Oregano essential oil microcapsules for long-term non-invasive antimicrobial protection of leather artifacts

Natural plant essential oils have antimicrobial properties; however, essential oils are difficult to maintain in a system because of their volatile nature. First, we prepared microcapsules from β-cyclodextrin and oregano essential oil and characterized their properties. Second, the effect of microcapsules on the preservation of freshly cut purple yam was studied using an edible coating technique. Purple yams immersed in distilled water were used as control, and their characteristics were compared with yams coated with citric acid, citric acid + sodium alginate, and citric acid + sodium alginate + β-cyclodextrin-oregano essential oil microcapsules (CA-SA-MC) and stored at 4 °C for 5 days. Microcapsules of oregano essential oil and β-cyclodextrin solution were successfully prepared via the inclusion method, with an optimal encapsulation efficiency of 55.14%. Scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis showed strong bonds between β-cyclodextrin and oregano essential oil. All edible coatings, particularly CA-SA-MC, significantly (P ≤ 0.05) maintained firmness, total soluble solids, ascorbic acid content, and anthocyanin content compared with control treatment. This treatment also prevented browning and extended the shelf life of purple yam. Oregano essential oil can be successfully encapsulated into cyclodextrin microcapsules. It has a great impact on the shelf life extension of purple yam and could be successfully applied to other fresh produce. © 2020 Society of Chemical Industry.

The aim of the study is to evaluate antibacterial properties of commercial essential oils (Oregano, Black pepper, Coriander, Cinnamon) against oral pathogens (Streptococcus mutans, Enterococcus faecalis). Nevertheless, we want to asses if the price of the essential oils (EO) which were purchased from 2 different retailers, can influence the quality of essential oil and the antimicrobial effect. Materials and methods: Essential oils from two different Producers (A-high price range, respectively B-low price range) with two opposite price ranges were purchased from local retailers. The inhibitory effect was assessed by disk diffusion. Bacterial inoculums of 0.5 McFarland units (~1.5 x 108 CFU/ml) were prepared from Streptococcus mutans Enterococcus faecalis. Muller-Hinton agar plates were inoculated with bacterial inoculums. Sterile paper disks with the diameter of 6 mm (Bioanalyse Ltd, Turkey) were dispensed on the medium surface. Five μl of essential oils were pipetted on corresponding disks. After 10 minutes (time needed for a proper diffusion of active components), the plates were incubated in normal atmosphere at 37°C. After 24 hours of incubation, the inhibition zone diameters (in millimeters) were read and noted in spreadsheet software, aside the average price in €/ml of essential oil. A cost-efficiency antibacterial activity index was also calculated.Results:With regard to EO from Producer A, the inhibition zone against Enteroccocus ranged from the weakest 14mm(Black pepper), 28mm(Coriander) to the strongest over 40 mm(Oregano and Cinnamon). With regard to volatile essential oils from Producer B, against the Enteroccocus, the smallest inhibition zone was observed for Coriander (10 mm), followed by Black pepper(11 mm); on the opposite side, the strongest inhibition zone presented both Oregano EO and Cinnamon EO (34 mm). Against S. mutans, the weakest inhibition zone showed Black pepper(6 mm), followed by Coriander EO(12 mm) and the strongest inhibition zone had Oregano EO(38 mm) and Cinnamon EO (40 mm). All the EO from the Producer A managed to successfully inhibit S. mutans growth. In both producers, Origanum vulgare EO was the most cost-efficient against E. faecalis (index=0.06 for Producer A and 0.03 for Producer B). In the case of Producer A, against S.mutans the best index was seen at Coriandrum sativum EO (0,05) and the weakest at Cinnamonum zeylanicum (0,14). In the case of Producer B, against E. faecalis, the lowest index was seen at Piper nigrum(0,13). The same pattern was seen against S. mutans, the highest index had Origanum vulgare(0,03) and the lowest Piper nigrum (0,23) Conclusions:Most of essential oils studied from both Producers, had better antibacterial effect against S. mutans compared to E. faecalis.All the EO from the Producer A managed to successfully inhibit S. mutans growth.The high price EO had a better antimicrobial effect compared to the low price EO.The strongest antimicrobial effect against E.faecalis had the high-price Oregano and Cinnamon EO and the weakest antimicrobial effect had low-price Coriander EO. Against S. mutans, the greatest efficacy had all high-price EO, and the lowest had the low-price Black pepper EO.The high price of some EO (Piper nigrum) does not make any difference regarding the antibacterial effect. Lower price EO may be still suitable in regards of antibacterial effect if considering the associated costs, even if the effect does not reach the potency of the higher-price alternatives.

1. An experiment was conducted to determine the individual and combined effects of two essential oils, oregano and garlic, on carcass characteristics, meat composition, colour, pH and sensory quality of broiler meat.2. The diets were supplemented with no essential oil (control), oregano essential oil or garlic essential oil at 300 mg/kg and oregano essential oil at 150 mg/kg + garlic essential oil at 150 mg/kg.3. Dietary oregano and garlic oil supplementation did not affect carcass yields, the relative weight of carcass parts, breast and thigh meat composition, pH or b* value of breast meat. Oregano + garlic oil supplementation significantly decreased the L* value. The a* value of breast meat in birds given a diet supplemented with oregano oil was lower than that in birds given a diet supplemented with garlic oil and oregano oil + garlic oil. The essential oil addition had no positive effect on the oxidative stability. There was no difference between the treatments in breast appearance.4. The juiciness, flavour, oxidised flavour and acceptability of breast meat samples were affected by treatments.

Preparation and characterization of oregano essential oil microcapsules by gelatin/polysaccharide composite coagulation method

This study evaluated the effects of oregano essential oil alone and in combination with cinnamon and peppermint essential oils on intestinal microbiota, the sensory and textural properties of cooked egg's and fatty acid profile. Intestinal microbiota/fatty acid profile correlations and health index were evaluated. Lohmann LSL-LITE strain laying hens were randomly divided into four groups and fed for 28 days: a control group receiving a basal diet (C); a group supplemented with 250mg/kg oregano essential oil (O), a group receiving 125mg/kg oregano plus 125mg/kg cinnamon essential oils (O + C), and a group receiving 125mg/kg oregano plus 125mg/kg peppermint essential oils (O + P). Sensory evaluation showed that the distinctive flavors and aromas of oregano, cinnamon, and peppermint essential oils were not detected. Essential oil supplemented diet did not affect the eggs' hardness, adhesiveness, cohesiveness, and resilience properties. Shear force was found to be significantly different in group O. Assessment of nutritional indices showed that high Linoleic Acid/α-Linolenic Acid ratio has given O and O + P groups eggs potential functional properties. While the coliforms, Enterobacteriaceae, and Enterococcus spp. in the essential oil supplemented groups were reduced, and Lactobacillus spp. increased. Also, essential oil feed achieved a correlation between lactic acid bacteria and Linoleic Acid/α-Linolenic Acid, omega6/omega3 ratio. Furthermore, behenic, palmitoleic, and palmitic fatty acids positively correlated with intestinal Lactobacillus spp. As a result, laying hens feed essential oil supplementation results in potential functional eggs that offer better nutritional indices for the consumer health, which were obtained without affecting the egg's characteristics.

Cellulose acetate active films incorporated with oregano ( Origanum vulgare ) essential oil and organophilic montmorillonite clay control the growth of phytopathogenic fungi

Antimicrobial activity of whey protein based edible films incorporated with oregano, rosemary and garlic essential oils

Physical and antifungal properties of β-cyclodextrin microcapsules and nanofibre films containing cinnamon and oregano essential oils

The use of synthetic preservatives and additives in food processing is becoming less popular due to adverse health effects linked to them. Consequently, there is a rising demand by consumers for clean-label food products. This study was therefore designed to evaluate how blends of Oregano Essential Oil (OEO) and Lemon Essential Oil (LEO) as natural preservative additives at 0.05% inclusion impacted the shelf life and quality characteristics of chicken patties. Breast muscles of healthy 8-week-old broiler chickens were harvested, manually deboned and ground. One kilogram each of chicken patty emulsion was prepared in six treatment combinations as follows: (T1) No essential oil, (T2) 100% OEO, (T3) 100% LEO, (T4) 50% OEO:50% LEO, (T5) 75% OEO:25% LEO and (T6) 25% OEO:75% LEO. Each treatment was done in triplicate and arranged using a completely randomised pattern. Each emulsion was then portioned into individual patties (100 g) and cooked at 180 ℃ in an oven until they reached an internal temperature of 72 ℃. Product yield, Thiobarbituric Acid Reactive Substances (TBARS), microbial load, and physicochemical properties were measured using standard methods at days 0, 7, 14, and 21 of storage. Sensory properties of patties were also evaluated by ten trained panellists, using a 9-point hedonic scale. Data collected were analysed with ANOVA at αα-0.05. Significant differences were observed in product yield, with T4 having a significantly higher (P <0.05) product yield (0.91±0.01), comparable to Control. Treatment 4 also had significantly lower (P <0.05) TBARS on Day 14 (0.69±0.00) and Day 21 (0.69±0.00). Treatment 2 had significantly lower (P <0.05) bacteria (6.55±0.07) and fungal (1.15±0.07) count at day 21. Sensory analysis showed no significant differences at day 21. Based on its positive effects of increasing product yield and reducing lipid oxidation, 50% OEO:50% LEO (T4) is rated as the best blend of Oregano and Lemon oil in chicken patty preparation and recommended for further study.

ABSTRACTChemical composition and phytotoxicity of oregano, marjoram and Thymus mastichina essential oils against Portulaca oleracea L., Lolium multiflorum Lam. and Echinochloa crus-galli (L.) Beauv. has been investigated. Seventy-seven compounds reaching 97.3% and 99.4% were identified by gas chromatography–mass spectrometry. Carvacrol (60.42 ± 0.07%), p-cymene (15.52 ± 0.02%) and γ-terpinene (5.19 ± 0.02%) were the main compounds in oregano essential oil, whereas large amounts of 1,8-cineol (59.59 ± 0.85%, 49.49 ± 0.37%), linalool (13.05 ± 0.04%, 5.66 ± 0.01%) and α-terpineol (3.36 ± 0.10%, 5.59 ± 0.01%), followed by β-pinene (4.35 ± 0.39, 5.54 ± 0.01%) and α-pinene (4.11 ± 0.53, 4.28 ± 0.01%) were found, respectively, in marjoram and T. mastichina essential oils. Oregano essential oil completely inhibited seed germination and seedling growth at all concentrations assayed (0.125–1 µL mL−1), whereas marjoram and T. mastichina essential oils only showed significant effects in hypocotyl and/or hypocotyl + radicle length depending on the weed and dose.

Origanum vulgare L. (oregano) is an aromatic plant with wide applications in the food and pharmaceutical industries. Cronobacter sakazakii, which has a high detection rate in powdered infant formula, adversely impacts susceptible individuals. Oregano essential oil (OEO) is a natural antibacterial agent that can be used to fight bacterial contamination. Here, OEO chemical compounds from eight oregano varieties were analyzed by gas chromatography–mass spectrometry and their antibacterial properties were assessed. The eight OEOs were clustered into two groups and were more diverse in group 2 than in group 1. Six compounds, including p-cymene, 3-thujene, γ-terpinene, thymol, carvacrol, and caryophyllene, were shared by eight OEOs. Among the eight oregano varieties, OEOs from O. vulgare sc2 had the strongest antibacterial activity against C. sakazaki, with the inhibition zone of 18.22mm. OEOs from O. vulgare jx, O. ‘Nvying’, O. vulgare ‘Ehuang’, and O. vulgare ssp. virens were also potent. Moreover, the antibacterial activity of OEOs was positively correlated with the relative content of thymol. As the main OEO antibacterial compound, thymol affected the normal growth and metabolism of C. sakazakii cells by destroying the bacterial membrane and decreasing the intracellular ATP concentration. Thus, in light of the antibacterial activity detected in the OEOs from the eight oregano varieties, this study provides a theoretical foundation for oregano cultivar management and development.

An essential oil is the volatile lipophilic component extracted from plants. Microencapsulation systems protect the essential oil from degradation and evaporation, and, at the same time, allow a sustained release. This work analyses and characterizes the oregano and sage essential oil microcapsules prepared by interfacial polymerization technique, using polyurea as wall material. Several instrumental techniques are used: optical microscopy, size particle, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), Termo gravimetric analysis (TGA), spectrophotometry, antimicrobial test and chromatography. Results show that oregano and sage oil have antimicrobial properties, and their microencapsulation allows knowing that these properties remain inside the microcapsules.

Anti-Salmonella activity of pyruvic and succinic acid in combination with oregano essential oil

Oregano essential oil (OEO) has gained attention for its broad pharmacological activities, such as anti-inflammatory, antimicrobial, and anticancer properties. This study aimed to analyze the phytochemical composition and biological activity of OEO obtained from wild-growing Origanum vulgare L. in Romania. Gas chromatography–mass spectrometry (GC–MS) analysis identified p-cymene (43.98%), γ-terpinene (22.16%), and thymol (11.46%) as major constituents, with notable differences from previously reported chemotypes. Antioxidant activity was assessed using the DPPH, ABTS radical scavenging assay, and TPC. OEO has a moderate antioxidant activity, with IC50 values of 134.67 ± 1.32 µg/mL (DPPH) and 88.15 ± 0.045 Inh% (ABTS) and a TPC of 159.63 mg GAE/g extract. The cytotoxicity of the simple water dispersion of OEO, OEO solubilized with polyethylene glycol 400 (OEO-PEG), and that solubilized with Tween 20 (OEO-Tw) was evaluated on human melanoma (A375) and human colorectal adenocarcinoma (HT-29) cancer cell lines, as well as on the normal human immortalized keratinocytes (HaCaT) cell line. The results demonstrated a significant inhibition of cancer cell viability with no recorded cytotoxic effect on normal cells. The highest inhibition of cell viability was recorded for OEO-PEG 200 µg/mL (7.22% ± 6.51 in A375 cell line and 22.25% ± 10.08 in HT-29 cell line). In cancer cells, OEO and its formulations significantly reduced malondialdehyde (MDA) levels (up to 41.24% in A375 cells and up to 48.58% in HT-29 cells), suggesting potent antioxidant activity. Moreover, treatment with OEO increased caspase 3/7 activation two-fold in treated A375 cells, while high-resolution respirometry studies revealed that OEO induces mitochondrial dysfunction by acting as a potential uncoupling agent. Molecular docking analysis suggested that β-caryophyllene oxide (CPO), a minor constituent of OEO, may act as a potential inhibitor of 3-phosphoinositide-dependent protein kinase-1 (PDPK1), indicating a possible mechanism of anticancer activity. Our findings highlight the potential of OEO as a natural anticancer agent, emphasizing the need for further investigations to elucidate its exact molecular mechanisms and therapeutic applicability.

The use of essential oils (EO's) as feed additive has been explored as tool to improve fish growth and health. The aim of this study was to evaluate the oregano essential oil (OEO) (Origanum vulgare) dietary supplementation for the catfish Lophiosilurus alexandri. Four diets supplemented with different OEO levels (0.0, 1.0, 2.0 and 4.0 g kg−1) were evaluated in a feed trial conducted with fish of 15.7 ± 1.8 g and 9.5 ± 0.45 cm for 13 weeks. Were evaluated growth performance, biochemical parameters, intestinal histomorphometry, whole-body composition and muscle growth. Polynomial analysis showed that weight gain, length gain and specific growth rate were improved in fish fed with OEO supplemented diets, being 2.37, 2.56 and 2.33 g kg−1 the respective levels that maximize these variables. Plasma glucose, cholesterol, triglycerides, LDL and HDL increased with OEO levels between 1.80–2.47 g kg−1. Intestinal histomorphometry was not affected by OEO. Body protein content and hyperplasic muscle fibres were maximized with 2.10 and 2.25 g kg−1 OEO, respectively. Body moisture, total lipids, ash and hypertrophic muscle fibres were not affected by OEO. In conclusion, dietary supplementation with 2.10–2.56 g kg−1 OEO improves growth performance, body protein retention and muscle growth of L. alexandri.