Effect of α-santalol and β-santalol from sandalwood on the central nervous system in mice.

Sandalwood (Byakudan in Japanese; Santalum album L.) is used as a popular sedative in Oriental medicine. Extracts of the wood of Santalum album were obtained by successively extracting with benzene, chloroform, methanol and water. Each of these fractions was tested for activity on the central nervous system of mice following intraperitoneal administration, i.e. potentiation of hexobarbital sleeping time, body temperature alterations, antinociceptive and spontaneous motor activity changes. The benzene extract was active in these assays and was then separated further into fractions 1, 2 and 3. Fraction 2 was shown to be the most active in the aforementioned assays, α- and β-Santalols were isolated from this active fraction as the major CNS active constituents. They were both active by the intragastric and intracerebroventricular routes of administration. Thus, it can be considered that α- and β-santalols contribute to the reputed sedative effect of sandalwood preparations in Oriental medicine. Additionally, α- and β-santalols significantly increased the levels of homovanillic acid, 3,4-dihydroxyphenylacetic acid and/or 5-hydroxyindoleacetic acid in the brain of mice, and chlorpromazine did the ones of homovanillic acid and 3,4-dihydroxyphenylacetic acid. These results showed that α- and β-santalols could be considered as neuroleptic by resemblance to the pharmacological activities of chlorpromazine.