Diallyl disulfide (DADS) and allyl methyl sulfide (AMS) have been known as a metabolic product of sulfur-containing foods, typically garlic. The odour of such organosulfur compounds following garlic ingestion is often considered as an unpleasant element. Although previous studies have identified the DADS and AMS associated with garlic breath, no study has been reported on the determination of both compounds emanating from human skin surface. This study aimed to demonstrate the effect of garlic ingestion on the dermal emissions of DADS and AMS using a passive flux sampler coupled with gas chromatography-mass spectrometry. Firstly, baseline levels were investigated for 30 healthy volunteers in their daily life. The results of 1 h-sampling at the forearm showed the emission fluxes of both compounds followed the lognormal distribution with a geometric mean of 0.18 ng cm−2 h−1 for DADS and 0.22 ng cm−2 h−1 for AMS. Subsequently, the garlic ingestion tests were conducted for selected volunteers. The emission flux of DADS increased just after grilled garlic ingestion and decreased gradually thereafter. In contrast, the dermal emission flux of AMS reached a peak at 30 min after ingestion, and then gradually decreased. This peak shift suggests AMS is relatively latent in the skin organs.

Most of the wood bark produced by the forestry production is discarded in spite of containing many kinds of the phytochemical ingredients. The aim of the present study was to identify secondary metabolites from the bark of Larix kaempferi generated as waste material and evaluate their potential as cosmetic agents. Eighteen compounds, including a novel phenanthrene, 4,6,7-trihydroxyphenanthrene-2-O-β-D-glucopyranoside (16), were isolated from the bark of L. kaempferi and identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and nuclear magnetic resonance (NMR). In addition, the tyrosinase inhibitory activity of these compounds was evaluated. Procyanidin B7 (18) exhibited the most potent inhibition with IC50 values of 31.0 μM and 61.8 μM when using L-tyrosine and L-dopa as the substrate, respectively, which were similar to those of the positive control, kojic acid. Interestingly, quercetin-3-O-α-L-rhamnopyranoside (10) was shown to possess the tyrosinase inhibition although the other series of 3-glycoylated flavonols were not active, suggesting that the rhamnosyl group at C-3 and the hydroxyl group at C-3ʹ played an indispensable role in the anti-tyrosinase activity. These findings indicate that a number of constituents from L. kaempferi bark may have potential as additives in cosmetics.

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In this study, three new garcinoic acid dimers, δ,δbigarcinoic acid (1), δ,δ-bi-O-garcinoic acid (2), and γ,δ-bi-Ogarcinoic acid (3), and a new benzophenone derivative, (8E)-4geranyl-3,5-dihydroxybenzophenone (4), as well as seven known compounds (5−11) were isolated from the seeds of Garcinia kola. The structures of the new compounds were elucidated using MALDI-TOF-MS and spectroscopic data, including 1D and 2D NMR and electronic circular dichroism spectra. All of the isolated compounds were evaluated for their antimicrobial activity against two oral pathogens, Porphyromonas gingivalis and Streptococcus sobrinus. Among them, 4 and δ-garcinoic acid (6) exhibited antimicrobial activity against both of these microorganisms (MICs of 31.3−62.5 μM for P. gingivalis and 15.6−31.3 μM for S. sobrinus). These results indicate that some chemical constituents in G. kola seeds have potential application in the prevention of oral diseases.

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