Antimicrobial and antioxidant properties of methanol extract, fractions and compounds from the stem bark of Entada abyssinica Stend ex A. Satabie

Abstract

BackgroundThe aim of this study was to evaluate the antimicrobial and antioxidant activities of the methanol extract, fractions and isolated compounds from Entada abyssinica stem bark, plant used traditionally against gastrointestinal infections.MethodsThe methanol extract of E. abyssinica stem bark was pre-dissolved in a mixture of methanol and water, and then partitioned between n-hexane, ethyl acetate and n-butanol. The ethyl acetate portion was fractionated by column chromatography and the structures of isolated compounds elucidated by analysis of spectroscopic data and comparison with literature data. Antimicrobial activity was assayed by broth microdilution techniques on bacteria and yeasts. The antioxidant activity was determined by DPPH radical scavenging method.ResultsFour known compounds [(5S,6R,8aR)-5-(carboxymethyl)-3,4,4a,5,6,7,8,8a-octahydro-5,6,8a-trimethylnaphthalenecarboxylic acid (1), methyl 3,4,5-trihydroxybenzoate (2), benzene-1,2,3-triol (3) and 2,3-dihydroxypropyltriacontanoate (4)] were isolated. Compared to the methanol extract, fractionation increased the antibacterial activities of the n-hexane and ethyl acetate fractions, while the antifungal activities increased in ethyl acetate, n-butanol and aqueous residue fractions. The isolated compounds were generally more active on bacteria (9.7 to 156.2 μg/ml) than yeasts (78.1 to 312.5 μg/ml). Apart from compound 1, the three others displayed DPPH· scavenging activity (RSa), with RSa50 values of 1.45 and 1.60 μg/ml.ConclusionThe results obtained from this study support the ethnomedicinal use of E. abyssinica in the treatment of gastrointestinal infections and the isolated compounds could be useful in the standardisation of antimicrobial phytomedicine from this plant.

Isolation, characterization and mode of antimicrobial action againstVibrio choleraeof methyl gallate isolated fromAcacia farnesiana

“…This compound has been found in plants of the genus Acacia such as A. nilotica and A. leucophloea (Chaubal et al 2005), as well as in Rhus javanica, Toona surei, Acer ginnala and Diospyrous kaki (Ahna et al 2005;Abou-Zaid et al 2009;Choi et al 2009;Ekaprasada et al 2009;Kaur et al 2011). This compound has been also isolated from Entada abyssinica Stend ex A. Satabie (Teke et al 2011) and Paeonia lactiflora Pallas (Ngan et al 2012). The isolated compound exhibited antimicrobial activity with MBC ranging from 19 to 312 lg ml À1 against Grampositive and Gram-negative bacteria (Teke et al 2011).…”

“…This compound has been also isolated from Entada abyssinica Stend ex A. Satabie (Teke et al 2011) and Paeonia lactiflora Pallas (Ngan et al 2012). The isolated compound exhibited antimicrobial activity with MBC ranging from 19 to 312 lg ml À1 against Grampositive and Gram-negative bacteria (Teke et al 2011). In addition, the antimicrobial properties of methyl gallate have been reported against micro-organisms such as Shigella dysenteriae, Streptococcus mutans, Candida albicans, Bacillus cereus, Staphylococcus epidermidis and Escherichia coli (Kim et al 2005;Choi et al 2009) as well as Salmonella and Enterobacter (Choi et al 2008).…”

Antiplasmodial Flavanonol From Tephrosia Subtriflora With Radical Scavenging Activity

“…The 3-hydroxy-di-(2,2-dimethylchromene-5:6,7:8)flavanonol (3) showed no significant cytotoxicity (CC 50 > 100 μg/mL) ( Table 2), showing that the observed antiplasmodial activity is not due to toxicity but the really activity of the copound. The subtriflavanonol (1) In the antioxidant activity test using the DPPH photometric assay (Teke et al, 2011),.…”

“…The dose that scavenged 50% of the free radicals (ED 50 ) was computed by linear intrapolation of the graph using Microsoft Excel as described by Teke et al, (2011).…”

TWO ISOLATED CRYSTALLINE SOLIDS FROM THE STEM OF Entada spiralis Ridl. (AKAR SINTOK)

“…Investigation also revealed entagenic acid isolated from seed kernels of E.rheedii which exhibited moderate cytotoxic potency and antioxidative properties [14]. Phenolic and flavonoid were isolated from the root of E. Africa [15], octadecanoic acid from the stem bark of E. abyssinica [16] and Entadoiside from kernel nut of E. phaseoloides [17].…”