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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/GSK3β, 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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

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 2 3 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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

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 β-arbutin permeating across the skin have not elucidated clearly yet. Herein we aimed to unveil how α-arbutin and β-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 β-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, β-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 β-arbutin, as confirmed by molecular simulation and 13 Carbon 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 β-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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

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-1β, 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-1β, IL-6, PGE-2, 5-LOX and COX-2 and oxidative biomarkers., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background: In Eastern culture, a fair complexion is the standard of beauty, leading to appearance-related distress among women with darker skin or facial pigmentation. Women seek whitening cosmetics to enhance their skin tone or correct their pigmentation, but their safety and effectiveness are paramount factors to consider. In this study, we evaluated the safety and whitening effects of a compound formula denoted as TEST comprising astaxanthin, nicotinamide, arbutin, and tranexamic acid., Methods: Primary skin irritation and skin-whitening efficacy were examined. Three qualified melanization areas were treated with TEST, 7% ascorbic acid, or a blank. Skin color, the individual type angle (ITA°), and the melanin index (MI) were compared among treatment areas., Results: TEST did not induce a skin response and exhibited a significantly higher ITA° than the blank, while no significant difference was observed with that of 7% ascorbic acid. Furthermore, the MI of TEST was significantly reduced posttreatment., Conclusions: TEST could be integrated into spot-fading and skin-whitening cosmeceuticals or functional cosmetics., (© 2024 The Authors. Journal of Cosmetic Dermatology published by Wiley Periodicals LLC.)

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-1β, 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., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest related to this study., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Accumulating evidence has revealed the anti-inflammatory effects of arbutin against various diseases. However, the effects of arbutin are not clarified in ulcerative colitis. This study was intended to investigate the protective effects and mechanisms of arbutin on DSS-induced colitis. Hematoxylin eosin staining was performed to determine the pathological damage of intestinal tissue in mice. Inflammatory factors levels in intestinal tissue were detected by enzyme linked immunosorbent assay (ELISA) assay. TUNEL staining showed the apoptosis levels of cells. Intestinal permeability was analyzed using the application of Fluorescein isothiocyanate Dextran (FD) 4. The levels of Zona Occludens 1 (ZO-1), occluding and claudin-1, and the related proteins in MAPK/ELK1 pathway were analyzed by Western blot. DSS promotes pathological injury, the levels of pro-inflammatory factors containing tumor necrosis factor alpha (TNF-α), Interleukin- 6 (IL-6) and myeloperoxidase (MPO), and cell apoptosis in the mouse colon. Additionally, intestinal permeability was increased and the levels of tight function-related proteins were increased following DSS induction. Its effects could be greatly improved by arbutin. Arbutin exerted effects by eliciting anti-inflammatory effects and maintaining normal intestinal mucosal barrier function, the action mechanism of which could be associated with MAPK/ELK1 pathway.

Alcoholic liver disease (ALD) is a pervasive ailment due to the excessive consumption of alcohol and there is no operative drug for its treatment. The current exploration was intended to examine the hepatoprotective efficacy of arbutin against ethanol-provoked liver injury in rats via the modulation of the Nrf-2/HO-1 signaling cascade. Wistar rats were challenged with the 3 g/kg/day (40% v/v) of ethanol for 4 weeks to provoke the ALD and concomitantly supplemented with 40 mg/kg of arbutin. The liver function markers enzymes, inflammatory cytokines, and oxidative stress markers levels were scrutinized by using the respective assay kits. The mRNA expression of Nrf-2/HO-1 signaling proteins was studied by reverse-transcription polymerase chain reaction. The histological alterations of liver tissues were examined. HepG2 cells were used for the in vitro studies. The levels of oxidative stress markers and liver marker enzymes were examined by using kits. Reactive oxygen species (ROS) and apoptotic cell death was detected by using fluorescent staining. There were no major differences in the body weight and liver weight of experimental animals. Arbutin treatment appreciably reduced the liver marker enzymes, upregulated superoxide dismutase, glutathione peroxidase, total antioxidant capacity, and the hydroxyl scavenging ability, and diminished the tumor necrosis factor-α and interleukin-6 levels in the serum of ethanol provoked animals. Arbutin triggered Nrf-2/HO-1 signaling cascade liver tissues of ethanol-provoked animals. Histological findings proved the preventing effects of arbutin. Arbutin did not demonstrate toxicity to the HepG2 cells. It reduced the aspartate aminotransferase and alanine aminotransferase, ROS, apoptotic cell death, lipid peroxidation and improved the antioxidants' levels in the ethanol-challenged HepG2 cells. In conclusion, our findings unveiled the hepatoprotective efficacy of arbutin against ethanol-provoked liver injury in rats. It could be a promising agent to treat alcoholic liver disease in the future., (© 2021 Wiley Periodicals LLC.)

In this study, polyacrylic acid-co-maleic acid (PAMA) and polyvinyl alcohol (PVA) (1:4) were used to fabricate dissolving microneedles (DMNs) and hydrogel forming microneedles (HMNs) which incorporated α-arbutin. Αlpha-arbutin is commonly used as a skin lightening agent. However, it has poor penetration ability due to its hydrophilic properties. The purpose of this study was to compare the permeation of α-arbutin into the skin using DMNs and HMNs. Both types of microneedles (MNs) were sharp, strong with elegant appearance and approximately 100% penetrated the neonatal porcine skin. All needles of α-arbutin loaded DMNs were completely dissolved within 45 min, whereas maximum swelling of HMNs was observed at 4 h. In vitro permeation studies showed that α-arbutin loaded DMNs and HMNs provided significantly about 4.5 and 2.8 times, respectively, greater α-arbutin permeability than gel and commercial cream (P < 0.05). In vivo study also showed high intradermal delivery of α-arbutin levels using DMNs (5.33 µg/mL) and HMNs (1.47 µg/mL) when compared to that of commercial cream 0.15 µg/mL. Moreover, the micro-holes caused by applying MNs can reseal within 1 h. MNs were also stable at 25 °C for 3 months. The results suggested that DMNs and HMNs developed have a promising platform for transdermal delivery., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Alpha-arbutin is one of the most efficient skin lightener agents, which shows the effect on reducing the pigmentation by competitively inhibiting human tyrosinase. However, alpha-arbutin has difficulty in skin permeability due to its hydrophilic property. The objective of this study was, therefore, to develop alpha-arbutin-loaded dissolving microneedles (DMNs) for improving the delivery of alpha-arbutin into the skin. The DMN patch was prepared using Gantrez™ S-97, hydroxypropyl methylcellulose (HPMC), polyvinylpyrrolidone K-90 (PVP), chitosan, and their combinations. The optimal 8% alpha-arbutin-loaded DMNs, aside from Gantrez™ S-97, was successfully formulated with combination of 8% w/w HPMC and 40% w/w PVP K-90 (HPMC/PVP) at the weight ratio of 1:1. Both DMNs had 100% of penetration into porcine skin. Over 12 h of skin permeation, the flux of Gantrez™ S-97 DMNs and the HPMC/PVP DMNs were 66.21 μg/cm 2 /h and 74.24 μg/cm 2 /h, respectively. The accumulation amount of alpha-arbutin in the skin from Gantrez™ S-97 DMNs and HPMC/PVP DMNs was 107.76 μg and 312.23 μg, respectively. In comparison to the gel formulations, Gantrez™ S-97 DMNs and HPMC/PVP DMNs increase the delivery of alpha-arbutin across the skin approximately 2 and 4.7 times, respectively. In vivo studies found that alpha-arbutin-loaded HPMC/PVP DMNs delivered more alpha-arbutin into the skin than commercial cream. Moreover, the skin can reseal naturally after removal of DMNs patch without any signs of infection and remain stable in accelerated conditions for 4 weeks. Accordingly, alpha-arbutin-loaded HPMC/PVP DMNs could be a promising delivery platform for promoting trans-epidermal delivery of alpha-arbutin for skin lightening.

Arbutin, a natural polyphenol, possesses numerous biological activities including whitening, anti-oxidant, anti-cancer, anti-inflammatory activities, as well as strong reducing power, making it an ideal bioactive ingredient for preparing gold nanoparticles (GNPs). Previously, we developed a novel green, mild synthetic method for GNPs using glycosides such as arbutin as reducing agents and stabilizers. Herein, we optimized the synthetic method for glycoside-GNPs using arbutin, methyl β-D-glucoside, and phenyl β-D-glucoside and validated their whitening efficacy in vitro and in vivo. The resulting glycoside-GNPs were predominantly mono-dispersed and spherical (10.30-17.13 nm diameter). Compared with arbutin itself, arbutin-GNP complexes (GNP-A1 and GNP-P2) displayed enhanced whitening capabilities. Furthermore, GNP-P2 exhibited enhanced anti-inflammatory activity and lacked the toxicity associated with arbutin. Bioactive glycoside-GNP complexes may open new directions for cosmeceuticals, and GNP-P2 may serve as a useful whitening ingredient in future cosmeceutical applications.

Objective: To evaluate the effectiveness and safety of oral administration of Linfadren ® in addition to conventional treatment in patients with post-trauma/surgery persistent hand edema., Design: Parallel-group randomized controlled trial., Setting: Outpatient rehabilitation center., Subjects: A total of 60 outpatients (mean age 48.5 (standard deviation (SD) = 12.3) years) with post-trauma/surgery persistent hand edema., Interventions: Patients were randomized to either receive six-week conventional treatment plus Linfadren ® (Study Group) or conventional treatment (Control Group)., Main Measures: Primary outcome was hand edema as measured by figure-of-eight method. Secondary outcomes were hand function, patient's overall perceived treatment effectiveness and rescue medication request. Tolerability of Linfadren ® was also evaluated. Assessments were performed at baseline, at the end of treatment and three months after the end of treatment., Results: All patients completed the six-week program and 57 patients (95%) completed the three-month follow-up. At six weeks, the Study Group had significantly greater improvement in hand edema (423.3 (SD = 23.8) mm vs 439.4 (SD = 22.6) mm; P = 0.009) and upper limb function ( Quick Disabilities of Arm, Shoulder and Hand questionnaire: 23.6 (SD = 13.6) vs 37.7 (SD = 15.9); P = 0.005) compared to the Control Group. Moreover, the percentage of patients who perceived treatment as effective was significantly higher in the Study Group than in the Control Group both after treatment (70% vs 37%, P = 0.002) and at follow-up (77% vs 30%, P < 0.0001). The rescue medication request was not different between groups. No adverse events were recorded., Conclusion: Linfadren ® in addition to conventional treatment was safe and more effective than conventional treatment alone in patients with post-trauma/surgery persistent hand edema.

Purpose: To assess the effectiveness and safety of a product containing diosmin, coumarin, and arbutin (Linfadren®) in addition to complex decongestive therapy (CDT) on the management of patients with a breast cancer-related lymphedema (BCRL)., Methods: Fifty outpatients (average age of 56.2 ± 2.7 years, range 28-71) with a BCRL were enrolled for this study. Patients were randomly assigned (1:1 ratio) to receive either CDT consisting of skin care, manual lymphatic drainage, remedial exercises, and elastic compression garment (control group, n = 25) or CDT plus Linfadren® (study group, n = 25). Patients were evaluated before and after treatment and 3 months after the end of treatment. Primary outcomes were reduction of upper limb excess volume (EV) and percentage reduction of excess volume (%REV). Secondary outcomes were improvement in Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire, and patient's perception of treatment effectiveness (PPTE)., Results: Addition of Linfadren® to CDT yielded an additional reduction of primary outcomes both after treatment (EV, - 521 ml vs. - 256 ml, P < 0.0001; %REV, - 66.4% vs. - 34%, P = 0.02) and at 3-month follow-up (EV, - 59 ml vs. + 24 ml, P < 0.0001; %REV, - 73.6% vs. - 31.4%, P = 0.004). Moreover, statistically significant differences were found between the two groups for the secondary outcomes after treatment (QuickDASH, P = 0.006; PPTE, P = 0.03) and at 3-month follow-up (QuickDASH, P = 0.006; PPTE, P = 0.02). No patient showed adverse events., Conclusions: Linfadren® in addition to CDT was a safe and effective therapy for reducing BCRL and was better than CDT alone.

Arbutin, a natural polyphenol isolated from the bearberry plant Arctostaphylos uvaursi, possesses whitening and anticancer properties. The effects of arbutin on melanogenesis and its pro-apoptotic effect on B16 murine melanoma cells have not yet been reported. In the present study, acetylated arbutin was prepared in order to improve the biological effects of arbutin, and it was found to significantly inhibit the biosynthesis of melanin and tyrosinase activity compared with parent arbutin in B16 murine melanoma cells. Interestingly, only acetylated arbutin strongly inhibited B16 murine melanoma cell migration in a dose-dependent manner. Both arbutin and acetylated arbutin significantly reduced cell viability, promoted cell apoptosis, caused G1 cell cycle arrest and induced mitochondrial disruption in B16 murine melanoma cells. Furthermore, reduced expression of B-cell lymphoma‑extra large (Bcl-xL) and Bcl-2 were observed in arbutin- and acetylated arbutin-treated cells. Therefore, arbutin and acetylated arbutin were found to exert pro-apoptotic effects on B16 murine melanoma cells, mediated through the mitochondrial pathway. The findings of the present study also support the use of acetylated arbutin as a new potential candidate agent for skin whitening and melanoma treatment.

Recently, the feasibility and effects of using microbubbles (MBs) as an ultrasound (US) contrast agent for enhancing the penetration in transdermal delivery in vivo have been demonstrated, but the mechanism and efficiency are unclear. This study demonstrates the penetration depth, concentration and efficiency of transdermal α-arbutin delivery during 4 weeks after US treatment with MBs in mice. Experimental animals were randomly divided into the following four groups (n = 5 animals per group): (1) penetrating α-arbutin alone (C), (2) US combined with penetrating α-arbutin, (3) US combined with MBs and penetrating α-arbutin, and (4) US combined with diluted MBs and penetrating α-arbutin (UBD). The penetration depths in agarose phantoms and pigskin were 47 and 84% greater for group UBD, respectively, than for group C. The in vitro skin penetration by 2% α-arbutin after 3 h was 83% greater in group UBD than in group C. The degree of in vivo skin whitening (quantified as the luminosity index) in group UBD significantly increased by 25% after 1 week, 34% after 2 weeks, and then stabilized after 3 weeks at 37% in C57BL/6J mice over a 4-week experimental period. Our results indicate that combined treatment with optimal US and MBs can increase skin permeability so as to enhance α-arbutin delivery to inhibit melanogenesis without damaging the skin in mice.

Background: Hyperpigmentation is a skin disorder characterized by elevated production of melanin. Current treatment approaches mainly rely on the application of skin lightening chemicals, most of which have safety issues. Efficacy of delivery of the active ingredients to the target organ has also been a challenge. Transdermal based drug delivery platform has been shown to improve drug bioavailability, avoiding the hepatic first pass metabolism, decrease gastrointestinal side effects, and eventually enhance patient compliance., Results: This article explores the utilization of micellar transdermal delivery technology to improve skin penetration and efficacy of arbutin, a hyperpigmentation agent. The suppression efficacy of cellular melanin production versus cell viability of four active ingredients commonly used in skin lightening products, namely allantoin, arbutin, glycolic acid, and hyaluronic acid were first compared. Arbutin was selected for the micellar delivery studies base on its comparatively low cytotoxicity and better performance in reducing melanin production. Micellar Arbutin cream was formulated using Urah® proprietary micellar technology and was assessed for its cellular melanin suppression efficacy and skin penetration capacity., Conclusion: The results show that micellar arbutin cream improved both the delivery and cellular melanin suppression, suggesting that micellar transdermal delivery may have potential application in addressing hyperpigmentation skin disorders. Graphical abstract Transdermal delivery of arbutin with micelles for melanin production suppression.

Conclusion of the Opinion: The SCCS considers the use of β-arbutin to be safe for consumers in cosmetic products in a concentration up to 7% in face creams provided that the contamination of hydroquinone in the cosmetic formulations remain below 1 ppm. A potential combined use of β-arbutin and other hydroquinone releasing substances in cosmetic products has not been evaluated in this Opinion., (Copyright © 2015. Published by Elsevier Inc.)

An attempt was made to produce and test, according to the guidelines of Polish Pharmacopeia VIII, new prescriptions of hydrogels which could be applied in the treatment of skin diseases associated with hyperpigmentation. Hydrogel formulations containing a substance of skin-whitening activity (arbutin) and glycol plant extract was produced on Carbopol Ultrez 10 base. Two glycol plant extracts of confirmed beneficial effect on skin were selected: an extract of ginkgo leaves and of rosemary. For comparative purposes also preparations with arbutin were produced in which propylene glycol was introduced instead of glycol plant extracts. The assumption of the carried out study was to investigate physicochemical properties of model formulations, estimation of arbutin pharmaceutical availability from the suggested formulations and the assessment of the effect of glycol plant extract components on the process of arbutin diffusion from the produced hydrogel formulations. The formulation viscosity parameters were determined using cone-plate digital rheometer. Gravimetric method was applied to estimate the kinetics of volatile components from the preparations. Potentiometric method was used to measure pH. The rate of arbutin release through a semipermeable membrane to the acceptor fluid was tested in vitro. Spectrophotometric method was used for the determination of the quantity of the released therapeutic substance at defined time intervals. All the proposed formulations are viscoelastic systems having yield stress. There is a strict dependence between rheological properties characterizing the tested hydrogels and the quantity of the arbutin released from them. The process of arbutin release to the acceptor fluid through a semipermeable membrane was most effective from the formulation containing glycol extract of ginkgo (F1A+M).

An attempt was made to estimate the effect of plant extract components (nettle extract, sage extract) on the process of arbutin release from new prescriptions of skin-bleaching gels. Formulations containing arbutin and dry standardized plant extracts were produced for this purpose. The suggested hydrogel vehicles were prepared on the base of two polymers: Carbopol Ultrez 10 and Noveon AA-1. The preparations were subjected to physicochemical tests. Viscosity parameters were determined using cone-plate digital rheometer. Potentiometric method was used to measure pH of the produced hydrogels. The rate of arbutin release through a semipermeable membrane to the acceptor fluid was tested in vitro. The rate of the process of release was determined at defined time intervals by spectrophotometric method. The effect of plant extract components on arbutin process of diffusion was estimated. The highest pharmaceutical availability of arbutin was obtained for hydrogels on Noveon AA-1 base with dry sage extract (F2-A+Sz). The area under the curve of arbutin release from this hydrogel was 25,94 c.u. The arbutin content in the last sample collected during the test of its release was 5,6509 mg/cm2 of the area of release. There were also obtained beneficial applicative rheological parameters, such as: low structural viscosity value (31497 mPa x s at shear rate 2,01 l/s) and yield stress (22,9 N/m2) for F2-A+Sz formulation. All tested formulations demonstrated rheological stability and high pharmaceutical availability after six months of storage.

The aims of this study were to encapsulate arbutin (AR) in liposome to enhance the skin-whitening activity, and to investigate the effect of liposome formulation on the entrapment efficiency (EE%), skin permeation rate and skin deposition. The liposomes were prepared by a film dispersion method with several different formulations and were separated from the solution by using the gel-filtration method. The physical (size distribution, morphology) and chemical (drug entrapment efficiency, hairless mouse skin permeation and deposition) properties of liposomes were characterized. The entrapment efficiency in all liposome formulations varied between 4.35% and 17.63%, and was dependent on the lipid content. The particle sizes of liposomes were in the range of 179.9-212.8 nm in all liposome formulations. Although the permeation rate of AR in the liposome formulations decreased compared with AR solution, the deposition amount of AR in the epidermis/dermis layers increased in AR liposomal formulation. These results suggest that liposomal formulation could enhance the skin deposition of hydrophilic skin-whitening agents, thereby enhancing their activities.

Bearberry leaves and preparations made from them are traditionally used for urinary tract infections. The urinary excretion of arbutin metabolites was examined in a randomized crossover design in 16 healthy volunteers after the application of a single oral dose of bearberry leaves dry extract (BLDE). There were two groups of application using either film-coated tablets (FCT) or aqueous solution (AS). The urine sample analysis was performed by a validated HPLC coolarray method (hydroquinone) and a validated capillary electrophoresis method (hydroquinone-glucuronide, hydroquinone-sulfate). The total amounts of hydroquinone equivalents excreted in the urine from BLDE were similar in both groups. With FCT, 64.8% of the arbutin dose administered was excreted; with AS, 66.7% was excreted (p = 0.61). The maximum mean urinary concentration of hydroquinone equivalents was a little higher and peaked earlier in the AS group versus the FCT group, although this did not reach statistical significance (Cur max = 1.6893 micromol/ml vs. 1.1250 micromol/ml, p = 0.13; tmax (t midpoint) = 3.60 h vs. 4.40 h, p = 0.38). The relative bioavailability of FCT compared to AS was 103.3% for total hydroquinone equivalents. There was substantial intersubject variability. No significant differences between the two groups were found in the metabolite patterns detected (hydroquinone, hydroquinone-glucuronide, and hydroquinone-sulfate).

Arbutin is a glycosylated hydroquinone found at high concentrations in certain plants capable of surviving extreme and sustained dehydration. In this paper, we examine a potential role of this molecule in anhydrobiosis. We have studied its effects on the physical properties of phospholipids and on preservation of liposomes during drying. Arbutin depresses the gel to liquid crystalline phase transition temperature of dry phospholipids, as measured by differential scanning calorimetry, with a pattern similar to that seen in phospholipids dried with the disaccharide trehalose. Unlike trehalose, however, arbutin does not protect dry liposomes from leaking their contents. Also, using Fourier transform infrared spectroscopy, we found an increase in the vibrational frequency of the phosphate asymmetric stretch in partially hydrated phospholipids in the presence of arbutin. Trehalose, by contrast, depresses the frequency of the phosphate in dry phospholipids, indicating that the modes of interaction of trehalose and arbutin with the bilayer are different. Previously, we have shown that phospholipases can be active in liposomes with surprisingly low water contents. Based on the structural similarity of arbutin to a known inhibitor of phospholipase A2 (PLA2), it appeared possible that arbutin might serve as an inhibitor of phospholipases. Liposomes of varying composition were lyophilized in the presence and absence of phospholipases. When the liposomes were partially rehydrated at 76% relative humidity, arbutin inhibited PLA2, but did not inhibit phospholipases B or C. Accumulation of enzyme product in the liposome membranes was measured by analytical thin layer chromatography, and was taken as a measure of enzyme activity. Arbutin did not inhibit any of the enzymes in the presence of excess water. Based on these data, hypotheses are presented concerning the mechanism of PLA2 inhibition by arbutin in the mostly dehydrated state.

A study was carried out to examine the combined effect of arbutin isolated from the leaves of Arctostaphylos uva-ursi (L.) Spreng. (Bearberry leaf) and prednisolone or dexamethazone on Type IV allergic reaction-induced immuno-inflammation. Contact dermatitis caused by picryl chloride (PC-CD) and sheep red cell delayed type hypersensitivity (SRBC-DTH) in mice was not inhibited by the oral application of arbutin at 2 divided doses immediately before and 16 h after the application, but arbutin at doses of 10, 50 mg/kg 24 h after the application speedily decreased the swelling of PC-CD and SRBC-DTH. Arbutin plus prednisolone or dexamethazone showed the inhibitory effect on the swelling of PC-CD and SRBC-DTH stronger than that of prednisolone or dexamethazone alone. Prednisolone and dexamethazone decreased the weight of thymus and spleen in intact, PC-CD and SRBC-DTH mice, but arbutin did not show these effects. These results suggest that arbutin may increase the inhibitory action of prednisolone and dexamethazone on PC-CD and SRBC-DTH, but further investigations are required to understand the mechanism involved.

The effect of 50% methanolic extract (U-ext) from Bearberry leaf on immuno-inflammation was studied by contact dermatitis caused by picryl chloride (PC-CD) in mice. The combined effect of U-ext and prednisolone was also investigated by using similar experimental model. When given orally twice immediately before and 16 h after the application of PC-CD, U-ext did not show an inhibitory effect on the swelling induced by PC-CD while it exhibited a significant therapeutic effect at a dose of 100 mg/kg or more once 24 h after the application. When U-ext (p.o.) and prednisolone (s.c.) in a given portion were simultaneously administered, the inhibitory effect was more potent than that of prednisolone alone in both administration immediately before and 16 h after or once 24 h after the application. Arbutin isolated from U-ext also increased the inhibitory effect of prednisolone similarly to that of U-ext. These results suggest that Bearberry leaf possesses a therapeutic effect against immuno-inflammation induced by PC-CD and also increases the inhibitory effect of prednisolone, and its active principle may be arbutin.