Extraction, characterization of bioactive compounds and biological activities of the leaves of Podocarpus lambertii Klotzch ex Endl

Abstract

Podocarpus species exhibit anti-inflammatory, antiseptic, astringent activities, and are useful in the treatment of fevers, asthma, coughs, and headaches. This study is the first with the objective of determining the effect of solvent extraction, characterization of bioactive compounds of the essential oil (EO) and plant extracts of Podocarpus lambertii leaves, as well as evaluating the antimicrobial activity by the broth microdilution technique, antioxidant activity by the 2,2-diphenyl-1-picryl hydrazyl (DPPH) method and activity on preformed bacterial biofilms. The yield of the EO was 0.36 %, of the methanolic extracts (ME) 14.9 % and ethanolic extracts (EE) 9.76 %. The analysis of EO (GC-MS) identified 16 compounds: the major components were Manool, 13-epi-, and Rimuene. The phytochemical prospection of the extracts revealed the presence of alkaloids, flavonoids, steroids, and tannins. The extracts showed high antimicrobial activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Enterococcus feacalis, Bacillus subtillis, and high antioxidant activity of the ME, with the percentage of DPPH radical sequestration of 84 %. The EO presented low antimicrobial and antioxidant activity. The ME showed high antibiofilm activity of and reduction of the biomass of the biofilm formed most of the bacterial strains tested. The results suggest that the plant extracts of P. lambertii are a promising alternative source of natural bioactive compounds for the control of resistant microorganisms, besides contributing to the knowledge of the species.