Screening ofEnhydra fluctuansfor Phytochemical Composition and Broad-Spectrum Antibacterial Activity against Clinical Bacterial Isolates

Phytochmical analysis and antibacterial property assessment of helencha (Enhydra fluctuans; Family: Asteraceae) extracts

“…As has been reported by Amin et al [12], both the methanolic and acetonic leaf extracts (400 µg/disc) of E. fluctuans showed efficacy against gram-positive (Bacillus cereus) and gram-negative (Escherichia coli) bacteria with ZDI of 10 mm. The toluene extract of E. fluctuans had antibacterial activity against all the test bacteria: Staphylococcus aureus (ZDI: 7 -15 mm), Escherichia coli (ZDI: 14 -20 mm), Klebsiella pneumoniae (ZDI: 11 -18 mm), while the methanolic E. fluctuans extracts showed inhibitory action against a single strain of Staphylococcus aureus (out of five strains tested), as has been demonstrated by Sarma et al [13]. In the current study, AEE had no zone of inhibition (ZDI: 6 mm) against P. aeruginosa, while concentration dependent activity was seen against A. baumannii (ZDI: 17 -21 mm), B. cereus (ZDI: 13 -17 mm) and L. monocytogenes (ZDI: 10 -12 mm) clinical isolates, while the MEE showed antibacterial activity against all gramnegative clinical (A. baumannii and P. aeruginosa) and standard (E. coli ATCC 25922) and all gram-positive clinical (B. cereus and L. monocytogenes) and standard (L. monocytogenes MTCC 657) bacteria tested, displaying ZDIs 12 -20 mm and 13 -24 mm, respectively.…”

“…Haoya et al [17] reported the presence of steroids, saponins, flavonoids and diterpenes, both in methanolic and ethanolic extracts of E. fluctuans, displaying antibacterial activity against E. coli (ZDI: 12 mm at 400 µg/disc) with the ethanolic extract. As per the report of Sarma et al [13], the E. fluctuans toluene and methanol extracts contained bioactive compounds (saponins, tannins, alkaloids, flavonoids, anthraquinones, cardiac glycosides and steroids) showing a broad spectrum of antibacterial activity. Yadava and Singh [18] isolated a novel bioactive component (from the methanolic extract of the leaves of Enhydra fluctuans): isoflavone glycoside, which has been found to exhibit growth inhibitory activity against gram-positive (Staphylococcus aureus and Bacillus cougulans) and gram-negative bacteria Escherichia coli.…”

“…The MEE had MICs of 2.5 -5 mg/ml against gram-positive clinical bacteria, while the values ranged 7.5 -10 mg/ml for gram-negative clinical bacteria; lower MIC (2.5 mg/ml) was seen for L. monocytogenes MTCC 657 strain compared to the MIC of 10 mg/ml, as displayed against ATCC E. coli 25922 (Figure 1); the AEE had MICs >10 mg/ml for all the test bacteria (not shown in the figure). As per the demonstration of Sarma et al [13], the E. fluctuans toluene extract MICs for the test clinical bacterial isolates ranged 25 -50 mg/ml, while the MICs of methanolic E. fluctuans extract was 100 mg/ml, for both the gram-negative and grampositive bacteria. Thus, in the current study, agar-well (in terms of ZDIs) as well as agar dilution (in terms of MICs) techniques achieved excellent antibacterial activity against gram-positive and gram-negative pathogenic bacteria.…”

“…Herein, the test has been performed on the combination effect between antibiotics (as selected on the basis of the test bacterial susceptibility to antibiotics) and MEE (5 mg/ml) against both gram-positive and gram-negative bacteria, and the results, in terms of ZDIs, are represented in Table 2. The toluene extract of E. fluctuans, when combined with oxacillin had increment of ZDI (from 6 mm to 10 -12 mm), against gram-positive bacteria (Staphylococcus aureus) compared to the oxacillin alone, whereas the extract, in combination with ceftazidime, had increased ZDIs, from 6 -7 mm (ceftazidime alone) to 12 -15 mm (from the action ceftazidime-E. fluctuans extract combination), when tested against gram-negative bacteria [13]. The GIIs from the combined action between MEE and antibiotics are depicted in Table 3.…”

Phytochemical and Pharmacological Potential of Enhydra fluctuans Available in Bangladesh

“…There are reports on antioxidant property of the methanolic extract, antimicrobial property of the toluene, chloroform and methanolic extract of E. fluctuans, moreover CNS depressant activity, anti-inflammatory activity of E. fluctuans have also been reported [27][28][29][30]. But there are insufficient records in literature, regarding pharmacological activities and phytochemical characteristics of E. fluctuans Lour available in Bangladesh which are known to differ with plant's geographical location.…”