Elevational Trends in Usnic Acid Concentration of Lichen Parmelia flexilis in Relation to Temperature and Precipitation
Bishnu Prasad Neupane *, Komal Prasad Malla, Anil Gautam, Dinesh Chaudhary, Sanjita Paudel, Sangita Timsina and Nirmala Jamarkattel
School of Health and Allied Sciences, Faculty of Health Sciences, Pokhara University, Lekhnath-12,
* Correspondence: firstname.lastname@example.org; Tel.: +977-9841-533-885
Academic Editors: Daniele Bocchiola and Yang Zhang
Received: 31 December 2016; Accepted: 25 May 2017; Published: 27 May 2017
Abstract: Usnic acid contents in acetone extracts of 31 samples of lichen Parmelia flexiliscollected from different altitudes were identified using thin layer chromatography (TLC) and determined by high-performance liquid chromatography (HPLC). The usnic acid content varied in between highest 5.13% to lowest 1.66% in oven dried (80 C) lichen samples. The species collected from lower altitudes all show high levels of usnic acid. The negative relationship between usnic acid and altitude was obtained. Statistically, it is revealed that there is a significant difference between average percentages of usnic acid in lichen samples with varying altitudes (p < 0.05). Besides these, the precipitation averages of the regions where the species have been collected were linked with the content of usnic acid. It is clear that lichens from the regions receiving the highest precipitation produced lower amounts of usnic acid. The results suggest that the production of secondary metabolite in lichens is altered due to the climatic variables like temperature and precipitation at different altitude gradients.