Essential oil composition of Zanthoxylum armatum leaves as a function of growing conditions

ABSTRACT

Variation in the composition of leaf essential oils of Zanthoxylum armatum in relation to altitude and soil chemistry was analyzed in Nepal. The essential oil was extracted by Clevenger apparatus and the components were analyzed through GC-MS. The results showed that: Yield of the essential oil obtained from the hydro-distillation of dried leaves ranged from 0.16% to 0.50%. GC-MS analysis revealed total of 17 compounds in the essential oil from the dried leaves of Z. armatum from different altitudes and populations (wild and cultivated). The three major components, linalool, limonene and undecan-2-one, present in higher proportion in all the samples were analyzed. Other components tridecan-2-one, myrcene, cinnamate(E)-methyl and alpha-bergamotene were also identified in most of the samples but in lower proportions. The highest number of components (12) was identified from the wild samples collected from 1990 m and the lowest number (7) was from 1060 m (wild) and 2030 m (cultivated populations). Linalool, a major component was found in higher amount (64.88%) at the lowest altitude of 1060 m. Results of the present study showed that the altitude, soil chemistry, and growing conditions significantly affect the essential oil components in Zanthoxylum armatum.

KEYWORDS:

• Zanthoxylum armatum
• essential oil
• altitude
• edaphic factor
• linalool
• limonene

Acknowledgments

The first author is thankful to Dabur Nepal for the grant 'Dabur CSR Fellowship (Late Sri Ashok Chand Burman) 01/2016ʹ. We would like to thank Mr. Tara Datt Bhatt, Scientific Officer, Department of Plant Resources for his valuable help in GC-MS analysis. Special thanks to Mr. Mohan Mahato from CIMMYT, Nepal for his assistance in statistical analysis. Mr. Krishna Pun from District Plant Resources Office, Salyan is thankfully acknowledged for his tremendous help during field visit. We also thank Mr. Shamik Mishra, Mr. Kiran Kumar Pokharel and Mr. Prabodh Satyal for their various helps. Sincere thanks to Prof. Dr. Mohan Siwakoti, Head, Central Department of Botany, Tribhuvan University for his encouragement. The authors declare that there is no conflict of interest regarding the publication of this paper.

Additional information

Funding

This work was supported by the Dabur Nepal [CSR 1/2016].