The vitality of B16 melanoma cells is inhibited by arbutin (0.3-5.4 mM; 24 hours, 48 hours, 72 hours; B16 melanoma cells) in a dose- and time-dependent way [2].

Arbutin (50 mg/kg, 100 mg/kg; side wall; daily; 17 days; model C57BL/6 model) simulates ventricular hypertrophy generated by ISO and has a substantial protective effect [3].

Cell Viability Assay[2]
Cell Types: B16 murine melanoma cells
Tested Concentrations: 0.3 mM, 0.7 mM, 1.4 mM, 2.1 mM 24 hrs (hours)) The sterilization rate of B16 murine melanoma cells treated with a dose of 5.4 mM[2]. , 2.9 mM, 3.6 mM, 5.4 mM
Incubation Duration: 24 hrs (hours), 48 hrs (hours) or 72 hrs (hours)
Experimental Results: Inhibited the viability of B16 mouse melanoma cells in a time- and dose-dependent manner.

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Apoptosis analysis [2]
Cell Types: B16 mouse melanoma cells
Tested Concentrations: 1.4 mM, 2.9 mM, 5.4 mM
Incubation Duration: 24 hrs (hours)
Experimental Results: Caused 19.3% of cell apoptosis.

Animal/Disease Models: Male C57BL/6 mice (20-25g) [3]
Doses: 50mg/kg, 100mg/kg
Route of Administration: Oral; daily; 17 days
Experimental Results: Improved myocardial damage caused by ISO.

Absorption, Distribution and Excretion
Arbutin was found to be extensively absorbed from the gastrointestinal tract where it is primarily converted to hydroquinone.
During the first 4 hours following ingestion of a single dose of 210 mg arbutin in healthy volunteers, 224.5 μmol/L hydroquinone glucuronide and 182 μmol/L of hydroquinone sulfate were recovered in the urine.
No pharmacokinetic data available.
No pharmacokinetic data available.
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 umol/mL vs. 1.1250 umol/mL, p = 0.13; tmax (t midpoint) = 3.60 h vs. 4.40 hr, 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).
To study the effects of aloesin and arbutin on normal cultured human melanocytes in synergetic method. Building up the system of cultured human melanocytes. The cultured melanocytes in vitro were treated with the mixture of aloesin and arbutin. The cell viability and tyrosinase activity was measured by MTT assay, utilization of L-Dopa as the substrate respectively; melanin content was measured by image analysis system. Furthermore, the effects of the mixture on melanocytes were compared with that of aloesin and arbutin. The mixture of aloesin and arbutin showed an inhibition on tyrosinase activity of human melanocytes and reduced significantly melanin content. Between the mixture and the single use of aloesin or arbutin, there is significant difference (P<0.05). On the other hand, the mixture has little influence on melanocytes viability and there is negative significance. The mixture of aloesin and arbutin can significantly inhibit the tyrosinase activity and melanogenesis of cultured human melanocytes. It showed the effects of aloesin and arbutin in a synergistic manner.

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Metabolism / Metabolites
Arbutin is readily susceptible to hydrolysis in dilute acids to yield D-glucose and hydroquinone. It is expected that orally administered arbutin is easily hydrolyzed to free hydroquinone molecules by stomach acid. Hydroquinone is further metabolized into the main metabolites, hydroquinone glucuronide and hydroquinone sulfate.

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Biological Half-Life
No pharmacokinetic data available.

Protein Binding
No pharmacokinetic data available.

[1]. Action of tyrosinase on alpha and beta-arbutin: A kinetic study. PLoS One. 2017 May 11;12(5):e0177330.

[2]. Investigation of the pro-apoptotic effects of arbutin and its acetylated derivative on murinemelanoma cells. Int J Mol Med. 2018 Feb;41(2):1048-1054.

[3]. Arbutin Attenuates Isoproterenol-Induced Cardiac Hypertrophy by Inhibiting TLR-4/NF-κB Pathway in Mice. Cardiovasc Toxicol. 2019 Sep 4.

Hydroquinone O-beta-D-glucopyranoside is a monosaccharide derivative that is hydroquinone attached to a beta-D-glucopyranosyl residue at position 4 via a glycosidic linkage. It has a role as a plant metabolite and an Escherichia coli metabolite. It is a beta-D-glucoside and a monosaccharide derivative. It is functionally related to a hydroquinone.
Extracted from the dried leaves of bearberry plant in the genus Arctostaphylos and other plants commonly in the Ericaceae family, arbutin is a beta-D-glucopyranoside of [DB09526]. It is found in foods, over-the-counter drugs, and herbal dietary supplements. Most commonly, it is an active ingredient in skincare and cosmetic products as a skin-lightening agent for the prevention of melanin formation in various skin conditions that involve cutaneous hyperpigmentation or hyperactive melanocyte function. It has also been used as an anti-infective for the urinary system as well as a diuretic. Arbutin is available in both natural and synthetic forms; it can be synthesized from acetobromglucose and [DB09526]. Arbutin is a competitive inhibitor of tyrosinase (E.C.1.14.18.1) in melanocytes, and the inhibition of melanin synthesis at non-toxic concentrations was observed in vitro. Arbutin was shown to be less cytotoxic to melanocytes in culture compared to [DB09526].
Arbutin has been reported in Camellia sinensis, Myrothamnus flabellifolia, and other organisms with data available.
See also: Arctostaphylos uva-ursi leaf (part of); Arbutin; octinoxate (component of); Adenosine; arbutin (component of) ... View More ...

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Drug Indication
Indicated for over-the-counter use for epidermal hyperpigmentation in various skin conditions, such as melasma, freckles, and senile lentigines.

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Mechanism of Action
Arbutin is a hydroquinone glycoside, however the hydroquinone moiety is not solely responsible for the de-pigmentating actions of arbutin. It acts as a competitive inhibitor of tyrosinase enzyme by acting on the L-tyrosine binding site to suppress melanogenesis and mediate its de-pigmenting actions on human skin. Tyrosinase is an enzyme involved in the regulation of rate-limiting steps during the synthesis of melanin; it regulates the conversion of L-tyrosine into L-dopa, and subsequent conversion of L-dopa to L-dopaquinone. Via inhibition of tyrosinase activity in a concentration-dependent manner, arbutin attenuates the production of melanin in melanocytes. While most studies suggest that arbutin has negligible effect on the tyrosinase mRNA expression, a study assessing the effect of arbutin on melanocyte differentiation inducement system using ES cells propose that arbutin may also downregulate the expression of tyrosinase in addition to its inhibitory action on the enzyme. The contradictory findings across studies may be due to previous studies using terminally-differentiated melanocytes and melanoma cells.
...This study ... presents evidence that cotreatment of aloesin and arbutin inhibits tyrosinase activity in a synergistic manner by acting through a different action mechanism. Aloesin or arbutin similarly inhibited enzyme activity of human- and mushroom-tyrosinases with an IC50 value of 0.1 or 0.04 mM, respectively. Lineweaver-Burk plots of the enzyme kinetics data showed that aloesin inhibited tyrosinase activity noncompetitively with a Ki value of 5.3 mM, whereas arbutin did it competitively (Maeda, 1996). We then examined whether cotreatment of these agents inhibits the tyrosinase activity in a synergistic manner. The results showed that 0.01 mM aloesin in the presence of 0.03 mM arbutin inhibited activity of mushroom by 80% of the control value and the reverse was also true. The inhibitory effects were calculated to be synergistic according to the Burgi method. Taken together, we suggest that aloesin along with arbutin inhibits in synergy melanin production by combined mechanisms of noncompetitive and competitive inhibitions of tyrosinase activity.

C12H16O7

272.2512

272.089

497-76-7

Arbutin-d4

440936

White to off-white solid powder

1.6±0.1 g/cm3

561.6±50.0 °C at 760 mmHg

195-198 °C

293.4±30.1 °C

0.0±1.6 mmHg at 25°C

1.650

-1.35

5

7

3

19

279

5

C1=CC(=CC=C1O)O[C@H]2[C@@H]([C@H]([C@@H]([C@H](O2)CO)O)O)O

BJRNKVDFDLYUGJ-RMPHRYRLSA-N

InChI=1S/C12H16O7/c13-5-8-9(15)10(16)11(17)12(19-8)18-7-3-1-6(14)2-4-7/h1-4,8-17H,5H2/t8-,9-,10+,11-,12-/m1/s1

(2R,3S,4S,5R,6S)-2-(hydroxymethyl)-6-(4-hydroxyphenoxy)oxane-3,4,5-triol

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ≥ 50 mg/mL (~183.65 mM)
H2O : ~33.33 mg/mL (~122.42 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (9.18 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (9.18 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (9.18 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 100 mg/mL (367.31 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)