Antimicrobial activity of Pelargonium essential oils added to a quiche filling as a model food system

Distinct metabolic pathways drive monoterpenoid biosynthesis in a natural population of Pelargonium graveolens

Pelargonium graveolens is a wild predecessor to rose-scented geranium hybrids prized for their essential oils used as fragrances and flavorings. However, little is known about their biosynthesis. Here we present metabolic evidence that at least two distinct monoterpene biosynthetic pathways contribute to their volatile profiles, namely, cyclic p-menthanes such as (-)-isomenthone and acyclic monoterpene alcohols such as geraniol and (-)-citronellol and their derivatives (referred to here as citronelloid monoterpenes). We established their common origin via the 2C-methyl-d-erythritol-4-phosphate pathway but found no indication these pathways share common intermediates beyond geranyl diphosphate. Untargeted volatile profiling of 22 seed-grown P. graveolens lines demonstrated distinct chemotypes that preferentially accumulate (-)-isomenthone, geraniol, or (-)-citronellol along with approximately 85 minor volatile products. Whole plant 13CO2 isotopic labeling performed under physiological conditions permitted us to measure the in vivo rates of monoterpenoid accumulation in these lines and quantify differences in metabolic modes between chemotypes. We further determined that p-menthane monoterpenoids in Pelargonium are likely synthesized from (+)-limonene via (+)-piperitone rather than (+)-pulegone. Exploitation of this natural population enabled a detailed dissection of the relative rates of competing p-menthane and citronelloid pathways in this species, providing real time rates of monoterpene accumulation in glandular trichomes.

The Phytochemical Composition, Biological Effects and Biotechnological Approaches to the Production of High-Value Essential Oil from Geranium

Geraniaceae family plants are highly reputed aromatic and medicinal perennial branched herbs. The high economic value of these plants is due to their secondary metabolites, especially essential oil of foliage, which is a complex mixture of volatile phytochemicals, such as terpenes, esters, aldehydes, alcohols, ketones and phenols. The main phytoconstituents of the essential oil belong to the terpenoid group of metabolites, such as monoterpenes, sesquiterpenes, diterpenes and their esters. Of these, geraniol, linalool, citronellol and their esters (50–70%) generally constitute a major portion of essential oil, responsible for its fragrance. Essential oil is biosynthesized in specialized tissues known as glandular trichomes present in leaves, green branches and fresh flowers. Geraniaceae family plants have been highly useful in the perfumery, cosmetics, aromatherapy, pharmaceuticals and food industries. Several pharmacological properties such as antifungal, anti-inflammatory, anti-cancerous, anti-depressant, antibacterial, antioxidant, antiseptic, anti-dysentery, and antidiabetic properties are attributed to the presence of geranium oil. Further, it improves blood circulation, treats congestion, cleans the lymphatic system, strengthens the immune system, and is effective in combating nervousness, constipation, insomnia, anxiety and high blood pressure. The chapter discusses the phytochemical composition, pharmacological properties, genomics of essential oil biosynthetic pathway, enhancement of essential oil yield, and several biotechnological approaches to enhance the quantity as well as quality of essential oil in geranium.

Fertilization and colors of plastic mulch affect biomass and essential oil of sweet-scented geranium

Sweet-scented geranium (Pelargonium graveolens L'Hér), a plant belonging to the Geraniaceae family, has medicinal and aromatic properties and is widely used in the cosmetic, soap, perfume, aromatherapy, and food industries. The aim of this study was to evaluate the influence of fertilization and the use of different colors of plastic mulch on sweet-scented geranium biomass and essential oil. Three colors of plastic mulch (black, white, and silver-colored) and a control without plastic mulch were assessed along with three fertilizers (20,000 L · ha(-1) of cattle manure; 1,000 kg · ha(-1) of NPK 3-12-6; and 20,000 L · ha(-1) of cattle manure + 1,000 kg · ha(-1) of NPK 3-12-6 fertilizer) and a control without fertilizer. The absence of a soil cover negatively influenced the agronomical variables, while coverage with plastic mulch was associated with increased biomass. The use of fertilizer had no effect on the evaluated agronomic variables. When cattle manure and NPK 3-12-6 were used together, combined with white or black plastic mulch, the highest yields of essential oil were obtained. For the silver-colored plastic mulch, higher amounts of essential oil (6,9-guaiadien) were obtained with mineral fertilizer.

Bacteriology of a most popular street food (Panipuri) and inhibitory effect of essential oils on bacterial growth

Bacteriology of Panipuri was studied and the antibacterial effect of eight essential oils (EOs) was established on pathogens found in Panipuri. Samples were collected from twelve respective vendors from different locations in Baripada city, Orissa. Samples were fractionated into two parts viz. khatta pani and smashed potato masala used in Panipuri. Total plate count and isolation of pathogenic bacteria were done on both basal and selective media. Coliforms were detected primarily by presumptive test and confirmed subsequently, using Eosine Methylene Blue Agar. Selected colonies were pure cultured and identified through staining and an array of biochemical reactions. Antibiogram pattern of the pathogens and their susceptibility towards eight different EOs were performed. Antibacterial efficacy of four EOs in food sample was studied. Aerobic bacterial load of solid samples was observed to be more than in the liquid samples. Coliform-positive samples were found to be of 80.33%. Pathogenic bacteria like Escherichia coli, Klebsiella sp., Enterobactor sp., Bacillus sp., Enterococcus sp., Micrococcus tetragens, Salmonella paratyphi, Shigella dysenteriae and Vibrio sp. were detected. Antibiogram studies of the isolates showed multiple antibiotic resistance index (MRI;%) ranging from 15 to 92%. Among the EOs studied Cinnamon and Clove oils showed maximum antibacterial activity. Antibacterial efficacy showed that Clove and Cinnamon oils were comparatively of superior quality than Turmeric leaf and Japanese mint oils to kill food borne pathogens. Although it was a preliminary endeavor, the present study is a prerequisite in understanding the significance of pathogenic microorganisms in street foods and use of EOs as both antibacterial agents and food preservatives.

The effect of cinnamomi aetheroleum used per os on fat content in broilers meat

The aim of the topic was to verify the effect of feed mixtures enriched with 0.1, 0.05 and 0.025% proportion of cinnamomi aetheroleum to the fat content in chicken meat with skin. The type of broilers Ross 308 was used within experiment. Cinnamomi aetheroleum was mixed with the corn flour and homogenized with other stuff of feed mixtures. Broilers were fed ad libitum. The content of fat was analyzed by chemical analyze of meat with skin which took place in the end of the experiment. The results of experiment show, that decreasing of cinnamomi aetheroleum proportion in feed mixture increased body weight and the weight of broilers carcass, whereby differences were statistically significant between broilers groups, which were fed with feed mixtures with 0.1% and 0.025% proportion of cinnamomi aetheroleum and with 0.05% and 0.025% proportion of cinnamomi aetheroleum. Lowest content of fat 9.5 g.100 g-1 in broilers meat with skin was in meat of broilers which were fed with feed mixtures with 0.05% proportion of cinnamomi aetheroleum. At 0.01% cinnamomi aetheroleum proportion in feed mixture 9.9 g.100 g-1 of fat content was noticed and the content of fat in broilers meat with skin increased to 10.45 g.100 g-1 at 0.025% proportion of cinnamomi aetheroleum. Differences in fat content between groups were not statistically significant.

Safety assessment of coriander (Coriandrum sativum L.) essential oil as a food ingredient

Coriander essential oil is used as a flavor ingredient, but it also has a long history as a traditional medicine. It is obtained by steam distillation of the dried fully ripe fruits (seeds) of Coriandrum sativum L. The oil is a colorless or pale yellow liquid with a characteristic odor and mild, sweet, warm and aromatic flavor; linalool is the major constituent (approximately 70%). Based on the results of a 28 day oral gavage study in rats, a NOEL for coriander oil is approximately 160 mg/kg/day. In a developmental toxicity study, the maternal NOAEL of coriander oil was 250 mg/kg/day and the developmental NOAEL was 500 mg/kg/day. Coriander oil is not clastogenic, but results of mutagenicity studies for the spice and some extracts are mixed; linalool is non-mutagenic. Coriander oil has broad-spectrum, antimicrobial activity. Coriander oil is irritating to rabbits, but not humans; it is not a sensitizer, although the whole spice may be. Based on the history of consumption of coriander oil without reported adverse effects, lack of its toxicity in limited studies and lack of toxicity of its major constituent, linalool, the use of coriander oil as an added food ingredient is considered safe at present levels of use.

Effects of essential oils of oregano and nutmeg on growth and survival of Yersinia enterocolitica and Listeria monocytogenes in barbecued chicken

The in vitro effects of plant essential oils (EOs) against pathogenic bacteria are well known, yet few studies have addressed the effects of these compounds against pathogens associated with ready-to-cook foods. Experiments were conducted to determine the effectiveness of oregano and nutmeg EOs on the growth and survival of Yersinia enterocolitica and Listeria monocytogenes in broth culture and in Iranian barbecued chicken. Ready-to-cook Iranian barbecued chicken was prepared according to the common practice with 1, 2, and 3 microl/g of oregano and nutmeg EOs. The test and control (without EOs) samples were inoculated with Y. enterocolitica and L. monocytogenes to a final concentration of 6 to 7 log CFU/g and stored at 3, 8, and 20 degrees C. Microorganisms were counted just before and at 24, 48, and 72 h after storage based on growth on Yersinia selective agar supplemented with cefsulodine, igrasan, and novobiocin and on Listeria selective agar supplemented with nalidixic acid and acriflavin. In the broth culture system, the nutmeg EO had a greater effect on L. monocytogenes (MIC = 0.20 nicrol/ml) than did the oregano EO (MIC = 0.26 microl/ml). However, the oregano EO had a greater effect on Y. enterocolitica (MIC = 0.16 microl/ml) than did the nutmeg EO (MIC = 0.25 microl/ml). In ready-to-cook Iranian barbecued chicken, the log CFU per gram of both bacteria after up to 72 h of incubation was not decreased significantly by various combinations of oregano and nutmeg EOs (1, 2, and 3 microl/g) and storage temperatures (3, 8, and 20 degrees C) when compared with control samples (without EOs). Although examination of spices in culture media can yield accurate microbiological data, without complementary tests in foods these data are of limited value for assessing food safety.

Application of Origanum majorana L. essential oil as an antimicrobial agent in sausage

This work reports on the antimicrobial activity in fresh sausage of marjoram (Origanum majorana L.) essential oil against several species of bacteria. The in vitro minimum inhibitory concentration (MIC) was determined for 10 selected aerobic heterotrophic bacterial species. The antimicrobial activity of distinct concentrations of the essential oil based on the highest MIC value was tested in a food system comprising fresh sausage. Batch food samples were also inoculated with a fixed concentration of Escherichia coli and the time course of the product was evaluated with respect to the action of the different concentrations of essential oil. Results showed that addition of marjoram essential oil to fresh sausage exerted a bacteriostatic effect at oil concentrations lower than the MIC, while a bactericidal effect was observed at higher oil concentrations which also caused alterations in the taste of the product.

Antimicrobial activity of some essential oils against microorganisms deteriorating fruit juices

Seventeen microbial species including 10 fungal taxa, two yeasts and five bacteria, were isolated from freshly prepared orange, guava and banana juices kept in open bottles at room temperature for 7 days. Eight different essential oils, from local herbs, were tested for their antimicrobial activity against these test organisms. The essential oils of Cymbopogon citratus, Ocimum basilicum and Origanum majorana were found to be highly effective against these microorganisms. Aspergillus niger, A. flavus and Saccharomyces cerevisiae, the most prevalent microorganisms in juice, showed the highest resistance against these essential oils. GC-MS analysis showed that while e-citral, a'-myrcene, and z-citral represent the major components (75.1%) of the essential oil of Cymbopogon citratus; bezynen,1-methyl-4-(2-propenyl), 1,8-cineole and trans-a'-bisabolene were the main components (90.6%) of Ocimum basilicum; whereas 3-cyclohexen-1-01,4-methyl-1(1-methylethyl)-(CAS), c-terpinene and trans-caryophyllene represent the major components (65.1%) of Origanum majorana. These three essential oils were introduced into juices by two techniques namely, fumigation and direct contact. The former technique showed more fungicidal effect than the latter one against A. flavus, A. niger, and S. cerevisiae. The essential oil of Cymbopogon citratus by comparison to other test oils showed the strongest effect against these fungi with a minimum inhibitory concentration of 1.5 µl/ml medium and a sublethal concentration of 1.0 µl/ml. The antimicrobial activity of this oil is thermostable at 121℃ for 30 min.

Influence of subinhibitory concentrations of plant essential oils on the production of enterotoxins A and B and alpha-toxin by Staphylococcus aureus

The data presented show the ability of subinhibitory concentrations of plant essential oils to influence the production of enterotoxins A and B and alpha-toxin by Staphylococcus aureus. Subinhibitory concentrations of the oils of bay, clove, cinnamon, nutmeg and thyme had no significant effect on the overall quantity of extracellular protein produced. Haemolysis due to alpha-toxin was significantly reduced after culture with all five plant essential oils. This reduction was greatest with the oils of bay, cinnamon and clove. These three oils also significantly decreased the production of enterotoxin A; the oils of clove and cinnamon also significantly decreased the production of enterotoxin B.

Topical hemostatic effect of a common ornamental plant, the geraniaceae Pelargonium zonale

Geranium has been traditionally used as a local hemostatic medicine in some Andean regions, but this effect has not been tested in controlled experiments. In the present report, the leaves of a geraniaceae (Pelargonium zonale) were tested on a bleeding rat model. The bleeding time was 50% shorter in the geranium leaf juice treatment group (18.10 +/- 2.03 min) and 80% shorter in the geranium crushed-leaf group (7.10 +/- 0.88 min) than in the control (nontreatment) group (37.6 +/- 3.04 min), p < 0.0001. Bleeding time with guava (Psidium guajava) crushed leaves (39.90 +/- 1.54 min) was not different from the control group. A proved hemostatic agent, gelatin sponge, had a similar effect as geranium juice (16.7 +/- 3.32 min) in the same animal model. A buffer solution at pH 3 (the same pH as the geranium leaf extract) did not have any hemostatic effect, and the bleeding time (39.3 +/- 2.71 min) was not different from the control group. The dilution 1:4 geranium leaf juice at pH 3(25.6 +/- 3.08 min) or pH 5 (28.8 +/- 3.98 min) still had a statistically significant hemostatic effect. The results confirm the hemostatic effect of P. zonale leaves and show that it is similar (geranium leaf juice) or better (crushed geranium leaves) than the hemostatic effect of a commercial hemostatic sponge. It seems that the hemostasis caused by P. zonale extract leaves is not due to its low pH. The potential benefits as a new, inexpensive, safe, and easily available natural topical hemostatic agent are discussed.

Antimicrobial effect of essential oils on the seafood spoilage micro-organism Photobacterium phosphoreum in liquid media and fish products

AIMS

To evaluate the antimicrobial effect of nine essential oils (EO) on P. phosphoreum and determine the effect of oregano oil on the shelf-life of modified atmosphere-packed (MAP) cod fillets.

METHODS AND RESULTS

The antimicrobial effect of EO was studied in a liquid medium and in product storage trials. Oils of oregano and cinnamon had strongest antimicrobial activity, followed by lemongrass, thyme, clove, bay, marjoram, sage and basil oils. Oregano oil (0.05%, v/w) reduced growth of P. phosphoreum in naturally contaminated MAP cod fillets and extended shelf-life from 11-12 d to 21-26 d at 2 degrees C.

CONCLUSIONS

Oregano oil reduced the growth of P. phosphoreum and extended the shelf-life of MAP cod fillets.

SIGNIFICANCE AND IMPACT OF THE STUDY

Mild and natural preservation using EO can extend the shelf-life of MAP seafood through inhibiting the specific spoilage organism P. phosphoreum.

Comparison of in vitro surface properties of clove oil-phospholipid suspensions with those of ALEC, Exosurf and Survanta

Dipalmitoyl phosphatidylcholine, the main component of lung surfactant is ineffective as a replacement surfactant due to its poor adsorption. We studied clove oil as a possible additive for improving the surface activity of protein-free phospholipid suspensions. We added low doses of clove oil, to phospholipid suspensions and studied the surface properties by in vitro analysis using a pulsating bubble surfactometer and a Wilhelmy balance. Survanta, ALEC and Exosurf were used as controls for comparison. The test surfactants, which were phospholipid-oil suspensions at 1% concentration, in buffer containing either 2 or 5 mM calcium, were pulsated at 40 cpm in a pulsating bubble surfactometer. The phospholipids studied were dipalmitoyl phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), binary mixtures of PC:PE (2:3) and PC:PG (2:3). The addition of clove oil (CO) to each of the above phospholipids was in the ratio of nine parts of phospholipid to one part of oil. The presence of CO caused a significant improvement in the adsorption and minimum surface tension of all the phospholipid suspensions studied. The mixtures PC with CO, both in the presence of 2 and 5 mM calcium, and PCPE with CO at 2 mM calcium concentration had surface properties significantly better than those of ALEC and Exosurf and equivalent to those of Survanta. The addition of clove oil helps improve the surface properties of phospholipids.

Efficacy of an herbal extract on the microbiological quality of broiler carcasses during a simulated chill

Protecta II, an herbal extract on an NaCl carrier, was evaluated in a 30-min, 1 C simulated chill for its effectiveness of lowering microbial counts on broiler carcasses. Eighteen broiler carcasses were obtained from a local processing plant after final wash but before chill, placed into an insulated container, and transported to the research facility for treatment. Six plant run controls (PRC) were immediately bagged on return to the pilot plant, and a whole-carcass rinse was performed. The remaining carcasses were subjected to a 30-min chill (1 C) in tap water or a 2% solution of Protecta II, (n = 6 per treatment). After treatment, carcasses were rinsed with tap water and subjected to the whole-carcass rinse procedure. All rinse diluents were microbiologically analyzed for total aerobes, coliforms, generic Escherichia coli, and Campylobacter. Six replications were analyzed on 6 different d for a total 36 carcasses per treatment and 36 PRC. The PRC carcasses had 3.7, 2.5, 2.1, and 2.0 log10 cfu/mL for total aerobes, coliforms, generic E. coli, and Campylobacter. Water treatment significantly reduced counts (2.6, 1.4, 0.7, and 0.9 log10 cfu/mL, respectively) when compared with the PRC. Protecta II treatment significantly reduced counts (P < 0.01) even further to counts of 0.06, 0.04, 0.01, and 0.00 log10 cfu/mL for total aerobes, coliforms, Campylobacter, and E. coli, respectively. Detectable levels of the monitored organisms were 1 cell/mL (log10 0) for the E. coli, coliforms, and total counts and 10 cells/mL (log10 1) for the Campylobacter. Microbial counts for carcasses treated with Protecta II would be considered too low to be detected (<1 cell/mL).