Antioxidant effect of essential oils of rosemary, clove and cinnamon on hazelnut and poppy oils

Chemical Composition, Antibacterial Properties and Mechanism of Action of Essential Oil from Clove Buds against Staphylococcus aureus

The essential oil of clove has a wide range of pharmacological and biological activities and is widely used in the medicine, fragrance and flavoring industries. In this work, 22 components of the essential oil obtained from clove buds were identified. Eugenol was the major component (76.23%). The essential oil exhibited strong antibacterial activity against Staphylococcus aureus ATCC 25923 with a minimum inhibitory concentration (MIC) of 0.625 mg/mL, and the antibacterial effects depended on its concentration and action time. Kill-time assays also confirmed the essential oil had a significant effect on the growth rate of surviving S. aureus. We hypothesized that the essential oil may interact with the cell wall and membrane first. On the one hand it destroys cell wall and membranes, next causing the losses of vital intracellular materials, which finally result in the bacterial death. Besides, essential oil penetrates to the cytoplasmic membrane or enters inside the cell after destruction of cell structure, and then inhibits the normal synthesis of DNA and proteins that are required for bacterial growth. These results suggested that the effects of the clove essential oil on the growth inhibition of S. aureus may be at the molecular level rather than only physical damage.

Effect of the phytochemicals curcumin, cinnamaldehyde, thymol and carvacrol on the oxidative stability of corn and palm oils at frying temperatures

Several active components naturally available in plants are strongly considered as good antioxidants to retard the lipid oxidation. Response surface methodology was used to investigate the effects of frying temperature (150-180 °C) and concentration of four plant-based active components (60-350 mg/kg oil); curcumin, cinnamaldehyde, thymol and carvacrol on oxidative stability of corn and palm oils. According to induction time values, the stability of oils drastically decreased with increasing temperature. Curcumin and cinnamaldehyde showed no significant effect (p > 0.05) on both oils. Carvacrol significantly increased induction times of corn and palm oils, but thymol was effective in palm oil only (p < 0.05). An actual frying experiment was carried out with only corn oil to confirm efficiency of carvacrol. The free fatty acid (%), peroxide value (meq/kg), para-anisidine, and total polar component values (%) of the fresh oil were 0.080, 2.55, 2.85, and 7.5, respectively. These values changed to 0.144, 1.47, 12.01, 10.0, respectively for the control oil; 0.138, 2.27, 11.49, 10.0 for BHT-added oil; 0.132, 1.42, 5.66, 9.5 for carvacrol-added oil after 30 frying cycles. Therefore, carvacrol could be considered as a good alternative to BHT for preservation of oils at frying temperatures.

Antioxidant Intake and Antitumor Therapy: Toward Nutritional Recommendations for Optimal Results

The role of the induction of oxidative stress as the mechanism of action of many antitumor drugs is acquiring an increasing interest. In such cases, the antitumor therapy success may be conditioned by the antioxidants present in our own body, which can be synthesized de novo (endogenous) or incorporated through the diet and nutritional supplements (exogenous). In this paper, we have reviewed different aspects of antioxidants, including their classification, natural sources, importance in diet, consumption of nutritional supplements, and the impact of antioxidants on health. Moreover, we have focused especially on the study of the interaction between antioxidants and antitumor therapy, considering both radiotherapy and chemotherapy. In this regard, we found that the convenience of administration of antioxidants during cancer treatment still remains a very controversial issue. In general terms, antioxidants could promote or suppress the effectiveness of antitumor treatment and even protect healthy tissues against damage induced by oxidative stress. The effects may depend on many factors discussed in the paper. These factors should be taken into consideration in order to achieve precise nutritional recommendations for patients. The evidence at the moment suggests that the supplementation or restriction of exogenous antioxidants during cancer treatment, as appropriate, could contribute to improving its efficiency.

Large-scale preparation of clove essential oil and eugenol-loaded liposomes using a membrane contactor and a pilot plant

Based on our previous study where optimal conditions were defined to encapsulate clove essential oil (CEO) into liposomes at laboratory scale, we scaled-up the preparation of CEO and eugenol (Eug)-loaded liposomes using a membrane contactor (600 mL) and a pilot plant (3 L) based on the principle of ethanol injection method, both equipped with a Shirasu Porous Glass membrane for injection of the organic phase into the aqueous phase. Homogenous, stable, nanometric-sized and multilamellar liposomes with high phospholipid, Eug loading rates and encapsulation efficiency of CEO components were obtained. Saturation of phospholipids and drug concentration in the organic phase may control the liposome stability. Liposomes loaded with other hydrophobic volatile compounds could be prepared at large scale using the ethanol injection method and a membrane for injection.

Effect of date (Phoenix dactylifera L.) seed extract on stability of olive oil

In this study, the antioxidant effect of date (Phoenix dactylifera L., Arecaceae) seed extracts at different concentrations (0.5 %, 1.0 % and 1.5 %) on the oxidative stability of olive oil at 60 °C was determined. Butylated hydroxyanisole (BHA) was used as positive control in the experiment. All extracts exhibited antioxidant activity compared to BHA up to 21 days. When antioxidant effect of extract concentrations were compared with BHA, the effect of 0.5 % extract concentration was more remarkable for olive oil up to 21 days. After 14 days of assay, all of seed extracts was effective at 60 °C in comparison with control. On the other hand, an important increase was observed in both the peroxide and free fatty acidity values during the experiment period. It concluded that date seed extract could be used as a oxidative inhibitor agent in oil and oil products.

Bioanalytical evaluation of Cinnamomum zeylanicum essential oil

This manuscript describes the antioxidant activity of essential oil of Cinnamon (Cinnamomum zeylanicum) bark extracted by supercritical fluid extraction (SCFE), hydro distillation and steam distillation. The cinnamon bark essential oil exhibited a wide range of total phenolic contents, total flavonoid contents, reducing power, inhibition of linoleic acid peroxidation and DPPH radical-scavenging activity (IC50). Bioactivity of cinnamon essential oil was assayed against various bacterial strains including Bacillus subtilis, Escherichia coli, Pastrurella multocida and Straphylococcus aureus and fungal strains including Aspergillus niger and Aspergillus flavus. More essential oil yield was obtained using SCFE in comparison to other methods. The oil extracted by SCFE was dominated by cinnamaldehyde, limonene, copaene, naphthalene, heptane, bicyclo[4.2.0]octa-1,3,5-triene and 2-propenal. Due to the presence of cinnamaldehyde in the essential oil of cinnamon bark it acts as a good antioxidant and antimicrobial agent.

Evaluation of cinnamon essential oil microemulsion and its vapor phase for controlling postharvest gray mold of pears (Pyrus pyrifolia)

BACKGROUND

Essential oil of cinnamon (CM) is a potential alternative to chemical fungicides. Thus this work aimed to investigate the possible effects of CM microemulsions on decay developments and qualitative properties of pears.

RESULTS

The decay incidence of samples treated with 500 µg L⁻¹ microemulsion was significantly reduced by 18.7% in comparison to that of 500 µg L⁻¹ non-microemulsion after 4 days' storage at 20 °C. In the vapor phase, the CM microemulsion with the lowest concentration had the best control for decay incidence and lesion diameter. The interval between inoculations also influenced decay development. Pears treated with Botrytis cinerea and immediately followed by CM microemulsion showed the lowest decay incidence. Moreover, in the natural decay experiment, the percentage of rotted pears was 3.8% in the CM microemulsion treatment and 5.8% in the control. CM microemulsion delayed the loss of ascorbic acid, yet it had no significant influence on pear qualities such as firmness and color.

CONCLUSION

CM microemulsion may be an alternative way to control the gray mold of pears without a negative influence on its qualities.

Bioactive lipids, radical scavenging potential, and antimicrobial properties of cold pressed clove (Syzygium aromaticum) oil

Health promoting cold pressed oils may improve human health and prevent certain diseases. It is hard to find any research concerning the composition and functional properties of cold pressed clove (Syzygium aromaticum) oil (CO). Cold pressed CO was evaluated for its lipid classes, fatty acid profiles, and tocol contents. In addition, antiradical and antimicrobial properties of CO were evaluated. The amounts of neutral lipids in CO was the highest (∼94.7% of total lipids), followed by glycolipids and phospholipids. The main fatty acids in CO were linoleic and oleic, which comprise together ∼80% of total fatty acids. Stearic and palmitic acids were the main saturated fatty acids. α- and γ-tocopherols and δ-tocotrienol were the main detected tocols. CO had higher antiradical action against DPPH• and galvinoxyl radicals than virgin olive oil. The results of antimicrobial properties revealed that CO inhibited the growth of all tested microorganisms. CO had a drastic effect on the biosynthesis of proteins and lipids in cells of Bacillus subtilis. In consideration of potential utilization, detailed knowledge on the composition and functional properties of CO is of major importance.

Impact of fatty acid chain length of rosmarinate esters on their antimicrobial activity against Staphylococcus carnosus LTH1502 and Escherichia coli K-12 LTH4263

The effect of the addition of a newly synthesized series of rosmarinic acid (RA) estes (REs) and alcohols with chain lengths of 1, 4, 8, 10, 12, 16, and 18 carbons (RE1 to 18) on the growth behavior of Staphylococcus carnosus LTH1502 and Escherichia coli K-12 LTH4263 was investigated. An initial microtiter dilution assay indicated activity of compounds against S. carnosus LTH1502, whereas esters with chain lengths, RA, n-methyl rosmarinate (RE1), n-dodecyl rosmarinate (RE12), and n-octadecyl rosmarinate (RE18) were used in a time-kill assay S. carnosus LTH1502. Compounds were added at 0.75 mM in the log phase, 5 mM in the exponential phase, 10 mM in the stationary phase. RA had no effect in the lag and exponential phase but decreased cell counts during the stationary phase. In contrast, RE1 and RE12 decreased cell number in all three phase, will RE12 reducing counts most rapidly. Addition of RE18 did not affect regardless of the growth phase. Appearance and physiological state of S. carnosus LTH1502 cells indicated difference in the way the compounds interacted with and damaged cells. Results were attributed to the different physicochemical properties of RA and its esters.

Application and stability of natural antioxidants in edible oils in order to substitute synthetic additives

Antioxidants are components which prevent auto-oxidation of oils and fats by giving their hydrogen to free radicals formed in the initiation and propagation stages of autoxidation. During the past two decades, a lot of researches using natural plants extract in edible oils have been carried out due to the trend to minimize or avoid the use of synthetic food additives. According to the most studies, there are various natural antioxidants which can be extracted from low cost resources, such as most parts of olive plant, green tea, sesame, medicinal plants, etc. One of the most important requirements for a suitable antioxidant in oils and fats is the thermal stability during heat processing. It has been shown that most of natural additives have more antioxidants activity and thermal stability than synthetic ones in different edible oils. In this review, recent advances in the application of natural antioxidants in the food industry will be covered.