STEM BARK
The chemical constituents of stem bark are sitosterol , alkaioid ( 4 - methoxv -1 - methyl - 2 - quinolone), lupeol , limonene ,and counmarins .At least coumarins are xanthyletin ,xanthoxyletin , umbelliferone , geranyl umbelliferone isopimpinellin , marmin , marmesin , 7 - methoxy -counmarin (herniarin),superposing ,exoxy superposing ,dithydrosuberenol ,superevene ,crenulatin (6 - forrmyl , 7 - methoxy coumarin )
 

USES AND APPLICATION
Thanakha plants are medicinal and all parts of this plant are very useful in medicine, indigenous medicine , cosmetics and perfumery . Thanakha is used as a natural make - up .
The importance of this plant from the medicinal point of view was advocated by many observers. In Myanmar , the paste from bark is used in making a fragrant paste for cosmetic purpose .

NATURAL COUMARINS
They absorb a wide range of ultraviolet light and generate intense fluorescence (usually blue) .

CLASSIFICATION OF NATURAL COUMARINS
Natural coumarins are classified as follows :

● SIMPLE COUMARINS
Coumarins substituted with - OH or - OCH at positions C-6 and C -7 .
e.g ., Herniarin

● PYRANOCOUMARINS
A Pyran ring is fused at C -6 and C - 7 of the coumarin ring system.
e .g ., Xanthoxyletin

● FURANOCOUMARINS
Furanocoumarins are principally found in species of the two plant families mbelliferae and Rutaceae. Furanocoumarin belong to two types furan ring is fused at C - 6 and C -7 (psoralen - type ) or C - 7 and C - 8 (angelicin - type ) or C - 7 and C - 8 (angelicin - type ) of the coumarin ring system.

● PHYSIOLOGICAL ACTIVITIES OF COUMARINS
Coumarins possess several useful physiological properties, it has the antibacterial , antifungal , anticoagulant , respiratory stimulation activities . Some coumarins have anti - arrhythmic action and some are capable of being used against radiation damage.