Compounds from Terminalli brownii Extracts with Toxicity against the Fish Pathogenic Bacterium Flavobacterium columnare

Abstract

The pond-raised channel catfish (Ictalurus punctatus) industry in the United States of America can incur losses of over a $100 million annually due to bacterial diseases including columnaris disease caused by Flavobacterium columnare. One management approach available to catfish producers is the use of medicatedfeed containing antibiotics. However, the negative attributes of antibiotic use in agriculture include public concerns and the potential development of antibiotic-resistant bacteria. Therefore, the discovery of environmentally-safe natural compounds for use as therapeutic agents would greatly benefit the catfish industry. In this study, a rapid bioassay was used to evaluate crude plant extracts as the first step in the discovery of natural therapeutants. Plant extracts from Terminalia brownii were found to be inhibitory towards F. columnare. The minimum inhibitory concentration (MIC) of the 5% water-methanol extract of T. brownii (stem bark) was 10 μg/mL and the 24 h 50% inhibition concentration (IC 50) was 40 μg/mL. Subsequent bioassay-guided fractionation of the T. brownii ethanol extract using reverse phase C-4 chromatography revealed the highest level of activity in the aqueous:methanol (50:50) fraction. HPLC analysis and subsequent purification of this fraction provided two compounds identified as ellagic acid (1) and 4-O-(3′′,4′′-di-O-galloyl--L-rhamnopyranosyl)ellagic acid (2). Compound 2 was the most active isolated compound, with a minimum inhibitory concentration (MIC) of 10±0 µg/mL and 24 h IC 50 of 31±1 µg/mL. Although 1 was more active according to a MIC of 6±5 µg/mL, its 24 h IC 50 was >100 µg/mL, and, therefore, it was less active overall of the two most active isolated compounds.

The Apoptotic Potential Activity of Terminalia Brownii Extracts against Various Cancer Cell Lines

“…The phytochemistry of Terminalia laxiflora and Terminalia brownie has been the focus of several studies. It has been discovered that the roots of both species and the stem bark of TB contain medium-polar-to-polar phenolic compounds, including gallic acid, ellagic acid, and its derivatives, gallotannins and the ellagitannins punicalagin, terchebulin, methyl-(S)-flavogallonate, and its isomer (Hanahan and Weinberg, 2011;Schrader et al, 2016;Yamauchi et al, 2016;Salih et al, 2017). Furthermore, the stem wood of T. laxiflora has been found to contain terchebulin, flavogallonic acid dilactone, and ellagic acid and its derivatives (Muddathir and Mitsunaga, 2013).…”

Phenolic substances as regulators of the intensity of lipid peroxidation processes of the strains Pleurotus eryngii, Fistulina hepatica and Agrocybe cylindracea

“…Plant extracts of Terminalia brownii, platanosides extracted from the leaves of the Platanus occidentalis tree, have been proven to be promising for the treatment of columnaris (Schrader et al, 2015;Schrader et al, 2016). Agaricus bisporus supplement has been found to enhance a nonspecific immune response that will reduce the mortality from F. columnare infection (Harikrishnan et al, 2018).…”