Chemical composition and fungitoxic activity of essential oil of Thuja orientalis L. grown in the north-western Himalaya.
The essential oil from fresh leaves of Thuja orientalis L. grown in the north-western Himalaya was isolated by means of hydrodistillation and analyzed by GC and GC/MS. Twenty-two compounds representing 94.0% of the total oil were identified. The leaf oil contained alpha-pinene (29.2%), Delta-3-carene (20.1%), alpha-cedrol (9.8%), caryophyllene (7.5%), alpha-humulene (5.6%), limonene (5.4%), alpha-terpinolene (3.8%) and alpha-terpinyl acetate (3.5%) as major constituents. The essential oil showed antifungal activity against Alternaria alternata in a direct bioautography assay. Two main bioactive compounds named as b1 (Rf = 0.54) and b2 (Rf = 0.80) were observed and tested for antifungal activity; they produced an inhibition zone of 5 and 10 mm in diameter, respectively. The components b1 and b2 were further purified by preparative thin layer chromatography and their antifungal efficacy was re-tested. The minimum inhibitory amount (MIA) of b1 and b2 against A. alternata was determined as 30.5 and 4.5 microg, respectively, using a bioautography assay. The bioactive constituent corresponding to b1 was determined as alpha-cedrol by using GC/MS analysis. The potential of essential oils as a source of natural biocides is discussed.
Division of Biochemistry and Plant Physiology, Sher-e-Kashmir University of Agricultural Sciences and Technology, Faculty of Agriculture, Chatha, Jammu-180 009, India. guleria71@rediffmail.com
Sanjay
S
Guleria
Ashok
A
Kumar
Ashok Kumar
AK
Tiku
D000528:Alternaria / Q000187:drug effects; D000935:Antifungal Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D002681:China; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D005659:Fungicides, Industrial / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D009822:Oils, Volatile / Q000737:chemistry* / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry*; D029783:Thuja / Q000737:chemistry*
D000935:Antifungal Agents; D005659:Fungicides, Industrial; D009822:Oils, Volatile