A pomegranate extract (PE) from the rind containing 90% ellagic acid was tested for its skin-whitening effect. PE showed inhibitory activity against mushroom tyrosinase in vitro, and the inhibition by the extract was comparable to that of arbutin, which is a known whitening agent. PE, when administered orally, also inhibited UV-induced skin pigmentation on the back of brownish guinea pigs. The intensity of the skin-whitening effect was similar between guinea pigs fed with PE and those fed with L-ascorbic acid. PE reduced the number of DOPA-positive melanocytes in the epidermis of UV-irradiated guinea pigs, but L-ascorbic acid did not. These results suggest that the skin-whitening effect of PE was probably due to inhibition of the proliferation of melanocytes and melanin synthesis by tyrosinase in melanocytes. PE, when taken orally, may be used as an effective whitening agent for the skin.

These findings indicate that the polyphenol fraction inhibits biofilm formation and the Arg-gingipain and Lys-gingipain activities of P. gingivalis.

SummaryWe performed a double-blind, placebo-controlled trial to clinically evaluate the protective and ameliorative effects of ellagic acid-rich pomegranate extract on pigmentation in the skin after ultraviolet ray (UV) irradiation, using female subjects in their 20s to 40s. Thirteen healthy volunteers per group were randomly assigned to three groups; namely, high dose (200 mg/d ellagic acid), low dose (100 mg/d ellagic acid) and control (0 mg/d ellagic acid: placebo). Each group received the respective test foods for 4 wk. Each subject received a 1.5 MED (minimum erythema dose) of UV irradiation on an inside region of the right upper arm, based on the MED value measured on the previous day. Luminance (L), melanin and erythema values were measured before the start of the test food intake, and after 1, 2, 3 and 4 wk following the start of the test food intake. Further, questionnaires were conducted regarding the condition of the skin before the start of the test food intake and at the termination of the test food intake. As a result, decreasing rates of L values from the baseline in the low-and high-dose groups were inhibited by 1.35% and 1.73% respectively, as compared to the control group. Further, a stratified analysis using subjects with a slight sunburn revealed an inhibited decrease of L values compared with the control group at 1, 2 ( p Ͻ 0.01, respectively) and 4 wk ( p Ͻ 0.05) after the start of the test food intake in the low-dose group, and at 2 and 3 wk ( p Ͻ 0.05) in the high-dose group. Furthermore, the results of questionnaires showed ameliorating tendencies due to the test food, in some items such as "brightness of the face" and "stains and freckles." Based on the above-mentioned results, it is suggested that ellagic acid-rich pomegranate extract, ingested orally, has an inhibitory effect on a slight pigmentation in the human skin caused by UV irradiation.

Cranberry extract inhibited H. pylori proliferation and it is suggested that polyphenols are responsible for this action. The morphological analysis suggested that cranberry induces H. pylori to develop a coccoid form, thereby inhibiting its growth bacteriostatically. Further basic studies to clarify these mechanisms in combination with in vivo studies are needed.

I. MASUDA‐NISHIMURA, S. FUKUDA, A. SANO, K. KASAI and H. TATSUMI.2000.We have developed a sensitive bioluminescence assay for β‐galactosidase using a luminescent substrate, d‐luciferin‐O‐β‐galactopyranoside (LuGal). The detection limit for β‐galactosidase was 3 × 10−20 mol per assay, which was approximately 50‐fold more sensitive than the test using a fluorescent substrate. This assay was applied to a positive/absent (P/A) test for coliforms. Observations made after 7 h of culture followed by a 10‐min enzyme assay using LuGal were comparable to those made after a 22–24‐h culture by the current method. Therefore, the LuGal method allows a rapid P/A test for coliforms.