Potentials of enhancing the physicochemical and functional characteristics of <em>Nigella sativa</em> oil by using the screw pressing technique for extraction

In the current investigation the crude oil of Nigella sativa was extracted from seeds using hydraulic and screw pressing techniques. Different parameters were evaluated in order to find out the appropriate technique to enhance the physicochemical and functional-related characteristics of the extracted crude oil. Results showed that the acid and peroxide values were significantly lower in the screw pressed oil (SPO) than in the hydraulic pressed oil (HPO). The total phenolic content of the SPO was significantly higher than that of HPO. Evaluation of the oxidative stability using the Rancimat test showed that SPO recorded a much higher oxidative stability index (40.07 h) than HPO (0.51 h). The yield of the volatile oil fraction and its contents of thymoquinone isolated from the SPO were higher than that from the HPO. Biological evaluation revealed that the SPO had significantly higher antimicrobial activity than HPO against Listeria monocytogenes and Staphylococcus aureus at 40 μL/well

The effect of harvest time on the bioactive properties and volatile components of lavender (Lavandula officinalis)

This study was designed to determine the effect of harvest time on the bioactive properties and volatile components of flowers, leaves and stems of Lavandula officinalis. The bioactive properties were examined in terms of total phenolic content, antiradical activity and antioxidant capacity by the Folin-Ciocalteu, 1.1-diphenyl-2-picrylhydrazyl scavenging and phosphomolybdenum methods, respectively. Volatile components were detected with gas chromatography-mass spectrometry. Water and methanol were used for extraction solvent and three different parts of the day (morning, midday and evening) were selected for harvest time. Water extracts had higher total phenolic contents (337.2-771.5 mg gallic acid equivalents (GAE)/g dry extract) than methanolic extracts (170.3-320.8 mg GAE/g dry extract), and in general, midday values were less than morning and evening rates and had a significant difference depending on harvest time. A similar feature was observed in respect to antioxidant properties. The inhibition rates (%) of flowers and leaves were higher than those of the stems for either extract. In terms of the volatile components linalool, camphor, 1,8-cineole, terpinen-4-ol and isoborneol were the most representative compounds in the samples

Effect of collection time on biological activity of Clary sage (Salvia sclarea)

Salvia sclarea (Clary sage, Lamiaceae) is commonly known as 'misk ada cayi' in Turkey. It is widely cultivated for extractive purposes in France, Bulgaria and USA. This study was designed to examine the effect of seasonal variation oil in vitro antimicrobial and antioxidant activities of methanolic extract of Clary sage. The results indicated that the extract of the plants collected in midday contained higher levels of phenolic content and revealed higher antioxidant capacities compared to the materials collected at other times of the day. No differences were found between the methanolic extract of the plants collected at the years of 2005 and 2006 for phenolic content and antioxidant activities. Antimicrobial activities of the extracts against thirteen microorganisms were also investigated. Salmonella typhimurium was the most resistant microorganism whereas Aeromonas hydrophila, Bacillus brevis and Bacillus cereus were the most sensitive microorganisms to the all extracts examined in this study

Effect of collection time on biological activity of Clary sage (Salvia sclarea)

Salvia sclarea (Clary sage, Lamiaceae) is commonly known as 'misk ada cayi' in Turkey. It is widely cultivated for extractive purposes in France, Bulgaria and USA. This study was designed to examine the effect of seasonal variation on in vitro antimicrobial and antioxidant activities of methanolic extract of Clary sage. The results indicated that the extract of the plants collected in midday contained higher levels of phenolic content and revealed higher antioxidant capacities compared to the materials collected at other times of the day. No differences were found between the methanolic extract of the plants collected at the years of 2005 and 2006 for phenolic content and antioxidant activities. Antimicrobial activities of the extracts against thirteen microorganisms were also investigated. Salmonella typhimurium was the most resistant microorganism whereas Aeromonas hydrophila, Bacillus brevis and Bacillus cereus were the most sensitive microorganisms to the all extracts examined in this study