Manami Senpuku, Kazuya Nonaka, Michiho Ito,* and Gisho Honda

Abstract: The chemical components of the essential oil obtained from the steam-distillation of Microtoena patchoulii leaves were investigated by GC and GC/MS, and twenty-one compounds were identified. The major compounds of the oil were patchouli alcohol (54.4%), 1-octen-3-ol (21.4%), and a-guaiene (2.4%). The composition of M. patchoulii oil is similar to that of commercial patchouli oil, and similar pharmacological effects could be expected when it is used as a substitute for Pogostemon cablin.

<i>Microtoena patchoulii</i> [(C.B. Clarke ex J.D. Hooker) C.Y. Wu et Hsuan] is a perennial plant belonging to the family Lamiaceae, growing in the highlands of northeastern India, Myanmar, and southern China (Yunnan) (1). Its fresh leaves have a strong fragrance and are used in folk medicine for coughs, asthma, abdominal pain, and enteritis among people in these areas (2), while Pogostemon cablin, growing in China, India, Indonesia, Malaysia, Philippines, and Sri Lanka (3), has been used for centuries as a fragrance component as well as a herbal drug for the treatment of vomiting, dermatitis, headache, fever, and diarrhea, as well as an aphrodisiac, anti-inflammatory, and antiseptic (4). These two herbal drugs are reported to be sometimes mixed together so that <i>M. patchoulii</i> can be found mixed in a bag of <i>P. cablin</i> produced in southeast Asia (1). This happens because both species have thick hairy leaves and a similar smell so they are difficult to distinguish when the leaves are dried and cut; however, from the standpoint of the quality control of patchouli oil, it is necessary to know the chemical composition of the essential oil of <i>M. patchoulii</i>. While taxonomical studies of <i>M. patchoulii</i> have been previously preformed, no phytochemical analysis of this plant has been reported. In this paper, we report the GC and GC/MS analysis of the essential oil of this plant for the first time.