Sandalwood

Sandalwood refers both to the heavy, yellowish, aromatic heartwood of trees in the genus Santalum and to the essential oil steam-distilled from that wood ^[2]. The trees are slow-growing hemiparasites that draw part of their nutrition from the roots of host plants. Indian sandalwood (Santalum album) is the most valued species, while Australian sandalwood (Santalum spicatum) and several Pacific species are also harvested ^[2]. The oil is dominated by sesquiterpene alcohols, with alpha-santalol and beta-santalol together making up the majority of its content and giving the wood its characteristic fragrance ^[2].

Native to parts of Insular Southeast Asia, Australia, and the Pacific, sandalwood spread across Asia through ancient maritime and incense trade routes ^[2]. It holds deep religious and cultural significance, as sandalwood paste and incense feature in Hindu, Buddhist, Jain, and other ceremonies, and the fine wood has long been favored for carving statues and ritual objects. In Ayurveda and traditional Chinese medicine the heartwood has been used for skin, cardiovascular, and respiratory complaints ^[2].

In perfumery, sandalwood oil is prized as a base note and fixative, valued for a soft, creamy, milky, woody scent that blends readily with florals and other woods ^[2]. It has also served niche technical roles, such as an immersion oil in microscopy. Because demand has long outstripped supply, Indian sandalwood has been heavily over-exploited, wild populations are considered threatened, and much production has shifted to managed plantations and to Australian sources ^[2].

Scientific interest centers on the oil and its santalols. Sandalwood album oil, also called East Indian sandalwood oil, has shown anti-inflammatory, antimicrobial, and anti-proliferative activity in laboratory work, and pharmaceutical-grade preparations have been studied in dermatology for acne, psoriasis, eczema, warts, and molluscum contagiosum ^[1]. Alpha-santalol has drawn particular attention for chemopreventive effects against skin and other cancers in cell and animal models, where it can trigger cell-cycle arrest and apoptosis ^[3]. Separately, a synthetic sandalwood-type odorant was found to activate the olfactory receptor OR2AT4 in skin keratinocytes and to promote wound-healing processes, illustrating that sandalwood-like molecules can act on receptors well outside the nose ^[4].

Sandalwood is sold as raw wood, chips and powder, incense, and steam-distilled essential oil, and pharmaceutical-grade oil has been developed for topical medical use ^[1]. It is not a scheduled drug, but several Santalum species are protected or regulated because of over-harvesting and conservation concerns ^[2].

Topical sandalwood oil can cause skin irritation or allergic reactions in sensitive people, so patch testing is smart. Essential oils should not be swallowed casually; ingesting concentrated oil can be toxic. As with most botanicals, pregnant or breastfeeding people should avoid concentrated use without guidance.