Volatile oils and flavones of Stemodia viscosa Roxb

INTRODUCTION Stemodia Benth. is a genus of about 40 species belonging to the family Scrophulariaceae occurring in tropical and subtropical regions of the world. The chemical investigation of this genus is restricted to five species from which flavonoids, labdane diterpenes, and diterpenes derivatives with a rare tetracyclic skeletal, named stemodane, were isolated. [1-3] The diterpenes of this genus are found to possess cytotoxic and antiviral properties. [4] Stemodia viscosa Roxb., an aromatic weed found in cultivated fields of India, is of Australian origin, which is also referred to as Sticky blue rod, Pintye-pintye etc. It is an erect, aromatic, viscidly pubescent herb with quadrangular stem reaching up to 60 cm high. Leaves are 4 cm long, sessile, oblong, and amplexicaul. Flowers axillary, violet in colour and bilipped. The fragrant leaves of this herb are placed in pillows to induce a restful sleep, or crushed and mixed with fat to make a rubbing medicine to treat cold and flu symptoms. It is used as an aboriginal healing rub along with olive oil and beeswax. The available chemical data of this plant pertain only to flavones such as diosmetin and luteolin along with their glycosides isolated from the leaves [2], and there are no previous reports on the volatile oil of this aromatic herb which is the cause of its medicinal properties. Therefore, in the present work, the plant was subjected to a chemical study on its volatile oil and other phenolics.