Antioxidant Effect of Sericin in Brain and Peripheral Tissues of Oxidative Stress Induced Hypercholesterolemic Rats

The impact of sericin on inflammation, oxidative stress, and lipid metabolism in female rats with experimental knee osteoarthritis

OBJECTIVE

This study investigated the effects of sericin on inflammation, oxidative stress, and lipid metabolism in female rats with experimental knee osteoarthritis (KOA), focusing on evaluating its effectiveness via the sterol regulatory protein (SREBP)-1C and SREBP-2 pathways.

METHODS

The rats were randomly assigned to three experimental groups: the C group (control), the KOA group (KOA control), and the sericin group (KOA + sericin). The KOA model was created by injecting monosodium iodoacetate (MIA) into the knee joint. Sericin was administered intra-articularly to rats on days 1, 7, 14, and 21 (0.8 g/kg/mL, 50 µL). After 21 days, the rats were sacrificed, and serum samples were analyzed using an ELISA to measure tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), IL-10, SREBP-1c, SREBP-2, acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), cholesterol, triglyceride, and total oxidant-antioxidant status (TOS-TAS) levels.

RESULTS

The KOA group exhibited higher serum TNF-α, IL-1β, TOS, SREBP-1C, ACC, FAS, triglyceride, SREBP-2, and cholesterol levels than the C group (P < 0.05). However, the levels of these cytokines, except cholesterol, were significantly lower in the sericin group than in the KOA group. The KOA group exhibited significantly lower serum TAS and IL-10 levels than the C group (P < 0.05). In the sericin group, there was a statistically significant increase (P < 0.05).

CONCLUSION

Sericin shows promising potential for reducing inflammation, oxidative stress, and lipid metabolism in experimental models of KOA in rats. However, further clinical research is necessary to validate the potential of sericin as a therapeutic agent for treating KOA. Key Points • Sericin can reduce knee osteoarthritis (KOA) symptoms in an experimental rat model. • In particular, in the serum of an experimental KOA rat model, sericin specifically reduces the levels of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β), and increases the levels of anti-inflammatory cytokines, such as IL-10. • Sericin reduced lipid metabolism via the sterol regulatory protein (SREBP)-1C and SREBP-2 pathways and oxidative stress in the serum of the experimental KOA rat model. • The intra-articular administration of sericin has been shown to significantly reduce lipid metabolism, oxidative stress, and inflammation, as supported by biochemical analysis. These findings suggest its promising potential as an alternative treatment option for KOA.

Sericin alleviates motor dysfunction by modulating inflammation and TrkB/BDNF signaling pathway in the rotenone-induced Parkinson's disease model

BACKGROUND

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the degeneration of nigrostriatal dopaminergic neurons and movement impairment. Based on theories, neuroinflammatory processes may be vital in the etiology of PD and other neurodegenerative diseases. Reports show that rotenone has neurotoxic, inflammatory, and motor impairment effects in PD. Sericin is a natural polymer with effective properties, such as neuroprotective and anti-inflammatory. Therefore, this study aimed to examine the effects of sericin administration on motor dysfunction by modulating inflammation and tyrosine kinase B/brain-derived neurotrophic factor (TrkB/BDNF) pathway in the rotenone-induced PD model.

METHODS

Wistar male rats (3-months-old) were treated with rotenone (2 mg/kg every 48 h for 30 days) to induce a rotenone-induced PD model. Also, sericin was administered orally at dose of 200 mg/kg every 48 h for 30 days. Rotarod and bar tests were performed for motor dysfunction. The protein levels of BDNF, c-fos, TrkB, tumor necrosis factor- α (TNF-α), interleukin-6 (IL-6) and catalase activity were evaluated in the striatum area.

RESULTS

Results showed that sericin increased latent time in the rotarod test and decreased the time staying on the pole in the bar test compared to the PD group (P < 0.001 for both tests). Moreover, sericin treatments decreased TNF-α (P < 0.001) and IL-6 (P < 0.001) concentration levels and enhanced the levels of BDNF (P < 0.001), c-fos (P < 0.001), TrkB (P < 0.001) proteins and catalase activity (P < 0.05) in the striatum area compared to the PD group.

CONCLUSION

These results support a protective benefit of sericin therapy in a rotenone-induced PD paradigm by reducing motor impairment, inflammatory response, and disruption of the TrkB/BDNF signaling pathway.

A comprehensive review of recent advances in silk sericin: Extraction approaches, structure, biochemical characterization, and biomedical applications

Silks are natural polymers that have been widely used for centuries. Silk consists of a filament core protein, termed fibroin, and a glue-like coating substance formed of sericin (SER) proteins. This protein is extracted from the silkworm cocoons (particularly Bombyx mori) and is mainly composed of amino acids like glycine, serine, aspartic acid, and threonine. Silk SER can be obtained using numerous methods, including enzymatic extraction, high-temperature, autoclaving, ethanol precipitation, cross-linking, and utilizing acidic, alkali, or neutral aqueous solutions. Given the versatility and outstanding properties of SER, it is widely fabricated to produce sponges, films, and hydrogels for further use in diverse biomedical applications. Hence, many authors reported that SER benefits cell proliferation, tissue engineering, and skin tissue restoration thanks to its moisturizing features, antioxidant and anti-inflammatory properties, and mitogenic effect on mammalian cells. Remarkably, SER is used in drug delivery depending on its chemical reactivity and pH-responsiveness. These unique features of SER enhance the bioactivity of drugs, facilitating the fabrication of biomedical materials at nano- and microscales, hydrogels, and conjugated molecules. This review thoroughly outlines the extraction techniques, biological properties, and respective biomedical applications of SER.

Fabrication of Nanoformulation Containing Carvedilol and Silk Protein Sericin against Doxorubicin Induced Cardiac Damage in Rats

Nanotechnology has emerged as an inspiring tool for the effective delivery of drugs to help treat Coronary heart disease (CHD) which represents the most prevalent reason for mortality and morbidity globally. The current study focuses on the assessment of the cardioprotective prospective ofanovel combination nanoformulation of sericin and carvedilol. Sericin is a silk protein obtained from Bombyx mori cocoon and carvedilol is a synthetic nonselective β-blocker. In this present study, preparation of chitosan nanoparticles was performed via ionic gelation method and were evaluated for cardioprotective activity in doxorubicin (Dox)-induced cardiotoxicity. Serum biochemical markers of myocardial damage play a substantial role in the analysis of cardiovascular ailments and their increased levels have been observed to be significantly decreased in treatment groups. Treatment groups showed a decline in the positivity frequency of the Troponin T test as well. The NTG (Nanoparticle Treated Group), CSG (Carvedilol Standard Group), and SSG (Sericin Standard Group) were revealed to have reduced lipid peroxide levels (Plasma and heart tissue) highly significantly at a level of p < 0.01 in comparison with the TCG (Toxic Control Group). Levels of antioxidants in the plasma and the cardiac tissue were also established to be within range of the treated groups in comparison to TCG. Mitochondrial enzymes in cardiac tissue were found to be elevated in treated groups. Lysosomal hydrolases accomplish a significant role in counteracting the inflammatory pathogenesis followed by disease infliction, as perceived in the TCG group. These enzyme levels in the cardiac tissue were significantly improved after treatment with the nanoformulation. Total collagen content in the cardiac tissue of the NTG, SSG, and CSG groups was established to be highly statistically significant at p < 0.001 as well as statistically significant at p < 0.01, respectively. Hence, the outcomes of this study suggest that the developed nanoparticle formulation is effective against doxorubicin-induced cardiotoxicity.

Silk sericin as building blocks of bioactive materials for advanced therapeutics

Silk sericin is a class of protein biopolymers produced by silkworms. Increasing attention has been paid to silk sericin for biomedical applications in the last decade, not only because of its excellent biocompatibility and biodegradability but also due to the pharmacological activities stemming from its unique amino acid compositions. In this review, the biological properties of silk sericin, including curing specific diseases and promoting tissue regeneration, as well as underlying mechanisms are summarized. We consider the antioxidant activity of silk sericin as a fundamental property, which could account for partial biological activities, despite the exact mechanisms of silk sericin's effect remaining unknown. Based on the reactive groups on silk sericin, approaches of bottom-up fabrication of silk sericin-based biomaterials are highlighted, including non-covalent interactions and chemical reactions (reduction, crosslinking, bioconjugation, and polymerization). We then briefly present the cutting-edge advances of silk sericin-based biomaterials applied in tissue engineering and drug delivery. The challenges of silk sericin-based biomaterials are proposed. With more bioactivities and underlying mechanisms of silk sericin uncovered, it is going to boost the therapeutic potential of silk sericin-based biomaterials.

Effects of diet-induced hypercholesterolemia and gold nanoparticles treatment on peripheral tissues

Cholesterol is a lipid molecule of great biological importance to animal cells. Dysregulation of cholesterol metabolism leads to raised blood total cholesterol levels, a clinical condition called hypercholesterolemia. Evidence has shown that hypercholesterolemia is associated with the development of liver and heart disease. One of the mechanisms underlying heart and liver alterations induced by hypercholesterolemia is oxidative stress. In this regard, in several experimental studies, gold nanoparticles (AuNP) displayed antioxidant properties. We hypothesized that hypercholesterolemia causes redox system imbalance in the liver and cardiac tissues, and AuNP treatment could ameliorate it. Young adult male Swiss mice fed a regular rodent diet or a high cholesterol diet for eight weeks and concomitantly treated with AuNP (2.5 μg/kg) or vehicle by oral gavage. Hypercholesterolemia increased the nitrite concentration and glutathione (GSH) levels and decreased the liver's superoxide dismutase (SOD) activity. Also, hypercholesterolemia significantly enhanced the reactive oxygen species (ROS) and GSH levels in cardiac tissue. Notably, AuNP promoted the redox system homeostasis, increasing the SOD activity in hepatic tissue and reducing ROS levels in cardiac tissue. Overall, our data showed that hypercholesterolemia triggered oxidative stress in mice's liver and heart, which was partially prevented by AuNP treatment.

Reactive Oxygen Species Scavenging Nanomedicine for the Treatment of Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of disability and mortality worldwide. Reactive oxygen species (ROS) have been shown to play key roles in the progression of diabetes, hypertension, and hypercholesterolemia, which are independent risk factors that lead to atherosclerosis and the development of IHD. Engineered biomaterial-based nanomedicines are under extensive investigation and exploration, serving as smart and multifunctional nanocarriers for synergistic therapeutic effect. Capitalizing on cell/molecule-targeting drug delivery, nanomedicines present enhanced specificity and safety with favorable pharmacokinetics and pharmacodynamics. Herein, the roles of ROS in both IHD and its risk factors are discussed, highlighting cardiovascular medications that have antioxidant properties, and summarizing the advantages, properties, and recent achievements of nanomedicines that have ROS scavenging capacity for the treatment of diabetes, hypertension, hypercholesterolemia, atherosclerosis, ischemia/reperfusion, and myocardial infarction. Finally, the current challenges of nanomedicines for ROS-scavenging treatment of IHD and possible future directions are discussed from a clinical perspective.

Effectual Endeavors of Silk Protein Sericin against Isoproterenol Induced Cardiac Toxicity and Hypertrophy in Wistar Rats

The silkworm cocoon has been used in the treatment of various ailments in different Asian countries. This research was designed to evaluate the effect of sericin on myocardial necrosis and hypertrophy in isoproterenol-challenged rats. The rats were administered with sericin (500 and 1000 mg/kg, p.o.) for 28 days, followed by administration of isoprenaline (85 mg/kg, s.c.) on the 29th and 30th days. The cardioprotective activity was assessed by various physical, enzymatic, and histopathological parameters along with apoptotic marker expression. The cardioprotective effect showed that pre-treatment of rats with sericin significantly increased the non-enzymatic antioxidants marker in serum and heart tissue (glutathione, vitamin E, and vitamin C). The results were the same in enzymatic antioxidant marker, mitochondrial enzymes, and protein. The grading of heart, heart/body weight ratio, gross morphology, cardiac markers, oxidative stress markers in serum and heart tissue, glucose, serum lipid profiling and Lysosomal hydrolases, heart apoptotic markers such as MHC expression by western blot, apoptosis by flow cytometry, total myocardial collagen content, fibrosis estimation, myocyte size were significantly decreased when compared with isoproterenol (ISG) group however histopathological studies showed normal architecture of heart in both control and treated rats. The pharmacological study reflects that sericin on both doses i.e., 500 mg/kg and 1000 mg/kg have potent cardioprotective action against the experimental model which was confirmed by various physical, biochemical, and histopathological parameters evaluated further research is required to examine the molecular mechanism of cardioprotective effect of sericin.

The Protective Effect of Sericin on AML12 Cells Exposed to Oxidative Stress Damage in a High-Glucose Environment

Two types of sericin peptides with high molecular weight (HS) and low molecular weight (LS) were obtained by the green water boiling ultrasonic method and the Ca(OH)2 ultrasonic method, respectively. In this experiment, a high-glucose medium was used to simulate a high-glucose environment in the body, and appropriate concentrations of normal alpha mouse liver 12 (AML12) hepatocytes were exposed to a series of concentrations of HS and LS. The effects of the two sericin peptides on AML12 cells in a high-glucose environment were investigated in detail in terms of oxidative stress and inflammatory factor expression in cells. HS and LS-groups reduced the levels of oxidative stress, inflammation, and tumor necrosis factor (TNF), and the latter significantly reduced the levels of TNF-α, interleukin (IL)-6, and nuclear factor (NF)-κB in AML12 cells. Additionally, it significantly reduced the oxidative stress damage caused by the high-glucose environment compared with normal AML12 cells. These results indicate that sericin may be an antioxidant recovered from industrial waste, and has potential and for use in the reduction of environmental pollution and the development of functional foods with antioxidation and antihyperglycemic effect.

Hepatoprotective effects of sericin on aging-induced liver damage in mice

Aging is a physiological process in which there is a progressive decline of function in multiple organs such as the liver. The development of natural therapies, such as sericin, for delaying age-associated diseases is of major interest in this regard. Twenty-seven mice were divided into three groups of nine, including young control group (8 weeks, received normal saline), aged control group (24 months, received normal saline), and sericin-treated aged mice (24 months, received sericin at dose 100 mg/kg/day) via oral administration for 14 days. The liver enzymes in serum and oxidative stress markers in liver tissue were evaluated using spectrophotometric/ELISA methods. Apoptotic proteins, pro-inflammatory cytokines, COX2, JNK, and P-38 levels were assessed by western blot analysis. β-galactosidase expression was determined by a qRT-PCR method. The findings showed that 100 mg/kg of sericin reduced liver enzymes in aged mice. Antioxidant capacity in treated aged mice showed an improvement in all indexes in the liver tissue. Also, sericin administration declined pro-inflammatory markers to varying degrees in aged-treated mice. Sericin also increased the expression level of Bcl-2 and decreased the expression level of Bax and cleaved caspase-3.In addition, treatment with sericin suppressed protein expression of p-JNK and p-JNK/JNK. Collectively, these findings would infer that sericin administration may have a hepatoprotective effect in aging-induced liver damage in mice.

Nonmulberry silk proteins: multipurpose ingredient in bio-functional assembly

The emerging field of tissue engineering and regenerative medicines utilising artificial polymers is facing many problems. Despite having mechanical stability, non-toxicity and biodegradability, most of them lack cytocompatibility and biocompatibility. Natural polymers (such as collagen, hyaluronic acid, fibrin, fibroin, and others), including blends, are introduced to the field to solve some of the relevant issues. Another natural biopolymer: silkworm silk gained special attention primarily due to its specific biophysical, biochemical, and material properties, worldwide availability, and cost-effectiveness. Silk proteins, namely fibroin and sericin extracted from domesticated mulberry silkwormBombyx mori, are studied extensively in the last few decades for tissue engineering. Wild nonmulberry silkworm species, originated from India and other parts of the world, also produce silk proteins with variations in their nature and properties. Among the nonmulberry silkworm species,Antheraea mylitta(Indian Tropical Tasar),A. assamensis/A. assama(Indian Muga), andSamia ricini/Philosamia ricini(Indian Eri), along withA. pernyi(Chinese temperate Oak Tasar/Tussah) andA. yamamai(Japanese Oak Tasar) exhibit inherent tripeptide motifs of arginyl glycyl aspartic acid in their fibroin amino acid sequences, which support their candidacy as the potential biomaterials. Similarly, sericin isolated from such wild species delivers unique properties and is used as anti-apoptotic and growth-inducing factors in regenerative medicines. Other characteristics such as biodegradability, biocompatibility, and non-inflammatory nature make it suitable for tissue engineering and regenerative medicine based applications. A diverse range of matrices, including but not limited to nano-micro scale structures, nanofibres, thin films, hydrogels, and porous scaffolds, are prepared from the silk proteins (fibroins and sericins) for biomedical and tissue engineering research. This review aims to represent the progress made in medical and non-medical applications in the last couple of years and depict the present status of the investigations on Indian nonmulberry silk-based matrices as a particular reference due to its remarkable potentiality of regeneration of different types of tissues. It also discusses the future perspective in tissue engineering and regenerative medicines in the context of developing cutting-edge techniques such as 3D printing/bioprinting, microfluidics, organ-on-a-chip, and other electronics, optical and thermal property-based applications.

Sericin Alleviates Thermal Stress Induced Anxiety-Like Behavior and Cognitive Impairment Through Regulation of Oxidative Stress, Apoptosis, and Heat-Shock Protein-70 in the Hippocampus

Exposure to heat stress (HS) has adverse effects on brain function, leading to anxiety-like behavior and memory impairment. Sericin is a silk derived protein with various neurobiological activities. The present study has investigated the effects of sericin on anxiety and cognitive impairments, in HS-received mice. The adult male mice were exposed to HS (43 ºC, 15 min once a day for 14 days) and simultaneously treated with 100, 150, and 200 mg/kg/day of sericin through oral gavage. Elevated plus-maze and Lashley III Maze tests were used to evaluate anxiety and learning and memory, respectively. The hippocampal BAX, BCL-2, caspase3, caspase9 and heat-shock protein-70 (HSP-70) were evaluated by western blotting and oxidative stress markers including malondialdehyde (MDA), total antioxidant capacity (TAC), super oxide dismutase (SOD) as well as glutathione peroxidase (GPx) were evaluated by spectroscopy method. The serum was collected for the analysis of the corticosterone levels. Treatment with sericin in higher doses reversed anxiety-like behavior and cognitive deficit induced by HS. Moreover, heat exposure increased serum corticosterone, hippocampal MDA, apoptotic proteins and HSP-70 levels. Sericin administration decreased serum corticosterone and enhanced hippocampal antioxidant defense and attenuated apoptosis and HSP-70 levels. The results show that the protective effects of sericin against HS-mediated cognitive dysfunction and anxiety-like behavior is possibly through suppressing HSP-70, oxidative stress and apoptosis.

Degraded Sericin Significantly Regulates Blood Glucose Levels and Improves Impaired Liver Function in T2D Rats by Reducing Oxidative Stress

Sericin could be degraded well into low-molecular-weight sericin (SS) through a novel and environmentally friendly recycling process using an ultrasonically degumming method in Ca(OH)₂ aqueous solution. The oral administration of the SS has an evidently hypoglycemic effect on STZ-induced T2D rats. At oral doses of 2.5 and 5% SS for four weeks, the fasting blood glucose decreased by over 60% compared with that in the untreated model group. Oral glucose tolerance and insulin tolerance were ameliorated by the peptide treatment. The serum insulin level was reduced by approximately 35%, the insulin resistance index was reduced by more than 66%. The 8-hydroxy-2 deoxyguanosine level showed a large reduction of 20%, and the total antioxidant activities significantly increased. Hematoxylin-eosin staining and fluorescent immunostaining sections showed that liver and pancreas damage was partly recovered in T2D rats. In summary, oral SS demonstrated evidently hypoglycemic effects mainly related to reducing oxidative stress in the damaged liver and pancreas of T2D rats. Therefore, these results have suggested that the degraded sericin has a potential use in SS-based healthy functional food or hypoglycemic drugs as a waste recovered from sericulture resources.

Sericin protects against acute sleep deprivation-induced memory impairment via enhancement of hippocampal synaptic protein levels and inhibition of oxidative stress and neuroinflammation in mice

Sleep deprivation (SD) induces learning and memory deficits via inflammatory responses and oxidative stress. On the other hand, sericin (Ser) possesses potent antioxidant and neuroprotective effects. We investigated the effect of different doses of Ser on the SD-induced cognitive impairment. Ser (100, 200, and 300 mg/kg) was administered to animals via oral gavage for 8 days, 5 days before to SD, and during SD. SD was induced in mice using a modified multiple platform model, starting on the 6th day for 72 h. Spatial learning and memory were assessed using the Lashley III maze. Serum corticosterone level, and hippocampal malondialdehyde (MDA), total antioxidant capacity (TAC), and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes were evaluated. The expression of growth-associated protein 43 (GAP-43), post-synaptic density-95 (PSD-95), synapsin 1 (SYN-1), and synaptophysin (SYP), and inflammation markers were detected by western blotting. SD caused cognitive impairment, while Ser pretreatment prevented such an effect. Serum corticosterone also increased with SD, but its levels were suppressed in SD mice receiving Ser. Furthermore, Ser normalized SD-induced reduction in the hippocampus activity of SOD and GPx, increased TAC, and decreased MDA levels. Besides, Ser pretreatment increased GAP-34, SYP, SYN-I, and PSD-95 and reduced IL1-β and TNF-α in the hippocampus. SD induced memory impairment and pretreatment with Ser improved memory via its antioxidant, anti-inflammation, and up-regulation of synaptic proteins in the hippocampus.

Sericin modulates learning and memory behaviors by tuning of antioxidant, inflammatory, and apoptotic markers in the hippocampus of aged mice

Sericin is a protein derived from silkworm cocoons and identified as an anti-aging agent. This study aimed to examine the effects of sericin administration on episodic and avoidance memories, social interaction behavior, and molecular mechanisms including oxidative stress, inflammation, and apoptosis in the hippocampus of aged mice. Sericin was administered at 250 mg/kg/day (oral gavage) to 2-year-old BALB/c mice for a duration of 21 consecutive days. Lashley III Maze and Shuttle-Box tests were performed to assess episodic and avoidance memories, respectively. Subjects also underwent social interaction test to reveal any changes in their social behavior. Besides, markers of oxidative stress (TAC, SOD, GPx, and MDA) and neuroinflammation mediators (TNF-α, IL-1β, and IL-10) were measured in the hippocampus. The extent of apoptosis in the hippocampal tissue was further determined by TUNEL assay and histological assessment. The obtained results suggest that sericin promotes episodic and avoidance memories and social behaviors in aged mice. As of the molecular assay outcomes, it was noted that sericin regulates hippocampal inflammation by inhibiting the pro-inflammatory cytokines, TNF-α and IL-1β, and by increasing the anti-inflammatory factor IL-10. Moreover, sericin suppressed oxidative stress by enhancing antioxidant markers (TAC, SOD, and GPx) and inhibiting MDA. It was also identified that sericin can substantially suppress the apoptosis in the hippocampal tissue. Overall, sericin modulates memory and sociability behavior by tuning hippocampal antioxidant, inflammatory, and apoptotic markers in the aged mice.

Extraction and antioxidant activity of sericin, a protein from silk

Abstract Sericin is a globular protein that represents 20% to 30% of the silk fiber from Bombyx mori silkworm cocoon. This protein is usually removed from the raw fiber and discarded by silk producers, a process known as degumming. However, sericin possesses significant biological properties that allows its application in various fields. The antioxidant activity is one of its most relevant benefits. Several authors have reported its anti-tyrosinase activity, lipid peroxidation inhibition and free radical neutralization. The antioxidant potential of sericin protein varies according to the extraction method used. Even though a wide variety of extraction techniques have been studied, simple technics including water at high temperature have exhibited efficient results. Furthermore, this method does not interfere with the safety of sericin for subsequent applications in food.

Sericin grafted multifunctional curcumin loaded fluorinated graphene oxide nanomedicines with charge switching properties for effective cancer cell targeting

Fluorinated graphene has recently gained much attention for cancer drug delivery, owing to its peculiar properties including high electronegativity difference, magnetic resonance imaging contrast agent, and the photothermal effect. However, the hydrophobic nature of fluorinated graphene greatly hinders its application as a biological material. Herein, a novel green method is reported for synthesis of a pH-sensitive charge-reversal and water-soluble fluorinated graphene oxide, modified with polyethyleneimine anchored to sericin-polypeptide (FPS). This nanocarrier was further loaded with curcumin (Cur), and characterized as a nanocarrier for anti-cancer drug delivery. The synthesized nanocarriers contain two different pH-sensitive amide linkages, which are negatively charged in blood pH (≈7.4) and can prolong circulation times. The amide linkages undergo hydrolysis once they reach the mildly acidic condition (pH≈6.5, corresponding to tumor extracellular matrix), and subsequently once reached the lower acidic condition (pH≈5.5, corresponded to endo/lysosomes microenvironment), the FPS charge can be switched to positive (≈+28 mV), which aids the nuclear release. This nanocarrier was designed to selectively enhance cell internalization and nuclear-targeted delivery of curcumin in HeLa, SkBr3 and PC-3 cancer cells. Moreover, FPS-Cur demonstrated high curcumin loading capacity, prolonged curcumin release and promotion of apoptosis in HeLa, SkBr3 and PC-3 cells. Therefore, with its pH-responsive charge-reversal properties, FPS-Cur would be a promising candidate for chemotherapy of cervical, breast and prostate cancers.

Identification and applications of neuroactive silk proteins: a narrative review

In traditional medicine, natural silk is regarded as a cognitive enhancer and a cure for ameliorating the symptoms of heart disease, atherosclerosis, and metabolic disorders. In this review, general characteristics of both silk proteins, fibroin and sericin, extracted from silkworm Bombyx mori and their potential use in the neuronal disorders was discussed. Evidence shows that silk proteins exhibit neuroprotective effects in models of neurotoxicity. The antioxidant, neuroprotective, and acetylcholinesterase inhibitory mechanisms of silk proteins could prove promising in the treatment of neurodegenerative diseases. Owing to their excellent neurocompatibility and physicochemical properties, silk proteins have been used as scaffolds and drug delivery materials in the neuronal tissue engineering. These data support the potential of silk proteins as an effective complementary agent for central and peripheral neurological disorders.

Phytochemical screening, antioxidant, antityrosinase, and antigenotoxic potential of Amaranthus viridis extract

OBJECTIVE:

Amaranthus viridis (Amaranthaceae) widely distributed all over the world, growing under a wide range of climatic conditions and has been utilized as a medicinal herb in traditional Ayurvedic medicine as antipyretic agents, also for the treatment of inflammation, ulcer, diabetic, asthma and hyperlipidemia. The aim of the study was designed to evaluate the chemical composition and antioxidant and biological properties of different fractions obtained from A. viridis.

MATERIALS AND METHODS:

Four different extracts of A. viridis were prepared using aqueous, methanol, chloroform, and hexane and investigated their antioxidant potential using free radical scavenging activities such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and nitric oxide (NO) radical scavenging activity, as well as metal chelating activity. In addition, antityrosinase and antigenotoxicity properties were also evaluated by the standard in vitro methods. Finally, the active methanolic extract (ME) was investigated for identifying the phenolic compounds using UPLC-MS/MS.

RESULTS:

In the present study, chlorogenic acid, gulonic acid, and kaempferol were found to be the major components responsible for the antioxidant activity of A. viridis extract as evidenced from UPLC-MS/MS. Furthermore, the ME of A. viridis revealed excellent antioxidant activities such as DPPH radical scavenging activity (IC₅₀= 47.23 ± 0.66 μg/mL), NO radical scavenging activity (IC₅₀= 64.33 ± 2.01 μg/mL), hydrogen peroxide (H₂O₂) radical scavenging activity (IC₅₀= 33.21 ± 3.3 μg/mL), ABTS radical scavenging activity (IC₅₀= 47.61 ± 1.31 μg/mL), metal chelating activity (IC₅₀= 32.1 ± 1.11 μg/mL), as well as lipid peroxidation inhibiting activity (IC₅₀= 112 ± 1.21 μg/mL). Furthermore, ME revealed that the protective effects of extract were observed on H₂O₂-induced DNA damages with alkaline comet assay.

CONCLUSIONS:

Taken together, the study concluded that the promising antioxidant capacities of A. viridis extract can further be utilized in various agricultural, pharmaceutical, and food applications.