Chemical profile and antimicrobial activity of extractable compounds of Betula litwinowii (Betulaceae) buds

In spite of the long history of therapeutic use of buds from different birch species in folk medicine the existing information on their chemical composition is insufficient. The main goal was to develop a method for GC-MS determination of the chemical profile of birch buds as well as their antimicrobial activity. 150 substances of different classes were identified in Betula litwinowii buds. The volatile elements of the buds were mainly represented by sesquiterpene compounds. Ether extracts also contained other biologically active components such as flavonoids and triterpenoids. However, a particular feature of this fraction was the high content of sesquiterpene phenylpropenoids, including esters of ferulic and caffeic acids with caryophyllene-type alcohols that had not been previously found in any biological samples. Apart from carbohydrates, a series of free amino acids were detected in methanol extracts. The antimicrobial activity of the ether extracts of the buds was observed against all of the microorganisms tested, with MIC values from 0.04 to 0.08 mg mL-1 for Gram-positive bacteria and Candida albicans. However, their inhibitory activities against tested Gram-negative bacteria were rather occasional.