GC-MS analysis of the alkaloid extract of Epdedra equisetina and in silico antiinflammatory activity of its alkaloids

Abstract

Epdedra equisetina is a potential medicinal plant in Tajikistan. It has been used for a long time in Tajik folk medicine for colds, joint pain, rheumatism, malaria, stomach and liver disorders. The alkaloid extract of Epdedra equisetina is obtained by acid-base extraction and analyzed by gas chromatography-mass spectrometry (GC-MS) and column chromatography (CC). The alkaloid extraction yield of Ephedra equisetina is 1.57%. Four alkaloids, namely ephedrine (pseudoephedrine), 2,3,4-trimethyl-5-phenyloxazolidine, trans-1,2-dimethyl-3-phenylaziridine and 3,4-dimethyl-2,5-diphenyloxazolidine have been identified in the alkaloid extract of Epdedra equisetina. In silico anti-inflammatory activity of Epdedra equisetina alkaloids have been tested against inhibition of cyclooxygenases-1 enzyme (COX-1) (PDB code 3N8Z), cyclooxygenases-2 enzyme (COX-2) (PDB code 3LN1), and P38 mitogen-activated protein kinase (p38MAPK) (PDB code 1OZ1). Celecoxib has been used as a positive control. Molecular docking values of alkaloids in Epdedra equisetina range between –5.2 and – 9.4 kcal/mol. The value for the reference drug (celecoxib) ranges between –6.6 and –12.2 kcal/mol. 3,4-Dimethyl-2,5- diphenyloxazolidine shows the highest molecular docking values of –7.0, –9.4, and –7.8 kcal/mol for COX-1, COX-2, and p38MAPK proteins, respectively. 3,4-Dimethyl-2, 5-diphenyloxazolidine can act as a natural alternative inhibitor of the COX-2 protein.