28-Day Oral Chronic Toxicity Study of Arctigenin in Rats

Arctigenin induces activated HSCs quiescence via AMPK-PPARγ pathway to ameliorate liver fibrosis in mice

Arctigenin (ATG), a traditional Chinese herbal medicine, is a natural lignan compound extracted from the seeds of burdock (Arctium lappa L, Asteraceae). As a natural product with multiple biological activities, the effect and mechanism of ATG against liver fibrosis are not fully elucidated yet. In current work, we first discovered that ATG could improve CCl4-induced liver injury reflected by lower plasma ALT and AST levels, liver coefficient and pathological scoring of ballooning. Furthermore, it also could reduce the positive areas of Masson, Sirius red and α-SMA staining, inhibit the expression of fibrosis-related genes (Col1a1, Col3a1, Acta2), and decrease the content of hydroxyproline, indicated ATG treatment had benefits in alleviating CCl4-induced liver fibrosis. In vitro, we observed that ATG can inhibit collagen production stimulated by TGF-β1 in LX2 cells. By analysis of the information obtained from SymMap and GeneCards databases and in vitro validation experiments, ATG was proven to be an indirect PPARγ agonist and its effect on collagen production was dependent on PPARγ. Subsequently, we confirmed that ATG activating AMPK was the contributor of its effect on PPARγ and collagen production. Finally, the transformation of activated hepatic stellate cells was determined after treated with ATG, in which ATG treatment could return activated LX2 cells to quiescence because of the elevated quiescent markers and lipid droplets. Our work has highlighted the potential of ATG in the treatment of liver fibrosis and clarified that ATG can activate AMPK/PPARγ pathway to restore the activated hepatic stellate cell to quiescence thereby improving liver fibrosis.

Lignans as multi-targeted natural products in neurodegenerative diseases and depression: Recent perspectives

As the global population ages, the treatment of neurodegenerative diseases is becoming more and more important. There is an urgent need to discover novel drugs that are effective in treating neurological diseases. In recent years, natural products and their biological activities have gained widespread attention. Lignans are a class of metabolites extensively present in Chinese herbal medicine and possess good pharmacological effects. Latest studies have demonstrated their neuroprotective pharmacological activity in preventing acute/chronic neurodegenerative diseases and depression. In this review, the pharmacological effects of these disorders, the pharmacokinetics, safety, and clinical trials of lignans were summarized according to the scientific literature. These results proved that lignans mainly exert antioxidant and anti-inflammatory activities. Anti-apoptosis, regulation of nervous system functions, and modulation of synaptic signals are also potential effects. Despite the substantial evidence of the neuroprotective potential of lignans, it is not sufficient to support their use in the clinical management. Our study suggests that lignans can be used as prospective agents for the treatment of neurodegenerative diseases and depression, with a view to informing their further development and utilization.

Associations between maternal serum phytoestrogens and liver function markers: a cross-sectional study from China

Phytoestrogens (PEs) may harm liver function. However, studies in pregnant women are limited. Our study was conducted in pregnant women to assess the effect of serum PEs on liver function markers. We conducted a cross-sectional study focusing in the first trimester of pregnancy. A total of 352 pregnant women were enrolled in the study. We used generalized linear model (GLM) to explore the associations between each PE and each marker of liver function. We used Quantile g-computation (Qgcomp) and Bayesian kernel machine regression (BKMR) models to explore the associations between mixed exposure to all PEs and liver function markers. The GLM results showed that equol (EQU), daidzein (DAD), genistein (GEN), enterolactone (ENT), and enterodiol (END) were negatively correlated with albumin (ALB). DAD and GEN were associated with elevated alanine aminotransferase (ALT). DAD, GEN, naringin (NAR), and glycitein (GLY) were related to elevated aspartate aminotransferase (AST). Mixed exposure model results showed that the mixture of PEs was associated with reduced ALB. Our results support the existence of associations between PEs and maternal liver function in the first trimester. Emphasizing the detrimental associations between serum PEs and liver function in pregnant women is essential to ensure maternal liver health during pregnancy.

Preventive Effect of Arctium lappa Polysaccharides on Acute Lung Injury through Anti-Inflammatory and Antioxidant Activities

The objective of this study was to investigate the preventive effects of polysaccharides extracted from the roots of Arctium lappa (ALP) against acute lung injury (ALI) models induced by lipopolysaccharide (LPS). The polysaccharides were extracted and characterized, and their anti-inflammatory and antioxidant capacities were assessed. The findings demonstrated that ALP could mitigate the infiltration of inflammatory cells and reduce alveolar collapse in LPS-induced ALI in mice. The expression levels of the pro-inflammatory factor TNF-α decreased, while the anti-inflammatory factor IL-10 increased. Furthermore, the administration of ALP improved the activities of lung antioxidant enzymes, including SOD, GSH, and CAT, and lowered MDA levels. These results suggest that ALP exhibits a preventive effect on ALI and has potential as an alternative treatment for lung injury.

Natural products as the calcium channel blockers for the treatment of arrhythmia: Advance and prospect

Arrhythmia is one of the commonly heart diseases with observed abnormal heart-beat rhythm that caused by the obstacles of cardiac activity and conduction. The arrhythmic pathogenesis is complex and capricious and related with other cardiovascular diseases that may lead to heart failure and sudden death. In particular, calcium overload is recognized as the main reason causing arrhythmia through inducing apoptosis in cardiomyocytes. Moreover, calcium channel blockers have been widely used as the routine drugs for the treatment of arrhythmia, but the different arrhythmic complications and adverse effects limit their further applications and demand new drug discovery. Natural products have always been the rich minerals for the development of new drugs that could be employed as the versatile player for the discovery of safe and effective anti-arrhythmia drugs with new mechanisms. In this review, we summarized natural products with the activity against calcium signaling and the relevant mechanism of actions. We are expected to provide an inspiration for the pharmaceutical chemists to develop more potent calcium channel blockers for the treatment of arrhythmia.

Toxicological evaluation of hydroethanol leaf extract of Pupalia lappacea (Linn.) Juss. (Amaranthaceae) in rodents

OBJECTIVES

Several studies have established the ethnobotanical benefits of Pupalia lappacea (PL) in laboratory animals without extensive toxicological evaluation of its safety profiles. Thus, an extensive toxicological investigation of sub-chronic oral administration of the hydroethanol leaf extract of P. lappacea in rodents was carried out in this study.

METHODS

Different groups of rats were treated orally with the extract (10, 50 and 250 mg/kg) daily for 90 consecutive days. The control group received distilled water (10 mL/kg). After 90 days, some rats were left for additional 30 days without treatment for reversibility study. Blood and organs samples were collected for different evaluations at the end of study periods.

RESULTS

The extract decreased the bodyweights, feeding and water intakes in female rats. PL increased the weights of the liver and kidney in male rats. PL increased the red blood cell (RBC), packed cell volume (PCV), hemoglobin (Hb), triglycerides (TRIG), cholesterol and high density lipoprotein (HDL) contents in rats. PL (250 mg/kg) significantly reduced the sperm motility and serum testosterone level. Cyto-architectural distortions of the testes, liver and spleen were visible.

CONCLUSIONS

The findings showed that P. lappacea is relatively safe at lower doses but cautions should be taken at higher dose.

Bioactive Compounds, Antioxidant, Anti-Inflammatory, Anti-Cancer, and Toxicity Assessment of Tribulus terrestris-In Vitro and In Vivo Studies

Tribulus terrestris L. belongs to the family Zygophyllaceae and integral part of various ancient medicinal systems including Chinese, Indian, and European to combat various health ailments. The aim of the present study was to assess the phytochemical constituents, in vitro antioxidant activity using DPPH, FRAP, and H2O2 assays, in vitro anticancer activity using MTT assay, and in vitro and in vivo anti-inflammatory properties of T. terrestris. The acute and sub-acute toxicity of extracts exhibiting most biological potential was examined using murine models. Liquid-liquid partitioning followed by RP-HPLC sub-fraction of crude extract was performed. After that, ESI-MS/MS analysis was done for the timid identification of bioactive metabolites responsible for bioactivities of sub-fractions and HPLC analysis to quantify the compounds using external standards. Among all extracts, T. terrestris methanol extract was noted to hold maximum phenolic (341.3 mg GAE/g) and flavonoid (209 mg QE/g) contents, antioxidant activity in DPPH (IC50 71.4 µg/mL), FRAP (35.3 mmol/g), and H2O2 (65.3% inhibition) assays, anti-inflammatory activities in vitro at 400 µg/mL (heat-induced hemolysis, % inhibition 68.5; egg albumin denaturation, % inhibition 75.6%; serum albumin denaturation, % inhibition 80.2), and in vivo at 200 mg/kg (carrageenan-induced paw edema, % inhibition 69.3%; formaldehyde-induced paw edema, % inhibition 71.3%) and anticancer activity against breast cancer cell (MCF-7) proliferation (IC50 74.1 µg/mL). Acute and sub-acute toxicity studies recorded with no change in body weight, behavior, hematological, serum, and histopathological parameters in treated rats with T. terrestris methanol extracts when compared to control group. Fraction B obtained through liquid-liquid partitioning resulted in more bioactive potential as compared to the parent methanol extract. RP-HPLC analysis of fraction B resulted with four sub-fractions (TBTMF1-TBTMF4), wherein TBTMF3 delineated notable bioactive capabilities as compared to other fractions and parent methanol extract. ESI-MS/MS analysis of TBTMF3 resulted with tentative identification of myricetin, rutin, liquitrigenin, physcion, and protodioscin. It can be stated that T. terrestris is a potential bearing herb and findings of current study further verify the claims made in ancient medicinal systems. However, after investigation of each identified compound, it must be considered for drug discovery.

Bladder cancer selective chemotherapy with potent NQO1 substrate co-loaded prodrug nanoparticles

Currently, clinical intravesical instillation chemotherapy has been greatly compromised by the toxicological and physiological factors. New formulations that can specifically and efficiently kill bladder cancer cells are in urgent need to overcome the low residence efficiency and dose limiting toxicity of current ones. The combination of mucoadhesive nanocarriers and cancer cell selective prodrugs can to great extent address these limitations. However, the insignificant endogenous stimulus difference between cancer cells and normal cells in most cases and the high local drug concentration make it essential to develop new drugs with broader selectivity-window. Herein, based on the statistically different NQO1 expression between cancerous and normal bladder tissues, the reactive oxygen species (ROS) activatable epirubicin prodrug and highly potent NQO1 substrate, KP372-1, was co-delivered using a GSH-responsive mucoadhesive nanocarrier. After endocytosis, epirubicin could be promptly activated by the NQO1-dependent ROS production caused by KP372-1, thus specifically inhibiting the proliferation of bladder cancer cells. Since KP372-1 is much more potent than some commonly used NQO1 substrates, for example, β-lapachone, the cascade drug activation could occur under much lower drug concentration, thus greatly lowering the toxicity in normal cells and broadening the selectivity-window during intravesical bladder cancer chemotherapy.

Lignans as Pharmacological Agents in Disorders Related to Oxidative Stress and Inflammation: Chemical Synthesis Approaches and Biological Activities

Plant lignans exhibit a wide range of biological activities, which makes them the research objects of potential use as therapeutic agents. They provide diverse naturally-occurring pharmacophores and are available for production by chemical synthesis. A large amount of accumulated data indicates that lignans of different structural groups are apt to demonstrate both anti-inflammatory and antioxidant effects, in many cases, simultaneously. In this review, we summarize the comprehensive knowledge about lignan use as a bioactive agent in disorders associated with oxidative stress and inflammation, pharmacological effects in vitro and in vivo, molecular mechanisms underlying these effects, and chemical synthesis approaches. This article provides an up-to-date overview of the current data in this area, available in PubMed, Scopus, and Web of Science databases, screened from 2000 to 2022.

Anti-IgE Effect of Small-Molecule-Compound Arctigenin on Food Allergy in association with a Distinct Transcriptome Profile

BACKGROUND

Excessive production of IgE plays a major role in the pathology of food allergy. In an attempt to identify anti-IgE natural products, Arctium Lappa was one of the most effective herbs among approximately 300 screened medicinal herbs. However, little is known about its anti-IgE compounds.

OBJECTIVE

To identify compounds from Arctium Lappa for targeted therapy on IgE production and explore their underlying mechanisms.

METHODS

Liquid-liquid extraction and column chromatographic methods were used to purify the compounds. IgE inhibitory effects were determined on IgE producing human myeloma U266 cells, peanut-allergic murine model, and PBMCs from food-allergic patients. Genes involved in IgE inhibition in PBMCs were studied by RNA sequencing.

RESULTS

The main compounds isolated were identified as arctiin and arctigenin. Both compounds significantly inhibited IgE production in U266 cells, with arctigenin the most potent (IC50=5.09μg/mL). Arctigenin (at a dose of 13.3 mg/kg) markedly reduced peanut-specific IgE levels, blocked hypothermia and histamine release in a peanut-allergic mouse model. Arctigenin also significantly reduced IgE production and Th2 cytokines (IL5, IL13) by PBMCs. We found 479 differentially expressed genes in PBMCs with arctigenin treatment (p<0.001 and fold-change ≥1.5), involving 24 gene ontology terms (p<0.001, FDR <0.05); cell division was the most significant. Eleven genes including UBE2C and BCL6 were validated by qPCR.

CONCLUSION

Arctigenin markedly inhibited IgE production in U266 cells, peanut allergic murine model and PBMCs from allergic patients by down-regulating cell division, cell cycle-related genes and up-regulating anti-inflammatory factors.

Treatment of microvascular invasion in hepatocellular carcinoma with drug-loaded nanocomposite platform under synergistic effect of magnetic field/near-infrared light

Despite progress in clinical treatment, microvascular invasion (MVI) remains a major factor for frequent recurrence and metastasis of hepatocellular carcinoma (HCC) after liver resection and surgery. Thus, this study constructed a target nanoplatform (αCD97-USPIO-Au-DDP) with magnetic field/near-infrared (NIR) light response using ultrasmall superparamagnetic iron oxide-gold nanoporous spheres (USPIO-Au) as multifunctional nanocarrier. Anticancer drug cisplatin (DDP) was loaded, and specifically expressed CD97 protein in MVI was taken as the therapeutic target. The αCD97-USPIO-Au-DDP showed favorable photothermal and stable properties under the NIR light at 808 nm wavelength. As suggested by in vitro and in vivo research, this composite nanopreparation could effectively reduce damage to normal organs and showed good biocompatibility. Excellent magnetic targeting function of nanocarrier and modification of αCD97 strengthened accumulation of composite nanodrug in tumor to inhibit tumor growth. This system may have important ramifications for treatment of MVI in HCC.

Screening of β1- and β2-Adrenergic Receptor Modulators through Advanced Pharmacoinformatics and Machine Learning Approaches

Cardiovascular diseases (CDs) are a major concern in the human race and one of the leading causes of death worldwide. β-Adrenergic receptors (β1-AR and β2-AR) play a crucial role in the overall regulation of cardiac function. In the present study, structure-based virtual screening, machine learning (ML), and a ligand-based similarity search were conducted for the PubChem database against both β1- and β2-AR. Initially, all docked molecules were screened using the threshold binding energy value. Molecules with a better binding affinity were further used for segregation as active and inactive through ML. The pharmacokinetic assessment was carried out on molecules retained in the above step. Further, similarity searching of the ChEMBL and DrugBank databases was performed. From detailed analysis of the above data, four compounds for each of β1- and β2-AR were found to be promising in nature. A number of critical ligand-binding amino acids formed potential hydrogen bonds and hydrophobic interactions. Finally, a molecular dynamics (MD) simulation study of each molecule bound with the respective target was performed. A number of parameters obtained from the MD simulation trajectories were calculated and substantiated the stability between the protein-ligand complex. Hence, it can be postulated that the final molecules might be crucial for CDs subjected to experimental validation.

Toxicological evaluation of hydroethanol leaf extract of Pupalia lappacea (Linn.) Juss. (Amaranthaceae) in rodents

OBJECTIVES

Several studies have established the ethnobotanical benefits of Pupalia lappacea (PL) in laboratory animals without extensive toxicological evaluation of its safety profiles. Thus, an extensive toxicological investigation of sub-chronic oral administration of the hydroethanol leaf extract of P. lappacea in rodents was carried out in this study.

METHODS

Different groups of rats were treated orally with the extract (10, 50 and 250 mg/kg) daily for 90 consecutive days. The control group received distilled water (10 mL/kg). After 90 days, some rats were left for additional 30 days without treatment for reversibility study. Blood and organs samples were collected for different evaluations at the end of study periods.

RESULTS

The extract decreased the bodyweights, feeding and water intakes in female rats. PL increased the weights of the liver and kidney in male rats. PL increased the red blood cell (RBC), packed cell volume (PCV), hemoglobin (Hb), triglycerides (TRIG), cholesterol and high density lipoprotein (HDL) contents in rats. PL (250 mg/kg) significantly reduced the sperm motility and serum testosterone level. Cyto-architectural distortions of the testes, liver and spleen were visible.

CONCLUSIONS

The findings showed that P. lappacea is relatively safe at lower doses but cautions should be taken at higher dose.

The Ameliorative Effects of Arctiin and Arctigenin on the Oxidative Injury of Lung Induced by Silica via TLR-4/NLRP3/TGF-β Signaling Pathway

Silicosis remains one of the most serious diseases worldwide, with no effective drug for its treatment. Our research results have indicated that arctiin and arctigenin could increase the mitochondrial membrane potential, which in turn reduces the production of reactive oxygen species (ROS), blocks the polarization of macrophages, and inhibits the differentiation of myofibroblasts to reduce oxidative stress, inflammation, and fibrosis. Further, our study revealed that arctiin and arctigenin suppressed the activation of NLRP3 inflammasome through the TLR-4/Myd88/NF-κB pathway and the silica-induced secretion of TNF-α, IL-1β, TGF-β, and α-SMA. Besides, the silica-induced increase in the levels of serum ceruloplasmin and HYP was also inhibited. Results of metabolomics indicated that arctiin and arctigenin could regulate the abnormal metabolic pathways associated with the development of silicosis, which involve pantothenate and CoA biosynthesis, cysteine and methionine metabolism, linoleic acid metabolism, and arginine and proline metabolism successively. Furthermore, the analysis of metabolomics, together with network topological analysis in different phases of silicosis, revealed that urine myristic acid, serum 4-hydroxyproline, and L-arginine could be regarded as diagnosis biomarkers in the early phase and formation of pulmonary fibrosis in the latter phases of silicosis. Arctiin and arctigenin could downregulate the increased levels of myristic acid in the early phase and serum 4-hydroxyproline in the latter phase of silicosis. Interestingly, the integration of TLR-4/NLRP3/TGF-β signaling and metabolomics verified the importance of macrophage polarization in the silicosis fibrosis process. To the best of our knowledge, this is the first study reporting that arctiin and arctigenin both can ameliorate silicosis effectively, and the former is a little stronger than its aglycone arctigenin because of its high oral bioavailability, low toxicity, and multimolecular active metabolites as determined by AdmetSAR and molecular docking analysis.

Biocompatibility Study of a New Dental Cement Based on Hydroxyapatite and Calcium Silicates: Focus on Liver, Kidney, and Spleen Tissue Effects

The effects of a new material based on hydroxyapatite and calcium silicates, named ALBO-MPCA, were investigated on the liver, kidney and spleen. The material was administrated orally for 120 days in an in vivo model in Wistar rats, and untreated animals served as a control. Hematological and biochemical blood parameters were analyzed. Qualitative histological analysis of tissues, change in mitotic activity of cells, and histological characteristics was conducted, as well as quantitative stereological analysis of parenchymal cells, blood sinusoids, and connective tissues. Additionally, the protein expressions of Ki67 and CD68 markers were evaluated. Histological analysis revealed no pathological changes after the tested period. It showed the preservation of the architecture of blood sinusoids and epithelial cells and the presence of mitosis. Additionally, the significantly increased number of the Ki67 in the presence of ALBO-MPCA confirmed the proliferative effect of the material noticed by stereological analysis, while immunoreactive CD68 positive cells did not differ between groups. The study showed non-toxicity of the tested material based on the effects on the hematological, biochemical, and observed histological parameters; in addition, it showed evidence of its biocompatibility. These results could be the basis for further steps toward the application of tested materials in endodontics.

Subacute toxicological evaluation of AT-533 and AT-533 gel in Sprague-Dawley rats

As a novel heat shock protein 90 inhibitor, AT-533 exhibits various biological activities in vitro, including anti-viral, anti-tumor and anti-inflammatory activities. Moreover, AT-533 gel, a gel dosage form of AT-533, has been suggested to have anti-keratitis and herpes simplex virus type-1 infection-induced effects on the skin lesions of animals. However, the safety evaluation of AT-533 and AT-533 gel has, to the best of our knowledge, not been examined in in vivo toxicological tests. Therefore, these toxicological tests were carried out in the present study. A 30-day subacute toxicity test for AT-533 was conducted at doses of 1, 2 and 4 mg/kg in Sprague-Dawley rats, while that for AT-533 gel was conducted using a single dose of 5 g/kg. The toxicological tests showed that a high-dose of AT-533 caused lethality and side effects in Sprague-Dawley rats. However, no mortality, loss of appetite and body weight, adverse reactions, or toxicologically relevant alterations in hematology, biochemistry and macroscopic findings (except for skin) occurred in rats exposed to low-dose AT-533 and single-dose AT-533 gel (5 g/kg) during a 30-day subacute dermic toxicity study. The aforementioned results suggested that AT-533 gel is non-toxic for Sprague-Dawley rats, as shown by a dermic subacute toxicity test and that except for slight skin irritation, AT-533 gel had almost no side effects when administered percutaneously for 30 days.

Arctigenin Suppressed Epithelial-Mesenchymal Transition Through Wnt3a/β-Catenin Pathway in PQ-Induced Pulmonary Fibrosis

Arctigenin (ATG), a major bioactive substance of Fructus Arctii, counters renal fibrosis; however, whether it protects against paraquat (PQ)-induced lung fibrosis remains unknown. The present study was to determine the effect of ATG on PQ-induced lung fibrosis in a mouse model and the underlying mechanism. Firstly, we found that ATG suppressed PQ-induced pulmonary fibrosis by blocking the epithelial-mesenchymal transition (EMT). ATG reduced the expressions of Vimentin and α-SMA (lung fibrosis markers) induced by PQ and restored the expressions of E-cadherin and Occludin (two epithelial markers) in vivo and in vitro. Besides, the Wnt3a/β-catenin signaling pathway was significantly activated in PQ induced pulmonary fibrosis. Further analysis showed that pretreatment of ATG profoundly abrogated PQ-induced EMT-like phenotypes and behaviors in A549 cells. The Wnt3a/β-catenin signaling pathway was repressed by ATG treatment. The overexpression of Wnt3a could weaken the therapeutic effect of ATG in A549 cells. These findings suggested that ATG could serve as a new therapeutic candidate to inhibit or even reverse EMT-like changes in alveolar type II cells during PQ-induced lung fibrosis, and unraveled that the Wnt3a/β-catenin pathway might be a mechanistic tool for ATG to control pulmonary fibrosis.

A mechanistic insight of phytoestrogens used for Rheumatoid arthritis: An evidence-based review

Assessment of the potential therapeutic benefits offered by naturally occurring phytoestrogens necessitate inspection of their potency and sites of action in impeding the chronic, systemic, autoimmune, joint destructing disorder Rheumatoid arthritis (RA). Possessing structural and functional similarity with human estrogen, phytoestrogen promisingly replaces the use of hormone therapy in eradicating RA symptoms with their anti-inflammatory, anti-oxidative, anti-proliferative, anti-angiogenesis, immunomodulatory, joint protection properties abolishing the harmful side effects of synthetic drugs. Scientific evidences revealed that use of phytoestrogens from different chemical categories including flavonoids, alkaloids, stilbenoids derived from different plant species manifest beneficial effects on RA through various cellular mechanisms including suppression of pro-inflammatory cytokines in particular tumor necrosis factor (TNF-α), interleukin(IL-6) and nuclear factor kappa B (NF-κB) and destructive metalloproteinases, inhibition of oxidative stress, suppressing inflammatory signalling pathways, attenuating osteoclastogenesis ameliorating cartilage degradation and bone erosion. This review summarizes the evidences of different phytoestrogen treatment and their pharmacological mechanisms in both in vitro and in vivo studies along with discussing clinical evaluations in RA patients showing phytoestrogen as a promising agent for RA therapy. Further investigations and more clinical trials are mandatory to clarify the utility of these plant derived compounds in RA prevention and in managing oestrogen deficient diseases in patients.

Toxicological Profile of Nanostructured Bone Substitute Based on Hydroxyapatite and Poly(lactide-co-glycolide) after Subchronic Oral Exposure of Rats

Novel three-dimensional (3D) nanohydroxyapatite-PLGA scaffolds with high porosity was developed to better mimic mineral component and microstructure of natural bone. To perform a final assessment of this nanomaterial as a potential bone substitute, its toxicological profile was particularly investigated. Therefore, we performed a comet assay on human monocytes for in vitro genotoxicity investigation, and the systemic subchronic toxicity investigation on rats being per oral feed with exactly administrated extract quantities of the nano calcium hydroxyapatite covered with tiny layers of PLGA (ALBO-OS) for 120 days. Histological and stereological parameters of the liver, kidney, and spleen tissue were analyzed. Comet assay revealed low genotoxic potential, while histological analysis and stereological investigation revealed no significant changes in exposed animals when compared to controls, although the volume density of blood sinusoids and connective tissue, as well as numerical density and number of mitosis were slightly increased. Additionally, despite the significantly increased average number of the Ki67 and slightly increased number of CD68 positive cells in the presence of ALBO-OS, immunoreactive cells proliferation was almost neglected. Blood analyses showed that all of the blood parameters in rats fed with extract nanomaterial are comparable with corresponding parameters of no feed rats, taken as blind probe. This study contributes to the toxicological profiling of ALBO-OS scaffold for potential future application in bone tissue engineering.

Diligent profiling of preclinical safety of the silk protein sericin

BACKGROUND

Sericin is a widely used protein in the pharmaceutical industry derived from the silkworm, Bombyx mori, and used for the treatment of various diseases and pathological conditions. It is the main ingredient of the Unani preparation khameera abresham. The study was conducted to evaluate the preclinical toxicity of the silk protein sericin in mice.

METHODS

In the acute toxicity study, sericin was administered once orally to different groups of animals at doses of 500, 1000, and 2000 mg/kg. Animals were observed for 14 days. In the sub-acute toxicity study, sericin was administered in mice for 4 weeks in the toxic group at doses of 500, 1000, and 2000 mg/kg, while in the recovery group it was administered for 4 weeks at doses of 500 and 2000 mg/kg followed by 2 weeks of distilled water administration.

RESULTS

In the acute toxicity study, the observed parameters showed no significant difference, and no mortality was reported. In the sub-acute toxicity study, there were no toxicological effects in any of the estimated parameters, while histopathological analysis showed inflammation in vital organs at the dose of 2000 mg/kg.

CONCLUSIONS

Results of our acute toxicity study suggest that sericin is safe at all administered doses, while the sub-acute study suggests that the NOAEL (no-observed-adverse-effect level) of sericin is below 2000 mg/kg, at which it can be considered safe.