Araçain, a tyrosol derivative and other phytochemicals from Psidium guineense Sw

Abstract

Psidium guineense Sw. (Myrtaceae) is a shrub distributed all over South America and Brazil. Its leaves are traditionally used to treat digestive problems and infections. Several biological activities have been reported for P. guineense extracts, however phytochemical studies are scarce. The present study is on the isolation of compounds from P. guineense leaf extracts using chromatographic and spectroscopic techniques and evaluation of their antibacterial activity.Araçain, a tyrosol derivative was isolated as a natural product for the first time.Other compounds isolated were ursolic acid, a phaeophorbide and three flavonoids. The extracts were tested for their antimicrobial activity against Klebsiella pneumoniae strains and they showed moderate to high antibacterial activity.

Three New Butenolides from the Green Alga Caulerpa racemosa var. turbinata

“…Additionally, seven known compounds were elucidated as ursolic acid ( 3 ), ( S )‐5‐hydroxy‐3,4‐dimethyl‐5‐propylfuran‐2(5 H )‐one ( 4 ), ( S )‐5‐hydroxy‐3,4‐dimethyl‐5‐pentylfuran‐2(5 H )‐one ( 5 ), (−)‐loliolide ( 6 ), (3 S ,5 R ,6 S ,7 E )‐5,6‐epoxy‐3‐hydroxy‐7‐megastigmen‐9‐one ( 7 ), (+)‐dehydrovomifoliol ( 8 ) and ficusic acid ( 9 ) by comparing their spectroscopic data with the reported literatures. In this work, all of the isolates were evaluated for their in vitro antibacterial activities ( Table ).…”

Antimicrobial Activities of Olive Oil Mill Wastewater Extracts against Selected Microorganisms

“…Extracts rich in these phenolic compounds with antimicrobial activities can also be obtained from olive leaves similar to OOMW [26,53]. On the other hand, in addition to olive-based products, Macaúbas-Silva et al [54] extracted a tyrosol derivative, araçain, from Psidium guineense Sw. and reported that this extract showed moderate to high antibacterial activity against Klebsiella pneumoniae strains. Gram-negative bacteria (e.g., E. coli and K. aerogenes) were found to be more resistant than Gram-positive bacteria (e.g., Bacillus and Staphylococcus strains) against polyphenolic compounds [55].…”