Geraniol

Geraniol is acyclic monoterpene-alcohol. Pure geraniol is a colourless oily liquid, with a sweet rose-like scent. When oxidized, geraniol becomes geranial or citral.

Geraniol is mainly used in perfumery and flavoring.

Synonyms

Lemonol, beta-Geraniol, trans-3,7-Dimethyl-2,6-octadien-1-ol

Distribution

Bergamot, carrot, coriander, lavender, lemon, lime, nutmeg, orange, rose, blueberry and blackberry.

Health Benefits of Geraniol

Geraniol is a natural antioxidant. Geraniol has been suggested to help prevent cancer. Carnesecchi S. et al demonstrated in his study "Geraniol, a component of Plant Essential Oils, Inhibits Grwoth and Polyamine Biosyntehsis in Human Colon Cancer Cells", (Pharmacology, July 2001) that geraniol caused a 50% increase of ornithine decarboxylase activity, which enhances during cancer growth. Geraniol inhibits DNA synthesis.

Burk YD concluded in his study "Inhibition of Pancreatic Cancer Growth by the dietary isoprenoids farnesol and geraniol" that geraniol, farnesol and perilll alcohol suppress pancreatic tumor growth.

Other animal studies have also demonstrated the anticancer effects of geraniol.

PDF summary: One Hundred Faces of Geraniol

This 2020 review examines geraniol, a naturally occurring monoterpene alcohol with a sweet, rose-like aroma, focusing on its sources, metabolism, biological effects, and potential therapeutic applications.

Key points

• Natural occurrence and uses
  • Geraniol occurs in more than 250 essential oils, including those from rose, palmarosa, citronella, geranium, basil, thyme, and lemongrass.
  • It is widely used as a fragrance and flavor ingredient in cosmetics, detergents, household products, and perfumes.
  • It is also being produced through engineered microorganisms such as E. coli and yeast.

• Pharmacokinetics and metabolism
  • Geraniol is readily absorbed through the intestinal barrier and can cross the blood–brain barrier.
  • It is rapidly cleared from the bloodstream, with a reported intravenous half-life of about 12 minutes in experimental studies.
  • Enzymes in the cytochrome P450 system metabolize geraniol, particularly CYP1A1, CYP3A5, and CYP2B6.
  • Because geraniol can inhibit CYP2B6, it may affect the metabolism of drugs such as bupropion, cyclophosphamide, efavirenz, tamoxifen, and others. This raises the possibility of drug interactions.

• Antimicrobial activity
  • Geraniol disrupts microbial cell membranes, increases membrane permeability, and may interfere with intracellular targets.
  • It has antibacterial activity against organisms including E. coli, Salmonella, Listeria, Staphylococcus, Helicobacter pylori, and Mycobacterium tuberculosis.
  • It also inhibits fungi such as Candida albicans and Saccharomyces cerevisiae, affecting ergosterol levels, mitochondrial function, ATPase activity, and cell-wall processes.
  • Encapsulation in nanoparticles or nanoemulsions improves its stability, dispersibility, and effectiveness in food preservation, on produce, and in deodorant formulations.
  • Geraniol sometimes acts synergistically with antibiotics, although the effect depends on the microorganism and drug combination.

• Anticancer potential
  • Cell and animal studies suggest activity against lung, colorectal, liver, pancreatic, skin, oral, prostate, kidney, and melanoma cancers.
  • Proposed mechanisms include:
    • Induction of apoptosis
    • Cell-cycle arrest
    • Generation of oxidative stress in cancer cells
    • Inhibition of the mevalonate/cholesterol pathway
    • Suppression of Ras, AKT, ERK, VEGF, and other signaling pathways
    • Inhibition of angiogenesis and tumor-cell migration
    • Modulation of inflammatory and antioxidant pathways
  • Geraniol enhanced the effects of some anticancer drugs, including 5-fluorouracil, gemcitabine, docetaxel, and simvastatin in experimental models.

• Other biological effects
  • The review reports antioxidant and anti-inflammatory activity.
  • Geraniol showed protective effects in experimental models of gastric ulcers, renal toxicity, oral carcinogenesis, and inflammatory skin damage.
  • It may also have insect-repellent and anthelmintic properties.

Overall conclusion

Geraniol is a versatile natural compound with established value as a fragrance ingredient and promising antimicrobial, antioxidant, anti-inflammatory, and anticancer properties. However, most therapeutic evidence comes from laboratory and animal studies, not clinical trials. Its rapid metabolism, volatility, limited water solubility, and potential interactions with drug-metabolizing enzymes must be addressed before it can be reliably developed as a medical treatment.

Bottom line: Geraniol is promising as a pharmaceutical and food-preservation compound, but its clinical effectiveness and safety still require substantial human research.

STUDIES

• A review of the pharmacological properties of geraniol.
• Lower doses of geraniol produced more potent anxiolytic, antidepressant, nootropic, and antioxidant effects as compared to the higher doses.
• Reversion of down-regulation of intestinal multidrug resistance-associated protein 2 in fructose-fed rats by geraniol and vitamin C.

Antibacterial

• In vitro and in vivo biofilm inhibitory efficacy of geraniol-cefotaxime combination against Staphylococcus spp.
• Geraniol relieves mycoplasma pneumonia infection-induced lung injury.

Anti-inflammatory

Geraniol has an anti-inflammatory effect in PMACI-stimulated mast cells.

Cancer

• Cytotoxic and genotoxic potential of geraniol in peripheral blood mononuclear cells and human hepatoma cell line (HepG2)
• Geraniol and lupeol inhibit growth and promote apoptosis in human hepatocarcinoma cells.
• Geraniol, a natural component of plant essential oils, exhibits potent chemopreventive effects in the colon

Candida

Modulation of efflux pump activity by geraniol and fluconazole synergism represent a promising approach for combinatorial treatment of candidiasis.

Diabetes

• Geraniol ameliorates diabetic nephropathy.
• Geraniol ameliorates the progression of high fat-diet/streptozotocin-induced type 2 diabetes mellitus.

Hepatoprotective

• Geraniol attenuates oxidative stress, bioaccumulation, serological and histopathological changes during aluminum chloride-hepatopancreatic toxicity in male rats.
• Geraniol protects against cyclophosphamide-induced hepatotoxicity.
• Role of geraniol against lead acetate-mediated hepatic damage and their interaction with liver carboxylesterase activity in rats
• Geraniol protects against lipopolysaccharide and D-galactosamine-induced fulminant hepatic failure by activating PPARγ.
• Geraniol protects against oxidative stress-induced apoptosis in hepatic ischemia-reperfusion injury.

IBS

Dietary geraniol ameliorates intestinal dysbiosis and relieves symptoms in irritable bowel syndrome patients.

Memory

Mechanistic insights into ameliorating effect of geraniol on D-galactose induced memory impairment.

Neuroprotective

Geraniol could be a novel therapeutic avenue for clinical intervention in neurodegenerative diseases especially for Parkinson's disease.

Osteoarthritis

Geraniol-mediated osteoarthritis improvement by down-regulating PI3K/Akt/NF-κB and MAPK signals.

Pain

Scientists found a cannabis compound that relieves pain without the high. Compounds responsible for the aroma of cannabis and many other plants may offer a surprising new way to relieve chronic pain. Researchers found that several cannabis-derived terpenes significantly reduced pain in mouse models of fibromyalgia and post-surgical pain, with one terpene, geraniol, showing especially strong effects. Unlike THC, these compounds are not associated with psychoactive effect

Pneumonia

Geraniol relieves mycoplasma pneumonia infection-induced lung injury.