Antimicrobial extract

A product from brown seaweed, Ascophyllum nodosum, has been shown to reduce E. coli 0157 shedding when fed at 2% dry matter intake in challenge studies (Bach et ah, 2008) and in feedlot trials (Braden et ah, 2004). The brown seaweed product also increased carcass marbling scores (Braden et ah, 2007) and although the antimicrobial extract of brown seaweed phlorotannin did reduce starch fermentation at high levels in vivo (Wang et ah, 2008), no effect on lamb growth was observed (Bach et ah, 2008). 

In this form of assay, the extract or pure compound is run on a TLC plate, which IS then covered by a medium seeded with the appropriate microorganism. As with direct bioautographic assays, both fungi and bacteria may be investigated. Rahalison et al. (54) have applied this technique for the evaluation of antimicrobial extracts against the yeast Candida albicans and the bacterium Bacillus subtilis. 

Mekkerdchoo, O., Patipasena, P, and Borompichaichartkul, C. 2009. Liposome encapsulation of antimicrobial extracts in pectin film for inhibition of food spoilage microorganisms. Asian J. Food Agro-Ind. 2 817-838. 

Numerous potential antimicrobials have been considered. Allyl isothiocyanate, an antimicrobial extracted from plants, has been approved as an additive in Japan - diffusing as a vapour it can extend the shelf life of meat, fish and cheese. 

In this method, the antimicrobial extracts are incorporated into live feed organisms such as Anemia or rotifers either directly or indirectly to ensure the complete acceptability of the incorporated compounds. This is the simplest and most effective method of delivering antimicrobial extracts to the early fish and shrimp post-larvae of PL 1-20. The herbal extracts are emulsified by mixing herbal extracts, egg yolk and cod liver oil in a ratio of 1 1 1. The enrichment schedule is 200 mg of emulsified diet mixed with 100 ml water and the nauplii density is 100/ml. After enrichment at several intervals they will be ready to use for feeding. 

Contraction in the number of EPA-allowed biocides has heightened efforts to develop naturally derived preservatives and microorganisms capable of countering microbial degradation. Neem oil A. dirachta indica seed extract) has been featured as an exceptional natural candidate for the preservation of cosmetic products. Naturally derived chemicals with antimicrobial properties have been used since antiquity as preservatives. However, displacement of successhil synthetic products by natural products in preservatives of any category remains to be witnessed. 

Astringents are designed to dry the skin, denature skin proteins, and tighten or reduce the size of pore openings on the skin surface. These products can have antimicrobial effects and are frequendy buffered to lower the pH of skin. They are perfumed, hydro-alcohoHc solutions of weak acids, such as tannic acid or potassium alum, and various plant extracts, such as bitch leaf extract. The alcohol is not only a suitable solvent but also helps remove excess sebum and soil from the skin. After-shave lotions generally function as astringents. 

The major dasses of antibiotics are secondary metabolic products of micro-organisms. Many were discovered by empirically screening culture filtrates or cell extracts for antimicrobial activity. A range of techniques (examples are methods using, impregnated discs, porous cylinders, cut wells, see Figure 6.2) have been used to carry out such screening. 

Antibiotics are produced by fermentation. The process may take a few days to obtain an extractable amount of product. Antibiotic production is done by the batch process. Oxygen transport is the major concern therefore sufficient polymeric sugar and protein with a trace amount of elemental growth factors are used to enhance production. An anti-biogram test is used to observe the amount of antimicrobial agent in the fermentation broth. A bioassay determines the activity unit of the bactericides. 

Plant Material - The yellow heartwood was separated from the sapwood of JL, tullplfera and air dried before grinding. Other plant parts (leaf, stem bark, root bark, root, fruit, and flower) were collected, but alcoholic extracts showed no antimicrobial activity. 

Extraction and Separation of Alkaloids - The air-dried ground heart-wood (2.2 kg) was extracted by percolation at room temperature with alcohol USP until a negative alkaloid test of the percolate was observed. Removal of the solvent at reduced pressure and at 40° left 71 g of residue that exhibited antimicrobial activity. A 35 g sample of the alcohol-soluble residue was partitioned between 125 ml each of ether and 2Z citric acid In water. The ether layer was extracted twice more with 125 ml of 2% citric acid, filtered to remove some lnterfaclal solids (5.8 g alkaloid negative, no antimicrobial activity), dried (sodium sulfate), and evaporated to dryness, giving 8.6 g of ether solubles that had no antimicrobial activity. 

The aqueous citric acid layers were combined, adjusted to pH 9-10 with ammonia, and extracted three times each with 1 liter of chloroform. The aqueous layer was neutralized, and a portion was evaporated to dryness and found to have no antimicrobial activity. 

The active chloroform-soluble residue (6.2 g) was separated into tertiary phenolic and nonphenolic fractions by dissolving the residue in 250 ml of chloroform and extracting three times each with 250 ml of 5% sodium hydroxide solution. After drying, the chloroform solution was evaporated to leave 4.7 g of tertiary nonphenolic alkaloids that possessed all of the antimicrobial activity. 

The combined aqueous solution of the base layers was treated with an excess of ammonium chloride until a cloudy suspension was noted. This suspension was extracted three times with an equal volume of chloroform. The chloroform layer, after washing with water and drying (sodium sulfate), was evaporated to give 1.4 g of tertiary phenolic bases that had no antimicrobial activity. 

Table II - Antimicrobial Activity of Extracts, Fractions, and Compounds...

Phenylacetic acid has been detected in fermented soya bean made with the strain Bacillus licheniformis as a starter, but has not been present in extracts of nonfermented soya bean. The phenylacetic acid produced by Bacillus licheniformis during the fermentation of soya bean is one of the main compounds of antimicrobial activity of Chungkook-Jang, a traditional Korean fermented-soya bean food with antimicrobial properties (Kim and others 2004). 

The extracts of T. affinis, T. arborea, T. divaricata, T. heyrteana, and T. pandacaqui showed some degree of antitumor activity, whereas the extracts of T. malaccensis, T. dichotoma, and T. crassa exhibited hypotensive effects (9). Recently a systematic antimicrobial, antiamoebic, and antiviral screening of 19 different Tabernaemontana species has been carried out with positive results (218). 

Engel S, Puglisi MP, Jensen PR, Fenical W (2006) Antimicrobial activities of extracts from tropical Atlantic marine plants against marine pathogens and saprophytes. Mar Biol 149 991-1002... 

Consider using antimicrobial essential oils or perfumes extracted from plants in place of proprietary preservatives to make products with natural protection claims. 

A variety of methods were developed for the identification and determination of the antimicrobial nitrofurans. They include LC, colorimetric and polarographic methods. Nitrofurans could be determined in animal tissues by extraction with acetonitrile, SPE and LC-UVD533. An LC-UVD method was statistically validated for the determination of nitrofuran drug residues in poultry534. 

About 120 chemical constituents have been identified in chamomile as secondary metabolites, including 28 terpenoids, 36 flavonoids and 52 additional compounds [4]. A substantial part of drag effects are determined by the essential oil content. Oil is collected from flower heads, either by steam distillation or solvent extraction, for yields of 0.24-1.90% of fresh or dry plant tissue. Among the essential oil constituents the most active are /-/-a-bisabolol and chamazulene. /-/-a-bisabolol has demonstrated anti-inflammatory, antispasmodic, antimicrobial, antiulcer, sedative and CNS activity. Chamazulene is also anti-inflammatory. Topical applications of chamomile preparation have shown benefit in the treatment of eczema, dermatitis and ulceration [5]. 

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