Sequential ultrasound-microwave technique as an efficient method for extraction of essential oil from Lavandula coronopifolia Poir

Advances in efficient extraction of essential oils from spices and its application in food industry: A critical review

With the increase of people's awareness of food safety, it is crucial to find natural and green antimicrobial agents to replace traditional antimicrobial agents. Essential oils of spices (SEOs) are low toxicity or nontoxic, which exhibited antioxidants and antimicrobial activity according to many in vitro and in situ experiments. Spices are widely available and low cost as a plant raw material for the extraction of SEOs. This review summarized highly efficient extraction techniques for SEOs, such as physical field assisted extraction technology, supercritical fluid extraction, and biological-based techniques. Furthermore, purification of SEOs and components were also recapitulated. Purification techniques of SEOs improve their utilization value due to the increased content of bioactive components. Finally, the review concentrated on the applications of SEOs in food industry, including food preservation, food active packaging by means of films or coatings, antioxidant properties. In addition, addressing the problem of unstability of SEOs and its role to inhibit the pathogenic bacteria, the encapsulation of SEOs for use in the food industrial sectors reduces the safety risk to human health.

Chemical Composition and Biological Activities of Lavandula coronopifolia Poir Extracts: A Comparison between Callus Culture and Native Plant

Nowadays, according to the development and high functions of in vitro cultivation, one of the questions that researchers are looking for is whether the characteristics and compositions of the obtained product meet the needs of the society or not. Therefore, this research was done aimed to compare the bioactive characteristics of callus and native plant aqueous extracts of Lavandula coronopifolia Poir. Thus, two different culture media were utilized for calluses’ growth. Extracts from these calluses and native plants were obtained using the sequential ultrasound-microwave assisted extraction (SUMAE) method. The extraction conditions were a constant temperature of 70°C ultrasound in 20 min at 250 W and 8 minutes at 800 W for microwave at 85°C. At first, results revealed that callus cultures were not able to produce any significant amounts of essential oil. Therefore, aqueous extracts obtained from calluses as well as the natural plant were examined in terms of antioxidant activity, total phenolic content, total flavonoid content, and antimicrobial activity. Moreover, their volatile components were detected with GC-MS. Both DPPH and FRAP techniques demonstrated that the callus on MS + Auxin had stronger antioxidant activity than the other callus and native plant. It also had the greatest total phenolic content. In terms of total flavonoid content, the native plant has the highest value. Generally, it can be concluded that the extract of callus on MS + Auxin has shown significant activity against the tested microorganisms than the other samples.

Effect of extraction technique on chemical compositions and antioxidant activities of freeze-dried green pepper

In this study, the yield, content of piperine, and antioxidant activity of pepper oleoresin obtained with the methods of maceration, ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and ultrasound-MAE (UMAE) were analyzed, and the microstructure of pepper residue was observed. For the yield and piperine content, the UMAE method had the best extraction capacity among the four methods. While, the oleoresin obtained with maceration had the highest total phenolic content, and the antioxidant activity of the oleoresin obtained by maceration was higher than that of the extracts acquired by UAE, MAE, and UMAE, and a high positive correlation was observed between the antioxidant activity and total phenolic content of the oleoresin obtained by these extraction methods. The ideal parameters for UMAE were an 80-mesh particle size and a 1 g/10 mL solid–liquid ratio. The kinetic parameters and models of the UMAE extraction process were also compared using first- and second-order models. The second-order kinetic equation with the lowest root mean square deviation and highest adjusted correlation coefficient proved to be more suitable for describing the extraction kinetics of pepper oleoresin. This study showed that UMAE is a fast, efficient, and cost-effective technique for the extraction of green pepper oleoresin.

Essential Oils of Tagetes minuta and Lavandula coronopifolia from Djibouti: Chemical Composition, Antibacterial Activity and Cytotoxic Activity against Various Human Cancer Cell Lines

The chemical composition of the essential oils of two plants (Tagetes minuta L. and Lavandula coronopifolia L.) harvested from the Day region (in the north of Djibouti) is the subject of this study. The extraction of essential oils was carried out by hydrodistillation, and the average yield was obtained at a rate of approximately 0.25% for Tagetes minuta L. and 0.42% for Lavandula coronopifolia L. The analyses of these essential oils by gas chromatography coupled with mass spectrometry identified 13 compounds in the essential oil of Tagetes minuta L., including dihydrotagetone (20.8%), artemisia (17.9%), (Z)-tagetenone (12.4%), (-)-spathulenol (11.0%) and estragole (9.5%), were obtained as majority compounds, with a percentage of 71.6%. The essential oil of Lavandula coronopifolia L. is characterized by the presence of 42 compounds, including cis-caryophyllene (18.9%), dehydronerolidol (12.8%), isolongifolanone (11.2%), caryophyllene oxide (8.2%), 10-epi-β-eudesmol (7.7%) and humulene (5.1%), were obtained as the majority chemical constituents, with a percentage of 63.9%. The antimicrobial activities of the essential oils at concentrations of 5% were measured against 12 bacterial strains (Gram positive: Staphylococcus aureus (ATCC 29213), Enterococcus faecalis (ATCC 29212), Streptococcus agalactiae (ATCC 27956), Staphylococcus epidermidis and Corynebacterium sp.; Gram Negative: Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 700603), Acinetobacter baumannii (ATCC 19606), Shigella sonnei (ATCC 9290), Salmonella enterica sv. Typhimurium (ATCC 13311) and Enterobacter cloacae), and the results of in vitro experiments showed inhibitory effects against most strains tested except Staphylococcus aureus, Enterococcus faecalis and Streptococcus agalactiae. Additionally, both oils were tested for their ability to selectively kill 13 human cancer cells (K562, A549, HCT116, PC3, U87-MG, MIA-Paca2, HEK293, NCI-N87, RT4, U2OS, A2780, MRC-5 and JIMT-T1), and the results obtained, according to the values of IC50, show the significant activity of two essential oils, particularly on the HCT116 and A2780 lines, which present values between 0.25 µg/mL and 0.45 µg/mL, respectively.