Citral / Lemonal / Geranial / Neral

Citral is an aldehyde mixture of geranial and neral. With a lemony aroma, it can be found in lemongrass, lemon scented tea tree, lemon, myrtle, verbena, Melissa, lemon basil, and lemon thyme.

• Geranial is the E isomer of citral, and also called citral a.
• Neral is the Z isomer of citral and also called citral b or beta-citral.

Citral can be a skin irritant in higher percentages, as with lemon.  It may be contraindicated with cancer, hyperplasia, and glaucoma.  Aldehydes have a powerful aroma used in perfumery.  Oxidation (exposure to oxygen) causes potential skin irritation and loss of aroma.

Links to Plants Containing Citral

Lemon

Lemon Balm (Melissa)

RESEARCH

The listings of research below represent a compilation of scientific articles found on the topic, with a very brief overview description of each article/study.  This compilation of research articles does not necessarily imply that there are adequate results to demonstrate safe and/or effective human use of any herb listed.

SAFETY

• Essential oils from C. limon, C. aurantifolia and C. limonia had a significant anti-inflammatory effect in vivo, likely related to the limonene constituent. However, C. aurantifolia, caused myelotoxicity in mice, likely related to the citral constituent. From: Amorim, J. L., Simas, D. L. R., Pinheiro, M. M. G., Moreno, D. S. A., Alviano, C. S., da Silva, A. J. R., & Fernandes, P. D. (2016). Anti-inflammatory properties and chemical characterization of the essential oils of four citrus species. PloS one, 11(4), e0153643.

HEPATOPROTECTIVE

• Ocimum basilicum demonstrated hepatoprotective action via geranial and citral constituents.  From:  Saha, S., Mukhopadhyay, M. K., Ghosh, P. D., & Nath, D. (2012). Effect of methanolic leaf extract of Ocimum basilicum L. on benzene-induced hematotoxicity in mice. Evidence-Based Complementary and Alternative Medicine, 2012.

ANTIOXIDANT

• With constituents of methylchavicol (47%), geranial (19%) and neral (15%),  Ocimum basilicum (basil) oil had radical scavenging and antioxidant activities and may be usable in treating oxidative damage and stress from certain inflammatory conditions.  From:  Kavoosi, G., & Amirghofran, Z. (2016). Chemical composition, radical scavenging and anti-oxidant capacity of Ocimum Basilicum essential oil. Journal of Essential Oil Research, 1-11.
• In lemonbalm, the most powerful scavenging compounds were neral/geranial, citronellal, isomenthone,menthone and E-caryophyllene. They had very strong inhibition of lipid peroxidation. The most effective antibacterial activity was against a multiresistant strain of Shigella sonei. A significant rate of antifungal activity was against a Trichophyton species.  From:  Mimica-Dukic, N., Bozin, B., Sokovic, M., & Simin, N. (2004). Antimicrobial and antioxidant activities of Melissa officinalis L.(Lamiaceae) essential oil. Journal of agricultural and food chemistry, 52(9), 2485-2489.

ANTIMICROBIAL / ANTIBACTERIAL / ANTIFUNGAL

• Antibacterial abilities of 96 essential oils and their constituents were assessed. Marigold, ginger, jasmine, patchouli, gardenia, cedarwood, carrot seed, celery seed, mugwort, spikenard, and orange bitter oils along with the constituents of cinnamaldehyde, estragole, carvacrol, benzaldehyde, citral, thymol, eugenol, perillaldehyde, carvone, and geranyl acetate were strongest against C. jejuni.  Those most active against E. coli were oregano, thyme, cinnamon, palmarosa, bay leaf, clove bud, lemon grass, and allspice oils and the constituents: carvacrol, cinnamaldehyde, thymol, eugenol, salicylaldehyde, geraniol, isoeugenol, citral, perillaldehyde, and estragole.  Those most active against L. monocytogenes were gardenia, cedarwood, bay leaf, clove bud, oregano, cinnamon, allspice, thyme, and patchouli and the constituents of cinnamaldehyde, eugenol, thymol, carvacrol, citral, geraniol, perillaldehyde, carvone S, estragole, and salicylaldehyde.  Those most active against S. enterica were thyme, oregano, cinnamon, clove bud, allspice, bay leaf, palmarosa, and marjoram oils as well as thymol, cinnamaldehyde, carvacrol, eugenol, salicylaldehyde, geraniol, isoeugenol, terpineol, perillaldehyde, and estragole.  From:  Friedman, M., Henika, P. R., & Mandrell, R. E. (2002). Bactericidal activities of plant essential oils and some of their isolated constituents against Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. Journal of Food Protection®, 65(10), 1545-1560.
• Cinnamaldehyde, piperidine, citral, furfuraldehyde and indole were potent candida inhibitors.  From:  Rajput, S. B., & Karuppayil, S. M. (2013). Small molecules inhibit growth, viability and ergosterol biosynthesis in Candida albicans. SpringerPlus, 2(1), 1.
• Lemongrass and the citral constituent were active against a variety of tested Candida ssp. In vitro.  From:  Silva, C. D. B. D., Guterres, S. S., Weisheimer, V., & Schapoval, E. E. (2008). Antifungal activity of the lemongrass oil and citral against Candida spp. Brazilian Journal of Infectious Diseases, 12(1), 63-66.
• Palmarosa and cinnamon oils along with their phenolic compounds of thymol and carvacrol were the most fungitoxic against Cryptococcus neoformans common in late stage AIDS patients.. Terpenoids, citral, geraniol, and citronellol also showed strong activity.  From:  Viollon, C., & Chaumont, J. P. (1994). Antifungal properties of essential oils and their main components uponCryptococcus neoformans. Mycopathologia, 128(3), 151-153.
• The essential oil of Citrus limon exhibited fungitoxicitiy against Epidermophyton floccosum, Microsporum gypseum and Trichophyton mentagrophytes with citral being the most active constituent.  From:  Misra, N., Batra, S., & Mishra, D. (1988). Fungitoxic properties of the essential oil of Citrus limon (L.) Burm. against a few dermatophytes. Mycoses, 31(7), 380-382.
• Essential oil constituents were tested against foodborne pathogens.  Carvacrol showed strong bactericidal activity against all tester strains, Citral, perillaldehyde, and citronellal were effective against V. vulnificus. Citral, geraniol, and perillaldehyde were effective against E. coli, and S. typhimurium.  From:  Kim, J., Marshall, M. R., & Wei, C. I. (1995). Antibacterial activity of some essential oil components against five foodborne pathogens. Journal of agricultural and food chemistry, 43(11), 2839-2845.
• The following essential oils and their constituents in order of effectiveness were active against pathogens in apple juice:  against E. coli: carvacrol, oregano oil, geraniol, eugenol, cinnamon leaf oil, citral, clove bud oil, lemongrass oil, cinnamon bark oil, and lemon oil, and against S. enterica:  melissa oil, carvacrol, oregano oil, terpeineol, geraniol, lemon oil, citral, lemongrass oil, cinnamon leaf oil, and linalool. From:  Friedman, M., Henika, P. R., Levin, C. E., & Mandrell, R. E. (2004). Antibacterial activities of plant essential oils and their components against Escherichia coli O157: H7 and Salmonella enterica in apple juice. Journal of agricultural and food chemistry, 52(19), 6042-6048
• Cineole, citral, geraniol, linalool and menthol were tested against a variety of bacteria and fungi, showing a range of antimicrobial activity.  From:  Pattnaik, S., Subramanyam, V. R., Bapaji, M., & Kole, C. R. (1996). Antibacterial and antifungal activity of aromatic constituents of essential oils. Microbios, 89(358), 39-46.

SEDATIVE

• Citral, limonene and myrcene showed sedative and motor relaxant effects.  From:  do Vale, T. G., Furtado, E. C., Santos, J. G., & Viana, G. S. B. (2002). Central effects of citral, myrcene and limonene, constituents of essential oil chemotypes from Lippia alba (Mill.) NE Brown. Phytomedicine, 9(8), 709-714.   4

ANXIOLYTIC

• Ingesting lemon essential oil containing components such as limonene and citral reduces both physical and psychological stress.  From:  Fukumoto, S., Morishita, A., Furutachi, K., Terashima, T., Nakayama, T., & Yokogoshi, H. (2008). Effect of flavour components in lemon essential oil on physical or psychological stress. Stress and Health, 24(1), 3-12.

DIGESTIVE AID

• Lemongrass decoctions had an anti-diarrhoeal effect in mice using three different experimental methods.  From:  Tangpu, V., & Yadav, A. K. (2006). Antidiarrhoeal activity of Cymbopogon citratus and its main constituent, citral. Pharmacologyonline, 2, 290-298.

INSECTICIDE

• Lemongrass essential oil and its constituent citral was effective against T. cruzi trypomastigotes and amastigotes.  From:  Santoro, G. F., Cardoso, M. G., Guimarães, L. G. L., Freire, J. M., & Soares, M. J. (2007). Anti-proliferative effect of the essential oil of Cymbopogon citratus (DC) Stapf (lemongrass) on intracellular amastigotes, bloodstream trypomastigotes and culture epimastigotes of Trypanosoma cruzi (Protozoa: Kinetoplastida). Parasitology, 134(11), 1649-1656.

ANTI-CANCER / ANTI-TUMOR

• Citrus oils of sweet orange, grapefruit, and lemon induced apoptosis of human leukemia cancer tumor cells and limonene, decanal, octanal and citral showed strong apoptotic activity.  From:  Hata, T., Sakaguchi, I., Mori, M., Ikeda, N., Kato, Y., Minamino, M., & Watabe, K. (2002). Induction of apoptosis by Citrus paradisi essential oil in human leukemic (HL-60) cells. In vivo (Athens, Greece), 17(6), 553-559
• Lemongrass essential oil ssp. And the key constituent of citral demonstrated cytotoxic action against prostate cancer and glioblastoma tumor cells in vitro.  From:  Bayala, B., Bassole, I. H., Maqdasy, S., Baron, S., Simpore, J., & Lobaccaro, J. M. A. (2018). Cymbopogon citratus and Cymbopogon giganteus essential oils have cytotoxic effects on tumor cell cultures. Identification of citral as a new putative anti-proliferative molecule. Biochimie, 153, 162-170.

ANALGESIC

• Essential oil constituents with an analgesic activity are reviewed. Included are p-cymene, carvacrol, linalool, eugenol, menthol, alpha-bisabolol, cinnamaldehyde, citronellal, citronellol, citronellyl acetate, alpha-phelandrene, alpha-terpeneol, vanillin, borneol, myrtenol, pulegone, citral, thymol, limonene, nerol, anethole, nerolidol, carvone, farnesol, and beta-caryphyllene. From: Lima, T., da Nóbrega, F., de Brito, A., & de Sousa, D. (2017). Analgesic-like activity of essential oil constituents: an update. International journal of molecular sciences, 18(12), 2392.

Compiled by: Kathy Sadowski

Updated: 9/13/19