Lupane triterpenoids, antioxidant potential and antimicrobial activity of Myrciaria floribunda (H. West ex Willd.) O. Berg.

Abstract

Chemical composition of the methanol extract of Myrciaria floribunda leaves was investigated. The nor-lupane triterpenoids platanic acid and messagenic I acid were identified, along with other known triterpenoids (betulinic aldehyde, ursolic acid acetate and betulinic acid), a new lupane triterpenoid (2α,6α,30-trihydroxybetulinic acid) and the flavonoids catechin, quercetrin and mirycitrin. The structures were determined by spectroscopic methods (NMR, LC-MS, GC-MS). The major isolated compound was betulinic acid. The methanol extract and 2α,6α,30-trihydroxybetulinic acid were evaluated for their DPPH scavenging potential. The tested triterpenoid was one hundred times more active than betulinic acid, but less active than the extract. Screening for antimicrobial activity showed that the methanol extract was active against Staphylococcus aureus and Escherichia coli, but inactive against Candida albicans and Candida krusei, while 2α,6α,30-trihydroxybetulinic acid was inactive to all tested microorganisms.

Keywords:

• Myrciaria floribunda
• 2α,6α,30-trihydroxybetulinic acid
• DPPH
• antibacterial activity
• betulinic acid

Acknowledgments

The authors thank Professor Carlos Emmerson Costa and Ozeias Monteiro Junior for the IR spectra, Professor Milton N. Silva for the LC-MS spectra and Professor Mara Arruda and Wandson Pinheiro for the optical rotation analysis.