Hepatoprotective effect of limonin, a natural limonoid from the seed of Citrus aurantium var. bigaradia, on D-galactosamine-induced liver injury in rats

Hepatoprotective effects of fruits pulp, seed, and peel against chemical-induced toxicity: Insights from in vivo studies

The liver is a vital organ in human physiology positioned in the upper right quadrant of the peritoneal cavity, which plats a critical role in metabolic processes, detoxification of various substances and overall homeostasis. Along with these critical functions, hepatic diseases impose as significant global health threat. Liver illness is the cause of two million fatalities every year, or 4% of all deaths. Traditionally, healthcare providers have prescribed antibacterial and antiviral medications to address liver illness. Nephrotoxicity is a frequently observed negative reaction to drugs, with the majority of such events happening in individuals who have advanced cirrhosis. Thus, recognizing this gap, there is a dire need of exploration of pharmaceutical alterative for hepatic diseases, with special focus on their efficacy and reduced toxicity. Fruits have long been known to therapeutic impact on human health, thus exploration of fruits components namely pulp, seeds and peels containing phytochemicals have emerged as a promising avenue for hepatoprotective interventions. Thus, review comprehends the information about worldwide burden of chemical induced toxicity and injuries as well as highlight the on-going challenges in hepatic disease management. It also shed light on the valuable contributions fruit parts and their phytocompounds obtained from different components of fruits. Fruit pulp, especially when rich in flavonoids, has demonstrated significant potential in animal model studies. It has been observed to enhance the activity of antioxidant enzymes and reduce the expression of pro-inflammatory markers. The methanolic and ethanolic extracts have demonstrated the most favorable outcomes. Further, this review also discusses about the safety assessments of fruits extracts for their utilization as hepatoprotective agents.

A comprehensive review of the classical prescription Yiguan Jian: Phytochemistry, quality control, clinical applications, pharmacology, and safety profile

ETHNOPHARMACOLOGICAL RELEVANCE

Yiguan Jian (YGJ) is a classical prescription, which employs 6 kinds of medicinal herbs including Rehmanniae Radix, Lycii Fructus, Angelicae sinensis Radix, Glehniae Radix, Ophiopogonis Radix, and Toosendan Fructus. YGJ decoction is originally prescribed in Qing Dynasty (1636 CE ∼ 1912 CE) in China, and is commonly used to treat liver diseases. There remain abundant literature investigating YGJ decoction from multiple aspects, but few reviews summarized the research and gave a precise definition, which impedes further applications and commercialization of YGJ decoction.

AIM OF THE REVIEW

The aim of this review is to provide comprehensive descriptions of YGJ decoction, tackling with issues in the research and development of YGJ decoction.

MATERIALS AND METHODS

The literature and clinical reports were obtained from the databases including Web of Science, Science Direct, PubMed, Google Scholar, China National Knowledge Infrastructure, China Science Periodical Database, China Science and Technology Journal Database, and SinoMed since 2000. The phytochemical characteristics, quality control, pharmaceutical forms, clinical position, pharmacological effects, and toxic events of YGJ decoction were included for analysis.

RESULT

This review firstly summarized the progress of the chemical existences of YGJ decoction and discussed the advanced methods in monitoring quality of YGJ decoction and its herbal ingredients, particularly in the form of granules. Whilst this review aims to identify the pharmacological actions and clinical impacts of YGJ decoction, the medicinal materials that could provide these benefits were observed in the remaining herbs to exert the anti-fibrotic effects, anti-inflammatory activities, anti-cancer, and anti-diabetic effects, and to universally treat liver and gastric diseases. This review provided supplementary descriptions on the safety issues, especially in Glehniae Radix and Toosendan Fructus, to define the alterations between hepatoprotective activities and unclear toxics in YGJ decoction application.

CONCLUSIONS

Our comprehensively organized review discussed the chemical characteristics and the research in altering or identifying these essences. The effects of YGJ decoction on the non-clinical and clinical tests exert the good management of sophisticated diseases. In this review, current issues are discussed to inform and inspire subsequent research of YGJ decoction and other classical prescriptions.

Limonin ameliorates cisplatin-induced acute liver injury by inhibiting 11β-hydroxysteroid dehydrogenase type 1

BACKGROUND

Acute liver injury (ALI) is a common side effect of cisplatin treatment in the clinic and can lead to liver failure if not treated promptly. Previous studies have revealed that Limonin, a critical bioactive substance in citrus fruits, can protect multiple organs from various medical conditions. However, whether Limonin could ameliorate cisplatin-induced ALI remains unclear.

METHODS

In vivo and in vitro models were induced by cisplatin in the present study. Non-targeted metabolomics was employed to analyze the metabolic changes in the liver after ALI. In addition, molecular docking was utilized to predict the potential targets of Limonin.

RESULTS

Limonin attenuated hepatic histopathological injury by reducing hepatocyte apoptosis, lipid peroxidation, and inflammation in cisplatin-challenged mice. Employing metabolomics, we revealed that Limonin mediated the balance of various disturbed metabolic pathways in the liver after cisplatin-induced ALI. Integrating public data mining, molecular docking studies, and in vitro experiments demonstrated that Limonin suppressed the expression and activity of its direct target, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), in the liver, thus reducing the production of corticosterone (CORT), a key metabolite promoted hepatocyte apoptosis.

CONCLUSIONS

Limonin improves the liver metabolic microenvironment by inhibiting 11β-HSD1 to protect against cisplatin-induced ALI.

Phytochemical Analysis, Antioxidant Activities In Vitro and In Vivo, and Theoretical Calculation of Different Extracts of Euphorbia fischeriana

Euphorbia fischeriana has a long-standing history of use in traditional medicine for the treatment of tuberculosis diseases. However, the plant's therapeutic potential extends beyond this specific ailment. The present study aimed to investigate the antioxidant properties of Euphorbia fischeriana and lay the groundwork for further research on its potential therapeutic applications. Phytochemical tests were performed on the plant, and 11 types of phytochemicals were identified. Ultraviolet-visible spectrophotometry was used to evaluate the active components and antioxidant properties of eight different solvent extracts, ultimately selecting acetone extract for further research. UHPLC-ESI-Q-TOF-MS identified 43 compounds in the acetone extract, and chemical calculations were used to isolate those with high content and antioxidant activity. Three stability experiments confirmed the extract's stability, while cell viability and oral acute toxicity studies demonstrated its relatively low toxicity. In rats, the acetone extract showed significant protective effects against D-galactosamine-induced liver damage through histopathological examination and biochemical analysis. These results suggest that Euphorbia fischeriana's acetone extract has potential in treating diseases related to oxidative imbalances. Therefore, this study highlights the plant's potential therapeutic applications while providing insight into its antioxidant properties.

Limonin ameliorates cardiovascular dysfunction and remodeling in hypertensive rats

AIMS

Limonin is a tetracyclic triterpenoid isolated from citrus fruits. Here, the effects of limonin on cardiovascular abnormalities in nitric oxide-deficient rats induced by N^ω-Nitrol-arginine methyl ester (L-NAME) were explored.

MAIN METHODS

Male Sprague Dawley rats were given L-NAME (40 mg/kg, drinking water) for 3 weeks and then treated daily with polyethylene glycol (vehicle), limonin (50 or 100 mg/kg) or telmisartan (10 mg/kg) for two weeks.

KEY FINDINGS

Limonin (100 mg/kg) markedly reduced L-NAME-induced hypertension, cardiovascular dysfunction and remodeling in rats (P < 0.05). Increases in systemic angiotensin-converting enzyme (ACE) activity and angiotensin II (Ang II) and a reduction in circulating ACE2 were restored in hypertensive rats treated with limonin (P < 0.05). Reductions in antioxidant enzymes and nitric oxide metabolites (NOx) and increases in oxidative stress components induced by L-NAME were relieved by limonin treatment (P < 0.05). Limonin suppressed the increased expression of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in cardiac tissue and circulating TNF-α in rats that received L-NAME (P < 0.05). Changes in Ang II receptor type I (AT1R), Mas receptor (MasR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB) and NADPH oxidase subunit 2 (gp91^phox) protein expression in cardiac and aortic tissue were normalized by limonin (P < 0.05).

SIGNIFICANCE

In conclusion, limonin ameliorated L-NAME-induced hypertension, cardiovascular dysfunction and remodeling in rats. These effects were relevant to restorations of the renin-angiotensin system, oxidative stress and inflammation in NO-deficient rats. The molecular mechanisms are associated with the modulation of AT1R, MasR, NF-ĸB and gp91^phox protein expression in cardiac and aortic tissue.

Limonin mitigates cardiometabolic complications in rats with metabolic syndrome through regulation of the IRS-1/GLUT4 signalling pathway

Limonin is a natural triterpenoid isolated from citrus fruit. In the present study, we examined the effects of limonin on cardiometabolic alterations in diet-induced metabolic syndrome. Metabolic syndrome was induced in rats by feeding them a high-fat (HF) diet plus 15% fructose in drinking water for 16 weeks. They were treated with limonin (50 or 100 mg/kg) (n = 8/group) for the final 4 weeks. Increases in body weight (BW), fasting blood glucose (FBG), serum insulin, total cholesterol (TC), blood pressure (BP), liver fat accumulation, and adipocyte hypertrophy, as well as oral glucose tolerance in rats with metabolic syndrome were alleviated by limonin treatment (p < 0.05). Limonin improved ejection fraction and left ventricular (LV) hypertrophy, and reduced angiotensin converting enzyme (ACE) activity and angiotensin II (Ang II) concentration in rats with metabolic syndrome (p < 0.05). It also reduced plasma tumour necrosis factor (TNF)-α, interleukin (IL)- 6, leptin, malonaldehyde (MDA), and superoxide generation, and increased catalase activity in rats with metabolic syndrome compared to controls (p < 0.05). Downregulation of insulin receptor substrate 1 (IRS-1) and glucose transporter type 4 (GLUT4) protein expression in epididymal fat pads and cardiac, liver, and gastrocnemius tissues was present in metabolic syndrome, and these were restored by limonin treatment (p < 0.05). In conclusion, limonin shows a potential effect in alleviating symptoms and improving cardiometabolic disorders. These beneficial effects are linked to the reduction of the renin-angiotensin system, inflammation, oxidative stress, and improvement of IRS-1/GLUT4 protein expression in the target tissue.

Limonin Alleviates Non-alcoholic Fatty Liver Disease by Reducing Lipid Accumulation, Suppressing Inflammation and Oxidative Stress

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and continues to rise in the worldwide. Limonin is a triterpenoid compound widely found in the fruits of citrus plants with a wide range of pharmacological effects, including anti-cancer, anti-inflammation, anti-viral, anti-oxidation and liver protection properties. However, the potential molecular mechanism of limonin on NAFLD in zebrafish remains unknown. In this study, zebrafish larvae were exposed to thioacetamide to establish an NAFLD model and the larvae were treated with limonin for 72 h simultaneously. The human liver cell line was stimulated with lipid mixture and meanwhile incubated with limonin for 24 h. The results showed that Limonin significantly reduced the accumulation of lipid droplets in the liver and down-regulated the levels of lipogenic transcription factors FASN and SREBP1 in NAFLD. Limonin suppressed macrophages infiltration and the down-regulated the relative expression levels of the pro-inflammatory factors IL-6, IL-1β and TNF-α secreted by macrophages. Besides, limonin could reversed the reduction of glutathione and the accumulation of reactive oxygen species through up-regulating NRF2/HO-1 signaling pathway in the liver. In conclusion, this study revealed that limonin has a protective effect on NAFLD due to its resistance to lipid deposition as well as antioxidant and anti-inflammatory actions.

Limonin ameliorates acute pancreatitis by suppressing JAK2/STAT3 signaling pathway

Acute pancreatitis (AP) is one of the most common acute abdomen of digestive system and has the characteristics of dangerous condition and rapid development. Limonin has been confirmed to hold anti-inflammatory and antioxidant effects in various diseases. However, its potential beneficial effect on AP and the concrete mechanisms have never been revealed. Here, two mouse models were used to investigate the protective effects of limonin on AP, the caerulein-induced mild acute pancreatitis (MAP) model and L-arginine-induced severe AP (SAP) model. Firstly, it was found that limonin administration attenuated lipase and serum amylase levels and ameliorated the histopathological manifestations of pancreatic tissue in a dose-dependent manner. Additionally, the amelioration of AP by limonin was associated with reduced levels of inflammation initiators (IL-6, IL-1β, CCL2, and TNF-α). Mechanistically, we found that limonin suppressed the Janus Activating Kinase 2 (JAK2)/Signal Transducer and Activator of Transcription 3 (STAT3) signaling pathway, as evident by the decreased levels of JAK2 and p-STAT3. And activation of JAK2 using JAK2 activator rescued the protective effects of limonin on AP. Thus, our results demonstrate that limonin can ameliorate AP in two mice models via suppressing JAK2/STAT3 signaling pathway.

Antioxidant Metabolites in Primitive, Wild, and Cultivated Citrus and Their Role in Stress Tolerance

The genus Citrus contains a vast range of antioxidant metabolites, dietary metabolites, and antioxidant polyphenols that protect plants from unfavorable environmental conditions, enhance their tolerance to abiotic and biotic stresses, and possess multiple health-promoting effects in humans. This review summarizes various antioxidant metabolites such as organic acids, amino acids, alkaloids, fatty acids, carotenoids, ascorbic acid, tocopherols, terpenoids, hydroxycinnamic acids, flavonoids, and anthocyanins that are distributed in different citrus species. Among these antioxidant metabolites, flavonoids are abundantly present in primitive, wild, and cultivated citrus species and possess the highest antioxidant activity. We demonstrate that the primitive and wild citrus species (e.g., Atalantia buxifolia and C. latipes) have a high level of antioxidant metabolites and are tolerant to various abiotic and biotic stresses compared with cultivated citrus species (e.g., C. sinensis and C. reticulata). Additionally, we highlight the potential usage of citrus wastes (rag, seeds, fruit peels, etc.) and the health-promoting properties of citrus metabolites. Furthermore, we summarize the genes that are involved in the biosynthesis of antioxidant metabolites in different citrus species. We speculate that the genome-engineering technologies should be used to confirm the functions of candidate genes that are responsible for the accumulation of antioxidant metabolites, which will serve as an alternative tool to breed citrus cultivars with increased antioxidant metabolites.

Fiber scaffold bioartificial liver therapy relieves acute liver failure and extrahepatic organ injury in pigs

Rationale: Acute liver failure (ALF) causes severe liver injury and a systemic inflammatory response, leading to multiorgan failure with a high short-term mortality. Bioartificial liver (BAL) therapy is a promising approach that is hampered by the lack of appropriate bioreactors and carriers to retain hepatic cell function and poor understanding of BAL treatment mechanisms in ALF and extrahepatic organ injury. Recently, we used a fiber scaffold bioreactor (FSB) for the high-density, three-dimensional (3D) culture of primary porcine hepatocytes (PPHs) combined with an absorption component to construct a BAL and verified its function in a D-galactosamine (D-gal)-induced ALF porcine model to evaluate its protective effects on the liver and extrahepatic organs. Methods: Male pigs were randomized into standard/supportive therapy (ST), ST+no-cell BAL (ST+Sham BAL) and ST+BAL groups and received treatment 48 h after receiving a D-gal injection. Changes in blood chemistry and clinical symptoms were monitored for 120 h. Tissues and plasma were collected for analysis by pathological examination, immunoblotting, quantitative PCR and immunoassays. Results: PPHs cultured in the FSB obtained sufficient aeration and nutrition for high-density, 3D culture and maintained superior viability and functionality (biosynthesis and detoxification) compared with those cultured in flasks. All the animals developed ALF, acute kidney injury (AKI) and hepatic encephalopathy (HE) 48 h after D-gal infusion and received corresponding therapies. Animals in the BAL group showed markedly improved survival (4/5; 80%) compared with those in the ST+Sham BAL (0/5; p < 0.001) and ST (0/5; p < 0.001) groups. The levels of blood ammonia and biochemical and inflammatory indices were alleviated after BAL treatment. Increased liver regeneration and attenuations in the occurrence and severity of ALF, AKI and HE were observed in the ST+BAL group compared with the ST (p = 0.0009; p = 0.038) and ST+Sham BAL (p = 0.011; p = 0.031) groups. Gut leakage, the plasma endotoxin level, bacterial translocation, and peripheral and neuroinflammation were alleviated in the ST+BAL group compared with those in the other groups. Conclusions: BAL treatment enhanced liver regeneration and alleviated the systemic inflammatory response and extrahepatic organ injury to prolong survival in the ALF model and has potential as a therapeutic approach for ALF patients.

Valorization and extraction optimization of Citrus seeds for food and functional food applications

Valorization of food byproducts has attracted recently considerable attention. Citrus fruits provide considerable non-edible residues reach 80% in juice production. They are considered agri-wastes to comprise peel, pulp and seeds. Previous investigations have focused on peel and pulp to recover value-added products. The review presents for the first-time phytochemical composition of Citrus seeds' products, i.e., oil and extracts. Fatty acids, phytosterols and tocopherols amounted as the major bioactives in Citrus seeds, in addition to limonoids, dietary fibers and flavonoids. Besides their nutritional values, these chemicals have promising applications including production of biodiesel, food enhancers and antioxidants, especially from mandarin and grapefruit seeds. Optimum conditions of the different Citrus seeds' valorization are discussed to improve extraction yield and lessen environmental hazards of solvent extraction. This review presents the best utilization practices for one of the largest cultivated fruit seeds worldwide and its different applications.

Limonin Attenuates LPS-Induced Hepatotoxicity by Inhibiting Pyroptosis via NLRP3/Gasdermin D Signaling Pathway

Lipopolysaccharide (LPS)-induced liver injury is the main factor in acute liver failure. The current study aims to investigate the protection of limonin, an antioxidant compound from citrus fruit, against LPS-induced liver toxicity and elucidate the potential mechanisms. We found that limonin elevated cell viability and reduced LDH release in LPS-treated HepG2 cells. Limonin also inhibited LPS-induced pyroptosis by inhibiting membrane rupture, reducing ROS generation, and decreasing gasdermin D activation. Moreover, limonin inhibited the formation of a NOD-like receptor protein 3 (NLRP3)/Apoptosis-associated speck-like protein containing a CARD (ASC) complex by reducing the related protein expression and the colocalization cytosolic of NLRP3 and caspase-1 and then suppressed IL-1β maturation. Ultimately, we established LPS-induced hepatotoxicity in vivo by using C57BL/6 mice administrated LPS (10 mg/kg) intraperitoneally and limonin (50 and 100 mg/kg) orally. We found that limonin dereased the serum ALT and AST activity and LDH release and increased the hepatic GSH amount in LPS-treated mice. Additionally, the liver histological evaluation revealed that limonin protects against LPS-induced liver damage. We further demonstrated that limonin ameliorated LPS-induced hepatotoxicity by inhibiting pyroptosis via the NLRP3/gasdermin D signaling pathway. In summary, this study uncovered the mechanism whereby limonin mitigated LPS-induced hepatotoxicity and documented that limonin might be a promising candidate drug for LPS-induced hepatotoxicity.

1-Cinnamoyltrichilinin from Melia azedarach Causes Apoptosis through the p38 MAPK Pathway in HL-60 Human Leukemia Cells

Acute myeloid leukemia (AML) is an aggressive type of human leukemia with a low survival rate, and its complete remission remains challenging. Although chemotherapy is the first-line treatment of AML, it exerts toxicity in noncancerous cells when used in high doses, thus necessitating the development of novel compounds with a high therapeutic window. This study aimed to investigate the anticancer effects of several compounds derived from the fruits of Melia azedarach (a tree with medicinal properties). Among them, 1-cinnamoyltrichilinin (CT) was found to strongly suppress the viability of HL-60 human leukemia cells. CT treatment induced apoptosis and increased nuclear fragmentation and fractional DNA content in HL-60 cells in a dose-dependent manner. CT induced phosphorylation of p38 mitogen-activated protein kinases (p38), though not of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), and activated Bcl-2 family proteins towards the proapoptosis and cleavage of caspase-3 and poly (ADP-ribose) polymerase. Both CT-mediated apoptosis and apoptotic protein expression were reversed by treatment with the p38 inhibitor, thereby indicating the p38 pathway to be critical in CT-stimulated apoptosis. The results collectively indicated CT to suppress HL-60 survival by activating the p38 pathway and inducing apoptosis, hence being a novel potential therapeutic agent for AML.

Comparisons of Chemical Profiles and Gastroprotective Effects of Citri Sarcodactylis Fructus Pre- and Poststeam Processing

BACKGROUND

Citri Sarcodactylis Fructus (CSF) is widely used as folk medicine in traditional Chinese medicine (TCM). The dried and steam-processed CSF (SCSF) has been employed for harmonizing the stomach over thousands of years under the guidelines of TCM theory. However, little is known about the differences in chemical compositions between CSF and SCSF. Moreover, the gastroprotective effects of CSF and SCSF on ethanol-induced gastric mucosal injuries in rats have yet to be investigated. Consequently, the present study aimed to investigate the chemical differences and gastroprotective effects of CSF and SCSF, providing some experimental framework for the development of CSF and SCSF.

METHODS

The chemical compositions of CSF and SCSF extracts were determined using an ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometer (UPLC-Q-TOF-MS), and their gastroprotective effects of different doses were assessed in rats with ethanol-induced gastric injuries on the levels of oxidative stress and inflammatory cytokines.

RESULTS

A total of 42 components were identified in CSF and SCSF, and most of them were flavonoids, limonoids, coumarins, and glycosides. There were no differences in the compositions between CSF and SCSF, but the relative contents of the components were different. Among them, nine screened compounds were considered as potential discriminating markers responsible for the differences between CSF and SCSF. Besides, pretreatments with CSF and SCSF markedly improved the gastric mucosal injuries in rats for their antioxidant and anti-inflammatory properties. And SCSF exhibited a better gastroprotective effect than CSF.

CONCLUSION

The compositions of CSF were unchanged after steam-processing, while the relative contents of their components were changed. These changes may be the major reasons for the differentiation of their efficacies. In addition, CSF and SCSF could alleviate ethanol-induced gastric mucosal injury through the enhancement of antioxidant and anti-inflammatory activities. SCSF exhibited a better gastroprotective effect than CSF, which emphasized the necessity of steam processing.

Natural limonoids protect mice from alcohol-induced liver injury

Background Alcoholic liver disease (ALD) is regarded as a global health problem with limited therapeutic options. Previous studies highlighted some anticancer, antiviral, and hepatoprotective activities of limonoids, but the effects of these compounds on ALD remain unknown. The present study aimed to evaluate the effect of some natural limonoids on ethanol-induced liver injury. Methods Thirty-five albino mice (Mus musculus) were administered with 40% ethanol in the presence or absence of the different limonoids [including three havanensin-type limonoids, TS1, TS3, Rubescin D isolated from an African medicinal plant, Trichilia rubescens Oliv. (Meliaceae), and one limonin], or silymarin at 50 mg/kg for 3 days. Thereafter, the effect of the most active compound was evaluated in a chronic model of ALD. For this purpose, 24 mice with each group consisting of six mice were administered orally with 40% ethanol and limonoid at different doses (50, 75, and 100 mg/kg) for 28 days. Finally, biochemical parameters such as alanine aminotransferase (ALT), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), triglyceride (TG), and tumor necrosis factor α (TNF-α) levels were quantified in liver homogenates. Results All tested limonoids significantly (p < 0.01) reduced ALT levels relative to the negative control in the acute model. However, in comparison to other limonoids, limonin at 50 and 75 mg/kg significantly reduced TG, MDA, and TNF-α levels (1.8-fold); alleviated leukocyte infiltration in liver tissue; significantly increased the activity of SOD; and decreased those of CAT better than silymarin used as a positive control at 50 mg/kg. Conclusions These data suggest that limonin possesses protective effects on long-term alcohol poisoning partially due to antioxidant and anti-inflammatory mechanisms.

Limonin ameliorates acetaminophen-induced hepatotoxicity by activating Nrf2 antioxidative pathway and inhibiting NF-κB inflammatory response via upregulating Sirt1

BACKGROUND

Limonin, a bioactive compound from citrus plants, exerts antioxidant activities, however its therapeutic potential in acetaminophen (APAP)-induced hepatotoxicity remains unclear.

PURPOSE

Our study aims to investigate the protective effect of limonin on APAP-induced hepatotoxicity and illuminate the underlying mechanisms.

STUDY

design In vitro, we chose L-02 cells to establish in vitro APAP-induced liver injury model. L-02 cells were treated with APAP (7.5 mM) for 24 h after pre-incubation with limonin (10, 25, 50 μM) or NAC (250 μM) for 2 h. In vivo, we used C57BL/6 mice as an in vivo APAP-induced liver injury model. C57BL/6 mice with pre-treatment of limonin (40, 80 mg/kg) or NAC (150 mg/kg) for 1 h, were given with a single dose of APAP (300 mg/kg).

METHODS

After pre-incubation with limonin (10, 25, 50 μM) for 2 h, L-02 cells were treated with APAP (7.5 mM) for 24 h.The experiments in vitro included MTT assay, Annexin V/PI staining, measurement of reactive oxygen species (ROS), quantitative real-time PCR analysis, Western blot analysis, immunofluorescence microscopy and analysis of LDH activity. Transfection of Nrf2 or Sirt1 siRNA was also conducted in vitro. In vivo, C57BL/6 mice with pre-treatment of limonin (40, 80 mg/kg) or NAC (150 mg/kg) for 1 h, were given with a single dose of APAP (300 mg/kg). Mice were sacrificed at 4, 12 h after APAP poisoning, and analysis of ALT and AST in serum, GSH level in liver tissues, liver histological observation and immunohistochemistry were performed.

RESULTS

Limonin increased the cell viability and alleviated APAP-induced apoptosis in hepatocytes. Limonin also inhibited APAP-induced mitochondrial-mediated apoptosis by decreasing the ratio of Bax/Bcl-2, recovery of mitochondrial membrane potential (MMP), inhibiting ROS production and cleavage of caspase-3 in L-02 cells. Moreover, limonin induced activation of Nrf2 and increased protein expression and mRNA levels of its downstream targets, including HO-1, NQO1 and GCLC/GCLM. The inhibition of limonin on apoptosis and promotion on Nrf2 antioxidative pathway were lessened after the application of Nrf2 siRNA. In addition, limonin inhibited NF-κB transcriptional activation, NF-κB-regulated genes and protein expression of inflammatory related proteins iNOS and COX2. Furthermore, limonin increased the protein expression of Sirt1. Sirt1 siRNA transfection confirmed that limonin activated Nrf2 antioxidative pathway and inhibited NF-κB inflammatory response by upregulating Sirt1. Finally, we established APAP-induced liver injury in vivo and demonstrated that limonin alleviated APAP-induced hepatotoxicity by activating Nrf2 antioxidative signals and inhibiting NF-κB inflammatory response via upregulating Sirt1.

CONCLUSION

In summary, this study documented that limonin mitigated APAP-induced hepatotoxicity by activating Nrf2 antioxidative pathway and inhibiting NF-κB inflammatory response via upregulating Sirt1, and demonstrated that limonin had therapeutic promise in APAP-induced liver injury.

Anticancer effect of Limonin against benzo(a)pyrene-induced lung carcinogenesis in Swiss albino mice and the inhibition of A549 cell proliferation through apoptotic pathway

The main purpose of the current study is to reveal the anticancer action of limonin against benzo(a)pyrene [B(a)P]-treated lung carcinogenesis in Swiss albino mice and A549 lung cancer cells. B(a)P was orally supplemented (50 mg/kg body weight) twice a week for four weeks induction of lung cancer in mice. The lung weight, body weight, incidence of tumor, lipid peroxidation, carcinoembryonic antigen (CEA), enzymatic and nonenzymatic antioxidants (superoxide dismutase, GPx, glutathione, glutathione reductase, catalase, and glutathione S-transferase), serum marker enzymes (aryl hydroxylase, lactate dehydrogenase, 5'-nucleotidases, and γ-glutamyl transpeptidase), and inflammatory mediators (interleukin-1β, interleukin-6, and tumor necrosis factor-α) were estimated. Moreover, a histopathological study of lung tissues was supported by the biochemical analysis. Furthermore, the anticancer activity of limonin on A549 cells was measured by cell viability, production of reactive oxygen species (ROS), apoptotic morphological changes by AO/EtBr staining. Additionally, the status of apoptosis protein (caspase-9 and -3) expressions was analyzed by the colorimetric analysis. B(a)P-induced mice showed increased lipid peroxidation, CEA, serum marker enzymes and inflammatory cytokines levels with simultaneously decreased in the nonenzymatic and enzymatic antioxidants levels. Limonin supplements significantly reverted back to all these changes in this manner, showing the efficiency of anticancer effect. Furthermore, our in vitro study also supported the anticancer effect of the treatment of limonin-enhanced apoptosis by loss of cell viability, improved ROS production, apoptotic morphological changes, and apoptosis protein expression were analyzed. Overall, these results suggest the anticancer potential of limonin against B(a)P-induced lung cancer in Swiss albino mice and A549 lung cancer cells.

Limonin: A Review of Its Pharmacology, Toxicity, and Pharmacokinetics

Limonin is a natural tetracyclic triterpenoid compound, which widely exists in Euodia rutaecarpa (Juss.) Benth., Phellodendron chinense Schneid., and Coptis chinensis Franch. Its extensive pharmacological effects have attracted considerable attention in recent years. However, there is no systematic review focusing on the pharmacology, toxicity, and pharmacokinetics of limonin. Therefore, this review aimed to provide the latest information on the pharmacology, toxicity, and pharmacokinetics of limonin, exploring the therapeutic potential of this compound and looking for ways to improve efficacy and bioavailability. Limonin has a wide spectrum of pharmacological effects, including anti-cancer, anti-inflammatory and analgesic, anti-bacterial and anti-virus, anti-oxidation, liver protection properties. However, limonin has also been shown to lead to hepatotoxicity, renal toxicity, and genetic damage. Moreover, limonin also has complex impacts on hepatic metabolic enzyme. Pharmacokinetic studies have demonstrated that limonin has poor bioavailability, and the reduction, hydrolysis, and methylation are the main metabolic pathways of limonin. We also found that the position and group of the substituents of limonin are key in affecting pharmacological activity and bioavailability. However, some issues still exist, such as the mechanism of antioxidant activity of limonin not being clear. In addition, there are few studies on the toxicity mechanism of limonin, and the effects of limonin concentration on pharmacological effects and toxicity are not clear, and no researchers have reported any ways in which to reduce the toxicity of limonin. Therefore, future research directions include the mechanism of antioxidant activity of limonin, how the concentration of limonin affects pharmacological effects and toxicity, finding ways to reduce the toxicity of limonin, and structural modification of limonin—one of the key methods necessary to enhance pharmacological activity and bioavailability.

Chemical composition, antioxidant and hepatoprotective activities of methanol extracts from leaves of Terminalia bellirica and Terminalia sericea (Combretaceae)

Background

Plants belonging to the genus Terminalia such as Terminalia bellirica and Terminalia sericea are used traditionally to treat several diseases and health disorders. Up to this date, the roots of Terminalia sericea and the fruits of Terminalia bellirica are the mostly studied plant parts. The phytochemical composition and the biological activities of the leaves of both species are not well identified so far.

Methods

The secondary metabolites of Terminalia bellirica and Terminalia sericea leaves were identified using HPLC-PDA-MS/MS. The antioxidant activities of the leaves extracts were determined by DPPH and FRAP assays. The hepatoprotective potential was evaluated in rats with D-galactosamine induced liver damage. The effect of the extracts on the expression of the anti-apoptotic marker Bcl-2 was measured in an immunohistochemical study. The most abundant compounds identified in the studied extracts were docked into Bcl-2: Bim (BH3) interaction surface using molecular operating environment software.

Results

A total of 85 secondary metabolites were identified in the leaf extracts of both species. Ellagitannins such as corilagin, chebulagic acid, galloylpunicalagin, and digalloyl-hexahydroxydiphenoyl-hexoside were found to be the major components in Terminalia bellirica whereas flavonoid glycosides including quercetin rutinoside and quercetin galloyl-glucoside were highly abundant in Terminalia sericea. The studied extracts exhibited pronounced antioxidant activities, moderate anti-apoptotic and hepatoprotective potential. In silico docking experiments revealed that the compounds abundant in the extracts were able to bind to Bcl-2: Bim (BH3) interaction surface with an appreciable binding free energy.

Discussion

The antioxidant and hepatoprotective activities exhibited by the studied extracts might be attributed to the high content of the polyphenols. The anti-apoptotic activity could be due to the interference with the apoptotic pathway mediated by Bcl-2: Bim interaction. These findings support the medicinal relevance of Terminalia bellirica and Terminalia sericea and provide a rational base for their utilization in folk medicine.

Molecular mechanism and research progress on pharmacology of traditional Chinese medicine in liver injury

CONTEXT

Liver disease is a common threat to human health, caused by a variety of factors that damage the liver. Recent studies have shown that active ingredients (for example: flavonoids, saponins, acids, phenols, and alkaloids) from Traditional Chinese Medicine (TCM) can have hepatoprotective benefits, which represents an attractive source of drug discovery for treating liver injury.

OBJECTIVE

We reviewed recent contributions on the chemically induced liver injury, immunological liver damage, alcoholic liver injury, and drug-induced liver injury, in order to summarize the research progress in molecular mechanism and pharmacology of TCM, and provides a comprehensive overview of new TCM treatment strategies for liver disease.

MATERIALS AND METHODS

Relevant literature was obtained from scientific databases such as Pubmed, Web of Science. and CNKI databases on ethnobotany and ethnomedicines (from January 1980 to the end of May 2018). The experimental studies involving the antihepatic injury role of the active agents from TCM and the underlying mechanisms were identified. The search terms included 'liver injury' or 'hepatic injury', and 'traditional Chinese medicine', or 'herb'.

RESULTS

A number of studies revealed that the active ingredients of TCM exhibit potential therapeutic benefits against liver injury, while the underlying mechanisms appear to contribute to the regulation of inflammation, oxidant stress, and pro-apoptosis signaling pathways.

DISCUSSION AND CONCLUSIONS

The insights provided in this review will help further exploration of botanical drugs in the development of liver injury therapy via study on the effective components of TCM.

Anti‑apoptotic effects of human placental hydrolysate against hepatocyte toxicity in vivo and in vitro

Apoptosis and oxidative stress are essential for the pathogenesis of acute liver failure and fulminant hepatic failure. Human placental hydrolysate (hPH) has been reported to possess antioxidant and anti-inflammatory properties. In the present study, the protective effects of hPH against D-galactosamine (D-GalN)- and lipopolysaccharide (LPS)-induced hepatocyte apoptosis were investigated in vivo. In addition, the molecular mechanisms underlying the anti-apoptotic activities of hPH against D-GalN-induced cell death in vitro were examined. Male Sprague-Dawley rats were injected with D-GaIN/LPS with or without the administration of hPH. Rats were sacrificed 24 h after D-GaIN/LPS intraperitoneal injection, and the blood and liver samples were collected for future inflammation and hepatotoxicity analyses. Changes in cell viability, apoptosis protein expression, mitochondrial mass, mitochondrial membrane potential, reactive oxygen species generation, and the levels of proteins and mRNA associated with a protective mechanism were determined in HepG2 cells pretreated with hPH for 2 h prior to D-GalN exposure. The findings suggested that hPH treatment effectively protected against D-GalN/LPS-induced hepatocyte apoptosis by reducing the levels of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, interleukin-6, and tumor necrosis factor-α, and increasing the level of proliferating cell nuclear antigen. It was also found that hPH inhibited the apoptotic cell death induced by D-GalN. hPH activated the expression of antioxidant enzymes, including superoxide dismutase, glutathione peroxidase, and catalase, which were further upregulated by the Kelch-like ECH2-associated protein 1-p62-nuclear factor-erythroid 2-related factor 2 pathway, a component of oxidative stress defense mechanisms. Furthermore, hPH markedly reduced cytosolic and mitochondrial reactive oxygen species and rescued mitochondrial loss and dysfunction through the reduction of damage-regulated autophagy modulator, p53, and C/EBP homologous protein. Collectively, hPH exhibited a protective role in hepatocyte apoptosis by inhibiting oxidative stress and maintaining cell homeostasis. The underlying mechanisms may be associated with the inhibition of endoplasmic reticulum stress and minimization of the autophagy progress.

A proanthocyanidin-rich extract from Cassia abbreviata exhibits antioxidant and hepatoprotective activities in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Cassia abbreviata is a small to medium sized branched umbrella-shaped deciduous tree. It is widely spread in the tropics, especially in Africa, having a long history in traditional medicine for the treatment of numerous conditions such as headaches, diarrhea, constipation, some skin diseases, malaria, syphilis, pneumonia, stomach troubles, uterine pains, and against gonorrhea.

AIM OF THE STUDY

We investigated the phytochemical constituents of a root extract from Cassia abbreviata using HPLC-PDA-ESI-MS/MS. We also determined the antioxidant activities in vitro and in vivo using the nematode Caenorhabditis elegans as a model organism. The hepatoprotective activities in case of D-galactosamine (D-GaIN)-induced hepatotoxicity were studied in a rat model.

MATERIALS AND METHODS

HPLC-PDA-ESI-MS/MS analysis allowed the identification of the secondary metabolites of the methanol extract. DPPH and FRAP assays were used to determine the antioxidant activities in vitro. Using the C. elegans model, survival rates under juglone induced oxidative stress, intracellular ROS content, quantification of Phsp-16.2: GFP expression and subcellular DAF-16: GFP localization were investigated to determine the antioxidant activities in vivo. The in vivo hepatoprotective potential of the root extract was evaluated for D-galactosamine (D-GaIN)-induced hepatotoxicity in rats. The activity of the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT), in addition to liver peroxidation product malondialdehyde (MDA) and glutathione content (GSH), as well as albumin and total bilirubin concentration, were determined. A histopathological study was also performed.

RESULTS AND CONCLUSIONS

C. abbreviata root extract is rich in polyphenolics, particularly proanthocyanidins. HPLC-PDA-ESI-MS/MS analysis resulted in the identification of 57 compounds on the bases of their mass spectra. (epi)-Catechin, (epi)-afzelechin, (epi)-guibourtinidol, and (ent)-cassiaflavan monomers as well as their dimers, trimers, and their diastereomers are the main components of the extract. The total phenolic content amounted for 474mg/g root extract expressed as gallic acid equivalent using the Folin-Ciocalteu method. The extract exhibited powerful antioxidant activity with EC₅₀ of 6.3μg/mL in DPPH and 19.15mM FeSO₄ equivalent/mg sample in FRAP assay. In C. elegans model, the extract (200μg/mL) was able to increase the survival rate by 44.56% and reduced the ROS level to 61.73%, compared to control group. Pretreatment of rats with 100mg extract/kg (b. wt.) reduced MDA by 47.36% and elevated GSH by 59.1%. The extract caused a significant reduction of ALT, AST and GGT activities by 11%, 35.7% and 65%, respectively. The findings of this study suggest that the proanthocyanidin-rich extract from C. abbreviata may be an interesting candidate for hepatoprotective activity in case of hepatocellular injury.

Polyphenols from Blossoms of Citrus aurantium L. var. amara Engl. Show Significant Anti-Complement and Anti-Inflammatory Effects

Citrus aurantium L. var. amara Engl. (CAVA) was traditionally used as a digestant or expectorant in China. Crude polyphenols (CAVAP-W) extracted from blossoms of CAVA were mainly composed of eriocitrin/neoeriocitrin, eriocitrin/neoeriocitrin, rhoifolin, hesperidin, naringin, rutin, veronicastroside, neohesperidin, and hesperetin by LC-MS analysis. CAVAP-W showed significant anticomplement and anti-inflammatory effects. Due to the close relationship between anticomplement and anti-inflammatory activity, the anti-inflammatory effect was further investigated and the results showed that CAVAP-W significantly suppressed production of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and mRNA expression of inducible nitric oxide synthase (iNOS), IL-6, TNF-α, IL-1β, and cyclooxygenase-2 (COX-2) in lipopolysaccharides-stimulated RAW264.7 cells. Furthermore, CAVAP-W inhibited mitogen-activated protein kinase (MAPK) phosphorylation and NF-κB activation through suppressing nuclear translocation of nuclear factor-kappa B (NF-κB) P65, degradation and phosphorylation of IκBα, phosphorylation of IκKα/ß, c-Jun N-terminal kinase (JNK), and P38, and activation of COX-2, thereby exerting the anti-inflammatory effects.

The Anti-Inflammatory Activity of Toonaciliatin K against Adjuvant Arthritis

Toonaciliatin K is a natural limonoid purified from the Toona ciliata Roem. var. ciliata (Meliaceae). This study is to reveal the inflammatory suppression effect of toonaciliatin K and further the intrinsic mechanism. Firstly, anti-inflammatory effect of toonaciliatin K was evaluated in lipopolysaccharide- (LPS-) induced RAW264.7 cells. RT-PCR results indicated that the mRNA expressions of TNF-α, IL-6, and IL-1β were downregulated by toonaciliatin K. The toonaciliatin K inhibited TNF-α, IL-6, and IL-1β levels stimulated by LPS. Furthermore, LPS elicited the excess iNOS and COX-2 mRNA and protein production and toonaciliatin K attenuated the excess production. Western blot assay demonstrated that MAPK and NF-κB signaling pathways play critical roles in the toonaciliatin K's anti-inflammatory activity. Secondly, toonaciliatin K inhibited carrageenan-induced paw edema in rats. Thirdly, toonaciliatin K alleviated the paw swelling and improved arthritis clinical scores in the adjuvant arthritis rats. Toonaciliatin K decreased the proinflammatory cytokines levels and Mankin scores in adjuvant arthritis rats. The HE staining, safranin O-fast green, and toluidine blue staining results demonstrated that toonaciliatin K alleviated the histological changes of paw, for example, pannus formation, focal loss of cartilage, bone erosion, and presence of extra-articular inflammation. Hence, toonaciliatin K is a promising agent for treatment of arthritis.

Hepatoprotective and hypoglycemic effects of a tannin rich extract from Ximenia americana var. caffra root

BACKGROUND

Liver diseases and diabetes are serious health disorders associated with oxidative stress and ageing. Some plant polyphenols can lower the risk of these diseases.

PURPOSE

We investigated the phytochemical profiling of a root extract from Ximenia americana var. caffra using HPLC-PDA-ESI-MS/MS. The antioxidant activities in vitro were investigated. The hepatoprotective activities were studied in rat models with d-galactosamine (d-GaIN)-induced hepatotoxicity and the antidiabetic activities in STZ-diabetic rats were also investigated.

MATERIALS AND METHODS

HPLC-PDA-ESI-MS/MS was used to identify plant phenolics. The antioxidant activities in vitro were determined using DPPH and FRAP assays. The in vivo hepatoprotective activities were determined for d-GaIN-induced hepatotoxicity in rats. We determined the liver markers alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT), liver peroxidation product malondialdehyde (MDA), glutathione content (GSH), albumin and total bilirubin concentration. The histopathological changes in rat liver were also studied. The antidiabetic activities were also investigated in STZ-diabetic rats and serum glucose, serum insulin hormone, and lipid peroxides were determined.

RESULTS

The root extract is rich in tannins with 20 compounds including a series of stereoisomers of (epi)catechin, (epi)catechin-(epi)catechin, (epi)catechin-(epi)catechin-(epi)catechin, and their galloyl esters. Promising antioxidant potential was observed in vitro in DPPH assay with EC₅₀ of 6.5 µg extract / 26 µg raw material and in FRAP assay with 19.54 mM FeSO₄ compared with ascorbic acid (EC₅₀ of 2.92 µg/ml) and quercetin (FeSO₄ 24.04 mM/mg), respectively. Significant reduction of serologic enzymatic markers and hepatic oxidative stress markers such as ALT, AST, MDA, GGT, and total bilirubin, as well as elevation of GSH and albumin were observed in rats with d-galactosamine-induced liver damage treated with the extract. These findings agree with a histopathological examination suggesting a hepatoprotective potential for the root extract. The root extract can mediate an antidiabetic effect by reducing elevated blood glucose and serum lipid peroxides levels and by increasing insulin in STZ-diabetic rats by -107, -31.1, +11.3%, respectively.

CONCLUSIONS

The results of this study suggest that the tannin-rich extract from Ximenia americana var. caffra could be an interesting candidate for the treatment of several health disorders associated with oxidative stress such as hepatocellular injury and diabetes.

Liver toxicity mechanisms of herbs commonly used in Latin America

Mexico owns approximately 4500 medicinal plants species, a great diversity that position it at the second place after China. According to the Mexican health department, 90% of common population consumes them to treat various diseases. Additionally, herbal remedies in Latin America (LA) are considered a common practice, but the frequency of use and the liver damage related to its consumption is still unknown. Despite the high prevalence and indiscriminate herbal consumption, the exact mechanism of hepatotoxicity and adverse effects is not fully clarified and is still questioned. Some herb products associated with herb induced liver injury (HILI) are characterized by presenting a different chemical composition that may vary from batch to batch, also the biological activity of many medicinal plants and other natural products are directly related to their most active component and its concentration. There are two main biological components that are associated with liver damage, alkaloids, and flavonoids, which are frequent constituents of commonly used herbs. The interaction with the different cytochrome P-450 isoforms, inflammatory, and oxidative activities seem to be the main damage pathway involved in the liver. It is important to know the herbal adverse effects and mechanisms involved; therefore, this article is focused on the beneficial and deleterious effects as well as the possible toxicity mechanisms and interactions of the herbs that are frequently used in LA, since the herb-host interaction may not always be the expected or desired depending on the clinical context in which it is administered.

The Chemistry and Pharmacology of Citrus Limonoids

Citrus limonoids (CLs) are a group of highly oxygenated terpenoid secondary metabolites found mostly in the seeds, fruits and peel tissues of citrus fruits such as lemons, limes, oranges, pumellos, grapefruits, bergamots, and mandarins. Represented by limonin, the aglycones and glycosides of CLs have shown to display numerous pharmacological activities including anticancer, antimicrobial, antioxidant, antidiabetic and insecticidal among others. In this review, the chemistry and pharmacology of CLs are systematically scrutinised through the use of medicinal chemistry tools and structure-activity relationship approach. Synthetic derivatives and other structurally-related limonoids from other sources are include in the analysis. With the focus on literature in the past decade, the chemical classification of CLs, their physico-chemical properties as drugs, their biosynthesis and enzymatic modifications, possible ways of enhancing their biological activities through structural modifications, their ligand efficiency metrics and systematic graphical radar plot analysis to assess their developability as drugs are among those discussed in detail.

Dose-response relationship in Schistosoma mansoni juvenile and adult stages following limonin treatment in experimentally infected mice

Preventive chemotherapy with praziquantel is the mainstay of schistosomiasis control. However, drug resistance is an imminent threat, particularly with large-scale administration of praziquantel, in addition to much less efficacy against young schistosomes. Several biological activities of limonin have been explored such as insecticidal, insect antifeedant, and growth-regulating activity on insects as well as antimalarial, antiviral, anticancer, cholesterol-lowering, and antioxidant activities. This study investigates limonin as an alternative antischistosomal compound using two novel, single, oral dose regimens. In the current work, the therapeutic efficacy of different limonin dosing protocols was evaluated in experimentally infected mice harboring Schistosoma mansoni (Egyptian strain) juvenile or adult stages. Oral administration of limonin in a single dose of 50 or 100 mg/kg on day 21 post-infection (p.i.) resulted in a significant worm burden reduction of 70.0 and 83.33 %, respectively. The same dose given on day 56 p.i. reduced total worm burdens by 41.09 and 60.27 %, respectively. In addition, significant reductions of 34.90 and 47.16 % in the hepatic and 46.67 and 56.1 % in the intestinal tissue egg loads, respectively, associated with significant alterations in the oogram pattern with elevated dead egg levels. Limonin produced ameliorations of hepatic pathology with reduction in dimensions and number of granulomas. Limonin also produced a variety of tegumental alterations in treated worms including tubercular disruption, edema, blebbing, and ulcerations. Results obtained by this work elucidated promising limonin bioactivity against S. mansoni juvenile and adult stages and provided a basis for subsequent experimental and clinical trials.

Preparation, in vitro and in vivo evaluation of mPEG-PLGA nanoparticles co-loaded with syringopicroside and hydroxytyrosol

This study investigated the therapeutic efficiency of monomethoxy polyethylene glycol-poly(lactic-co-glycolic acid) (mPEG-PLGA) co-loaded with syringopicroside and hydroxytyrosol as a drug with effective targeting and loading capacity as well as persistent circulation in vivo. The nanoparticles were prepared using a nanoprecipitation method with mPEG-PLGA as nano-carrier co-loaded with syringopicroside and hydroxytyrosol (SH-NPs). The parameters like in vivo pharmacokinetics, biodistribution in vivo, fluorescence in vivo endomicroscopy, and cellular uptake of SH-NPs were investigated. Results showed that the total encapsulation efficiency was 32.38 ± 2.76 %. Total drug loading was 12.01 ± 0.42 %, particle size was 91.70 ± 2.11 nm, polydispersity index was 0.22 ± 0.01, and zeta potential was -24.5 ± 1.16 mV for the optimized SH-NPs. The nanoparticle morphology was characterized using transmission electron microscopy, which indicated that the particles of SH-NPs were in uniformity within the nanosize range and of spherical core shell morphology. Drug release followed Higuchi kinetics. Compared with syringopicroside and hydroxytyrosol mixture (SH), SH-NPs produced drug concentrations that persisted for a significantly longer time in plasma following second-order kinetics. The nanoparticles moved gradually into the cell, thereby increasing the quantity. ALT, AST, and MDA levels were significantly lower on exposure to SH-NPs than in controls. SH-NPs could inhibit the proliferation of HepG2.2.15 cells and could be taken up by HepG2.2.15 cells. The results confirmed that syringopicroside and hydroxytyrosol can be loaded simultaneously into mPEG-PLGA nanoparticles. Using mPEG-PLGA as nano-carrier, sustained release, high distribution in the liver, and protective effects against hepatic injury were observed in comparison to SH.

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.

Comparative metabolism of four limonoids in human liver microsomes using ultra-high-performance liquid chromatography coupled with high-resolution LTQ-Orbitrap mass spectrometry

RATIONALE

Limonoids, characterized by a triterpenoid skeleton with a furan ring, are unique secondary metabolites widely distributed in the families of Rutaceae, particularly in Citrus species and Meliaceae. Studies on health benefits have demonstrated that limonoids have a range of biological activities. Dietary intake of citrus limonoids may provide a protective effect against the onset of various cancers and other xenobiotic related diseases. However, few studies about the metabolic profiles of limonoids have been carried out.

METHODS

The objectives of this study were to investigate the metabolic profiles of four limonoids (limonin, obacunone, nominin and gedunin) in human liver microsomes (HLMs) using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC/HRMS) and to identify the cytochrome P450 (CYP) enzymes involved in the formation of their metabolites by recombinant human CYP enzymes.

RESULTS

Based on the accurate HR-MS/MS spectra and the proposed MS/MS fragmentation pathways, four metabolites of limonin (M1-1, M1-2, M1-3 and M1-4), eight metabolites ofobacunone (M2-1, M2-2, M2-3, M2-4, M2-5, M2-6, M2-7 and M2-8), six metabolites of nominin (M3-1, M3-2, M3-3, M3-4, M3-5 and M3-6) and three metabolites of gedunin (M4-1, M4-2 and M4-3) in HLMs were tentatively identified and the involved CYPs were investigated.

CONCLUSIONS

The results demonstrated that reduction at C-7 and C-16, hydroxylation and reaction of glycine with reduction limonoids were the major metabolic pathways of limonoids in HLMs. Among them, glycination with reduction was the unique metabolic process of limonoids observed for the first time. CYP2D6 and CYP3A4 played an important role in the isomerization and glycination of limonoids in HLMs, whereas other CYP isoforms were considerably less active. The results might help to understand the metabolic process of limonoids in vitro such as the unidentified metabolites of limonin glucoside observed in the medium of microbes and the biotransformation of limonin in juices. Moreover, it would be beneficial for us to further study the pharmacokinetic behavior of limonoids in vivo systematically.

Protective effect of wild ginseng cambial meristematic cells on d-galactosamine-induced hepatotoxicity in rats

Background

Panax ginseng has a wide range of biological activities including anti-inflammatory, antioxidant, and immunomodulatory functions. Wild ginseng cambial meristematic cells (CMCs) were obtained from P. ginseng cambium. This study examined the protective mechanism of wild ginseng CMCs against d-galactosamine (GalN)-induced liver injury. GalN, a well-known hepatotoxicant, causes severe hepatocellular inflammatory damage and clinical features similar to those of human viral hepatitis in experimental animals.

Methods

Hepatotoxicity was induced in rats using GalN (700 mg/kg, i.p.). Wild ginseng CMCs was administered orally once a day for 2 wks, and then 2 h prior to and 6 h after GalN injection.

Results

Wild ginseng CMCs attenuated the increase in serum aminotransferase activity that occurs 24 h after GalN injection. Wild ginseng CMCs also attenuated the GalN-induced increase in serum tumor necrosis factor-α, interleukin-6 level, and hepatic cyclooxygenase-2 protein and mRNA expression. Wild ginseng CMCs augmented the increase in serum interleukin -10 and hepatic heme oxygenase-1 protein and mRNA expression that was induced by GalN, inhibited the increase in the nuclear level of nuclear factor-kappa B, and enhanced the increase in NF-E2-related factor 2.

Conclusion

Our findings suggest that wild ginseng CMCs protects liver against GalN-induced inflammation by suppressing proinflammatory mediators and enhancing production of anti-inflammatory mediators.

Species-related difference between limonin and obacunone among five liver microsomes and zebrafish using ultra-high-performance liquid chromatography coupled with a LTQ-Orbitrap mass spectrometer

RATIONALE

Limonin and obacunone are two major limonoids distributed in the Rutaceae and Meliaceae families. Their defined anti-tumor activity is closely connected with the furan ring and the multi-carbonyls in their structures. In vivo and in vitro biotransformations may influence their structures and further change their effects. The metabolic profiles of limonin and obacunone have not been studied previously. In order to clarify their in vivo and in vitro metabolism, a comparative investigation of their metabolic pathways in five different species of liver microsomes and zebrafish was carried out.

METHODS

In the present study, ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC/HRMS) and related electrospray ionization (ESI) tandem mass spectrometric (MS/MS) dissociation of limonin and obacunone were applied for the analysis. Each metabolite was identified by its accurate mass data. Human liver microsomes (HLMs), monkey liver microsomes (MLMs), dog liver microsomes (DLMs), rat liver microsomes (RLMs), mice liver microsomes (XLMs) and zebrafish were included in the biotransformations.

RESULTS

One phase I metabolite of limonin (M1-1) and two phase I metabolites of obacunone (M2-1, M2-2) were identified by accurate mass measurement and MS/MS fragmentation behaviors. A reduction reaction was regarded as the major metabolic pathway of limonoids in liver microsomes. The reduction reaction site of M1-1 and M2-1 was at the C-16 carbonyl, while for M2-2 it was at C-7. M1-1 was the major and unique metabolite of limonin and the metabolic rate of limonin varied from 11.5% to 17.8% in liver microsomes (LMs). M2-2 was the main metabolite of obacunone in LMs and zebrafish. M1-1 and M2-1 were only detected in LMs while M2-2 was found in both LMs and zebrafish incubation systems. The metabolic rate of obacunone varied from 2.5% to 19.1% and the content of M2-2 was about five times higher than that of M2-1.

CONCLUSIONS

The ESI-HR-MS/MS fragmentation behaviors of limonin and obacunone were investigated for the first time. A qualitative and semi-quantitative method was developed for the in vivo and in vitro metabolic analysis of limonin and obacunone. The results demonstrated that the metabolic processes of limonin and obacunone were different between LMs and zebrafish. However, both of these two parent compounds presented similar metabolic processes in five species of LMs. This was caused by the metabolic difference between mammals and fish or because limonin probably cannot be absorbed in zebrafish.