].Cosmet. Sci.J 58, 35-44 Qanuary/February 2007)
High-performance liquid chromatographic determination of
arbutin in skin-whitening creams and medicinal
plant extracts
WISANU THONGCHAI, BOONSOM LIAWRUANGRATH,
and SAISUNEE LIAWRUANGRATH, Department of
Pharmaceutical Sciences, Faculty of Pharmacy (W. T., B.L.), and
Department of Chemistry, Faculty of Science (S.L.), Chiang Mai
University, Chiang Mai, 50200, Thailand.
Accepted for publication November 1, 2006.
Synopsis
A high-performance liquid chromatographic method was developed for quantitative analysis of arbutin. The
arbutin was separated on an ODS Hypersil® C
18 column with a mobile phase of water:methanol:0.1 M
hydrochloric acid (89: 10: l, v/v/v). The level of arbutin was measured by means of UV detection at 222 nm.
The optimum conditions for arbutin quantitative analysis were investigated. The calibration curve was
found to be linear up to 1,000 �1g/ml- 1 of arbutin concentration, and the working calibration curve for
arbutin determination over the range 0.5-30.0 µg/ml-1 of arbutin (r2 =0.9999) was established. The
relative standard deviations for intraday and interday were found to be 0.98% and 1.15%, respectively. A
detection limit (3CT) and quantitation limit (lOCT) of 0.02 µg/ml- 1 and 0.2 µg/ml- 1
,respectively, and a mean
percentage recovery of the spiked arbutin of99.88 ± 1.12% were obtained. The proposed method has been
applied to the determination of arbutin in commercial skin-whitening creams (Arbuwhite® cream, Super
Whitening® cream, and Shiseido® cream) with average contents of 7.60, 5.30, and 57.90 mg/g-1, respec-
tively. It was also applied to the determination of arbutin in medicinal plant extracts from Betula alnoides
Buch. Ham., Clerodendrum petasites S. Moore, Curculigo latifolia Dryand. Var. latifolia, and HeJperethusa
crenulata (Roxb.) Roem, levels of which were found to be 3.50, 1.50, 1.10, and 0.12 µg/g- 1
,respectively (no
article reported in the literature about arbutin analysis). The proposed HPLC method is rapid, simple, and
selective for routine analysis.
INTRODUCTION
Skin-whitening products have become increasingly in demand in the past few years. The
main purpose for skin-lightening products is to lighten the skin as well as to even out
skin tone or to treat pigmentation disorders such as freckles, melasma, pregnancy marks,
and age spots (1). The most successful recent and natural skin-whitening agents are
arbutin, vitamin C, kojic acid, licorice extract, burner root extract, scutellaria extract,
Address all correspondence to Boonsom Liawruangrath.
35

36 JOURNAL OF COSMETIC SCIENCE
and mulberry. These agents are all tyrosinase inhibitors, which inactivate tyrosinase (the
enzyme responsible for skin pigmentation) by chelating with its vital copper ion and
suppressing tautomerization from dopachrome to DHICA. Normal skin color is formed
by melanin, a natural pigment that also determines hair and eye color. In the skin, the
enzyme tyrosinase biochemically converts the amino acid tyrosine into melanin. Hyper-
pigmentation occurs when too much melanin is produced and forms deposits in the skin.
Hyperpigmentation is not a medically harmful condition. However, it is always advis-
able to have new brown spots checked by a dermatologist to make sure they are not skin
cancers (2). Arbutin is a naturally occurring glycoside of hydroquinone (Figure 1).
Arbutin is found in the bark and leaves of various plants, usually occurring together with
methylarbutin. Naturally occurring arbutin was first characterized by Kawalier (3), who
obtained it from bearberry leaves. It is also found in the leaves of blueberry, cranberry,
and pear. Synthetic arbutin was first reported by Mannich (4), and later by others.
Commercial arbutin is almost always synthetic in origin. Because of its antibacterial
properties, arbutin is a constituent of the traditional medicine uva ursiJ and it is widely
used in a variety of formulations (5). The ability of arbutin to inhibit human melanin
synthesis has given rise to its wide use in many cosmetic formulations (6). Arbutin
protects the skin against damage caused by free radicals. It is a skin-whitening agent that
is very popular in Japan and Asian countries for skin depigmentation. Arbutin inhibits
the formation of melanin pigment by inhibiting tyrosinase activity (7). Back in the 18th
century arbutin was first used in medical areas as an anti-inflammatory and antibacterial
agent. It was used particularly for cystitis, urethritis, and pyelitis. These uses have been
applied until today, when natural medicine uses only natural ingredients to treat any
disease. It may be used to repress the virulence of bacterial pathogens and to repress
contaminating bacteria. It is also used for treating allergic inflammation of the skin. It
can be used to whiten the skin, to prevent liver spots and freckles, to treat sunburn
marks, and to regulate melanogenesis (8).
Arbutin is a very safe skin-whitening agent for external use, which does not have
toxicity, a stimulating effect, an unpleasant odor, or side effects such as hydroquinone
(Figure la). Hydrophilic arbutin can be incorporated in lipophilic media by encapsu-
lation. Arbutin has three main properties: a whitening effect, an anti-aging effect, and
a UVB/UVC filter (9). Arbutin is determined by many methods: the spectrophotometric
method (10-12), capillary zone electrophoresis (13 ),and thin-layer chromatography-
densitometry (14). The proposed HPLC method for determining arbutin in skin-
whitening cosmetic products and some medicinal plants is more sensitive, precise, and
less time-consuming than the previous HPLC methods described in the literature (15-
OH
Hydroquinone
(a)
Arbutin
(b)
Figure 1. Chemical structures of hydroquinone (a) and arbutin (b).