Monday, February 6, 2012
Essential oils: Lemongrass - the science
This study (1) concluded that "...limited exposure of yeasts to lemongrass oil at subcidal concentration can suppress growth for more than 24h. Altogether, the results obtained indicate that lemongrass oil possessed antifungal and antibiofilm activities and could modulate candidal colonization. Therefore, the efficacy of lemongrass oil merits further development of this agent for the therapy of oral candidiasis."
This study (1a) "...evaluated the antifungal activity of lemongrass oil against Malassezia furfur, an opportunistic yeast associated with dandruff...Two percent lemongrass oil shampoo provided the required qualities necessary for commercial use." Interesting!
This study concluded that "Lemongrass oil could be used to manage aflatoxin formation and fungal growth of A. flavus in stored rice."
And this study (1b) "evaluated the antifungal activity of lemongrass oil and citral against yeasts of Candida species (Candida albicans, C. glabrata, C. krusei, C. parapsilosis and C. tropicalis). This study showed that lemongrass oil and citral have a potent in vitro activity against Candida spp."
This study (2) noted that "The tested organisms, particularly gram-negative organisms had shown high resistance towards different antibiotics whereas they were found to be inhibited by lemongrass oil even at lower concentration. Thus lemongrass oil is effective against drug resistant organisms. It can be suggested that use of lemongrass oil would be helpful in the treatment of infections caused by multidrug resistant organisms."
Click here for a really detailed PDF on antimicrobial activity of lemongrass. Quick summary: "The EOs were tested against nine bacteria by using disc diffusion and microdilution methods. C. giganteus EO showed antimicrobial effects against all microorganisms tested whereas C. citratus EO failed to inhibit Pseudomonas aeruginosa. The antimicrobial activity of combinations of the two EOs was quantified by the checkerboard method. Combinations of the two EOs exerted synergistic, additive and indifferent antimicrobial effects. Results of the present investigation provide evidence that the combinations of plant EOs could be assessed for synergistic activity in order to reduce their minimum effective dose."
The anti-oxidant properties of lemongrass in a mouthwash was reviewed in this study (3). "A total of 40 subjects were included in this study. Subjects were divided into 4 groups i.e. 3 test groups and one control group...The lemongrass oil mouthwash was found to have anti oxidant activity at all the three concentrations levels."
Here's the thing...we know that being able to kill yeast or bacteria in a petri dish isn't the same as killing them in our products. But the work on lemongrass in products - mouthwash and shampoo - is very interesting. I don't think it's a good idea to use lemongrass as the preservative in a product as we really can't extrapolate this information to conclude that we can throw our preservatives out and use lemongrass essential oil - but we could use it as an active ingredient in our products. We won't be making claims here, but it sounds like it could be a good inclusion in a shampoo for dandruff!
I don't know how to make a mouthwash because I can't confirm that any of the preservatives we have are edible. I have seen references to a few of them being edible, but I'm not taking any chances there! What if you eat them and get sick? Fine lawsuits abound!
Join me for a bit more science tomorrow, and then we're on to applications!
Why we can't use essential oils as preservatives.
When should you use a preservative?
Chemistry of essential oils: Terpenes
(1) S. Taweechaisupapong (a, b., P. Ngaonee, (., P. Patsuk, (., W. Pitiphat, (., & W. Khunkitti, (. (n.d). Antibiofilm activity and post antifungal effect of lemongrass oil on clinical Candida dubliniensis isolate. South African Journal Of Botany
(1a) Wuthi-udomlert, M., Chotipatoomwan, P., Panyadee, S., & Gritsanapan, W. (n.d). INHIBITORY EFFECT OF FORMULATED LEMONGRASS SHAMPOO ON MALASSEZIA FURFUR: A YEAST ASSOCIATED WITH DANDRUFF. Southeast Asian Journal Of Tropical Medicine And Public Health, 42(2), 363-369.
(1b) da Silva, C., Guterres, S., Weisheimer, V., & Schapoval, E. (n.d). Antifungal activity of the lemongrass oil and citral against Candida spp. Brazilian Journal Of Infectious Diseases, 12(1), 63-66.
(2) Mohd Irfan Naik, (., Bashir Ahmad Fomda (b, *., Ebenezar Jaykumar, (., & Javid Ahmad Bhat, (. (2010). Document heading: Antibacterial activity of lemongrass (Cymbopogon citratus) oil against some selected pathogenic bacterias. Asian Pacific Journal Of Tropical Medicine, 3535-538
(3) Anand, K., Goyal, R., Bhat, G., Kamath, S., Aggarwal, M., Bhandarkar, M. A., & ... Sukreeth, S. (2011). ANTIOXIDANT PROPERTY OF A NOVEL LEMONGRASS OIL MOUTH WASH: AN EXPERIMENTAL STUDY. Recent Research In Science & Technology, 3(10), 14.