Heat stable antimicrobial activity of Allium ascalonicum against bacteria and fungi.

To study antimicrobial activity of shallot in comparison with that of garlic and onion against 23 strains of fungi and bacteria, water extracts of garlic, shallot and onion bulbs were prepared. Each extract was studied in different forms for their antimicrobial activity viz., fresh extract, dry extract and autoclaved extract. Minimal inhibitory concentration and minimal lethal concentrations of these extracts were determined against all organisms by broth dilution susceptibility test. Fresh extract of garlic showed greater antimicrobial activity as compared to similar extracts of onion and shallot. However, dried and autoclaved extracts of shallot showed more activity than similar extracts of onion and garlic. Fungi were more sensitive to shallot extract than bacteria. Amongst bacteria, B. cereus was most sensitive (MIC=5 mg ml(-1)). The lowest minimum bactericidal concentration of shallot extract amongst bacteria tested was 5 mg ml(-1) for B. cereus. Amongst fungi, Aureobasidium pullulans and Microsporum gypseum were most sensitive (MIC= 0.15 mg ml(-1)). The lowest minimum lethal concentration was 2.5 mg ml(-1) for Microsporum gypseum and Trichophyton mentagrophytes. It was therefore, expected that the antimicrobial principle of shallot was different than the antimicrobial compounds of onion and garlic. In addition, the antimicrobial component of the shallot extract was stable at 121 degrees C.

In Vitro antibacterial activity of Shallot [Allium ascalonicum] crude juice

Shallot [Allium hirtifolium Bosis] belongs to genus Liliaceae There is more than 500 species in this genus. Shallot produces a cluster of bulbs from a single planted bulb. This plant has been used as an additive in foods for many years, but there is little study about antibacterial activity of Shallot. The aim of this study was to determine antibacterial activity of Shallot against clinical isolated bacteria. Crude juice of shallot [Allium hirtifolium] was tested for it's growth inhibitory effect on 4 Gram-negative and 2Gram-positive species Minimal inhibitory concentration [MIC] was determined using dilution method. All test organisms were inhibited by shallot juice. The MIC for Gram-negative enteric rods including Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis ranged between 78-624 micro /ml. while the MIC for pseudomonas aeruginosa was 20-80mg/ml.The MIC for Gram -positive bacteria including Staphylococcus aureus strains and Staphylococcus epidermidis strains were 156-312 micro /ml and 19.5-78 micro /ml respectively. It is concluded that Crude juice of shallot has antibacterial activity against both gram positive cocci and Gram-negate rods. It is believed that antibacterial activity of shallot depends on its thiosulfinate components