Preparation, Characterization and Biological Activities of an Oil-in-Water Nanoemulsion from Fish By-Products and Lemon Oil by Ultrasonication Method

Fish by-product oil and lemon oil have potential applications as active ingredients in many industries, including cosmetics, pharmaceuticals and food. However, the physicochemical properties, especially the poor stability, compromised the usage. Generally, nanoemulsions were used as an approach to stabilize the oils. This study employed an ultrasonication method to form oil-in-water nanoemulsion of lemon and fish by-product oils (NE-FLO). The formulation is produced at a fixed amount of 2 wt% fish by-product oil, 8 wt% lemon oil, 10 wt% surfactant, 27.7 wt% co-surfactants and 42 min of ultrasonication time. The size, polydispersity index (PDI) and zeta potential obtained were 44.40 nm, 0.077, and −5.02 mV, respectively. The biological properties, including antioxidant, antibacterial, cell cytotoxicity, and anti-inflammatory, showed outstanding performance. The antioxidant activity is comparable without any significant difference with ascorbic acid as standard and is superior to pure lemon oil. NE-FLO successfully inhibits seven Gram-positive and seven Gram-negative bacterial strains. NE-FLO’s anti-inflammatory activity is 99.72%, comparable to nordihydroguaiaretic acid (NDGA) as the standard. At a high concentration of 10,000 µg·mL⁻¹, NE-FLO is non-toxic to normal skin cells. These findings demonstrate that the NE-FLO produced in this study has significant potential for usage in various industries.

In vitro cytotoxicity of cardamom oil, lemon oil, and jasmine oil on human skin, gastric, and brain cancer cell line

Objective

The main objective of the study was to evaluate the cytotoxicity of selected essential oils on human skin, gastric, and brain cancer cell lines using microculture tetrazolium test.

Materials and Methods

Phytochemical analysis, as well as acute oral toxicity tests, was carried out in female albino mice with cardamom oil, lemon oil, and jasmine oil according to the Organization for Economic Co-operation and Development guidelines 425. Anticancer activities of the above test drugs were performed using human cancer cell lines. The studies were carried out at Skanda Life Sciences Pvt. Ltd., Bengaluru.

Results

Phytochemical analysis has shown the presence of carbohydrates and flavonoids in cardamom oil. While lemon oil has shown the presence of carbohydrates, flavonoids, steroids, terpenoids, and tannins, jasmine oil has shown the presence of carbohydrates, alkaloids, flavonoids, steroids, terpenoids, and glycosides. Toxicity studies showed that cardamom oil, lemon oil, and jasmine oil were all found to be safe up to 2000 mg/kg body weight. Results have shown that lemon oil exhibited the strongest cytotoxicity toward three human cancer cell lines, namely skin cancer (A431), gastric cancer (MKN-45), and brain cancer (U-87 MG) cell lines, with higher IC₅₀ values of 62.82 μg/ml, 220.9 μg/ml, and 440.1 μg/ml compared to standard. Jasmine oil exhibited the strongest cytotoxicity toward skin cancer and brain cancer cell lines, whereas cardamom oil has shown stronger cytotoxicity only toward skin cancer cell line but did not show any level of inhibition of growth of brain and gastric cancer cells.

Conclusion

Our study reveals that lemon oil, jasmine oil, and cardamom oil possess potent antitumor activity compared to standard. At different concentrations, lemon oil has shown statistically significant (***P < 0.0001) anticancer activity toward all the three human cancer cell lines. While jasmine oil has shown statistically significant (***P < 0.0001) anticancer activity toward skin and brain cancer cell line, cardamom oil has also shown statistically significant (***P < 0.0001) anticancer activity but only toward skin cancer cell line.

In vitro cytotoxicity of cardamom oil, lemon oil, and jasmine oil on human skin, gastric, and brain cancer cell line

OBJECTIVE

The main objective of the study was to evaluate the cytotoxicity of selected essential oils on human skin, gastric, and brain cancer cell lines using microculture tetrazolium test.

MATERIALS AND METHODS

Phytochemical analysis, as well as acute oral toxicity tests, was carried out in female albino mice with cardamom oil, lemon oil, and jasmine oil according to the Organization for Economic Co-operation and Development guidelines 425. Anticancer activities of the above test drugs were performed using human cancer cell lines. The studies were carried out at Skanda Life Sciences Pvt. Ltd., Bengaluru.

RESULTS

Phytochemical analysis has shown the presence of carbohydrates and flavonoids in cardamom oil. While lemon oil has shown the presence of carbohydrates, flavonoids, steroids, terpenoids, and tannins, jasmine oil has shown the presence of carbohydrates, alkaloids, flavonoids, steroids, terpenoids, and glycosides. Toxicity studies showed that cardamom oil, lemon oil, and jasmine oil were all found to be safe up to 2000 mg/kg body weight. Results have shown that lemon oil exhibited the strongest cytotoxicity toward three human cancer cell lines, namely skin cancer (A431), gastric cancer (MKN-45), and brain cancer (U-87 MG) cell lines, with higher IC₅₀ values of 62.82 μg/ml, 220.9 μg/ml, and 440.1 μg/ml compared to standard. Jasmine oil exhibited the strongest cytotoxicity toward skin cancer and brain cancer cell lines, whereas cardamom oil has shown stronger cytotoxicity only toward skin cancer cell line but did not show any level of inhibition of growth of brain and gastric cancer cells.

CONCLUSION

Our study reveals that lemon oil, jasmine oil, and cardamom oil possess potent antitumor activity compared to standard. At different concentrations, lemon oil has shown statistically significant (***P < 0.0001) anticancer activity toward all the three human cancer cell lines. While jasmine oil has shown statistically significant (***P < 0.0001) anticancer activity toward skin and brain cancer cell line, cardamom oil has also shown statistically significant (***P < 0.0001) anticancer activity but only toward skin cancer cell line.

Microemulsions as delivery systems of lemon oil and β-carotene into beverages: stability test under different light conditions

BACKGROUND

Microemulsions have been proposed as delivery systems for different lipophilic substances in transparent water-based systems. The chemical stability of the delivered compounds is a key factor to broaden the application of microemulsions in the food sector. The stability of a model beverage containing a microemulsion delivering β-carotene and lemon oil was tested under increasing light intensity up to 6000 lx at 20 °C.

RESULTS

The transparent microemulsion resulted physically stable during storage indicating that no coalescence phenomenon occurred. On the contrary, both colour and flavour of the microemulsion degraded as a consequence of limonene and β-carotene oxidation. Kinetic data obtained at increasing light intensity were used to estimate the light dependence of beverage spoilage and the mathematical relationship obtained was used to predict spoilage rate under different light conditions. Finally, a shelf life predictive model was proposed.

CONCLUSIONS

Transparent microemulsions can be successfully used to deliver flavoured oil and colourants into beverages. However, the photostability of the delivered compounds should be carefully studied to estimate product shelf life. To this aim, the availability of models predicting shelf life as a function of enlightening conditions could largely contribute to speed up the process. © 2019 Society of Chemical Industry.

Comparison of the Fungistatic Activity of Selected Essential Oils Relative to Fusarium graminearum Isolates

The aim of the study was to determine the chemical composition of lemon, rosewood, geranium and rosemary oils, and compare their effect on the sensitivity of Fusarium graminearum ZALF 24 and Fusarium graminearum ZALF 339 isolated from infected cereals. The tested oils were added to Potato Dextrose Agar (PDA) medium at concentrations of 0.125%, 0.25%, 0.5%, 1.0% and 2.0%. The activity of the oils on inhibition of the linear growth of mycelium was evaluated by measuring the growth of fungal colonies (growth index), while the fungistatic activity was evaluated on the basis of the percentage growth inhibition of a fungal colony and calculated according to Abbott's formula. The sensitivity of the test strains was variable and depended on the type and concentration of the tested oils. Geranium and rosewood oils in all of the concentrations completely inhibited the growth of the used isolates. In contrast, lemon oil relative to F. graminearum ZALF 339 showed the highest activity at a concentration of 1.0% and rosemary oil, 0.5%. The highest activity against F. graminearum ZALF 24 was shown by the oils of rosemary and lemon at concentrations from 1.0% to 2.0%. The susceptibility of Fusarium graminearum isolates was differentiated and depended on the type and concentration of tested oils.

Combined effect of ultrasound and essential oils to reduce Listeria monocytogenes on fresh produce

Salads prepared from contaminated fresh produce have a high risk of causing food-borne illnesses. Essential oils obtained from plants have antimicrobial activity and may provide a natural approach to reduce the pathogens on fresh produce. Additionally, ultrasound treatments have been shown to reduce the microbial counts on different foods. The objective of this study was to investigate the antimicrobial activities of cinnamon and lemon essential oils in vitro and in food applications. Mixtures of lettuce, parsley and dill were inoculated with Listeria monocytogenes and then dip-treated for 5 min in one of the following treatments: sterile tap water, chlorinated water, 1% lemon essential oil, 2% cinnamon essential oil or 2% cinnamon essential oil + ultrasound. The samples were stored at 4 ℃ and collected at d 0, 1, 3, 5, 7 and 9 post inoculation. The 1% lemon (4 log) and 2% cinnamon (2 log) essential oil washes provided partial inhibition against L. monocytogenes by d 1. The combined application of 2% cinnamon oil and ultrasound resulted in only 0.85 log inhibition by d 1; however, the number of L. monocytogenes increased during storage and became nearly equal to the control at d 9. Therefore, different combinations of essential oils with other antimicrobials or novel technologies are required.