Role of Adhatoda vasica (L.) Nees leaf extract in the prevention of aflatoxin-induced toxicity in Wistar rats

Antifungal Activity of Juglans-regia-Mediated Silver Nanoparticles (AgNPs) against Aspergillus-ochraceus-Induced Toxicity in In Vitro and In Vivo Settings

Aflatoxins produced by some species of Aspergillus are considered secondary toxic fungal by-products in feeds and food. Over the past few decades, many experts have focused on preventing the production of aflatoxins by Aspergillus ochraceus and also reducing its toxicity. Applications of various nanomaterials in preventing the production of these toxic aflatoxins have received a lot of attention recently. The purpose of this study was to ascertain the protective impact of Juglans-regia-mediated silver nanoparticles (AgNPs) against Aspergillus-ochraceus-induced toxicity by exhibiting strong antifungal activity in in vitro (wheat seeds) and in vivo (Albino rats) settings. For the synthesis of AgNPs, the leaf extract of J. regia enriched with high phenolic (72.68 ± 2.13 mg GAE/g DW) and flavonoid (18.89 ± 0.31 mg QE/g DW) contents was used. Synthesized AgNPs were characterized by various techniques, including TEM, EDX, FT-IR, and XRD, which revealed that the particles were spherical in shape with no agglomeration and fine particle size in the range of 16-20 nm. In vitro antifungal activity of AgNPs was tested on wheat grains by inhibiting the production of toxic aflatoxins by A. ochraceus. According to the results obtained from High-Performance Liquid Chromatography (HPLC) and Thin-Layer Chromatography (TLC) analyses, there was a correlation between the concentration of AgNPs and a decrease in the production of aflatoxin G1, B1, and G2. For in vivo antifungal activity, Albino rats were administrated with different doses of AgNPs in five groups. The results indicated that the feed concentration of 50 µg/kg feed of AgNPs was more effective in improving the disturbed levels of different functional parameters of the liver (alanine transaminase (ALT): 54.0 ± 3.79 U/L and aspartate transaminase (AST): 206 ± 8.69 U/L) and kidney (creatinine 0.49 ± 0.020 U/L and BUN 35.7 ± 1.45 U/L), as well as the lipid profile (LDL 22.3 ± 1.45 U/L and HDL 26.3 ± 2.33 U/L). Furthermore, the histopathological analysis of various organs also revealed that the production of aflatoxins was successfully inhibited by AgNPs. It was concluded that the harmful effects of aflatoxins produced by A. ochraceus can be successfully neutralized by using J. regia-mediated AgNPs.

Therapeutic Potential of Selected Medicinal Plant Extracts against Multi-Drug Resistant Salmonella enterica serovar Typhi

Salmonella enterica serovar Typhi is Gram negative, rod shaped, facultative anaerobic bacterium, belongs to enterobacteriaceae family that causes typhoid fever in humans. This bacterium has become a super bug due to acquisition of multi drug resistance. Bacteria is transmitted through food and water contaminated with human feaces. Present study reports the screening of Adhatoda vasica, Amaranthus hybridus and Aloe barbadensis and their evaluation against multi-drug resistant Salmonella enterica serovar Typhi. Qualitative analysis of ten phytochemicals was conducted using chemical method and Gas Chromatography-Mass Spectrometry (GCMS). Antibacterial activity of plants was carried out by agar well diffusion method on Mueller Hinton agar. Total tannins, total alkaloids and total flavonoids of different parts of three plants were estimated through spectrophotometer. Total tannins content in different parts of plants was present in the given order Amaranthus hybridus leaf > Aloe barbadensis leaf > Adhatoda vasica leaf > Adhatoda vasica flower > Adhatoda vasica stem. Whereas, the order of total flavonoid concentration was Amaranthus hybridus leaf > Aloe barbadensis leaf > Adhatoda vasica leaf > Amaranthus hybridus seed. Total alkaloids have order, Adhatoda vasica leaf > Amaranthus hybridus leaf > Adhatoda vasica flower > Amaranthus hybridus seed > Aloe barbadensis leaf. Results of phytochemical analysis suggested that plants have strong profile of antioxidants, total phenolic contents and various enzymes proposing them best alternate to cure bacterial infections. GC-MS analysis further confirmed stronger phytochemical profile that can be utilized as antagonists to Salmonella enterica serovar Typhi.

The Intervention and Mechanism of Action for Aloin against Subchronic Aflatoxin B1 Induced Hepatic Injury in Rats

As a class of difurancoumarin compounds with similar structures, aflatoxins (AF) are commonly found in the environment, soil, and food crops. AF pose a serious threat to the health of humans, poultry, and livestock. This study aimed to investigate the neuroprotective effect and detailed mechanism of aloin on hepatic injury induced by subchronic AFB1 in rats. The result showed that aloin could significantly inhibit the decrease in food intake, body weight growth, immune organ index, and serum albumin content caused by long-term AFB1 exposure. Meanwhile, aloin reduced the level of serum liver function and improved renal swelling and pathological changes of liver tissue. Aloin could also inhibit liver lipid peroxidation and improve liver antioxidant capacity. Further investigation revealed that aloin inhibited the activity and expression of hepatic CYP1A2 and CYP3A4 and down-regulated IL-1β expression in subchronic AFB1-induced liver injury rats. The above study demonstrated that aloin played an important role in blocking or delaying the development process of subchronic AFB1-induced hepatotoxicity. Therefore, aloin is considered to have a potential role as a protective agent against AFB1.

Ameliorative potential of Adhatoda vasica against anti-tubercular drugs induced hepatic impairments in female Wistar rats in relation to oxidative stress and xeno-metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Adhatoda vasica Nees is widely used herb of indigenous system to treat various ailments especially upper respiratory tract infections. Not only, anti-tubercular efficacy of crude extract and phytoconstituents of A. vasica has been documented but its hepatoprotective role against various drugs mediated hepatic alterations in different animal models has also been observed.

BACKGROUND AND PURPOSE

Isoniazid, rifampicin and pyrazinamide (H-R-Z) are anti-tubercular drugs normally prescribed by health professionals for the treatment of tuberculosis, however along with their medical effectiveness these drugs also exhibit hepatotoxicity among TB patients. Unexpectedly, substantial toxicological data on the metabolism of anti-TB drugs are available but the mystery behind these xenobiotics is too complex and partly implicit. In this study, we further explored the hepatotoxic effects of these xeno-metabolic products and their amelioration by Adhatoda vasica Nees by elucidating its mechanistic action.

METHODS

We generated a hepatotoxic rodent model by oral administration of H, R and Z (30.85, 61.7 and 132.65 mg/kg body weight) drugs for 25 days in Wistar rats. Additionally, to achieve hepatoprotection two different doses of Adhatoda vasica Nees ethanolic leaf extract (200 and 300 mg/kg body weight) were used along with H-R-Z dosage, orally and once daily for 25 days and tried to ascertain their mechanistic action. For this, initially phytoconstituents of the extract were evaluated followed by extract standardization using RP-HPLC and FTIR methods. Furthermore, antioxidant activity of the extract was analyzed by DPPH assay. Finally, different treated groups were analyzed for hepatic oxidative stress markers, antioxidant markers, histopathological changes and gene expression study including CYP2E1, CYP7A1, NAT, NR1I2 and UGT1A1 genes involved in phase I and phase II xeno-metabolism.

RESULTS

Estimated content of vasicine in RP-HPLC method and free-radical scavenging activity in DPPH assay was found to be 134.519 ± 0.00269μg/10mg of leaf extract and 47.81 μg/mL respectively. In H-R-Z treated group, a significant increase in the levels of thiobarbituric acid, significant reduction in the levels of GSH, and enzymatic markers and marked changes in hepatic histological architecture were observed. In addition, there was significance up-regulation of CYP7A and NAT genes, down-regulation of CYP2E1 gene and insignificant expression levels of NR1I2 and UGT1A1 genes were observed in H-R-Z group. Conversely, high dose of A. vasica extract effectively diminished these alterations by declining oxidative stress and boosting of antioxidant levels. In addition, it acted as bi-functional inducer of both phase I (CYP2E1) and phase II (NAT and UGT1A1) enzyme systems.

CONCLUSION

Hence, we concluded that anti-TB drugs exposure has potential to generate reactive metabolites that eventually cause hepatotoxicity by altering oxidant-antioxidant levels and their own metabolism. This study not only emphasized on xeno-metabolism mediated hepatic alterations but also explore the benefit of A. vasica on these toxic insults.

The protective effect of Veronica ciliata Fisch. Extracts on relieving oxidative stress-induced liver injury via activating AMPK/p62/Nrf2 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Veronica ciliata Fisch. existed in various Tibetan medicine prescriptions, which was recorded to treat liver diseases in the Tibetan medicine roll of Chinese materia medica.

HYPOTHESIS/PURPOSE

The current study aimed to examine the effect of active constituents from V.ciliata relieving oxidative stress-mediated liver injury and clarify the underlying mechanism.

MATERIALS AND METHODS

tert-Butyl hydroperoxide (BHP) induced liver injury in mice model was established to evaluate the hepatoprotective effect of ethyl acetate extract of V. ciliata (EAFVC). Serum and liver indicators, as well as the histopathological change of liver were examined. Next, the constituents of EAFVC were separated and characterized by high-speed countercurrent chromatography (HSCCC) and Ultra performance liquid chromatography-mass spectrometer (UPLC-MS), respectively. Based on the above, the antioxidant activity of EAFVC and two fractions was evaluated using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2, 2'-azino-bis (3-ethylbenzothiazoli- ne-6-sulfonic acid) (ABTS) free radical scavenging assays. The hepatoprotective activity of EAFVC and its fractions/compounds attenuating ethanol-induced hepatocyte damage in BRL-3A cells was evaluated using the MTT method. The effect of the fraction and compounds with the strongest protective activity on ethanol-induced cytotoxicity, reactive oxygen species (ROS) accumulation, and glutathione (GSH) depletion was investigated. mRNA expression of nuclear factor-E2-related factor 2 (Nrf2) and nuclear factor of κB (NF-κB), as well as their downstream target genes, was determined by RT-qPCR. Finally, the potential mechanism of fraction 1 and luteolin on the AMPK/p62/Nrf2 signal pathway was studied using western blotting.

RESULTS

Firstly, EAFVC could relieve liver impairment induced by t-BHP in mice. Next, fraction 1 enriched with polyphenolic compounds and luteolin derived from EAFVC were screened to yield the highest hepatoprotective activity against ethanol-induced hepatocyte damage. Further study demonstrated that fraction 1 and luteolin relieved BRL-3A cells damage by decreasing the aspartate aminotransferase (AST), alanine transaminase (ALT) and lactate dehydrogenase (LDH) activities, ROS accumulation, as well as the depletion of GSH. Also, we determined that fraction 1 and luteolin suppressed inflammation and apoptosis of BRL-3A cells. The mechanistic studies indicated that fraction 1 could attenuate oxidative stress, inflammation, and apoptosis by activating AMPK phosphorylation, which promotes autophagy associated protein expression (LC3-B, Beclin1 and p62) as well as promote phosphorylation of p62 -dependent autophagic degradation of Keap1, to induce Nrf2 dissociation from Keap1 and translocate to nuclear. Nrf2 in the nuclear activate cytoprotective related genes to exert hepatoprotective function. Finally, we found that luteolin activated the protein expression of p-AMPK, p-p62, p62, Nrf2, and its downstream target genes.

CONCLUSIONS

This study clarified that fraction 1 enriched phenolic compounds could attenuate ethanol-induced liver injury in BRL-3A cells via activating AMPK/p62/Nrf2 pathway. Luteolin could serve as the major bioactive component in the therapeutic effect of fraction 1. These active constituents in V. ciliata could be used as the potential drugs targeted activation of AMPK or p62 for relieving oxidative stress-mediated liver disorders.

Phytochemical characterization and hepatoprotective effect of active fragment from Adhatoda vasica Nees. against tert-butyl hydroperoxide induced oxidative impairment via activating AMPK/p62/Nrf2 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Adhatoda vasica Nees., which existed in a large; number of Tibetan medicine prescriptions for hepatopathy, used as an adjuvant to treat liver diseases.

HYPOTHESIS/PURPOSE

Oxidative stress is the key player in the development and progression of liver pathogenesis. In recent years, research is increasingly being focused on exploitation of the active components from medicinal plants to combat the liver oxidative injury. In our study, we aimed to screen the active principles from A. vasica and clarify whether they could relieve oxidative damage induced by tert-Butyl hydroperoxide (t-BHP) and its potential mechanism via activating AMPK/p62/Nrf2 pathway.

MATERIALS AND METHODS

Ultra performance liquid chromatography (UPLC) was adopted for analysis of chemical composition in the extracts. Furthermore, the antioxidant activity of the fractions was evaluated using DPPH, ABTS and reducing power assay. Along with this, the compounds in this fraction with highest antioxidant activity were analyzed using UPLC-MS. Based on this, the condition for extracting flavonoids of this subfraction was optimized via response surface method. CCK-8 assay was used to detect cell viability. Detection kits were used to measure the activity changes of AST, ALT, LDH and CAT as well as MDA and GSH levels induced by t-BHP. Detection of reactive oxygen species (ROS) production was used DCFH-DA probe. DAPI staining and flow cytometry was used to detect cell apoptosis. In terms of the mechanistic studies, the expression of proteins involved in AMPK/p62/Nrf2 pathway was measured using western blotting.

RESULTS

Eventually, 70% ethanol extract from leaf of A. vasica was chosen due to its highest active components compared with other extracts. Further, ethyl acetate fraction derived from 70% ethanol extract in A. vasica (AVEA) possess highest ability for scavenging DPPH and ABTS free radicals as well as strongest reducing power than other fractions. Chemical composition analysis showed that AVEA contained 17 compounds, including 1 quinazoline alkaloid, 12 flavonoid-C-glycosides and 4 flavonoid-O-glycosides. In addition, the conditions (ratio of solid-liquid 1:14, the concentration of ethanol 73%, and the temperature 65 °C) were selected to enrich the flavonoids in AVEA. Furthermore, AVEA could attenuate t-BHP induced hepatocyte damage via increasing the cell viability, restoring abnormal the activities of AST, ALT, LDH and CAT as well as the levels of MDA and GSH. ROS fluorescence intensity was reduced by AVEA. Meanwhile, it could inhibit the cell apoptosis of BRL 3 A cells, as evidenced by restoration of cell morphology and decreasing the number of apoptotic cells. Further mechanistic studies indicated AVEA could promote p-AMPK expression to further induce autophagy adaptor-p62 protein expression, which could autophagic degradation of Keap1, leading to Nrf2 release and translocation into nucleus to induce antioxidant genes (HO-1, NQO-1, GCLC and GCLM) expression.

CONCLUSION

In our study, AVEA was first to screen as the active fraction in A. vasica with alkaloids and abundant flavones. Moreover, the fraction potentiates its beneficial aspect by displaying the protective role on relieving t-BHP induced oxidative stress and activating AMPK/p62/Nrf2 pathway. AVEA helps maintain the redox homeostasis of hepatic cells and could be considered as an effective candidate against oxidative stress related liver disorders.

Novel strategies for degradation of aflatoxins in food and feed: A review

Aflatoxins are toxic secondary metabolites mainly produced by Aspergillus fungi, posing high carcinogenic potency in humans and animals. Dietary exposure to aflatoxins is a global problem in both developed and developing countries especially where there is poor regulation of their levels in food and feed. Thus, academics have been striving over the decades to develop effective strategies for degrading aflatoxins in food and feed. These strategies are technologically diverse and based on physical, chemical, or biological principles. This review summarizes the recent progress on novel aflatoxin degradation strategies including irradiation, cold plasma, ozone, electrolyzed oxidizing water, organic acids, natural plant extracts, microorganisms and enzymes. A clear understanding of the detoxification efficiency, mechanism of action, degradation products, application potential and current limitations of these methods is presented. In addition, the development and future perspective of nanozymes in aflatoxins degradation are introduced.

Dietary vegetable choline improves hepatic health of Nile tilapia (Oreochromis niloticus) fed aflatoxin-contaminated diet

Aflatoxin B_{1 (}AFB₁) is one of the most important mycotoxins due to its hepatotoxic and carcinogenic effects on animals. The effect of dietary supplementation with vegetable choline (VC) at 400, 800, and 1200 mg/kg against the deleterious effects of AFB₁ (2 ppm/kg diet) in the liver of Nile tilapia (Oreochromis niloticus) was studied. The experimental period was 81 days, and the diet with VC was offered to the fish for 60 days prior to challenge with AFB₁. Diets with AFB₁ were tested in three replications and animals were analyzed at days 14 and 21 of dietary intake. The addition of VC to tilapia diet increased body weight (days 30 and 60 pre-challenge and day 21 post-challenge). The group fed aflatoxin-contaminated diet presented significantly reduced antioxidant enzymes and increased reactive oxygen species (ROS) levels, thiobarbituric acid reactive species (TBARS) levels, and protein carbonyl (PC) content in the liver. Dietary supplementation with VC at 800 and 1200 mg/kg demonstrated a significant protective effect, avoiding the increase of ROS, TBARS, and PC levels in the liver of tilapia from the aflatoxin contaminated groups. Thus, dietary VC supplementation may be used in tilapia to increase antioxidant status and reduce the negative effects caused by AFB₁ toxicity. Based on the findings, it is recommended to use VC as a food supplement for Nile tilapia in order to avoid AFB₁ toxication. In addition, decreased aflatoxin toxicity can be attributed to the VC antioxidant property.

Immunotoxicity of aflatoxin M1 : as a potent suppressor of innate and acquired immune systems in a subacute study

BACKGROUND

Although, to date, there have been several in vitro and in vivo studies of immunomodulatory effects of aflatoxin M₁ (AFB₁ ), little is known about the effect of AFM₁ on various aspects of innate and acquired immunity. In the present study, AFM₁ was administered intraperitoneally, at doses of 25 and 50 μg kg^-1 , body mass for 28 days and various immunological parameters were measured.

RESULTS

Several parameters related to immune function were suppressed: organ mass, cellularity of spleen, proliferation response to lipopolysaccaride and phytohemagglutinin-A, hemagglutination titer, delayed type of hypersensitivity response, spleen cell subtypes, serum hemolytic activity, serum immunoglobulin G level and cytokine production. AFM₁ did not cause changes in body mass, hematological parameters or the concentration of immunoglobulin M in blood serum.

CONCLUSIONS

Overall, the data suggested that AFM₁ suppressed innate and acquired immunity. Therefore, with respect to consumer safety, it is extremely important to further control the level of AFM₁ in milk, and this should be considered as a precedence for risk management actions. © 2018 Society of Chemical Industry.

Aflatoxin in foodstuffs: Occurrence and recent advances in decontamination

Aflatoxins are highly toxic compounds produced as secondary metabolites by some Aspergillus species, whose occurrence have been reported predominantly in several types of foods of low moisture content, while aflatoxin biotransformation products have been reported mainly in milk and milk products. This review deals with the occurrence of aflatoxins in some of the major food products in the last 5 years including regulatory aspects, and recent advances in detoxification strategies for contaminated foods. Aflatoxin contamination in cereals including corn and peanut is still a public health problem for some populations, especially in African countries. Despite that most of physical and chemical methods for aflatoxin detoxification may affect the nutritional properties of food, or are not safe for human consumption, gamma-radiation and ozone applications have demonstrated great potential for detoxification of aflatoxins in some food matrices. Biological methods based on removal or degradation of aflatoxins by bacterial and yeast have good perspectives, although further studies are needed to clarify the detoxification mechanisms by microorganisms and determine practical aspects of the use of these methods in food products, especially their potential effects on sensory characteristics of foods.

Toxicological Assessment of Pseudospondias microcarpa (A. Rich.) Engl. Hydroethanolic Leaf Extract in Rats: Haematological, Biochemical, and Histopathological Studies

Pseudospondias microcarpa is used traditionally for treating various diseases. However, although parts of the plant are extensively used in African traditional medicine, no scientific study has been reported on its toxicity. Therefore, this study evaluated the acute and subacute toxicity studies of the ethanolic extract of P. microcarpa in rats. Male Sprague-Dawley rats (120–150 g) were treated orally with the extract (30, 100, 300, 1000, and 3000 mg kg⁻¹) or distilled water (10 ml kg⁻¹) for 2 weeks and observed daily for general appearance and signs of toxicity. In addition, blood was collected for both biochemical and haematological assays. Sections of tissues from liver, kidney, spleen, brain, and stomach were also used for histopathological examination. Administration of the extract for 14 consecutive days caused no deaths, with an LD₅₀ above 3000 mg kg⁻¹. Except for lymphocytes (%) that showed a significant decrease (F_5,23 = 3.93, P = 0.013), all other haematological parameters remained unaffected by the extract. The extract at 100 mg kg⁻¹ showed a significant decrease in the levels of triglyceride and very-low-density lipoproteins (both at P < 0.05). Weight change as well as histological evaluation of the organs indicated no toxicity. The study demonstrates that an ethanolic extract of P. microcarpa given orally to rats is safe.