De novo biosynthesis of ß-Arbutin in Komagataella phaffii based on metabolic engineering strategies.

BACKGROUND: ß-Arbutin, found in the leaves of bearberry, stands out as one of the globally acknowledged eco-friendly whitening additives in recent years. However, the natural abundance of ß-Arbutin is low, and the cost-effectiveness of using chemical synthesis or plant extraction methods is low, which cannot meet the requirements. While modifying the ß-Arbutin synthesis pathway of existing strains is a viable option, it is hindered by the limited synthesis capacity of these strains, which hinders further development and application. RESULTS: In this study, we established a biosynthetic pathway in Komagataella phaffii for ß-Arbutin production with a titer of 1.58 g/L. Through diverse metabolic strategies, including fusion protein construction, enhancing shikimate pathway flux, and augmenting precursor supplies (PEP, E4P, and UDPG), we significantly increased ß-Arbutin titer to 4.32 g/L. Further optimization of methanol concentration in shake flasks led to a titer of 6.32 g/L titer after 120 h of fermentation, representing a fourfold increase over the initial titer. In fed-batch fermentation, strain UA3-10 set a record with the highest production to date, reaching 128.6 g/L in a 5 L fermenter. CONCLUSIONS: This is the highest yield in the fermentation tank level of using microbial cell factories for de novo synthesis of ß-Arbutin. Applying combinatorial engineering strategies has significantly improved the ß-Arbutin yield in K. phaffii and is a promising approach for synthesizing functional products using a microbial cell factory. This study not only advances low-cost fermentation-based production of ß-Arbutin but also establishes K. phaffii as a promising chassis cell for synthesizing other aromatic amino acid metabolites.

Investigation of the Inhibitory Activity of ß-Arbutin and Its Analogues on Tyrosinase Based on Molecular Docking and Enzyme Inhibition Kinetics.

ß-Arbutin, a natural glucoside hydroquinone derivative known for its skin-whitening properties through tyrosinase inhibition in melanin synthesis, may pose potential risks of allergy and carcinogenicity due to the release of hydroquinone during use. This study explores the inhibitory effects of phenyl-ß-D-pyranoglucoside (compound 1), 4-methoxyphenyl-ß-D-pyranoglucoside (compound 2), 4-hydroxymethylphenyl-ß-D-pyranoglucoside (compound 3), and ß-arbutin (compound 4) on tyrosinase using enzyme kinetics, molecular docking, and molecular dynamics simulations. Results show compounds 1, 3, and 4 exhibit competitive inhibition, while compound 2 shows mixed inhibition. Docking analysis reveals phenyl rings of all compounds interact with the enzyme's active site, with compound 3 forming a metal bond with copper ions. MD simulations indicate high stability for compounds 2, 3, and 4, with compound 3 showing the lowest RMSD and compact Rg, suggesting stronger binding. Compound 1 is less stable and less inhibitory. These insights are valuable for designing effective tyrosinase inhibitors.

Liposome preparation of alpha-arbutin: stability and toxicity assessment using mouse B16F10 melanoma cells.

Melanoma is the most aggressive type of skin cancer, with few therapeutic alternatives following metastasis development. In recent years, drug delivery-associated nanotechnology has shown promising targeted results with diminished adverse effects compared to conventional treatments. This study aimed to (1) examine the effects of plant-derived α-arbutin, a natural compound and (2) compare these findings with bioactively developed liposomes containing α-arbutin utilizing the B16-F10 murine melanoma cell line as a model. Liposomes were obtained through reversed-phase evaporation by applying a spray dryer to assess their stability. The following biologic assays were measured cytotoxicity/antiproliferative (MTT, Neutral Red, and dsDNA PicoGreen). In addition, the levels of melanin and purinergic enzymes were also measured. The production of reactive oxygen species (ROS) and nitric oxide (NO) was determined as a measure of oxidative state. Treatment with nano-liposome containing alpha-arbutin induced a significant 68.4% cytotoxicity, similar to the positive control, in the B16-F10 murine melanoma cell line at 72 hr. Further, arbutin and liposomes containing alpha-arbutin increased levels of ROS and nitrite formation at 72 hr at the highest concentration (100 and 300 µg/ml) of treatments. Arbutin and liposomes containing alpha-arbutin reduced melanin levels at all tested concentrations. In addition, arbutin and alpha-arbutin containing liposomes lowered nucleotides (AMP, ADP, and ATP) and nucleoside (adenosine) levels in melanoma cells. Evidence suggests that α-arbutin containing liposome can be considered as an alternative immunosuppressive agent stimulated in melanoma treatment.

Effects of Strawberry Tree (Arbutus unedo L.) Aqueous Leaf Extract and Arbutin on PK-15 and HepG2 Cells.

The antioxidant properties of the leaves of the Mediterranean strawberry tree (Arbutus unedo L.) are mainly attributed to the main bioactive compound, the phenolic glycoside arbutin. In this study, the safety profile of strawberry tree aqueous leaf extract (STE) and arbutin at the DNA level was assessed in vitro using porcine PK-15 kidney cells and HepG2 cells derived from human hepatomas. To examine the effects on cell viability and DNA damage, cells were treated for 24 h with STE or arbutin at three concentrations presumed to be non-toxic (400, 200, and 11.4 µg/mL). Assessments were performed using the MTS viability assay, dual acridine orange/ethidium bromide fluorescent staining, and alkaline comet assay. Results showed that the highest concentration (400 µg/mL) of both tested compounds had no significant cytotoxic effects on either PK-15 or HepG2 cells. Apoptosis was the predominant type of cell death and the total amount of DNA damage in treated cells was within acceptable limits. These results on the in vitro cytocompatibility of arbutin and STE with PK-15 and HepG2 cells could serve to make more reliable judgements about safe levels of arbutin in cosmetic products and functional foods, given the increased popularity of the compound in recent years.

Nano-vesicular systems for melanocytes targeting and melasma treatment: In-vitro characterization, ex-vivo skin retention, and preliminary clinical appraisal.

Melasma represents an acquired melanogenesis disorder resulting in skin's hyperpigmentation effect. Although several approaches are adopted for melasma treatment, nanotechnology presents the most convenient one. Therefore, the present work aimed to formulate and characterize three nano-vesicular systems namely, liposomes, penetration enhancer containing vesicles (PEVs) and invasomes to enhance the topical delivery of the skin whitening agent; alpha arbutin (α-arbutin) for the treatment of melasma. Liposomes were prepared according to a 23 full factorial design and the selected formula was further employed for the preparation of PEVs and invasomes. Results showed that the three vesicular systems exhibited nano-sizes ranging from 151.95 to 672.5 nm, negative charges ranging from -12.50 to -28.20 mV, high entrapment efficiencies ranging from 80.59 to 99.53 %, good stability and prolonged-release of α-arbutin for 24 h after dispersion in hydrogel form. The deposition study from the vesicular hydrogel confirmed their effectiveness for the drug's accumulation in the skin reaching an average of 1.6-fold higher in the stratum corneum, 1.6-1.8-fold higher in the epidermis, and 1.6-1.8-fold higher in the dermis compared to the free drug dispersion in hydrogel. A preliminary clinical split-face study on patients suffering from melasma revealed that α-arbutin-loaded liposomes and PEVs in hydrogel forms showed better clinical outcomes compared to the free α-arbutin hydrogel as well as to the previously published α-arbutin encapsulated in chitosan nanoparticles and dispersed in hydrogel form. This delineates the aforementioned nano-vesicular systems as effective and clinically superior delivery means for melasma management.

Pharmacological and biochemical insights into lead-induced hepatotoxicity: Pathway interplay and the protective effects of arbutin via the oral and intraperitoneal routes in silico and in vivo.

INTRODUCTION: Lead acetate (PbAc), a hazardous heavy metal, poses significant threats to human health and the environment because of widespread industrial exposure. PbAc exposure leads to liver injury primarily through oxidative stress and the disruption of key regulatory pathways. Understanding these mechanisms and exploring protective agents are vital for mitigating PbAc-induced hepatotoxicity. Therefore, we aimed to investigate the molecular pathways implicated in PbAc-induced liver damage, focusing on Sirt-1, Nrf2 (HO-1, NQO1, and SOD), Akt-1/GSK3ß, m-TOR, and P53. Additionally, we aimed to assess the hepatoprotective effects of arbutin, which is administered orally and intraperitoneally, to determine the most effective delivery method. METHODOLOGY: In silico analyses were conducted to identify relevant protein networks associated with Sirt-1 and AKT-1/GSK-3B pathways. The pharmacodynamic properties of arbutin were examined, followed by molecular docking studies to elucidate its interactions with the selected protein network. In vivo preclinical studies were carried out on adult male rats randomly assigned to 6 different treatment groups, including PbAc exposure and PbAc exposure treated with arbutin either orally or intraperitoneally. RESULTS: PbAc exposure led to hepatic oxidative stress, as evidenced by elevated MDA levels and SIRT-1 inhibition, disrupting antioxidant pathways and activating antiautophagic and proapoptotic pathways, ultimately resulting in hepatocyte necrosis. Both oral and intraperitoneal arbutin administration effectively modifed these effects, with intraperitoneal delivery showing superior efficacy in mitigating PbAc-induced histological, immunological, and biochemical alterations. CONCLUSION: This study provides insights into the molecular mechanisms underlying PbAc-induced liver injury and highlights the hepatoprotective potential of arbutin. These findings suggest that arbutin, particularly when administered intraperitoneally, holds promise as a therapeutic agent for combating PbAc-induced hepatotoxicity.

Effects of Strawberry Tree Water Leaf Extract and Arbutin on Biochemical Markers and DNA Integrity in Brain Cells of Lewis Rats.

There is growing evidence that arbutin and plant extracts rich in arbutin, such as extracts of the strawberry tree (Arbutus unedo L.), exert a range of beneficial effects, including cyto- and genoprotective properties. This study evaluated the effects of strawberry tree water leaf extract (STE) and arbutin in the brain tissue of Lewis rats. STE or arbutin were administered per os to male and female rats at a dose of 200 mg/kg body weight/day for 14 or 28 days. Treatment outcomes were evaluated using biochemical markers (lipid peroxidation and the activities of the antioxidative enzymes catalase and superoxide dismutase). The effects of the tested substances on DNA integrity in brain cells were evaluated using the alkaline comet assay. The results suggest a high biocompatibility of both tested substances with rat brain tissue. No significant harmful disturbances were observed in the oxidative/antioxidative status or impairments of DNA integrity in the rat brain cells. Nearly all post-treatment values were within tolerable limits as compared to the matched control rats. Such encouraging findings support further research using other subtle biomarkers to clarify the safety aspects of arbutin and STE prior to the development of specific nutraceutical products.

The molecular mechanisms underlying optical isomer arbutin permeating the skin: The molecular interaction between arbutin and skin components.

Arbutin, a typical optical isomer, has garnered widespread acclaim in the whitening cosmetics for its favorable efficacy and safety. However, the molecular mechanisms underlying α-arbutin and ß-arbutin permeating across the skin have not elucidated clearly yet. Herein we aimed to unveil how α-arbutin and ß-arbutin interacted with keratin or SC lipids, further demonstrating their relationship with their drug permeability. We found that α-arbutin displayed significantly higher drug accumulation into the porcine skin than ß-arbutin within 24 h through in vitro permeation test. Moreover, α-arbutin predominantly induced the alternations of secondary structure of amide II during the drug permeation, which was favorable for α-arbutin permeation. On the contrary, ß-arbutin exhibited an observable effect on the stretching vibration of SC lipids, possessing a significantly stronger mixing energy, binding energy and compatibility with ceramide (Cer) than that of α-arbutin, which ultimately restricted its permeation. Interestingly, free fatty acids and ceramides of the SC lipids specifically utilized its oxygen atom of carboxyl group to dock the arbutin molecules, enhancing their affinity with ß-arbutin, as confirmed by molecular simulation and 13Carbon Nuclear Magnetic Resonance. Nevertheless, a favorable compatibility between α-arbutin and keratin was observed. It was emphasized that the distinct spatial configuration and opposite optical rotation of arbutin was the leading factor impacting the intermolecular force between arbutin and the SC, and resulted in a diverse drug permeation. In cellular and in vivo skin pharmacokinetic studies, α-arbutin also possessed a higher cellular uptake and topical bioavailability than ß-arbutin. This study revealed the transdermal permeation mechanisms of optical isomer arbutin at the molecular levels, providing methodological reference for the investigations of permeation behaviors of other isomers with similar spatial configuration.

[Research progress in biosynthesis of arbutin].

Arbutin, a glycosylated compound of hydroquinone, exists in two forms of ß-arbutin and α-arbutin based on the configuration of the glycosidic bond. As a safe and stable whitening agent, arbutin is widely used in cosmetics, and it has antioxidant, antimicrobial, anti-inflammatory, and anti-tumor activities. The production of arbutin by plant extraction faces challenges such as long plant growth periods, complex extraction processes, and low yields. The chemical synthesis of arbutin suffers from harsh reaction conditions, poor stereo-selectivity, and low yields. In recent years, biosynthesis emerges as the most popular method to produce arbutin because of the simple and mild reaction conditions, low costs, and environmental friendliness. This review summarizes the research progress in four biosynthetic strategies for arbutin, including plant conversion, enzyme catalysis, whole-cell catalysis, and microbial fermentation. The advantages and limitations of these biosynthetic strategies are discussed, and future research directions are proposed.

Targeting JAK2/STAT3, NLRP3/Caspase-1, and PK2/PKR2 Pathways with Arbutin Ameliorates Lead Acetate-Induced Testicular Injury in Rats.

The reproductive system of males is adversely impacted by lead (Pb), a toxic heavy metal. The present study examined arbutin, a promising hydroquinone glycoside, for its potential ameliorative impact against Pb-induced testicular impairment in rats. The testicular injury was induced by the intraperitoneal administration of Pb acetate (20 mg/kg/day) for 10 consecutive days. Thirty-six rats were divided into six experimental groups (n = 6 per group): control, control treated with oral arbutin (250 mg/kg), control treated with intraperitoneal arbutin (75 mg/kg), untreated Pb, Pb treated with oral arbutin, and Pb treated with intraperitoneal arbutin. The treatments were administered daily for 10 days. Arbutin was administered by the oral and intraperitoneal routes to compare the efficacy of both routes in mitigating Pb acetate-induced testicular dysfunction. The current data revealed that both oral and intraperitoneal administration of arbutin significantly enhanced serum testosterone and sperm count/motility, indicating the amelioration of testicular dysfunction. In tandem, both routes lowered testicular histopathological aberrations and Johnsen's damage scores. These favorable outcomes were driven by dampening testicular oxidative stress, evidenced by lowered lipid peroxidation and increased glutathione and catalase antioxidants. Moreover, arbutin lowered testicular p-JAK2 and p-STAT3 levels, confirming the inhibition of the JAK2/STAT3 pro-inflammatory pathway. In tandem, arbutin suppressed the testicular NLRP3/caspase-1/NF-B axis and augmented the cytoprotective PK2/PKR2 pathway. Notably, intraperitoneal arbutin at a lower dose prompted a more pronounced mitigation of Pb-induced testicular dysfunction compared to oral administration. In conclusion, arbutin ameliorates Pb-evoked testicular damage by stimulating testicular antioxidants and the PK2/PKR2 pathway and inhibiting the JAK2/STAT3 and NLRP3/caspase-1 pro-inflammatory pathways. Hence, arbutin may be used as an adjunct agent for mitigating Pb-induced testicular impairment.

One new triterpene glycoside from Cyclocarya paliurus.

One previously undescribed triterpene glycoside (1) and two known compounds were isolated from the leaves of Cyclocarya paliurus (2-3). Their structures were elucidated based on methods of spectroscopic analysis and NMR data comparison with those in the literature. Compound 1 showed a moderate inhibitory effect on melanogenesis with an IC50 value of 282.3 µM, with the positive drug arbutin showing an IC50 value of 168.5 µM.

Integrated Metabolomics and Transcriptomics Analyses of the Biosynthesis of Arbutin and 6'-O-Caffeoylarbutin in Vaccinium dunalianum Cell Suspension Cultures Fed with Hydroquinone.

Arbutin and 6'-O-caffeoylarbutin (CA) from Vaccinium dunalianum Wight are known for their ability to inhibit melanin synthesis. To boost the production of arbutin and CA, precursor feeding with hydroquinone (HQ) was studied in V. dunalianum suspension cells. The effect of HQ on the biosynthesis of arbutin and CA in the suspension cells was investigated using high-performance liquid chromatography (HPLC), and possible molecular mechanisms were analyzed using metabolomics and transcriptomics analyses. HPLC analysis only showed that the addition of HQ significantly enhanced arbutin synthesis in cells, peaking at 15.52 ± 0.28 mg·g-1 after 0.5 mmol·L-1 HQ treatment for 12 h. Subsequently, metabolomics identified 78 differential expression metabolites (DEMs), of which arbutin and CA were significantly up-regulated metabolites. Moreover, transcriptomics found a total of 10,628 differential expression genes (DEGs). The integrated transcriptomics and metabolomics revealed that HQ significantly enhanced the expression of two arbutin synthase (AS) genes (Unigene0063512 and Unigene0063513), boosting arbutin synthesis. Additionally, it is speculated that CA was generated from arbutin and 3,4,5-tricaffeoylquinic acid catalyzed by caffeoyl transferase, with Unigene0044545, Unigene0043539, and Unigene0017356 as potentially associated genes with CA synthesis. These findings indicate that the precursor feeding strategy offers a promising approach for the mass production of arbutin and CA in V. dunalianum suspension cells and provides new insights for CA biosynthesis in V. dunalianum.

De novo biosynthesis of ß-arbutin in Corynebacterium glutamicum via pathway engineering and process optimization.

BACKGROUND: ß-Arbutin, a hydroquinone glucoside found in pears, bearberry leaves, and various plants, exhibits antioxidant, anti-inflammatory, antimicrobial, and anticancer effects. ß-Arbutin has wide applications in the pharmaceutical and cosmetic industries. However, the limited availability of high-performance strains limits the biobased production of ß-arbutin. RESULTS: This study established the ß-arbutin biosynthetic pathway in C. glutamicum ATCC13032 by introducing codon-optimized ubiC, MNX1, and AS. Additionally, the production titer of ß-arbutin was increased by further inactivation of csm and trpE to impede the competitive metabolic pathway. Further modification of the upstream metabolic pathway and supplementation of UDP-glucose resulted in the final engineered strain, C. glutamicum AR11, which achieved a ß-arbutin production titer of 7.94 g/L in the optimized fermentation medium. CONCLUSIONS: This study represents the first successful instance of de novo ß-arbutin production in C. glutamicum, offering a chassis cell for ß-arbutin biosynthesis.

[Molecular modification of cyclodextrin glucosyltransferase and its application in the synthesis of α-arbutin].

α-arbutin has important applications in cosmetics and medicine. However, the extraction yield from plant tissues is relatively low, which restricts its application value. In this study, we investigated the synthesis of α-arbutin using maltodextrin as the donor and hydroquinone as the acceptor, using a cyclodextrin glucosyltransferase (CGTase) from Anaerobranca gottschalkii. We performed site-saturated and site-directed mutagenesis on AgCGTase. The activity of the variant AgCGTase-F235G-N166H was 3.48 times higher than that of the wild type. Moreover, we achieved a conversion rate of 63% by optimizing the reaction pH, temperature, and hydroquinone addition amount. Overall, this study successfully constructed a strain with improved conversion rate for the synthetic production of α-arbutin and hydroquinone. These findings have significant implications for reducing the industrial production cost of α-arbutin and enhancing the conversion rate of the product.

Arbutin's Potential in Neuroprotection: A Promising Role in Mitigating Neurodegenerative Diseases.

Naturally occurring glycosylated hydroquinone Arbutin, has drawn interest due to its possible function in reducing the risk of neurodegenerative diseases such as Huntington's disease, amyotrophic lateral sclerosis, Parkinson's disease, and Alzheimer's disease. Arbutin is well-known for its anti-inflammatory and antioxidant properties, which are essential in preventing oxidative stress and neuroinflammation. Research has shown that arbutin might alter important physiological pathways connected to protein misfolding, synapse function, and neuronal survival processes linked to the development of neurodegenerative diseases. Arbutin can also penetrate the blood- -brain barrier, which increases its therapeutic potential. Arbutin's neuroprotective properties and promise as a therapeutic agent for neurodegenerative illnesses are summarized in this review, which also emphasizes the need for further study into the molecular processes behind these effects.

Arbutin attenuates CFA-induced arthritis by modulating expression levels of 5-LOX, NF­κB, IL-17, PGE-2 and TNF-α.

Arbutin, a naturally soluble glycosylated phenol has antioxidant, antimicrobial, antitumor and anti-inflammatory properties. The current exploration appraises the treatment of arthritis by use of Arbutin (25, 50 and 100 mg/kg) orally in CFA-induced rat arthritis model. Body weight changes, paw size, and joint diameter were recorded till the 28th day in the arthritic-induced rats. Hematological, biochemical, oxidative and inflammatory biomarkers were measured through the blood samples of anesthetized rats. Arbutin markedly decreased paw volume, PGE-2, anti-CCP and 5-LOX levels, however, maintained metabolic and hematological balance and prevented weight loss. Radiology and histology changes improved significantly in the ankle joints of rats. Moreover, Arbutin increased gene pointers such as IL-10 and IL-4 while significantly reducing the levels of CRP and WBCs, whereas Hb, platelets and RBCs count markedly raised in post-treatments. Antioxidant levels of SOD, CAT and GSH were improved and MDA level was reduced in treated groups. Rt-PCR investigation showed a significant reduction of the interleukin-1ß, TNF-α, interleukin-6, cyclooxygenase-2, NF-κB and IL-17 and increased expression of gene pointers like IL-4, and IL-10 in treated groups. Assessment of molecular docking revealed a strong binding interaction of Arbutin against 5-LOX, IL-17, TNF-alpha and interleukin-6, cyclooxygenase-2, nuclear factor-κB, IL-4 and iNOS providing a strong association between experimental and theoretical results. As a result, Arbutin has significantly reduced CFA-induced arthritis by modulation of anti-inflammatory cytokines, i.e., IL-10 and IL-4, the pro-inflammatory cytokines panel such as NF-κB, TNF-alpha, IL-1ß, IL-6, PGE-2, 5-LOX and COX-2 and oxidative biomarkers.

Arbutin intervention ameliorates memory impairment in a rat model of lysolecethin induced demyelination: Neuroprotective and anti-inflammatory effects.

Cognitive impairment (CI) and memory deficit are prevalent manifestations of multiple sclerosis (MS). This study explores the therapeutic potential of arbutin on memory deficits using a rat hippocampal demyelination model induced by lysophosphatidylcholine (LPC). Demyelination was induced by bilateral injection of 1% LPC into the CA1 area of the hippocampus, and the treated group received daily arbutin injections (50 mg/kg, i.p) for two weeks. Arbutin significantly improved memory impairment 14 days post-demyelination as assessed by Morris water maze test. Histological and immunohistochemical analyses demonstrated that arbutin reduced demyelination suppressed pro-inflammatory markers (IL-1ß, TNF-α) and increased anti-inflammatory cytokine IL-10. Arbutin also diminished astrocyte activation, decreased iNOS, enhanced anti-oxidative factors (Nrf2, HO-1), and exhibited neuroprotective effects by elevating myelin markers (MBP) and brain derived neurotrophic factor (BDNF). These findings propose arbutin as a potential therapeutic candidate for multiple sclerosis-associated memory deficits, warranting further clinical exploration.

Arbutin abrogates cisplatin-induced hepatotoxicity via upregulating Nrf2/HO-1 and suppressing genotoxicity, NF-κB/iNOS/TNF-α and caspase-3/Bax/Bcl2 signaling pathways in rats.

BACKGROUND: Cisplatin is a potent anticancer agent widely employed in chemotherapy. However, cisplatin leads to toxicity on non-targeted healthy organs, including the liver. We investigated the hepatoprotective mechanism of arbutin (ARB), a glycosylated hydroquinone, against cisplatin-induced hepatotoxicity. METHODS: Rats were orally administered with ARB (ARB1 = 50 mg/kg; ARB2 = 100 mg/kg) for 14 consecutive days against hepatotoxicity induced by a single dose of cisplatin (10 mg/kg) on day 15. Three days after the intraperitoneal cisplatin injection, serum and liver tissue were collected for subsequent analyses. RESULTS: Cisplatin triggered marked increases in serum AST, ALT, and ALP activities, hepatic malondialdehyde (MDA) and reactive oxygen species (ROS) coupled with a considerable diminution in hepatic activities of superoxide dismutase (SOD), catalase (CAT) and the concentration of reduced glutathione (GSH). The gene expressions of interleukin-1ß (IL-1ß), tumor necrosis factor (TNF-α), and IL-6 were notably increased. The pre-administration of ARB1 and ARB2 reduced AST, ALT and ALP in serum and restored SOD, CAT, GSH, ROS, MDA and cytokine levels which was also evidenced by alleviated hepatic lesions. Further, cisplatin-induced prominent alterations in the gene expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), iNOS, NF-κB, Bax, Bcl-2, caspase-3 and 8-OHdG in the liver. Interestingly, ARB protected the liver and mitigated the cisplatin-induced alterations in serum AST, ALT, ALP, and reduced hepatic redox markers, 8-OdG, inflammatory markers and gene expressions. CONCLUSION: The findings demonstrate that ARB is a potential protective adjuvant against cisplatin-induced hepatotoxicity via inhibition of hepatic oxidative stress, inflammation, and apoptosis.

Quantification of Arbutin and its degradation products, hydroquinone and p-Benzoquinone, in hyperpigmentation topical formulation: Effect of extraction procedure and interference assessment.

The utilization of Hydroquinone (HQ) in over-the-counter skincare items is subject to restrictions. Consequently, Arbutin (AR) serves as a reliable alternative for addressing hyperpigmentation in non-prescription topical formulations. Nevertheless, AR undergoes decomposition into HQ and p-Benzoquinone (BZ) when exposed to temperature stress, ultraviolet light, or dilution in an acidic environment, all of which can induce skin toxicity. The intention of this paper is to investigate the effect of extraction procedure on the conversion of AR to HQ and or BZ and to evaluate kinetics of AR hydrolysis to HQ. Meanwhile this study aims to evaluate AR and BZ interference with the United States Pharmacopoeia (USP) identification and assessment method for HQ Hydrolytic stress during extraction conditions underwent optimization through systematic screening tests. Subsequent assessment of the residual drug and its degradation products were achieved by HPLC method. The resulting data were meticulously fitted to various kinetic models. To analyze the potential interference of AR in HQ measurement using USP method, the standard concentrations of AR and HQ were analyzed through UV-VIS spectrophotometry. For enhanced certainty, a validated HPLC method analysis was also conducted. Notably, the acid hydrolysis of AR exhibited independence from its initial concentration. So, the hydrolytic degradation of AR exhibited a Zero-order kinetic profile. Furthermore, the proven interference of AR in the UV-VIS spectrophotometry method was identified within the context of the USP method. This study successfully utilized an adopted HPLC method for the concurrent quantification of AR, HQ, and BZ. The potential interference of AR in the UV-VIS spectrophotometric assay for HQ may lead to false results especially for regulatory purposes.

[Arbutin ameliorates liver fibrosis in mice by inhibiting macrophage recruitment and regulating the Akt/NF-κB and Smad signaling pathways].

OBJECTIVE: To investigate the protective effect of arbutin against CCl4-induced hepatic fibrosis in mice and explore the underlying mechanisms. METHODS: Twenty-four C57BL/6 mice were randomly divided into control group, model group, and low- and high-dose arbutin treatment (25 and 50 mg/kg, respectively) groups. Mouse models of liver fibrosis were established by intraperitoneal injection of CCl4, and arbutin was administered daily via gavage for 6 weeks. After the treatments, serum biochemical parameters of the mice were tested, and liver tissues were taken for HE staining, Sirius Red staining and immunohistochemical staining. RT-qPCR was used to detect the mRNA levels of α-SMA, Pdgfb, Col1α1, Timp-1, Ccl2 and Tnf-a, and Western blotting was performed to detect α-SMA protein expression in the liver tissues. In the cell experiment, the effect of arbutin treatment for 24 h on THP-1 and RAW264.7 cell migration and recruitment was examined using Transwell migration assay and DAPI staining; The changes in protein levels of Akt, p65, Smad3, p-Akt, p-p65, p-Smad3 and α-SMA in arbutintreated LX-2 cells were detected with Western blotting. RESULTS: Arbutin treatment significantly lowered serum alanine aminotransferase and aspartate aminotransferase levels, alleviated liver tissue damage and collagen deposition, and reduced macrophage infiltration and α-SMA protein expression in the liver of the mouse models (P < 0.05 or 0.001). Arbutin treatment also significantly reduced CCl4-induced elevation of a-SMA, Pdgfb, Col1α1, Timp-1, Ccl2 and Tnf-a mRNA levels in mice (P < 0.05). In the cell experiment, arbutin treatment obviously inhibited migration and recruitment of THP-1 and RAW264.7 cells and lowered the phosphorylation levels of Akt, p65 and Smad3 and the protein expression level of α-SMA in LX-2 cells. CONCLUSION: Arbutin ameliorates liver inflammation and fibrosis in mice by inhibiting hepatic stellate cell activation via reducing macrophage recruitment and infiltration and suppressing activation of the Akt/NF-κB and Smad signaling pathways.