Lemongrass (Cymbopogon flexuosus). Out of the 50+ varieties of lemongrass, Cymbopogon flexuosus is 1 of the 2 categorized by the US FDA as safe for human consumption, including its distillates, essential oil and hydrosol. See the list here.

Lemongrass : pertinent studies

No resistance formation & antimutagenic

(Details at the bottom) Lemongrass and Citronella's mode of action is via antioxidant, destroys the protein that holds microbes' wall together.

Since the nucleus was never attacked, it has no record of what destroyed it. And since it is left exposed in the environment it would easily decay.

Resistance becomes virtually impossible simply because that are far too many antioxidants and monoterpenes to adapt with, while ATP's (cell/virus energy) depeleting too fast due to a destroyed or leaking wall.

 

Our Lemongrass Oil Extract Constituents

And our list of antioxidants and monoterpenes is long, 77 to 85% citral (3,7-dimethyl-2,6-octadien-1-al), with test results that slightly vary from time to time due to differences in the amount of rain, sunlight and soil nutrients:

1,8-cineole
alpha-terpineole
beta-myrcene (MYR, 7-methyl-3-methylene-1,6 octadiene)
borneol
carene-2
citronellal
(+)-cymbodiacetal
estragole
farnesol
geraniol (some species higher in this compound than citral)
geranyl acetate (3,7-dimethyl-2,6-octadiene-1-ol acetate)
limonene
methyleugenol
myrcene
pinene
piperitone
proximadiol
z-citral

 

Synergism with antimicrobial drugs .. longer version

and No resistance formation

There are countless studies showing that in comparison to other essential oils, lemongrass and citronella exhibited the most effective antimicrobial, anti-biofilm and anti-fungal activity. Let us highlight their synergism, anti-mutagenic and anti-resistance-formation properties of both oils.

In the words of the studies themselves, " According to the laboratory tests made by Betoni, Mantovani, Barbosa, Di Stasi, and Fernandes published with Memorias do Instituto Oswaldo Cruz in 2006, "clove, guava, and lemongrass presented the highest synergism rate with antimicrobial drugs."

"..lemongrass oil presented the highest synergism rate with antimicrobial drugs (penicillin, oxacillin, vancomycin, ampicillin, chloramphenicol, gentamicin, netilmicin, tetracycline, erythromycin, cotrimoxazole, and ofloxacin) against Staphylococcus aureus." (Betoni, 2006)

Antimutagen, a substance that reduces or interferes with the mutagenic effects of another substance.

"Constituents of lemongrass have been tested on their antimutagenic effects against cyclophosphamide, mitomycin-C, and nickel chloride. In one study with mice, citral prevented the nuclear damage induced by cyclophosphamide, mitomycin-C, and nickel chloride."

"In fact, studies done by Ohno, Kita, etal, from the Third Department of Internal Medicine, show that lemongrass are effective against microbes (i.e. H. pylori, ulcer-causing bacteria) without developing resistance!"

"Constituents of lemongrass have been tested on their antimutagenic effects against cyclophosphamide, mitomycin-C, and nickel chloride. In one study with mice, citral prevented the nuclear damage induced by cyclophosphamide, mitomycin-C, and nickel chloride."

"Citral exhibited anti-mutagenic effect against the three tested clastogens. A significant (p< 0.01) prevention of MN level was observed in CP, MMC and NiCl2 administered groups. Anova analysis showed highly significant (p< 0.001) group difference at 72 h (F=107.23 for PCEs and F=203.38 for NCEs) ".

Sources

Kauderer, B., Zamith, H., Paumgartten, F. J., and Speit, G. Evaluation of the mutagenicity of beta-myrcene in mammalian cells in vitro. Environ Mol Mutagen 1991;18(1):28-34.

Rabbani, S. I., Devi, K., and Zahra, N. Anti-clastogenic effects of citral. Iranian Journal of Pharmacology and Therapuetics 2005;4:28-31 or PDF is available for download here.)

Ohno T, Kita M, Yamaoka Y, Imamura S, Yamamoto T, Mitsufuji S, Kodama T, Kashima K, Imanishi J., Antimicrobial activity of essential oils against Helicobacter pylori, Helicobacter. 2003 Jun;8(3):207-15.