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The antibacterial and antioxidant activities of methanol and acetone extracts of three marine algae, including Hypnea hamulosa, Gracilaria corticata and Enteromorpha intestinalis wereinvestigated.Antioxidant activities were determined by means of total antioxidant capacity, total phenolic compounds, DPPH radical scavenging activity and ferric reducing antioxidant power. Antibacterial activity was determined using a paper disc diffusion method against pathogenic bacteria, including Listeria monocytogenes, Escherichia coli and Bacillus subtilis. Acetone extract of E. intestinalis showed the highest antioxidant activity and contained the highest phenolic compounds. The highest percentage of DPPH radical scavenging activity was observed in the methanol extract of H. hamulosa (p<0.05). The highest ferric reducing antioxidant power was observed in the methanol extract of Glacilaria (p<0.05). The strongest inhibition (p<0.05) against L. monocytogenes was shown by the methanol extract of E. intestinalis and the highest inhibition against B. subtilis and E. coli was observed in the acetone extract (p<0.05). In conclusion, E. intestinalis extracts showed favorable antioxidant and antibacterial activity suggesting its application in food and pharmacological industries.

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Research subject: With the rapid development of science and technology, cerium and cerium oxide are widely used in various fields, including in the manufacture of aluminum, aluminum alloys, some steels and in permanent magnets, catalysts, Polishing powder, Glass, Cinema, and Ceramic Technology. Solvent extraction is one of the effective techniques for extraction, separation, and purification of cerium.
Research approach: The extraction of cerium­(IV) from sulfuric acid solutions using Cyanex 921 in kerosene was investigated. The different parameters affecting the extraction process of cerium(IV) such as pH of aqueous solutions­, reagent, metal ion concentration, contact time as well as temperature, are separately investigated. Experiments in the pH range of 0.5 to 5.5, at 25±1 ^oC­, using Cyanx 921 in the concentration range of 0.06 to 0.4 mol L^-1, and a mixture of Cyanx 921 and D2EHPA was performed in different ratios.
Main results: From the temperature study, the extraction reaction for Ce­(IV) was found to be exothermic in nature. The results indicated that the effective extraction of cerium(IV) from sulfuric acid solutions cannot be achieved in a single equilibration because the solubility of Cyanex 921 in aliphatic diluents is limited at ambient temperature. To rectify this issue, the possibility of using a synergistic mixture of Cyanex 921 and D₂EHPA as extractant system to recover cerium(IV) from sulfuric acid solutions was investigated. Mixtures of Cyanex 921 and D₂EHPA resulted in synergistic extraction of cerium­(IV) from sulfuric acid solutions. The results indicated that, under experimental conditions, the maximum synergistic coefficient was obtained at the molar ratio of (0.6M D₂EHPA_­/­0.2_­M Cyanex 921) 3.0, and cerium(IV) was extracted into organic phase in the form of Ce(SO₄)(HSO₄₎₂.­Cyanex 921.

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The phenolic compounds of pomegranate (Punica granatum L.) peel extracted by two methods (solvent and ultrasound-assisted) with five solvents (acetone, methanol, ethanol, water and ethyl acetate) were compared with supercritical fluid extraction (SFE). The total phenolic compounds were determined according to the Folin-Ciocalteu reagent using tannic acid as standard. The overall results showed that acetone with sonication produced the maximum amount of phenolic compounds from pomegranate peel extracts (PPE). Furthermore, the effect of the acetone extract of pomegranate peel (0.010-0.050 %) on the stability of soybean oil during heating at 60oC (oven test method) was determined by measuring peroxide and thiobarbitoric acid values. At a 0.050 % level of pomegranate peel extract, its antioxidant activity was greater than 0.02 % of the two synthetic antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). The pomegranate peel extract possessed a relatively high antioxidant activity and might be considered as a rich source of natural antioxidant.

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Brown algae are a valuable source of natural antioxidant compounds, especially Phlorotannins. In this study, the effect of solvent concentration (water / ethanol) on the the amount of Phlorotannin compounds and antioxidant properties of extracts from brown alga Sargassum angustifolium were investigated. The extraction was performed by solvent method at room temperature (28-26 °C) with ethanol/ water solvent with three ratios (30:70), (50:50) and (70:30). The amount of Phlorotannin, total phenolic content, ferric reducing antioxidant power, DPPH radical scavenging activity and total antioxidant capacity of different extracts were evaluated. The results showed that the yield of Phlorotannin extraction was dependent on the solvent concentration and with increasing polarity of the solvent, its amount increased, So its amount in ethanol/ water treatment (30:70) is significantly more than the other two treatments (P<0.05). Also, the highest amount of DPPH radical scavenging activity was obtained in ethanol/ water treatments 50:50 and 70:30 which contained less Phlorotannin. Finally, it was found that the ethanol/ water treatment 30:70 of the brown alga Sargassum angustifolium was a good choice for extracting Phlorotannin compounds as a natural bioactive compound for food and medicine purposes.

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Tea and sesame seed oils extracted by different methods (including supercritical fluid extraction (SFE), at a pressure of 350 atm, a temperature of 60oC, a static extraction time of 20 minutes, a dynamic extraction time of 30 minutes and 150 g kg-1 of ethanol as a modifier). Solvent (SE) and ultrasound-assisted solvent extraction (UE)), as natural anti-oxidants, were evaluated during 15 days storage by monitoring their effects on refined sunflower oil at 60oC. The peroxide value (PV) and the thiobarbituric acid (TBA) value were used to assess the antioxidant activity of these extracted oils. The highest extraction yields were from SE and SFE, while UE gave a lower yield. Considering oil extraction yield and antioxidant activity, SE and SFE were the preferred methods. The results showed that tea seed oil had strong antioxidant activity, which was almost equal to sesame oil. Therefore, tea seed oil can be used in the same way as sesame seed oil in fat, oil and other food products as a natural antioxidant to suppress lipid oxidation.

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DPPH radical-scavenging activity of the bene hull oil (BHO), sesame oil (SEO), rice bran oil (RBO), the oils' methanolic (CH₃OH/H₂O, 80:20 v/v) or hexane extracts, and their unsaponifiable matters fraction were measured and compared with each other. As a radical-scavenger, SEO was significantly stronger than RBO and BHO, respectively. Unlike BHO and RBO, the unsaponifiable (USM) fraction of the SEO could not considerably scavenge the free radicals at the concentrations studied. The contribution of aqueous methanolic and hexane extracts of the SEO to the inhibition of the DPPH radicals were calculated to be about 75 and 25%, respectively. The aqueous methanolic extract of the RBO could not considerably scavenge the free radicals at the concentrations experimented and the inhibition activity belonged mainly to the hexane extract. The DPPH radical-scavenging active components of the BHO were approximately distributed equally (48 and 52%) between the two extracts.

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In the present study, the extract containing bioactive compounds from marigold (Calendula officinalis L.) medicinal plant was extracted using water, ethanol, acetone, ethanol/water and acetone/water as solvent. Among the solvents studied, the ethanolic extract contained the highest total phenolic compounds. The effect of the solvent to raw material ratio (40:1-10:1 mL/g) and particle size (0.5-2.36 mm) on the quantitative and qualitative properties of ethanolic extract at ambient temperature (25°C) were investigated. Based on the results, the highest crude extraction yield and total phenolic compounds equal to 3.5 ± 0.17% and 36.94 ± 0.81 mg GAE/gram of sample was obtained using a ratio of 30:1 mL/g and a particle size of 1 mm at ambient temperature. At the concentration of 1 mg/ml, the antioxidant activity of the extract was 62.95 ± 2.68 % and 153.18 ± 1.20 μΜ Fe²⁺/L, respectively. The high correlation coefficient (R²>09594) between total phenolic compounds and antioxidant activity indicates the key role of phenolic compounds in antioxidant activity. Finally, the ethanolic extract obtained from C. officinalis under mentioned conditions can be introduced as a natural source of phenolic antioxidants for application in the food and nutraceutical industry as a natural preservative.

 

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In this research extraction of Salvia leriifolia leaf was carried out using two extraction methods including traditional solvent extraction (with different solvent ratio of water /ethanol 50:50, 60:40 and 70:30 at temperature 70, 80 and 90 ºC and time duration of  30, 75 and 120 min), and superheated solvent extraction (at temperature 130, 145 and 160 ºC, time duration of 10, 20 and 30 minutes and solvent ratio of water/ethanol 60:40, 80:20 and 100:0) and the antimicrobial activity of extracts against some of food microorganisms  using minimum inhibition concentration and minimum bactericidal concentration methods were measured. In both extraction methods, the MIC of most microorganisms was 0.5 mg/ml, while the MBC, depending on the microorganism, was between 5 and 500 mg/ ml. In the conventional solvent extraction procedure, the treatment was carried out at a temperature of 80 ° C, 75 minutes, and equal ratio of two solvents, and in superheated solvent extraction method, treatment including temperature of 160 ° C, time of 20 minutes, and water/ Ethanol ratio of 80 to 20 showed the most antimicrobial activity. Based on the results, it can be stated that the type of plant extraction method has a significant effect on inhibiting or preventing the growth of food borne  or spoilage microorganisms, and if any of the plant extraction technique are optimized, they can be better used to increase the shelf life of food.