Deodorant effects of a supercritical hops extract: antibacterial activity against Corynebacterium xerosis and Staphylococcus epidermidis and efficacy testing of a hops/zinc ricinoleate stick in humans through the sensory evaluation of axillary deodorancy
Article first published online: 1 SEP 2009
© 2009 Wiley Periodicals, Inc.
Journal of Cosmetic Dermatology
Volume 8, Issue 3, pages 197–204, September 2009
How to Cite
Dumas, E. R., Michaud, A. E., Bergeron, C., Lafrance, J. L., Mortillo, S. and Gafner, S. (2009), Deodorant effects of a supercritical hops extract: antibacterial activity against Corynebacterium xerosis and Staphylococcus epidermidis and efficacy testing of a hops/zinc ricinoleate stick in humans through the sensory evaluation of axillary deodorancy. Journal of Cosmetic Dermatology, 8: 197–204. doi: 10.1111/j.1473-2165.2009.00449.x
- Issue published online: 1 SEP 2009
- Article first published online: 1 SEP 2009
- Accepted for publication June 7, 2009
- sensory evaluation panel;
- hops extract;
- zinc ricinoleate
Background There is little scientific evidence to support the efficacy of natural deodorants and therefore, such products may be perceived as inefficacious. The evaluation of the in vitro antibacterial activity of a hop extract and the evaluation of the odor-reducing capacity of a hops/zinc ricinoleate-containing product by a sensory evaluation panel is employed to verify deodorant performance.
Aims The goal of this study was to evaluate the in vitro antibacterial activity of a hop extract against Corynebacterium xerosis and Staphylococcus epidermidis and to verify in vivo deodorant performance of a hops/zinc ricinoleate-containing product.
Methods The hops extract was evaluated on a culture of an armpit swab from six volunteers. Furthermore, the extract was submitted to a zone of inhibition test and an agar-dilution assay against two major odor-causing bacteria. The clinical evaluation of the finished product was carried out according to a standard method for substantiating deodorant efficacy using trained odor judges for the assessment of axillary malodor (ASTM method E 1207-87 Standard Practice for the Sensory Evaluation of Axillary Deodorancy).
Results The supercritical hops extract showed good antibacterial activities in all three tests. Minimum inhibitory concentration values of 6.25 and 25 μg/mL against C. xerosis and S. aureus, respectively, were obtained in the agar-dilution assay. In the clinical underarm odor-reduction evaluation, the mean malodor score dropped from 6.28 (±0.70) to 1.80 (±0.71) after 8 h of application. There was still a noticeable effect at both 12 and 24 h after the application, with a score of 1.82 (±0.74) and 2.24 (±0.77), respectively.
Conclusion The hops extract has good in vitro antibacterial properties and, in combination with zinc ricinoleate in an appropriate base, delivers in vivo odor reduction. The clinical efficacy is likely due to a combination of the base ingredients and the antibacterial actives.