aqueous two-phase system (ATPS) of ethanol/K₂HPO₄ as extraction solvent, the composition of the ATPS, extraction temperature and time were investigated, respectively. Then VADLLME process also was optimized by investigating type and volume of extracting and dispersive solvents, vortex-assisted time and salt addition. The optimum conditions were as follows: the ATPS composition of ethanol concentration 30.0% (w/w) and K₂HPO₄ concentration 25% (w/w), extraction temperature 70 °C and extraction time 15 min for UAATPE; 1-dodecanol 200 μL as extraction solvent, ethanol 1.25 mL as dispersive solvent, vortex-assisted time 1.5 min and addition of NaCl 4% (w/v) for VADLLME. Ethanol as extraction solvent and dispersive solvent could directly connect UAATPE with VADLLME without extra steps. By means of HPLC-DAD detection, nine pesticides had good linearity ranged from 0.0200 to 13.59 μg/mL (R² ≥ 0.9957). LODs and LOQs were in the range of 0.005576-0.01740 μg/mL and 0.01859-0.05010 μg/mL, respectively. UAATPE-VADLLME coupled to HPLC was successfully applied to simultaneous determination of multiple pesticides in Longan fruit, and mean recoveries and RSDs were between 76.95% and 98.63%, 1.2% and 9.8%, respectively. Furthermore, myclobutanil, fenpropathrin and deltamethrin were detected in pericarp and pulp of Longan samples from different districts, respectively.

Corilagin in Cancer: A Critical Evaluation of Anticancer Activities and Molecular Mechanisms

Corilagin (β-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-d-glucose), an ellagitannin, is one of the major bioactive compounds present in various plants. Ellagitannins belong to the hydrolyzable tannins, a group of polyphenols. Corilagin shows broad-spectrum biological, and therapeutic activities, such as antioxidant, anti-inflammatory, hepatoprotective, and antitumor actions. Natural compounds possessing antitumor activities have attracted significant attention for treatment of cancer. Corilagin has shown inhibitory activity against the growth of numerous cancer cells by prompting cell cycle arrest at the G2/M phase and augmented apoptosis. Corilagin-induced apoptosis and autophagic cell death depends on production of intracellular reactive oxygen species in breast cancer cell line. It blocks the activation of both the canonical Smad and non-canonical extracellular-signal-regulated kinase/Akt (protein kinase B) pathways. The potential apoptotic action of corilagin is mediated by altered expression of procaspase-3, procaspase-8, procaspase-9, poly (ADP ribose) polymerase, and Bcl-2 Bax. In nude mice, corilagin suppressed cholangiocarcinoma growth and downregulated the expression of Notch1 and mammalian target of rapamycin. The aim of this review is to summarize the anticancer efficacy of corilagin with an emphasis on the molecular mechanisms involving various signaling pathways in tumor cells.

Longan fruit increase bone mineral density in zebrafish and ovariectomized rat by suppressing RANKL-induced osteoclast differentiation

BACKGROUND

The receptor activator of nuclear factor-kappa B ligand (RANKL)-induced nuclear factor-kappa B (NF-κB) signaling pathway plays essential roles in osteoclast differentiation and may serve as an attractive target for the development of therapeutics for osteoporosis.

PURPOSE

This study aimed to identify plant extracts that attenuated RANKL-induced NF-κB signaling pathway and examine their anti-osteoporotic effects in animal model systems.

METHODS

Osteoclast differentiation was determined by western blot analysis, RT-PCR, and tartrate-resistant acid phosphatase (TRAP) assay. The effect of Longan (Dimocarpus longan Lour.) fruit extract (LFE) on bone mineral density was evaluated by calcein staining in zebrafish and micro-CT analysis in ovariectomized (OVX) rat.

RESULTS

LFE nullified RANKL-induced down-regulation of inhibitor of NF-κB, which keeps NF-κB sequestered in the cytosol, thereby inhibiting translocation of NF-κB to the nucleus, in RAW264.7 cells. In addition, LFE decreased the nuclear levels of c-Fos and nuclear factor of activated T-cells c1, which play crucial roles in RANKL-induced osteoclast differentiation, in RAW264.7 cells. LFE repressed RANKL-activated cathepsin K and TRAP expression in RAW264.7 cells, resulting in a reduction of the number of TRAP-positive multinucleated cells, without cytotoxicity. Furthermore, LFE increased bone mineralization in zebrafish and prevented bone loss in OVX rat.

CONCLUSION

Collectively, our findings suggest that LFE exerts its anti-osteoporotic activity through inhibition of osteoclast differentiation and may have potential as a herbal therapeutic or preventive agent for the treatment of osteoporosis.

Polyphenols and Alkaloids in Byproducts of Longan Fruits (Dimocarpus Longan Lour.) and Their Bioactivities

The longan industry produces a large amount of byproducts such as pericarp and seed, resulting in environmental pollution and resource wastage. The present study was performed to systematically evaluate functional components, i.e., polyphenols (phenolics and flavonoids) and alkaloids, in longan byproducts and their bioactivities, including antioxidant activities, nitrite scavenging activities in simulated gastric fluid and anti-hyperglycemic activities in vitro. Total phenolic and total flavonoid contents in pericarp were slightly higher than those in seeds, but seeds possessed higher alkaloid content than pericarp. Four polyphenolic substances, i.e., gallic acid, ethyl gallate, corilagin and ellagic acid, were identified and quantified using high-performance liquid chromatography. Among these polyphenolic components, corilagin was the major one in both pericarp and seed. Alkaloid extract in seed showed the highest DPPH radical scavenging activity and oxygen radical absorbance capacity. Nitrite scavenging activities were improved with extract concentration and reaction time increasing. Flavonoids in seed and alkaloids in pericarp had potential to be developed as anti-hyperglycemic agents. The research result was a good reference for exploring longan byproducts into various valuable health-care products.

Longan (Dimocarpus longan) and lychee (Litchi chinensis): Functional ingredients in chocolate pralines

Fresh and half-dried fruits of lychee (Litchi Chinensis) and longan (Dimocarpus longan) were processed by air drying and implemented in diverse forms as fillings in order to produce chocolate pralines. Both dried fruits and chocolate pralines were characterized with total polyphenols, proanthocyanidins, flavan-3-ols and antioxidant capacity (2, 2-diphenyl-1-picrylhydrazyl, 2, 2-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic acid) were determined by spectrophotometric and sensory analyses by quantitative descriptive analysis. Specific polyphenolic compounds were quantified using high-performance liquid chromatography coupled with photodiode array detector. The bioactive content and profile of chocolate pralines produced with the addition of longan and lychee were not significantly altered when compared to plain chocolate, but the sensory analysis revealed a preference for lychee-containing pralines, due to characteristic fruity sensory properties. Since longan and lychee fruits are still underutilized as raw materials and ingredients in food production, preservation by drying and incorporation into new products may enable their popularization and increase functional food production. PRACTICAL APPLICATIONS: Since both longan and lychee are still underutilized as raw materials and ingredients in food production, preservation by drying and incorporation into new products may enable their popularization and increase functional food production.

Protective effects of polyphenolic extracts from longan seeds promote healing of deep second-degree burn in mice

The objective of this study was to evaluate the ability of a polyphenolic extract from longan seeds as a wound-healing material for deep second-degree burn wounds.

Corilagin induces apoptosis, autophagy and ROS generation in gastric cancer cells in vitro

Corilagin, a unique component of the tannin family, has been identified in several medicinal plants. In previous literature, corilagin exhibited a marked anticancer property in a variety of human cancer cells. However, the biological effects of corilagin on gastric cancer and the mechanisms involved remain to be fully elucidated. In the present study, it was reported that corilagin induced inhibition of cell growth in SGC7901 and BGC823 cells in a concentration-dependent manner. It was found that corilagin exhibited less toxicity towards normal GES-1 cells. Furthermore, the study showed that corilagin induced the apoptosis of gastric cancer cells mainly via activating caspase-8, -9, -3 and poly ADP-ribose polymerase proteins. Simultaneously, it was verified that corilagin triggered autophagy in gastric cancer cells and the inhibition of autophagy improved the activity of corilagin on cell growth suppression. In addition, corilagin significantly increased intracellular reactive oxygen species production, which is important in inhibiting the growth of gastric cancer cells. Finally, it was shown that necroptosis cannot be induced by corilagin-incubation in SGC7901 and BGC823 cell lines. Consequently, these findings indicate that corilagin may be developed as a potential therapeutic drug for gastric cancer.

Hierarchical Structure, Gelatinization, and Digestion Characteristics of Starch from Longan (Dimocarpus longan Lour.) Seeds

Starch was isolated from longan seeds of three widely distributed cultivars (Chuliang, Shixia, and Caopu) in China. Comparisons of the multi-level structure of the starch of longan seeds among various cultivars were made, and the relations between these structural and property characteristics are discussed. The isolated starch, accounting for 44.9–49.5% (w/w) in longan seeds, had an oval or an irregular polygonal shape with a smooth surface. Their chain-length distributions (CLDs) varied with longan cultivar; Chuliang showed a larger proportion of longer amylopectin chains with a degree of polymerization (DP) 30~100. This is attributed to the slightly higher relative crystallinity of Chuliang longan seed starch. Apparent differences were also detected in amylose structure. Caopu showed a higher amylose content than Chuliang and Shixia, resulting in its lower gelatinization temperatures and enthalpy change. All longan seed starch had a typical A-type crystal structure with relative crystallinity ranging 28.6–28.9%. For raw starch, Caopu showed the lowest digestion rate, followed by Chuliang; Shixia showed the highest. This is because Caopu had the highest amylose content. Chuliang had a more intact structure than Shixia, as suggested by its higher crystallinity, although they had similar amylose content. After being fully gelatinized, all starch showed a similar digestion process, indicating that the digestibility of gelatinized starch does not differ with starch source or structure.

The potential use of thermosensitive chitosan/silk sericin hydrogels loaded with longan seed extract for bone tissue engineering

In this study, hydrogels that were thermosensitive at body temperature were developed using chitosan (CS)/silk sericin (SS)/β-glycerophosphate (β-GP) loaded with longan seed extract (LE) for use in bone tissue engineering. These hydrogels were transformed into a gel at 37 °C within 10 min via interactions between CS and β-GP. The incorporation of SS resulted in a shorter gelation time of 5-7 min. The morphological structure of the thermosensitive CS/β-GP hydrogels exhibited an irregular pore structure, whereas the morphological structure of the thermosensitive CS/SS/β-GP hydrogels became more slender and porous. The incorporation of SS affected the network structure of the CS hydrogels, which degraded more rapidly. Moreover, the cumulative amounts of both gallic acid (GA) and ellagic acid (EA) released from the hydrogels loaded with LE increased with an increase in the SS content. Finally, these thermosensitive hydrogels were non-toxic to both a mouse fibroblast cell line (NCTC clone 929) and a mouse osteoblast cell line (MC3T3-E1) and promoted the attachment of MC3T3-E1 cells to the surface of the hydrogels. Therefore, these thermosensitive hydrogels might be a promising candidate for bone tissue engineering.

Corilagin from longan seed: Identification, quantification, and synergistic cytotoxicity on SKOv3ip and hey cells with ginsenoside Rh2 and 5-fluorouracil

Corilagin content from different parts of longan (Dimocarpus longan Lour.) was determined by ultra performance liquid chromatography (UPLC) method. Additionally, the potential synergistic effects of corilagin + ginsenoside Rh2 (Rh2), and corilagin + 5-fluorouracil (5-FU) on ovarian cancer cells, and cancer-preventing activities, including inhibition of tyrosinase, properties of antioxidant and nitrite-scavenging, and blocking of nitrosamine synthesis were investigated. The results showed the content of corilagin from different parts of longan varied widely, while corilagin content in longan seed was high with a value of 542.15 ± 10.30 μg/g. Then the corilagin from longan seed was chosen for further study, since longan seed was easily obtained from by-product of longan fruit processing with low cost. Furthermore, the combinations of corilagin + Rh2, and corilagin + 5-FU showed an increased synergistic cytotoxicity on SKOv3ip and Hey cells. Moreover, corilagin inhibited exhibited effects of inhibiting tyrosinase, antioxidation, scavenging nitrite and blocking nitrosamine synthesis.

The role of nutrition in influencing mechanisms involved in environmentally mediated diseases

Human exposure to environmental contaminants such as persistent chlorinated organics, heavy metals, pesticides, phthalates, flame retardants, electronic waste and airborne pollutants around the world, and especially in Southeast Asian regions, are significant and require urgent attention. Given this widespread contamination and abundance of such toxins as persistent organic pollutants (POPs) in the ecosystem, it is unlikely that remediation alone will be sufficient to address the health impacts associated with this exposure. Furthermore, we must assume that the impact on health of some of these contaminants results in populations with extraordinary vulnerabilities to disease risks. Further exacerbating risk; infectious diseases, poverty and malnutrition are common in the Southeast Asian regions of the world. Thus, exploring preventive measures of environmental exposure and disease risk through new paradigms of environmental toxicology, optimal and/or healthful nutrition and health is essential. For example, folic acid supplementation can lower blood arsenic levels, and plant-derived bioactive nutrients can lower cardiovascular and cancer risks linked to pollutant exposure. Data also indicate that diets enriched with bioactive food components such as polyphenols and omega-3 polyunsaturated fatty acids can prevent or decrease toxicant-induced inflammation. Thus, consuming healthy diets that exhibit high levels of antioxidant and anti-inflammatory properties, is a meaningful way to reduce the vulnerability to non-communicable diseases linked to environmental toxic insults. This nutritional paradigm in environmental toxicology requires further study in order to improve our understanding of the relationship between nutrition or other lifestyle modifications and toxicant-induced diseases. Understanding mechanistic relationships between nutritional modulation of environmental toxicants and susceptibility to disease development are important for both cumulative risk assessment and the design and implementation of future public health programs and behavioral interventions.

Corilagin, a promising medicinal herbal agent

Corilagin, a gallotannin, is one of the major active components of many ethnopharmacological plants. It was isolated from Caesalpinia coriaria (Jacq.) Willd. (dividivi) by Schmidt in 1951 for the first time. In the past few decades, corilagin was reported to exhibit anti-tumor, anti-inflammatory and hepatoprotective activities, etc. However, little attention was paid to its pharmacological properties due to the complicated and inefficient extract method. In recent years, with the development of extraction technology corilagin was much easier to obtain than before. Thus, people return to pay attention to its anti-tumor, hepatoprotective, and anti-inflammatory activities, particularly as an anti-tumor agent candidate. Our research team had focused on the distribution, preparation and anti-tumor activity of corilagin since 2005. We found corilagin showed good anti-tumor activity on hepatocellular carcinoma and ovarian cancer. What's more, corilagin showed a low level of toxicity toward normal cells and tissues. Due to the extensive attention that corilagin has received, we present a systematic review of the pharmacological effects of corilagin. In this review, we summarized all the pharmacological effects of corilagin with a focus on the molecular mechanism of anti-tumor activity and show you how corilagin affected the signaling pathways of tumor cells as well as its physicochemical properties, distribution and preparation methods.

Biosynthesis, Antibacterial Activity and Anticancer Effects Against Prostate Cancer (PC-3) Cells of Silver Nanoparticles Using Dimocarpus Longan Lour. Peel Extract

Metal nanoparticles, particularly silver nanoparticles (AgNPs), are developing more important roles as diagnostic and therapeutic agents for cancers with the improvement of eco-friendly synthesis methods. This study demonstrates the biosynthesis, antibacterial activity, and anticancer effects of silver nanoparticles using Dimocarpus Longan Lour. peel aqueous extract. The AgNPs were characterized by UV-vis absorption spectroscopy, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscope (FTIR). The bactericidal properties of the synthesized AgNPs were observed via the agar dilution method and the growth inhibition test. The cytotoxicity effect was explored on human prostate cancer PC-3 cells in vitro by trypan blue assay. The expressions of phosphorylated stat 3, bcl-2, survivin, and caspase-3 were examined by Western blot analysis. The longan peel extract acted as a strong reducing and stabilizing agent during the synthesis. Water-soluble AgNPs of size 9-32 nm was gathered with a face-centered cubic structure. The AgNPs had potent bactericidal activities against gram-positive and gram-negative bacteria with a dose-related effect. AgNPs also showed dose-dependent cytotoxicity against PC-3 cells through a decrease of stat 3, bcl-2, and survivin, as well as an increase in caspase-3. These findings confirm the bactericidal properties and explored a potential anticancer application of AgNPs for prostate cancer therapy. Further research should be focused on the comprehensive study of molecular mechanism and in vivo effects on the prostate cancer.

Ellagitannins in Cancer Chemoprevention and Therapy

It is universally accepted that diets rich in fruit and vegetables lead to reduction in the risk of common forms of cancer and are useful in cancer prevention. Indeed edible vegetables and fruits contain a wide variety of phytochemicals with proven antioxidant, anti-carcinogenic, and chemopreventive activity; moreover, some of these phytochemicals also display direct antiproliferative activity towards tumor cells, with the additional advantage of high tolerability and low toxicity. The most important dietary phytochemicals are isothiocyanates, ellagitannins (ET), polyphenols, indoles, flavonoids, retinoids, tocopherols. Among this very wide panel of compounds, ET represent an important class of phytochemicals which are being increasingly investigated for their chemopreventive and anticancer activities. This article reviews the chemistry, the dietary sources, the pharmacokinetics, the evidence on chemopreventive efficacy and the anticancer activity of ET with regard to the most sensitive tumors, as well as the mechanisms underlying their clinically-valuable properties.

Longan (Dimocarpus longan Lour.) inhibits lipopolysaccharide-stimulated nitric oxide production in macrophages by suppressing NF-κB and AP-1 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Flower, seed, and fruit of longan (Dimocarpus longan Lour.) have been used in the Traditional Chinese Medicine (TCM) serving as a common herb in relief of swelling which can be applied in cases of inflammatory diseases. However, the scientific evidence related to their effects on inflammation especially the possible cellular and molecular mechanisms of longan need to be clarified.

AIM OF THE STUDY

To evaluate the anti-inflammatory effect of the various parts of longan including flower, seed, and pulp. The mechanisms and molecular targets involved in their effects were also investigated.

MATERIALS AND METHODS

Different longan extracts were analyzed for their bioactive compounds and evaluated for anti-inflammation. Corilagin, ellagic acid, and gallic acid were detected using HPLC-DAD. In vitro anti-inflammatory effect of longan extracts and their polysaccharides were examined by analyzing nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Expression of the proteins that involved in NO production was detected by Western blot.

RESULTS

Flower extract contained the highest amounts of total phenolics, total flavonoids, proanthocyanidins, corilagin and ellagic acid when compared to seed and pulp extracts. The extracts of different longan parts inhibited LPS-induced NO production with different potency. The highest potency for the inhibition of NO production was shown with flower extract follow by seed and pulp (IC50=128.2, 1127.4, and 1260.2μgmL(-1), respectively). The mechanisms of this anti-NO production were associated with their NO scavenging effect and their decreasing the expression and catalytic activity of an inducible nitric oxide synthase (iNOS). Moreover, these longan extracts suppressed LPS-induced degradation of IκBα and activation of NF-κB, activator protein-1 (AP-1), Akt, and mitogen activated protein kinases (MAPKs).

CONCLUSION

These results suggest that the longan extracts possess anti-inflammatory property. Therefore, longan could provide potential dietary supplement for the treatment of inflammatory-related diseases.

Longan fruit juice mediated synthesis of uniformly dispersed spherical AuNPs: cytotoxicity against human breast cancer cell line MCF-7, antioxidant and fluorescent properties

In the present work AuNPs were synthesized by an eco-friendly, fast, one-pot and green synthetic route using Longan fruit juice as a reducing, capping and stabilizing agent.

Application of α-aminoisobutyric acid and β-aminoisobutyric acid inhibits pericarp browning of harvested longan fruit

BACKGROUND

Pericarp browning is a critical problem resulting in reduced commercial value and shelf life of longan fruit.

RESULTS

Two non-protein amino acids, α-aminoisobutyric acid (AIB) and β-aminoisobutyric acid (BAIB) at 100 and 1 mM were applied to longan fruit prior to storage for up to 8 days at 25 °C respectively. Contents of the major five phenolics (gallic acid, catechin, corilagin, epicatechin and gallocatechin gallate) were assayed by high-performance liquid chromatography (HPLC). Physiological properties related to pericarp browning of longan fruit were investigated during storage. Respiration rate, membrane permeability, malondialdehyde (MDA) content, and activities of polyphenol oxidase (PPO) and peroxidase (POD) were down-regulated by AIB or BAIB treatments, with significantly lower pericarp browning index and higher proportion of edible fruit than the control. Moreover, exogenous application of AIB and BAIB maintained higher contents of catechin, corilagin, epicatechin and gallocatechin gallate, but lower content of gallic acid compared to the control in the pericarp of longan fruit during storage, which was associated with the oxidation of browning substrate.

CONCLUSIONS

Pericarp browning was inhibited and storage life of longan fruit was extended effectively by AIB and BAIB treatments with AIB treatment being more significant than BAIB. The findings may provide a new strategy for controlling pericarp browning of harvested longan fruit.