JOURNAL OF COSMETIC SCIENCE 282 by UV-Vis spectroscopy (Varian Cary 100 UV-visible spectrophotometer), fl uorescence spectroscopy (RF-5301PC Shimadzu spectrofl uorophotometer), and particle size analysis (Mastersizer X and Hitachi S3000 scanning electron microscope). CHARACTERIZATION OF WILD PLUM Particle size Analysis. The particle size was measured with a Hitachi S3000 scanning elec- tron microscope and a Mastersizer X from Malvern Instruments in order to determine if Wild Plum has appropriate granularity for cosmetic applications. UV-Vis. Visible spectroscopy was performed to determine the absorbance profi le of Wild Plum. A 4.78 × 10−8 M solution of Wild Plum in DMSO was prepared. The sample was placed in a quartz cuvette and measured using a Varian Cary 100 UV-visible spectro- photometer. Fluorescence. A 4.78 × 10−9 M solution of Wild Plum in DMSO was prepared for solution fl uorescence in order to determine if blue fl uorescence emission was achieved in medium- to-high intensity. For solid-state fl uorescence, Wild Plum was mixed with talcum pow- der and placed in a 1-mm quartz cuvette. The cuvette was placed into the sample holder at a 45° angle to the incident beam. The sample was measured using a Shimadzu RF- 5301PC spectrofl uorophotometer (λex = 364 nm). Quantum yield. The quantum yield of Wild Plum was measured by the protocol of Jobin Yvon (Horiba), using 9,10-diphenylanthracene and quinine sulfate as quantum yield standards (20). IN VIVO TESTING OF WILD PLUM The female model was photographed with a Panasonic DMC-TC1 digital camera under fl uorescent offi ce light without makeup, with makeup, and with makeup that was formu- lated with Wild Plum. L*, a*, and b* values were determined using Adobe Photoshop CS2. This procedure was performed 15 times for each photo, each time selecting color from a different place on the picture and then averaging. Sampling regions were matched between different images. EXPERIMENTAL RESULTS WILD PLUM FLUORESCENCE Absorption of light energy excites molecules in these colored materials to their excited states. Fluorescence has occurred when relaxation of these excited states takes place via radiative decay, resulting in emission of light at a longer wavelength than that of the absorbed light. Unlike many other optical brighteners that are active only to ultraviolet light, Wild Plum particles are optically active to visible light and alter the perceived appearance of the skin by emitting favorable light. As seen in Figure 2, this report dem- onstrates that Wild Plum has a photoluminescence of blue light, with the emission centered between 400 nm and 500 nm (λmax = 450 nm). Wild Plum has a fl uorescence quantum yield

WILD PLUM IN COSMETIC FORMULATIONS 283 of 0.29 ± 0.03, allowing for suffi cient fl uorescence to produce the desired effect without blinding the observer with blue light (data not shown). Wild Plum emits a blue glow similar to the measured blue fl uorescence of non-sun-damaged skin (Figure 1), suggest- ing that Wild Plum has the ability to mimic natural, healthy skin. To the observer, this effect provides an unusual radiance to the skin. IN VIVO RESULTS The effi cacy of Wild Plum was determined quantitatively by skin color data obtained from the CIELAB color space (21). Color coordinates a∗, b∗, and L∗ are considered to cor- relate with color changes preceived by the human eye. An increase in the L∗ coordinate indicates lightening and a decrease indicates darkening of the skin surface. Table I shows that L∗ increases when Wild Plum is added to a commercial foundation. When the a∗ and b∗ coordinates increase, reddening and yellowing increase, respectively. Compared to skin without makeup, the addition of Wild Plum to a commercial foundation shows a decrease in red and yellow but an increase in lightness as preceived by the digital camera. Overall, the data demonstrate that luminosity increases while reddening decreases. In vivo data show that Wild Plum quantifi ed the wrinkle condition as we employed a ten-point monadic scale, with one [1] representing the fewest, least prominent fi ne lines and wrinkles and ten [10] showing the maximum number of deep fi ne lines and wrinkles. Figure 2. (Left) UV-Vis spectrum of Wild Plum at 0.02% in DMSO. (Right) Fluorescence emission spec- trum of Wild Plum at 2.0% and 0.02% in talcum powder (λex = 390 nm λem = 450 nm). Table I Skin Color Data Obtained from Adobe Photoshop CS2 No makeup Makeup Makeup with Wild Plum L* 67.4 66.5 75.8 a* 16.3 19.2 15.2 b* 20.5 26.5 25.2 L* Coordinate a* Coordinate b* Coordinate Increase Lightening Red Yellow Decrease Darkening Green Blue