Lemongrass and Perilla Essential Oils Synergistically Increased Antimicrobial Activity.

We postulated that disinfection of viable Trichophyton species in shoes would help reduce the number of patients with tinea pedis in Japan and that this might be accomplished safely using volatile components of essential oils. As vapor of lemongrass (Cymbopogon citratus) oil and citral have strong antimicrobial activities against Trichophyton, we examined the conditions under which lemongrass oil or citral show optimal antimicrobial activity in shoes. First, we investigated whether or not a strong antimicrobial effect could be obtained by combining with terpene aldehydes or aromatic aldehydes. When combined with citral, perillaldehyde showed superior antimicrobial activity to citronellal, cinnamaldehyde, cuminaldehyde, hydroxycitronellal, and vanillin. The combined effects of citral and perillaldehyde against Trichophyton mentagrophytes, Bacillus subtilis, and Candida albicans as volatile components dotted on filter paper placed away from the petri dish inoculated with fungi or bacteria were examined. Citral (2.5 mg/mL) and perillaldehyde (2.5 mg/mL) showed a greater inhibitory effect on growth of C. albicans than either solution alone in the aromatogram (disc diffusion) descent method (fractional inhibitory concentration [FIC] index of 0.58). Citral (2.5 mg/mL) and perillaldehyde (1.25 mg/mL) vapors in a closed box synergistically inhibited growth of B. subtilis and T. mentagrophytes (FIC indexes of 0.5 and 0.38, respectively). These results suggested that this combination would be safe and useful for disinfection of shoes.

[Anti-Candida activity of aroma candy and its protective activity against murine oral candidiasis].

A daily eatable candy that has possible protective activity against oral candidiasis was experimentally produced. The candy was made from reduced-maltose as main constituent and from several natural products, such as oligonol (depolymerized polyphenols derived from lychee), cinnamon (cassia), citral, and capric acid, which are known to have anti-Candida activity in vitro and in vivo. The candy effectively inhibited the mycelial growth of C. albicans, even when it was diluted 1,000 times with culture media. We assessed the protective activity of the candy against murine candidiasis. When 50µl of candy dissolved and diluted 4 times with water was administered 3 times into the oral cavity of Candida infected mice, the score of lesions on the Candida-infected tongues improved on day 2. These findings suggest that this candy has potential as food that provides protective activity against oral candidiasis.

[The effects of an aroma candy on oral Candida albicans colony-forming units (CFU) and oral hygiene states in healthy elderly carrying Candida albicans].

In a preceding paper, we showed that aroma candy containing oligonol, capric acid, and cinnamon (cassia) powder had potent inhibitory activity against mycelial growth of Candida albicans in vitro and protective activity against murine oral candidiasis. In order to assess the effects of this candy (the test candy) on oral C. albicans colony-forming units (CFU) and oral hygiene states, a placebo-controlled double-blind crossover comparative study was performed. Twenty subjects were divided into two groups. One group ingested the test candy in the first 7 days followed by 2 weeks washing-off period, then ingested the placebo candy (control candy) for 7 days. The other group was vice versa. C. albicans CFU in all oral rinse samples from the subjects before and after 7 days ingestion of candy was measured. The degree of oral malodor in all subjects was monitored using a portable measuring instrument. The results showed no statistically significant difference between test-candy group and placebo group for C. albicans CFU. However, C. albicans CFU in test-candy group with>4,000 CFUs was significantly decreased after 7 days ingestion of test-candy (p<0.05). Scores of oral malodor in the test-candy group was significantly decreased after 7 days ingestion of test-candy (p<0.05). A questionnaire survey of oral hygiene states indicated that in the test-candy group, oral malodor, glutinous feeling, and refreshing feeling significantly improved in comparison with control-candy group (p<0.05). Our study suggests that the aroma candy is effective in oral health care of elderly carrying C. albicans.