Sandalwood Oil

Scientific Name(s): Santalum album L.
Common Name(s): East Indian sandalwood oil, Sandalwood, Santal oil, White or yellow sandalwood oil, White saunders oil

Medically reviewed by Drugs.com. Last updated on Jun 8, 2022.

Clinical Overview

Use

The oil has mainly been used as a fragrance enhancer.

Dosing

None well documented. The oil should not be ingested internally in its natural state.

Contraindications

None well documented.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Sandalwood oil can cause dermatitis, although it is generally considered to be nonirritating to human skin.

Toxicology

Sandalwood oil has generally recognized as safe (GRAS) status as a flavoring agent in food by the Flavor and Extract Manufacturers' Association, and the US Food and Drug Administration (FDA) also recognizes sandalwood oil as a natural flavoring.

Scientific Family

• Santalaceae

Botany

Indigenous to India and Indonesia, sandalwood is an evergreen tree that grows to 8 to 12 m in height and 2.5 m in girth.(Burdock 2008) The bark is smooth and gray-brown in color, and the small flowers have numerous short stalks.

History

Sandalwood oil has a warm, woody odor and is commonly used as a fragrance in incense, cosmetics, perfumes, and soaps.(Burdock 2008) It also is used as a flavoring for foods and beverages. The wood has been valued in carving because of its dense character.(Duke 1985, Hongratanaworakit 2004, Fox 2000)

In traditional medicine, sandalwood oil has been used as an antiseptic and astringent, and for the treatment of headache, stomachache, and urogenital disorders. In India, the essential oil, emulsion, or paste of sandalwood is used in the treatment of inflammatory and eruptive skin diseases.(Dwivedi 1997) The oil has been used in Ayurvedic medicinal system as a demulcent, diuretic, and mild stimulant.(Burdock 2008) The leaves and bark of Santalum have been used by early Hawaiians to treat dandruff, lice, dermatitis, and sexually transmitted diseases.(Kumar 2006) Sandalwood oil has also demonstrated repellency against the crop pest, Tetranychus urticae (two-spotted spider mite), with santalol suggested as the active component.(Roh 2012)

Chemistry

The essential oil of sandalwood is obtained from the heartwood of the tree.(Zhang 2011) Alpha-santalol is a naturally occurring sesquiterpene that is derived from sandalwood oil.(Bommareddy 2017) The light yellow, volatile oil contains about 90% santalols with 35% to 49% being alpha-santalol, 14% to 33% beta-santalol, 0% to 5% alpha-trans-bergamotol, and 1% to 7% epi-beta-santalol.(Setzer 2009) The santalols are responsible for the pleasant odor of sandalwood, although 2-furfuryl pyrrole may also contribute an effect.(Duke 1985)

The seeds yield about 50% of a viscid, dark red, fixed oil containing stearolic acid and santalbic acid.(Wang 1991)

Uses and Pharmacology

Sandalwood is a fragrant wood from which an oil is derived for use in foods and cosmetics. The oil is rarely used medicinally today, but its widespread use as a popular fragrance continues. Tertiary resources document the oil as having both diuretic and urinary antiseptic properties.(Leung 1980)

Antimicrobial effects

In vitro data

Some of the isolates from Santalum album were found to be active against Helicobacter pylori.(Ochi 2005) S. album was also found to inhibit Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, with the aqueous leaf extract showing a higher inhibition zone than the stem extract.(Kumar 2006)

Antiviral

In vitro data

Sandalwood oil inhibited the replication of herpes simplex viruses (HSV) 1 and 2, with inhibition was more pronounced against HSV-1. The effect was dose dependent, and the oil was not virucidal.(Benencia 1999) Another in vitro study found sandalwood oil to exert inhibitory activity against HSV-2 (IC₅₀ of 0.0015%).(Koch 2008)

Sandalwood oil (along with the essential oils of thyme and hyssop) was found to exert virucidal activity against acyclovir-sensitive and resistant strains of HSV-1. The investigators suggested that the mechanism of action must differ from that of acyclovir, given that it was effective against acyclovir-resistant strains and might be attributed to inactivation of the virus before it enters the cell.(Schnitzler 2007)

Beta-santalol was also found to exert antiviral activity against influenza A/HK (H3N2), with a suggested mechanism of inhibition in late viral RNA synthesis.(Paulpandi 2012)

Cardio-metabolic risk

Animal and in vitro data

In a study of streptozocin-induced diabetic rats, S. album petroleum ether fraction 10 mcg/kg given twice daily for 60 days was associated with a reduction in blood glucose, hemoglobin A_1c. In addition, total cholesterol, triglycerides, and low-density lipoprotein cholesterol levels were reduced, while high-density lipoprotein cholesterol levels increased.(Kulkarni 2012)

Chemopreventive activity

Alpha-santalol is believed to exert its chemopreventive effects, particularly against skin cancer, through the induction of apoptosis and tumor suppressor protein. It also inhibits cell proliferation through induction of G₂/M phase arrest.(Zhang 2011)

Animal and in vitro data

Daily oral feedings of sandalwood oil to adult male Swiss albino mice for 10 and 20 days led to a dose-dependent increase on glutathione S-transferase (GST) activity and acid soluble sulfhydryl (SH) levels. The enhancement of GST activity and acid-soluble SH levels may suggest a possible chemoprophylactic action against carcinogenesis.(Banerjee 1993)

Similarly, alpha-santalol was found in a dose-response study to decrease DMBA-TPA–induced skin tumor incidence and multiplicity, ODC activity, and DNA synthesis in CD-1 mice. A superior effect was noted with a 5% application of alpha-santalol as opposed to 1.25% and 2.5%. Additionally, alpha-santalol in 2.5% and 5% concentrations as pretreatment reduced ultraviolet B-initiated skin tumor development.(Zhang 2011)

Alpha-santalol activated caspase-3 activity, causing apoptosis in androgen-dependent and -independent human prostate cancer cells. The survival of these cells was affected by alpha-santalol in both a concentration- and time-dependent manner.(Bommareddy 2012) It was also shown that alpha-santalol in human prostate cancer cells caused AKT/survivin pathway inhibition which enhanced apoptotic cell death.(Bommareddy 2020) Alpha-santalol also induces autophagy by targeting the ΑKT–mTOR pathway in prostate cancer cells, which may serve as a protective mechanism.(Walters 2021)

Alpha santalol, was also shown to inhibit migration of breast cancer cells by targeting the beta-catenin pathway in vitro.(Bommareddy 2018)

Additionally, various lignans from S. album were also found to exert cytotoxic effects against HL-60 human promyelocytic leukemia cells and A549 human lung adenocarcinoma cells.(Matsuo 2010)

CNS effects

In vitro data

Intraperitoneal administration of alpha- and beta-santalols in mice increased hexobarbital-induced sleeping time. Oral, intraperitoneal, and intracerebroventricular administration of alpha-santalol reduced rectal temperature and spontaneous motor activity more effectively than beta-santalol. However, beta-santalol was found to decrease acetic acid-induced writhing more effectively than alpha-santalol.(Okugawa 1995)

Clinical data

Though not statistically significant, leg and foot massage with sandalwood oil reduced anxiety in patients.(Kyle 2006) Topical administration of sandalwood oil produced "harmonizing" effects (ie, a reduction in the level of autonomic nervous system arousal but no behavioral level deactivation) in healthy volunteers, whereas alpha-santalol had relaxing/sedative effects.(Hongratanaworakit 2004) Inhalational sandalwood essential oil and alpha-santalol affected various physiological parameters and self-ratings of arousal in humans.(Heuberger 2006)

Dermatology

Animal and in vitro data

Sandalwood oil may have chemoprophylactic effects on skin papillomas. Treatment (5% in acetone, w/v) on 7,12-dimethylbenz[a]anthracene-(DMBA)-initiated and 12-O-tetradecanoyl phorbol-13-acetate(TPA)-promoted skin papillomas and TPA-induced ornithine decarboxylase (ODC) activity in CD1 mice significantly decreased papilloma incidence by 67% and TPA-induced ODC activity by 70%.(Dwivedi 1997)

A marked decrease in inflammatory markers have also been shown with alpha-santalol administration in skin tissue models.(Bommareddy 2017) The antifungal and ichthyotoxic properties of sesquiterpenoids from S. album heartwood have also been reported.(Kim 2017)

Clinical data

One small study (N=10) evaluated the effectiveness of sandalwood oil for cutaneous viral warts caused by the human papillomavirus. Sandalwood oil was applied topically twice daily for 12 weeks to cutaneous warts on any area of the body. At the end of the study, 80% had complete resolution of all treated warts. There were no complaints or other adverse events reported.(Haque 2018)

One study (N=42) into a proprietary topical 0.5% salicylic acid-based treatment regimen containing sandalwood oil applied to adolescents and adults with mild to moderate acne had positive outcomes.(Winkleman 2018)

Dosing

None well documented. The oil should not be ingested internally in its natural state.(Burdock 2008, van Wyk 2004)

Pregnancy / Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Sandalwood oil can cause dermatitis in sensitive persons, although it is generally considered to be nonirritating to human skin.(Duke 1985, Leung 1980, Uter 2010) A case report described a 65-year-old man with a scaly, hyperpigmented plaque on his forehead and fissuring of his fingers (markedly on the thumb and index finger). He reported daily use of sandalwood paste on the lesions for 8 years, and a patch test with sandalwood was positive. The lesions disappeared after discontinuation of sandalwood, although hyperpigmentation remained.(Sharma 1987) Another case report described a photoallergic reaction resulting from exposure to a cosmetic product containing sandalwood oil.(Starke 1967) Masseurs and cosmeticians have an increased risk of sensitization to essential oils such as sandalwood.(Geier 2022)

Toxicology

Sandalwood oil has GRAS status as a flavoring agent in food by the Flavor and Extract Manufacturers' Association, and the FDA also recognizes sandalwood oil as a natural flavoring.(Burdock 2008)

The oral toxicity of sandalwood oil in rats was found to be 5.58 g/kg and 3.8 g/kg for alpha-santalol. The dermal toxicity of sandalwood oil and alpha-santalol in rabbits was reported as more than 5 g/kg.(Burdock 2008)

The santalols and related compounds have been identified in the blood of mice that inhaled sandalwood fumes under experimental conditions, indicating that systemic absorption of these compounds can occur.(Jirovetz 1992)

References

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This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.

This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.

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