Antioxidative and anti-inflammatory properties of Citrus sulcata extracts

Narirutin ameliorates alcohol-induced liver injury by targeting MAPK14 in zebrafish larvae

BACKGROUND

Alcohol-associated liver disease (ALD) encompasses a range of hepatic abnormalities, including isolated alcoholic steatosis, steatohepatitis, and cirrhosis. The flavanone-7-O-glycoside narirutin (NRT), the primary flavonoid in citrus peel, has antioxidant, anti-inflammatory, and lipid-lowering activity. We investigated the effects of NRT on liver injury induced by alcohol and explored the underlying mechanisms.

METHODS

Zebrafish larvae were used to investigate the effects of NRT on acute exposure to ethanol (EtOH). Liver phenotypic, morphological, and biochemical assessments were performed to evaluate the hepatoprotective effects of NRT. Network pharmacology and molecular docking analyses were conducted to identify candidate targets of NRT in EtOH-induced liver injury. A drug affinity responsive target stability (DARTS) assay was conducted to evaluate the binding of NRT to mitogen-activated protein kinase 14 (MAPK14). The mechanism of action of NRT was validated by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot analysis.

RESULTS

The liver phenotypic, morphological, and biochemical assessments revealed that NRT has potential therapeutic effects against acute EtOH-induced liver injury. RT-qPCR confirmed that NRT reversed the change in the expression of genes related to oxidative stress, lipogenesis, and the endoplasmic reticulum (ER)/unfolded protein response pathway. Network pharmacology and molecular docking analyses identified potential targets of NRT's protective effects and confirmed that NRT regulates the p38 MAPK signaling pathway by targeting mitogen-activated protein kinase 14 (MAPK14).

CONCLUSIONS

NRT mitigates alcohol-induced liver injury by preventing lipid formation, protecting the antioxidant system, and suppressing ER stress-induced apoptosis through MAPK14 modulation.

Influence of solvent selection and extraction methods on the determination of polyphenols, antioxidant, lipoxygenase and tyrosinase inhibition activities of Opuntia ficus-indica fruits peel and pulp collected from the Kingdom of Saudi Arabia (KSA)

The effect of extracting solvents used by two methods on the TPC, TFC, antioxidant as well as lipoxygenase, and tyrosinase inhibition activities of O. ficus-indica fruit (peel and pulp) were studied. The results manifest that extracts with solvent polarities showed different levels of polyphenols contents and antioxidant activities. The extracts acquired by the Soxhlet method were the most fascinating. Interestingly, peel extracts contain more polyphenols than pulp and showed activities. Lipoxygenase and tyrosinase inhibitory activity of the fruit peel and pulp extracts was reported for the first time. The promising results obtained prompted to the formulation of a stable phytocosmetic emulsion system loaded with 1% pre-concentrated peel extract, aiming to revive facial skin properties. The efficacy of the formulations was determined through SPF and UVA protection factors. To the in vitro safety assessment CAM-TBS, HET-CAM, and red blood cell tests were achieved. Importantly, the formulation did not induce any toxicity.

Prospective multifunctional roles and pharmacological potential of dietary flavonoid narirutin

Plant-based phytochemicals are now being used to treat plenty of physiological diseases. Herbal drugs have gained popularity in recent years because of their strength, purity, and cheap cost-effectiveness. Citrus fruits contain significant amounts of flavanones, which falls to the category of polyphenols. Flavanones occupy a major fraction of the total polyphenols present in the plasma when orange juice is taken highly or in moderate states. Narirutin is a disaccharide derivative available in citrus fruits, primarily dihydroxy flavanone. From a pharmacological viewpoint, narirutin is a bioactive phytochemical with therapeutic efficacy. Many experimental researches were published on the use of narirutin. Anticancer activity, neuroprotection, stress relief, hepatoprotection, anti-allergic activity, antidiabetic activity, anti-adipogenic activity, anti-obesity action, and immunomodulation are a couple of the primary pharmacological properties. Narirutin also has antioxidant, and anti-inflammatory activities. The ultimate goal of this review is to provide the current scenario of pharmacological research with narirutin; to make a better understanding for therapeutic potential of narirutin, as well as its biosynthesis strategies and side effects. Extensive literature searches and studies were undertaken to determine the pharmacological properties of narirutin.

Conditions of enzyme-assisted extraction to increase the recovery of flavanone aglycones from pectin waste

The citrus pectin by-product (CPB), generated from pectin industry, is a rich-source of flavanones, but not explored until now. As most of these compounds are inside vacuoles or bound to cell wall matrix, enzymatic hydrolysis was applied on their recovery, followed by hydroalcoholic and ultrasound extraction. Different parameters were studied: enzymes (β-glucosidase, tannase, and cellulase), their concentration (5, 10, and 20 U g^-1 CPB), and reaction time (6, 12, and 24 h). Extracts were characterized in total phenolic content (TPC), antioxidant capacity (ORAC and DPPH assays), and polyphenolic profile (HPLC-DAD). All enzymatic treatments significantly improved CPB antioxidant capacity and TPC, compared with hydroalcoholic and ultrasound extraction. β-glucosidase (5 U) for 24 h was the most effective in polyphenol extraction and bioconversion, followed by β-glucosidase (5 U) for 12 h and tannase (5 U) for 24 h. Thus, the concentration of these enzymes was increased (10 and 20 U) to improve flavanones extraction. β-glucosidase at 20 U offered the highest amount of naringenin (77.63 mg 100 g^-1 of CPB) and hesperetin (766.44 mg 100 g^-1) obtained so far by biological processes. According to Person's correlation analysis, TPC and antioxidant activity were highly correlated with CPB contents of hesperetin and naringenin. The aglycone flavanones are rarely found in natural sources and have higher biological potential than their glycosylated forms. Our results indicated enzyme-assisted extraction as a good choice for recovering aglycone flavanones from CPB, and increased knowledge on the biological activity of this agroindustrial waste, amplifying their application in food and pharmaceutical field.

Citrus Peel Flavonoids as Potential Cancer Prevention Agents

Citrus fruit and in particular flavonoid compounds from citrus peel have been identified as agents with utility in the treatment of cancer. This review provides a background and overview regarding the compounds found within citrus peel with putative anticancer potential as well as the associated in vitro and in vivo studies. Historical studies have identified a number of cellular processes that can be modulated by citrus peel flavonoids including cell proliferation, cell cycle regulation, apoptosis, metastasis, and angiogenesis. More recently, molecular studies have started to elucidate the underlying cell signaling pathways that are responsible for the flavonoids' mechanism of action. These growing data support further research into the chemopreventative potential of citrus peel extracts, and purified flavonoids in particular. This critical review highlights new research in the field and synthesizes the pathways modulated by flavonoids and other polyphenolic compounds into a generalized schema.

Virulence Genes Analysis of Vibrio parahaemolyticus and Anti-vibrio Activity of the Citrus Extracts

Vibrio parahaemolyticus (VP) is a marine bacterium that opportunistically caused foodborne gastroenteritis in human and some diseases in marine animals. The isolated strain of V. parahaemolyticus WS001 from Samut Sakhon, Thailand has a presence of ldh (~ 450 bp) toxA (~ 333 bp) and toxB (~ 1269 bp) genes which showed pathogenicity in shrimp. This strain is suspected as low pathogenicity in human due to the lack of tdh and trh genes for encoding thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH), respectively. The shrimp pathogenic strain was tested and revealed the multi-antibiotic resistances but was susceptible to norfloxacin (10 μg/ml). Citrus peel extracts were examined because they are rich in bioactive compounds such as saponins, tannins, flavonoids, steroids, and alkaloids that are effective in anti-VP activities. The ethanolic peel extracts of Citrus aurantifolia (Christm.) Swingle and Citrus hystrix DC. were found to be more anti-VP effect than other solvent extracts by Agar disc diffusion method at an optimum concentration of 50 mg/ml and Broth micro-dilution method (MICs of 50-100 mg/ml and MBCs of 100-200 mg/ml). Thus, C. aurantifolia (Christm.) Swingle peel extract was a distinctive candidate for the development of alternative natural agent to control the spreading of diseases in shrimp.

Nutraceutical Oils Produced by Olives and Citrus Peel of Tuscany Varieties as Sources of Functional Ingredients

The essential oils extracted from the peels of two Tuscany Citrus of the Massa province have been characterised. Moreover, the flavedo of these species has been used in the production of two Citrus olive oils (COOs) obtained with an innovative method in which the citrus peels are cryomacerated and then pressed with the olives. The presence of functional compounds, such as carotenoids, naringenin and minor phenolics, classifies these COOs as nutraceuticals with the potential to develop enriched foods able to promote a healthy diet. Moreover, the increased presence of tyrosol and hydroxytyrosol, compared to the unflavoured oil, further highlights the nutritional value to the two COOs, being these phenolic compounds recognized as good possible therapeutic candidates for the inhibition of neurodegenerative diseases as the Parkinson’s disease. In this perspective, the citrus peels, rich in bioactive compounds, have been valued transforming their waste nature in an innovative resource.

Effects of heat treatment on the antioxidative and anti-inflammatory properties of orange by-products

This study investigated the changes in the functional components, antioxidative activities, antibacterial activities, anti-inflammatory activities of orange (Citrus sinensis (L.) Osbeck) by-products (OBP) on heat treatment at 50 and 100 °C (hereafter denoted 50D and 100D extracts, respectively). Optimal heating conditions were also investigated. The total phenolic content, flavonoid content and antioxidative activities of OBP extracts significantly increased on heat treatment. The lag time of Cu²⁺-induced oxidation of human LDL was increased by 2.61, 8.61 and 8.76-fold with the addition of 0.6, 0.8 and 1.0 mg ml^-1 100D extracts, respectively. The 100D extracts may significantly inhibit the growth of E. coli O157, Salmonella typhimurium and Listeria monocytogenes. 1 μg mL^-1 of 100D extract may suppress the TNF-α-induced ICAM-1 protein expression. The optimal heating time for OBP was 26 h at 100 °C, which resulted in the highest antioxidant activities.

Citrus fruits as a treasure trove of active natural metabolites that potentially provide benefits for human health

Citrus fruits, which are cultivated worldwide, have been recognized as some of the most high-consumption fruits in terms of energy, nutrients and health supplements. What is more, a number of these fruits have been used as traditional medicinal herbs to cure diseases in several Asian countries. Numerous studies have focused on Citrus secondary metabolites as well as bioactivities and have been intended to develop new chemotherapeutic or complementary medicine in recent decades. Citrus-derived secondary metabolites, including flavonoids, alkaloids, limonoids, coumarins, carotenoids, phenolic acids and essential oils, are of vital importance to human health due to their active properties. These characteristics include anti-oxidative, anti-inflammatory, anti-cancer, as well as cardiovascular protective effects, neuroprotective effects, etc. This review summarizes the global distribution and taxonomy, numerous secondary metabolites and bioactivities of Citrus fruits to provide a reference for further study. Flavonoids as characteristic bioactive metabolites in Citrus fruits are mainly introduced.

Bioassay guided isolation and identification of anti-inflammatory active compounds from the root of Ficus formosana

Activity-directed fractionation and purification processes were employed to identify the anti-inflammatory active compounds using lipopolysaccharide (LPS)-stimulated mouse macrophage (RAW264.7) in vitro. Air-dried roots of Ficus formosana were extracted with methanol and separated into n-hexane, chloroform, ethyl acetate, n-butanol, and water layers. Among them, the chloroform layer showed strong activity and was subjected to separation and purification by using various chromatographic techniques. Five compounds showing potent activity were identified by comparing spectral data to be β-sitosterol, stigmasterol, psoralen, kaempferol, carpachromene, and syringic aldehyde. When macrophages were treated with psoralen and kaempferol together with LPS, a concentration-dependent inhibition of nitric oxide (NO) and tumor necrosis factor (TNF-α) productions were detected. Western blotting revealed that kaempferol, psoralen, and carpachromene blocked protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated macrophages. The results confirmed that the traditional use of F. formosana could be a potential anti-inflammatory agent.

Sonochemical effects on free phenolic acids under ultrasound treatment in a model system

Sonochemical effects on seven free phenolic acids under ultrasound treatment in a model system have been investigated. The degradation products have also been tentatively identified by FTIR and HPLC-UV-ESIMS. Five phenolic acids (protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, p-coumaric acid, and ferulic acid) proved to be stable, while two others (caffeic acid and sinapic acid) were degraded under ultrasound treatment. The nature of the solvent and the temperature has been identified as important factors in determining the degradation reaction. Liquid height, ultrasonic intensity, and duty cycle of the ultrasound exposure affected only the degradation rate and did not change the nature of the degradation. The degradation rates of caffeic acid and sinapic acid decreased with increasing temperature. The degradation kinetics of these two acids under ultrasound conformed to zeroth-order reactions at -5 to 25 °C. Both decomposition and polymerization reactions occurred when caffeic acid and sinapic acid were subjected to ultrasound. Degradation products, such as the corresponding decarboxylation products and their dimers, have been tentatively identified.

Characterization of bioactive compounds in Tunisian bitter orange (Citrus aurantium L.) peel and juice and determination of their antioxidant activities

Citrus aurantium peel and juice aroma compounds were investigated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), whereas phenolic compounds analysis was performed by reversed-phase high-performance liquid chromatography (RP-HPLC). Limonene was the major volatile compound of bitter orange peel (90.25%) and juice (91.61%). HPLC analysis of bitter orange peel and juice methanolic extracts indicated that phenolic acids constitute their main phenolic class representing 73.80% and 71.25%, respectively, followed by flavonoids (23.02% and 23.13%, resp.). p-Coumaric and ferulic acids were the most abundant phenolic compounds representing 24.68% and 23.79%, respectively, in the peel, while the juice contained 18.02% and 19.04%, respectively. The antioxidant activities of bitter orange peel and juice methanolic extracts have been evaluated using four in vitro assays, and the results were compared with the standard antioxidants (BHT, BHA, and ascorbic acid). Our findings demonstrated that Citrus aurantium peel and juice possess antioxidant activities which were less effective than those of antioxidant standards. Both extracts may be suggested as a new potential source of natural antioxidant.

Purification of a novel nitric oxide inhibitory peptide derived from enzymatic hydrolysates of Mytilus coruscus

Shellfish contain significant levels of high quality protein and are therefore a potential source for biofunctional high-value peptides. To purify a novel anti-inflammatory peptide from Mytilus coruscus (M. coruscus), we applied enzymatic hydrolysis and tangential flow filtration (TFF) and investigated its nitric oxide inhibitory property. To prepare the peptide, eight proteases were employed for enzymatic hydrolysis. Flavouzyme hydrolysates, which showed clearly superior nitric oxide inhibitory activity on lipopolysaccharide (LPS)-stimulated RAW264.7, were further purified using a TFF system and consecutive chromatographic methods. Finally, a novel anti-inflammatory peptide composed of 10 amino acid residues was obtained, and the sequence was identified as Gly-Val-Ser-Leu-Leu-Gln-Gln-Phe-Phe-Leu at N-terminal position. The peptide from M. coruscus effectively inhibited nitric oxide production on macrophage cells. This is the first report of an anti-inflammatory peptide derived from the hydrolysates of M. coruscus.

Evaluation of Citrus aurantifolia peel and leaves extracts for their chemical composition, antioxidant and anti-cholinesterase activities

BACKGROUND

The replacement of synthetic antioxidants by safe natural antioxidants fosters research on the screening of vegetables and food as sources of new antioxidants. Moreover, oxidative degeneration of cells is associated with neurodegenerative diseases such as Alzheimer's disease. On the basis of these considerations this work aimed to investigate the antioxidant properties [by using the diphenyl picryl hydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and ferric reducing ability of plasma assays, and the β-carotene bleaching test] and the anti-cholinesterase activity of Citrus aurantifolia peel and leaves from different areas of growth.

RESULTS

Methanol extracts of the peel and leaves demonstrated the strongest radical scavenging activity. A similar trend was observed with the reducing ability, with values from 112.1 to 146.0 µmol L(-1) Fe(II) g(-1). The relationship between phenol and flavonoid contents and antioxidant activity was statistically investigated. Based on analysis by high-performance liquid chromatography, the most abundant flavonoids found in C. aurantifolia extracts were apigenin, rutin, quercetin, kaempferol and nobiletin. n-Hexane fractions of both peel and leaves showed a good acetylcholinesterase inhibitory activity with IC(50) values in the range 91.4-107.4 µg mL(-1). Gas chromatography-mass spectrometry analysis revealed the presence of monoterpenes and sesquiterpenes as most common components.

CONCLUSION

The findings of this study suggest a potential use of C. aurantifolia peel and leaves for supplements for human health.

Antioxidant, anti-inflammatory, and antiproliferative activities of Taxillus sutchuenensis

Inflammation is related to several chronic diseases, including cancer and atherosclerosis. Taxillus sutchuenensis (Lecomte) Danser is a special folk medicinal plant in Taiwan. The aim of this study was to evaluate the antioxidant, anti-inflammatory, and antiproliferative activities of the aqueous-thanol extract from T. sutchuenensis (AETS) and its fractions. TEAC, DPPH radicals, total phenolic compounds, total flavonoid content, inhibition of NO production in LPS-induced RAW264.7 cells, and inhibition of cancer cell proliferation were tested. Among all fractions, the ethyl-acetate (EA) fraction showed the highest TEAC and DPPH radical scavenging activities. The EA fraction also had the highest polyphenol and flavonoid content. The EA fractions also decreased LPS-induced NO production and the expression of iNOS and COX-2 in RAW264.7 cells. The antiproliferative activities of the aqueous/ethanol extract and fractions were studied in vitro using A549 cells, and the results were consistent with their antioxidant capacities. EA fractions had the highest antiproliferative activity with an IC(50) of 454.38 ± 1.48 μg/ml. Quercetin also had antioxidant, anti-inflammatory, and antiproliferative activities. Quercetin might be an important bioactive compound in T. sutchuenensis. The experimental data indicated that T. sutchuenensis is a potent antioxidant medicinal plant, and such efficacy may be mainly attributed to its polyphenolic compounds.

Antioxidant, anti-inflammatory and antiproliferative activities of Kalanchoe gracilis (L.) DC stem

Oxidative stress and inflammation are related to several chronic diseases including cancer and atherosclerosis. Kalanchoe gracilis (L.) DC is a special folk medicinal plant in Taiwan. The aim of this study was to evaluate the antioxidant, anti-inflammatory and antiproliferative activities of the methanolic extract and fractions of the stem of K. gracilis. TEAC, total phenolic compound content, total flavonoid content, DPPH radical scavenging activity, reducing power, inhibition of NO production in LPS-induced RAW264.7 cells, and inhibition of cancer cell proliferation were analyzed. Among all fractions, the chloroform fraction showed the highest TEAC and DPPH radical scavenging activities. The chloroform fraction also had the highest content of polyphenols and flavonoids. Chloroform fractions also decreased LPS-induced NO production and expressions of iNOS and COX-2 in RAW264.7 cells. The antiproliferative activities of the methanolic extract and fractions were studied in vitro using HepG2 cells, and the results were consistent with their antioxidant capacities. Chloroform fractions had the highest antiproliferative activity with an IC(50) of 136.85 ± 2.32 μg/ml. Eupafolin also had good pharmacological activity in the antioxidant, anti-inflammation and antiproliferative. Eupafolin might be an important bioactive compound in the stem of K. gracilis. The above experimental data indicated that the stem of K. gracilis is a potent antioxidant medicinal plant, and such efficacy may be mainly attributed to its polyphenolic compounds.

Protective effect of methanol extract from citrus press cakes prepared by far-infrared radiation drying on H(2)O(2)-mediated oxidative damage in Vero cells

In the present study, a suitable drying method was developed for citrus press cakes (CPCs), which are produced as a by-product in citrus juice plants, and the protective effect of methanol extract of CPCs prepared by far-infrared radiation (FIR) drying against H(2)O(2)-induced DNA damage was evaluated versus that of freeze-dried CPCs. Methanol extract of FIR-dried CPCs exhibited comparatively good ROS scavenging activity versus the freeze-dried CPCs at the concentration of 100 µg/mL. The extract strongly enhanced the cell viability against H(2)O(2)-induced oxidative damage in Vero cells. Lipid peroxidation inhibitory activity of the extract from FIR-dried CPCs was comparable to that of the extract from freeze-dried CPCs. This sample also exhibited good protective effects against H(2)O(2)-mediated cell apoptosis as demonstrated by decreased apoptotic body formation in the nuclear staining with Hoechst 33342. In the comet assay, the CPC extracts exhibited strong inhibitory effects against H(2)O(2)-mediated DNA damage in a dose-dependent manner. Thus, this study demonstrated that FIR drying effectively preserves CPC as a functionally important natural antioxidant source and the FIR drying can be adapted for drying CPCs and is more economical for massive production than freeze drying.

Phytochemical profile, antioxidant, anti-inflammatory and hypoglycemic potential of hydroalcoholic extracts from Citrus medica L. cv Diamante flowers, leaves and fruits at two maturity stages

Since the past decade consumption of certain foods has been reported to have a positive effect on health. The object of the study was to determine for the first time the chemical composition and the antioxidant, anti-inflammatory and hypoglycemic potential of Citrus medica L. cv Diamante flowers, leaves and fruits (endocarp and mesocarp) at two maturity stages. Flowers and leaves were characterized by the highest total phenols and flavonoids content. A declining trend was observed during maturity of fruits for both phenols and flavonoids. The antioxidant activity evaluated by the β-carotene bleaching test showed a strong activity for flowers and endocarp of mature fruits with IC50 values of 2.8 μg/mL and 3.5 μg/mL, respectively, after 30 min of incubation. Interestingly, the mature fruits endocarp (IC50 value of 426.0 μg/mL) could inhibit α-amylase with an IC50 value 2-fold higher than immature fruits. None of the tested extracts affected the proliferation of human skin fibroblasts 142BR. The obtained results suggest a potential use of C. medica L. cv Diamante as new valuable Citrus species with functional properties for food or nutraceutical product on the basis of high content of phytochemicals.

Anti-inflammatory activities of tormentic acid from suspension cells of Eriobotrya Japonicaex vivo and in vivo

Anti-inflammatory effects of tormentic acid (TA) were investigated ex vivo and in vivo. TA decreased the paw edema at the 4th and 5thhour after λ-carrageenin (Carr) administration, and increased the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in the liver tissue. TA also significantly attenuated the thiobarbituric acid reactive substances (TBARS) level in the edematous paw at the 5thhour after Carr injection. TA decreased the nitric oxide (NO) levels on the serum level and diminished the serum tumour necrosis factor (TNF-α) at the 5thhour after Carr injection. Western blotting revealed that the TA decreased Carr-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions. As per results, the anti-inflammatory mechanisms of TA might be correlated to the decrease in the level of TBARS, iNOS, and COX-2 in the edema paw via increasing the activities of CAT, SOD, and GPx in the liver.