scholarly journals Antimicrobial properties of plant secondary metabolites

2004 ◽  
Vol 63 (4) ◽  
pp. 621-629 ◽  
Author(s):  
R. John Wallace

Increasing awareness of hazards associated with the use of antibiotic and chemical feed additives has accelerated investigations into plants and their extracts as feed additives. The present review mainly discusses two classes of plant secondary compounds in this context, i.e. essential oils and saponins. The broader potential of plants and their extracts is illustrated by the progress of an EC Framework 5 project, ‘Rumen-up’. Dietary inclusion of a commercial blend of essential oils causes markedly decreased NH3production from amino acids in rumen fluid taken from sheep and cattle. This effect is mediated partly by the effects on hyper-NH3-producing bacteria and the protein- and starch-fermenting rumen bacterium,Ruminobacter amylophilus. Saponin-containing plants and their extracts suppress the bacteriolytic activity of rumen ciliate protozoa and thereby enhance total microbial protein flow from the rumen. The effects of some saponins are transient, because saponins are hydrolysed by bacteria to their corresponding sapogenin aglycones, which are much less toxic to protozoa. Saponins also have selective antibacterial effects that may prove useful in, for example, controlling starch digestion. The ‘Rumen-up’ project began with a targetted collection of European plants and their extracts, which partners have tested for their effects on rumen proteolysis, protozoa, methanogenesis and lactate production. A success rate of about 5% in terms of positive hits illustrates that plant secondary compounds, of which essential oils and saponins comprise a small proportion, have great potential as ‘natural’ manipulators of rumen fermentation to benefit the farmer and the environment in the future.

2008 ◽  
Vol 48 (2) ◽  
pp. 175 ◽  
Author(s):  
D. N. Kamra ◽  
A. K. Patra ◽  
P. N. Chatterjee ◽  
Ravindra Kumar ◽  
Neeta Agarwal ◽  
...  

Plants rich in secondary metabolites (saponins, tannins, essential oils, etc.) have antimicrobial activity which can be exploited for selective inhibition of a particular group of microbes in the rumen. We have screened a large number of plant extracts for their potential to inhibit methanogenesis and ciliate protozoa in an in vitro gas production test using buffalo rumen liquor as the inoculum. Out of 93 plant extracts tested, 11 inhibited in vitro methanogenesis to the extent of 25–50% and nine plant extracts inhibited methanogenesis more than 50%. Among 20 extracts exhibiting antimethanogenic activity, nine were ethanol extracts, 10 were methanol extracts and only one was a water extract. Some of these plant extracts inhibited ciliate protozoa as tested by microscopic examination and 14C-labelled radioisotopic technique, but the protozoa inhibition was not correlated with methane inhibition, indicating that the methanogens sensitive to plant secondary metabolites may or may not be having any symbiotic relationship with ciliate protozoa. Methane inhibition was accompanied by a drastic fall in the number of methanogens as determined by real time PCR. Plants that appeared to have some potential as feed additives to control methanogenesis by the ruminants are: (i) seed pulp of Sapindus mukorossi (rich in saponins) and Terminalia chebula (rich in tannins); (ii) leaves of Populus deltoides, Mangifera indica and Psidium guajava (rich in tannins and essential oils); and (iii) flower buds of Syzygium aromaticum and bulb of Allium sativum (rich in essential oils). Some of the plants reported in literature exhibiting antimethanogenic activity include Equisetum arvense, Lotus corniculatus, Rheum palmatum, Salvia officinalis, Sapindus saponaria, Uncaria gambir and Yucca schidigera.


2021 ◽  
Author(s):  
◽  
Hannah Allen

Concerns and changes in policy related to use of antimicrobials in livestock has led to increased interest in using alternative feed additives such as essential oils (EO). Essential oils are plant secondary metabolites with characteristic odors. Essential oils are reported to alter ruminal fermentation (Hart et al., 2008) and animal performance (Calsamiglia et al., 2007). There is also evidence to suggest that EOs may manipulate feeding behavior in cattle (Tager and Krause, 2011). An experiment was conducted to evaluate the effects of a blend of EO in a commercially available complete feed (MFA Cattle Charge, MFA Inc., Columbia, MO) on performance, health, and feeding behavior of steers during the backgrounding phase. Eighty beef steers (initial BW = 267 [plus or minus] 2.6 kg) were obtained from 3 different sources and assigned risk groups based on distance traveled, previous health management, and incidence of disease. Pen fed EO tended (P = 0.09) to have a greater DMI than control. After 56 days on feed, steers exposedto moderate stress and fed EO had greater BW than steers exposed to moderate stress and fed control, but EO had no impact on final BW among steers exposed to small or large amounts of stress. Addition of EO did not have an effect on concentrations of anti-egg albumin IgG (P = 0.99). Under conditions of this experiment, inclusion of essential oils in a complete feed appeared to improve dry matter intake and weight gain in calves during the backgrounding phase. Meal intervals among calves in this study was 28 minutes and 40 seconds between the end time of a feeding event and start time of the next feeding event. Addition of EO to a complete feed influenced feeding rate through an interaction between treatment and days on feed (P = 0.02). Specifically, feeding rate was greater on days 11 and 44 in steers offered EO than steers offered control. Addition of EO to a complete feed may improve animal performance, health, and feeding behavior but under the conditions of this experiment, cattle source influenced the response to EO supplementation.


2018 ◽  
Vol 40 ◽  
pp. 2
Author(s):  
Maria Vanaina Souza Gonçalves ◽  
Luiz Everson da Silva ◽  
Wanderlei Amaral Do Amaral ◽  
Diomar Augusto de Quadros ◽  
Rodrigo Arantes Reis ◽  
...  

Plant secondary metabolites have attracted considerable attention from the industry as consumers are increasing their interest for natural products over chemically synthesized reagents to be used as additives in food, cosmetics or pharmaceuticals. Some plant essential oils show significant antimicrobial properties and this could be exploited to produce new food preservatives or novel antimicrobial formulations. Here we describe the extraction, chemical analysis and antimicrobial properties of grass lemon Cymbopogon citratus and Cymbopogon flexuosus essential oils. Essential oils were extracted from dried leaves using hydrodestilation and their composition was established by gas chromatography coupled to mass spectrometry. Agar diffusion assays indicated that C. citratus and C. flexuosus essential oils act as antimicrobial agents against both gram negative and gram positive model organisms.  These data support that lemon grass essential oils can be used as an alternative for microbiological control.


2017 ◽  
Vol 2 (6) ◽  
pp. 63 ◽  
Author(s):  
Diky Ramdani ◽  
Abdul S. Chaudhry ◽  
Iman Hernaman ◽  
Chris J. Seal

Tea leaves are a rich source of plant secondary metabolites such as tannins and saponins that have the potential to manipulate rumen fermentation and to lessen methane (CH4) production.Samples of green tea (GTL), black tea (BTL), their spent leaves after water extraction (SGTL and SBTL), ryegrass hay (RH), ryegrass silage (RS), paddy straws (PS), barley straws (BS), and wheat straws (WS) were compared for their rumen in-vitro organic matter degradability (IVOMD, g/kg DM), pH, ammonia (NH3, mg/L), total volatile fatty acids (tVFA, mmol/L), total gas production (tGP, L/kg OM), and methane output (CH4,L/kg OM) after 28h incubation with buffered rumen fluid under anaerobic conditions at 39oC in glass syringes. One-way ANOVA on Minitab 16 was used to examine differences between products at P<0.05 for four replicate samples. There were no differences between tea leaf products, RH and RS but the straws tended to have lower IVOMD compared with tea leaf products and other forages. GTL produced the lowest NH3 followed by BTL, SGTL, SBTL, and other forages. There were no differences between most tea leaf products, RH, RS, and the straws for tVFA concentration but PS and WS produced the lowest tVFA. GTL, SGTL, and RH had higher tGP than BTL, SBTL, and the straws but they had a lower tGP than RS. GTL, BTL, and SBTL produced similar levels of CH4 as the straws but this was less than RS and SGTL. The results suggest that if tea leaf products are included in the straw-based diets as natural feed additives, they may improve degradability, tVFA, NH3,and tGP production without increasing CH4 output. Low NH3 production for tea leaf products could be the sign of more by-pass protein to be absorbed in small intestine.Keywords: Tea leafproducts, in-vitro measurements, and ruminants.


Author(s):  
Hayrettin Çayıroğlu

Essential oils are secondary compounds obtained from several parts of plants. They play an important role in the protection of the plants as antibacterials, antivirals, antifungals, insecticides in nature. Along with the prohibition of the use of antibiotics as feed additives in a lot of countries around the world, scientists have accelerated the search for safer and more natural feed additive. In this respect, essential oils and their active components have come to the fore as an alternative feed ingredient. In this review, effects of essential oils on feed intake, feed efficiency, nutrient digestibility, rumen fermentation, milk yield and its composition in dairy cattle were evaluated.


2020 ◽  
Vol 26 (5) ◽  
pp. 519-541 ◽  
Author(s):  
Giovanna Ferrentino ◽  
Ksenia Morozova ◽  
Christine Horn ◽  
Matteo Scampicchio

Background: The use of essential oils is receiving increasing attention worldwide, as these oils are good sources of several bioactive compounds. Nowadays essential oils are preferred over synthetic preservatives thanks to their antioxidant and antimicrobial properties. Several studies highlight the beneficial effect of essential oils extracted from medicinal plants to cure human diseases such as hypertension, diabetes, or obesity. However, to preserve their bioactivity, the use of appropriate extraction technologies is required. Method: The present review aims to describe the studies published so far on the essential oils focusing on their sources and chemical composition, the technologies used for their recovery and their application as antioxidants in food products. Results: The review has been structured in three parts. In the first part, the main compounds present in essential oils extracted from medicinal plants have been listed and described. In the second part, the most important technologies used for extraction and distillation, have been presented. In detail, conventional methods have been described and compared with innovative and green technologies. Finally, in the last part, the studies related to the application of essential oils as antioxidants in food products have been reviewed and the main findings discussed in detail. Conclusions: In summary, an overview of the aforementioned subjects is presented by discussing the results of the most recent published studies.


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2124
Author(s):  
Giulia Vanti ◽  
Ekaterina-Michaela Tomou ◽  
Dejan Stojković ◽  
Ana Ćirić ◽  
Anna Rita Bilia ◽  
...  

Food poisoning is a common cause of illness and death in developing countries. Essential oils (EOs) could be effective and safe natural preservatives to prevent and control bacterial contamination of foods. However, their high sensitivity and strong flavor limit their application and biological effectiveness. The aim of this study was firstly the chemical analysis and the antimicrobial evaluation of the EOs of Origanum onites L. and Satureja thymbra L. obtained from Symi island (Greece), and, secondly, the formulation of propylene glycol-nanovesicles loaded with these EOs to improve their antimicrobial properties. The EOs were analyzed by GC-MS and their chemical contents are presented herein. Different nanovesicles were formulated with small average sizes, high homogeneity, and optimal ζ-potential. Microscopic observation confirmed their small and spherical shape. Antibacterial and antifungal activities of the formulated EOs were evaluated against food-borne pathogens and spoilage microorganisms compared to pure EOs. Propylene glycol-nanovesicles loaded with O. onites EO were found to be the most active formulation against all tested strains. Additionally, in vitro studies on the HaCaT cell line showed that nanovesicles encapsulated with EOs had no toxic effect. The present study revealed that both EOs can be used as alternative sanitizers and preservatives in the food industry, and that their formulation in nanovesicles can provide a suitable approach as food-grade delivery system.


2014 ◽  
Vol 463 (2) ◽  
pp. 137-145 ◽  
Author(s):  
Ioannis Liakos ◽  
Loris Rizzello ◽  
David J. Scurr ◽  
Pier Paolo Pompa ◽  
Ilker S. Bayer ◽  
...  

Molecules ◽  
2012 ◽  
Vol 17 (4) ◽  
pp. 3989-4006 ◽  
Author(s):  
Imaël Henri Nestor Bassolé ◽  
H. Rodolfo Juliani

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