Abstract
Because axillary odors are generated by specific bacteria (axillary odorous bacteria), existing deodorant agents contain antimicrobial agents. These antimicrobials inhibit the growth of a wide range of skin bacteria, including skin resident bacteria. Axillary odorous bacteria may acquire resistance to antimicrobial agents. Additionally, these antimicrobial agents may not inhibit the growth of unknown axillary odorous bacteria. Thus, new deodorant materials with effective antimicrobial activity are needed. We aimed to isolate new axillary odorous bacteria and explore new materials capable of inhibiting the production of 3-hydroxy-3-methyl-hexanoic acid (HMHA), which is one of the main contributors of axillary odor. We isolated two bacteria, Anaerococcus sp. and Corynebacterium genitalium. We also found that pentagalloylglucose (PGG), extracted and purified from the Chinese Gall plant, inhibited the release of HMHA by both bacteria. An open study was conducted to evaluate the deodorant effects of PGG on the axillary odor and to analyze the HMHA content in the axillary odor gas, which was collected with a newly developed axillary odor-sampling device. The results of the visual analog scale analyses indicate that the PGG solution reduced axillary odors in vivo. However, the HMHA concentration measured by gas chromatography-mass spectrometry (GC/MS) did not significantly decrease after the application of PGG under the present conditions. With respect to the effects of PGG on skin microbiota, PGG application significantly reduced axillary odorous bacteria and caused minimal changes to other axillary microbiota. These results strongly indicate that PGG is a potentially innovative deodorant material that significantly affects odorant bacteria among axillary microbiota.
