Twcnty-three constituents of the essential oil of St. auriculafus could be identified. lsoborncol (6), its isobutyratc 10, and 8-(iso-butyryl0xy)isobornyl isobutyrate ( 22) are the main components (ditogcthcr 82%). 22 and further oxidized isoborneol derivatives 15, 17-19.21 are new naturally occumng compounds.
The genus Strobilanthes (Acunthaceae) was rarely examined until now. St. cusia [Nees.] Iml. (St. Huccidifolius Nees.) leaves are used as adstringent'). From St. crispus (L.) leaves, known as a remedy for kidney, bladder and gall bladder diseases 'I, a caffeic acid derivative, verbascoside, was isolated2). The essential oil of St. lupulinus is known, but its constituents were not investigated 3a).
As part of an extensive screening program of odoriferous plants from wild sources of the Kashmir region of India4*" we investigated the essential oil of St. auriculatus. This plant is an aromatic shrub, found in the Sub-Himalayan tract, east of river Ravi, in Kumaon and Dehradun regions and in Central India in Manipur, and in Khasi and Lushai hills between the altitudes of 300-1200 m. The wild plant was collected from Dehra Gopipur area at an altidude of 750 m in Palampur (Himachal Pradesh) in February 1985. The essential oil was prepared by steam distillation of the inflorescence part of the plant in a yield of 0.4% based on fresh weight. This oil is also used in Indian perfumery industry.
Preliminary GLC (see Figure l), MS and 'H NMR examinations indicated to our surprise that more than 50% of the oil consisted of (-)-isoborneol (6) and its isobutyrate 3i ! 1 7 I 161 2