Phytoextracts as Antibacterials: A Review.

Botanicals have been cultured to flavour food, to treat health disorders and to put a stop to diseases caused by various microorganisms. The awareness of curative features of different medicinal plants has been spread among human communities. The application of herbal products as antimicrobial agents may be a better choice for the extensive and imprudent use of synthetic antibiotics. World Health Organization recommended traditional medicines as the safest remedies for the treatment of diseases of microbial origin. The plant extracts are generally nonhazardous, available in plenty at reasonable prices, biodegradable, eco-friendly and sometimes show broad-spectrum activities against different microorganisms. The current knowledge on plant extracts, phytochemicals and their antibacterial activity, target specific mechanism of action, solvents deployed during extraction, properties of an active ingredient isolated may help in biological control of bacteria. Antimicrobial properties of different plant parts, which act in a low dose, have been organised separately for easy understanding.

Isolation and identification of bioactive antibacterial components in leaf extracts of Vangueria spinosa (Rubiaceae).

OBJECTIVE: The column chromatographic fraction of ethyl acetate (EA1, EA2, EA3, EA4 and EA5) leaf extracts of Vangueria spinosa (V. spinosa) were screened for antibacterial activity and phytochemical analysis. METHODS: EA3 fraction was isolated and identified by column chromatography, thin layer chromatography, spectral data analysis and phytochemical screening were used for analysis. RESULTS: EA3 fraction was significantly active at 4 to 64 mg/L against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa with minimum inhibitory concentration of 1.5625 to 3.1250 mg/mL. The active fraction (EA3) revealed the presence of flavonoid with retention factor value (R(f)) of 0.39. The active antibacterial agent in the most potent fraction (EA3) was isolated and identified as flavonoid (-)-epicatechin-3-O-ß-glucopyranoside by thin layer chromatography (TLC) and phytochemical screening. EA1 and EA2 show inhibitory activity at 4 to 64 mg/L against Staphylococcus aureus only where as fraction EA4 and EA5 do not shows any inhibitory activity within that range of concentration against any bacteria. CONCLUSIONS: The results support the ethnomedicinal use of leaf of V. spinosa for the treatment of bacterial diseases.

n-alkane profile of Argemone mexicana leaves.

An n-hexane extract of fresh, mature leaves of Argemone mexicana (Papaveraceae), containing thin-layer epicuticular waxes, has been analysed for the first time by TLC, IR and GLC using standard hydrocarbons. Seventeen long-chain alkanes (n-C18 to n-C34) were identified and quantified. Nonacosane (n-C29) was established as the n-alkane with the highest amount, whilst octadecane (n-C19) was the least abundant component of the extracted wax fraction. The carbon preference index (CPI) calculated for the hydrocarbon sample with the chain lengths between C18 and C34 was 1.2469, showing an odd to even carbon number predominance.

Water quality assessment near an industrial site of Damodar River, India.

An assessment on the water quality parameters coliform including the bacterial abundance from a point source of river Damodar (24 degrees 26(') N and 86 degrees 53(') E), West Bengal, India was carried out during the period of 2004-2007. The site received mining and industrial effluents from the collieries and industries. The water samples collected on a monthly basis revealed the presence of the coliform bacteria Escherichia coli and Streptococcus sp., between 2,600 and 20,000 colony-forming unit/100 ml throughout the study period with peak abundance during the months of September to December, the post-monsoon period. The relative abundance of the two bacterial species was found to be y(E. coli) = 1.41x (Streptococcus) - 8.07 and were positively correlated (r = + 0.868, df = 34). Principal component analysis revealed three factors to clarify for the observed variance of the environmental variables. The mean values of the physicochemical parameters of the river water at the sampling sites were consistently higher than the levels specified by WHO and other regulatory bodies and qualify as polluted water. The presence of the coliform bacteria in these water samples warrants for proper measure to reduce the pollution at the point source and proper remediation strategies to combat contamination in the domestic water usage from river Damodar from this site and downstream.

In vitro synergistic effect of doxycycline & ofloxacin in combination with ethanolic leaf extract of Vangueria spinosa against four pathogenic bacteria.

BACKGROUND & OBJECTIVES: The in vitro antibacterial activity of ethanolic leaf extract of Vangueria spinosa Roxb. (Rubiaceae) alone and in combination with antibiotics (doxycycline and ofloxacin) by means of fractional inhibitory concentration indices (FICI) as well as by the use of time-kill assays against one Gram-positive bacterium (Staphylococcus aureus) and three Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) was studied. METHODS: Antibacterial activity was assayed by using the microdilution method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for the ethanolic leaf extract of V. spinosa alone and also in combination with antibiotics using the fractional inhibitory concentration (FIC) and time-kill assay method. Synergism was also tested using checker board dilution method. RESULTS: MIC/MBC values for ethanolic leaf extract of V. spinosa against all the tested bacteria ranged between 25.5-52.6/22.4-60.5 microg/ml, for doxycycline 4.0/4.0-4.5 microg/ml and for ofloxacin 0.625-2.5/1. 25-5.0 microg/ml respectively. The average log reduction in viable cell count in time-kill assay ranged between 2.4 log(10)-4.5 log(10) cfu/ml after 1 h of interaction and between 3.9 log(10)-5.0 log(10) cfu/ml after 3 h interaction in 1 x MIC to 4 x MIC. When leaf extract and antibiotics were combined, the average log reduction in viable cell count for doxycycline from 1.5 log(10)-5.18 log(10) cfu/ml and for ofloxacin 3.06 log(10)-5.39 log(10) cfu/ml. Synergistic actions were observed in all the cases except against P. aeruginosa which showed an additive effect for ofloxacin and plant extract combination. INTERPRETATION & CONCLUSION: This study provides a preliminary report of synergistic activity of V. spinosa Roxb, ethanolic leaf extract with antibiotics.

Antibacterial potentiality of Argemone mexicana solvent extracts against some pathogenic bacteria.

The sensitivity of two Gram positive (Staphylococcus aureus and Bacillus subtilis) and two Gram negative (Escherichia coli and Pseudomonas aeruginosa) pathogenic multi-drug resistant bacteria was tested against the crude extracts (cold aqueous, hot aqueous, and methanol extracts) of leaves and seeds of Argemone mexicana L. (Papaveraceae) by agar well diffusion method. Though all the extracts were found effective, yet the methanol extract showed maximum inhibition against the test microorganisms followed by hot aqueous extract and cold aqueous extract.

Antibacterial potentiality of Argemone mexicana solvent extracts against some pathogenic bacteria

The sensitivity of two Gram positive (Staphylococcus aureus and Bacillus subtilis) and two Gram negative (Escherichia coli and Pseudomonas aeruginosa) pathogenic multi-drug resistant bacteria was tested against the crude extracts (cold aqueous, hot aqueous, and methanol extracts) of leaves and seeds of Argemone mexicana L. (Papaveraceae) by agar well diffusion method. Though all the extracts were found effective, yet the methanol extract showed maximum inhibition against the test microorganisms followed by hot aqueous extract and cold aqueous extract.