Extraction of Siphonochilus aethiopicus Essential Oil by Steam Distillation

Siphonochilus aethiopicus is an indigenous South African plant also known as African ginger. It has often been used for its medicinal properties to treat various ailments such as flu, colds, and so forth. The research aim of this study was to optimize the process parameters of steam distillation for the extraction of oil from African ginger rhizomes. This technology is the oldest and well known for extracting essential oils due to its economic viability and the higher final oil purity. The effects of operating parameters such as extraction duration, moisture content, particle size, and temperatures between 80°C and 100°C were studied for maximum oil recovery. The oil recovery of 0.61% (w/w) was achieved after 270?min of extraction time, using 6.37% (dry) moisture content of particle size 2.4?mm–4?mm at a maximum temperature of 100°C. Fick’s first law was used to mathematically model the experimental data of this study.     

Development of Phospholipids Vesicular Nanocarrier for Topical Delivery of Tea Tree Oil in Management of Atopic Dermatitis Using BALB/c Mice Model

This work aims to develop and evaluate the efficacy of tea tree oil (TTO) ethosomal cream with improved deposition in skin layers for treatment of atopic dermatitis (AD). Ethosomes of TTO are developed using phosphatidylcholine (2% and 3% w/v) and ethanol (20%, 30%, and 40% w/v). Ethosomes are evaluated for percent entrapment efficiency (%EE), vesicle size, zeta potential, and in vitro drug diffusion. Ethosomal creams with optimized ethosomal dispersion are developed and evaluated for physicochemical parameters, thermal stability, ex vivo permeation, skin retention, and in vitro cytotoxicity using HaCat skin cell lines in comparison to conventional creams of TTO. In vivo investigations of optimized creams are performed using BALB/c mice model. The %EE, vesicle size, and zeta potential for optimized ethosomes are found to be 76.19 ± 3.26%, 333.6 nm, and –35.3 mV, respectively. Ethosomal creams showed higher deposition in the epidermis and dermis. The optimized creams are non-cytotoxic to HaCat cell lines. The creams significantly reduce the inflammatory response by decreasing the clinical score and infiltration of white blood cells, eosinophils, and IgE antibodies. Overall efficacy of ethosomal cream is higher than conventional cream. In conclusion, optimized ethosomal cream of TTO shows good efficacy for treatment of AD. Practical applications : The method used for the formulation of ethosomes is simple and can be easily scaled up on the industrial level. The loading of TTO within ethosomes can increase the efficiency by enhanced drug deposition in the epidermis and might also improve its stability against oxidative degradation. Topical ethosomal cream of TTO can improve patient compliance by avoidance of adverse effects linked with corticosteroids and could be a possible complementary or alternative therapy in management of AD.     

Iron‐mediated lipid oxidation in 70% fish oil‐in‐water emulsions: effect of emulsifier type and pH

The objective of this study was to investigate the protective effect of five different emulsifiers on iron‐mediated lipid oxidation in 70% fish oil‐in‐water emulsions. The emulsifiers were either based on protein (whey protein isolate and sodium caseinate) or based on phospholipid (soy lecithin and two milk phospholipids with different phospholipid contents, MPL20 and MPL75). Lipid oxidation was studied at pH 4.5 and 7.0, and results were compared to lipid oxidation in neat fish oil. Results showed that all emulsions oxidised more than neat oil. Furthermore, emulsions prepared with proteins oxidised more at low pH than at high pH, and casein emulsions oxidised the least (Peroxide value (PV) at day 7 was 0.5–0.7 meq kg^?1). Among emulsions prepared with phospholipids, emulsions with MPL75 were the most oxidised followed by emulsions prepared with lecithin and MPL20. Thus, PV in MPL75 emulsions was 5.0–5.5 meq kg^?1 at day 7 compared with 0.9–1.9 meq kg^?1 in MPL20 emulsions.     

Impact of microfluidization or ultrasound processing on the antimicrobial activity against Escherichia coli of lemongrass oil-loaded nanoemulsions

The effect of the ultrasonication and microfluidization processing conditions on the antimicrobial activity of lemongrass oil–alginate nanoemulsions was studied. Sonication led to less effective nanoemulsions against Escherichia coli, being the loss of antimicrobial potential dependent on the amplitude and treatment time applied. Namely, nanoemulsions sonicated at 100 μm for 180 s almost completely lost their bactericidal action, leading to 0.3 log-reductions of E. coli population after 30 min of contact time. On the contrary, nanoemulsions processed by microfluidization exhibited an enhanced antimicrobial activity, which was proportional to the number of cycles through the microfluidization chamber. In fact, whereas the coarse emulsion reduced the E. coli population up to 0.66, 2.25 and 5.85 log-units after 5, 15 and 30 min of contact time, the microfluidized nanoemulsions (10 cycles, 150 MPa) achieved 1.37, 5.29 and 7.07 log-reductions. Therefore, nanoemulsions with an improved functionally could be obtained by microfluidization, whereas ultrasounds seem to have a deleterious impact on the antimicrobial activity of lemongrass essential oil.     

Molecular dynamics simulations of mutated Mycobacterium tuberculosis l-alanine dehydrogenase to illuminate the role of key residues

l-Alanine dehydrogenase from Mycobacterium tuberculosis (l-MtAlaDH) catalyzes the NADH-dependent interconversion of l-alanine and pyruvate, and it is considered to be a potential target for the treatment of tuberculosis. The experiment has verified that amino acid replacement of the conserved active-site residues which have strong stability and no great changes in biological evolutionary process, such as His96 and Asp270, could lead to inactive mutants [Ågren et al., J. Mol. Biol. 377 (2008) 1161–1173]. However, the role of these conserved residues in catalytic reaction still remains unclear. Based on the crystal structures, a series of mutant structures were constructed to investigate the role of the conserved residues in enzymatic reaction by using molecular dynamics simulations. The results show that whatever the conserved residues were mutated, the protein can still convert its conformation from open state to closed state as long as NADH is present in active site. Asp270 maintains the stability of nicotinamide ring and ribose of NADH through hydrogen bond interactions, and His96 is helpful to convert the protein conformation by interactions with Gln271, whereas, they would lead to the structural rearrangement in active site and lose the catalytic activity when they were mutated. Additionally, we deduce that Met301 plays a major role in catalytic reaction due to fixing the nicotinamide ring of NADH to prevent its rotation, and we propose that Met301 would be mutated to the hydrophobic residue with large steric hindrance in side chain to test the activity of the protein in future experiment.     

Improved oil treatment conditions for soft degumming

“Soft degumming” is a new physicochemical degumming process. It involves the complete elimination of phospholipids by using a chelating agent, EDTA, in the prescence of an emulsifying additive. To study the optimal cost of the process, a laboratory study was undertaken to find a method based on substituting the emulsifying additive by endogenous phospholipids. The phospholipids were first extracted from the oil by an initial hot-water treatment. In a second stage, a solution containing a chelating agent was incorporated. The mixture was then vigorously stirred to form an emulsion. The degummed oil was obtained after centrifugation. A comparative study carried out on several oils provided an indication of the efficiency of this alternative procedure. The phospholipid content of the processed oils was about 5 ppm phosphorus.     

Influence of the Oil Phase on the Microencapsulation by Complex Coacervation

The influence of oil type on the process yield, efficiency of encapsulation, particle size and morphological aspects of coacervated microparticles was investigated. Firstly, several factors affecting microencapsulation of oils by complex coacervation were simultaneously examined. The results indicated that the process yield is mainly dependent on the velocity of homogenization, temperature and polymer ratio. Using optimum conditions for producing microparticles [pH 4.0, 14,000 rpm, 50 °C, gelatin:gum arabic (GE:GA) 1:1 and 2.5 % w/v], different core materials were tested: a vegetable oil (almond oil), an oil with higher hydrophilic lipophilic balance (vetiver essential oil) and a highly hydrophobic oil (mineral oil). The oil phase exerted an influence on microparticle formation, disturbing the complexation of polymers and modifying the core distribution within the particles. Some of the polymers were complexed when mineral oil was used, and the highest efficiency of encapsulation (91.8 %) was obtained with vetiver oil, followed by the almond (70.6 %) and mineral (38.0 %) oils. Particles produced with vetiver oil were larger (43.5 μm) than those produced with mineral oil (35.0 μm) and almond oil (19.2 μm), and the increase in the size is due to the encapsulation of many small droplets of emulsion, characterizing these particles as multinucleate ones.     

Preservative effectiveness of essential oils in vapor phase combined with modified atmosphere packaging against spoilage bacteria on fresh cabbage

This study was conducted to investigate the antibacterial effects of various essential oils (EOs) against pathogens using the disc volatilization method. Also, combined effects of EOs in vapor phase and MAP were evaluated for reducing levels of total mesophilic microorganisms on fresh cabbage. The vapor phase activities of EOs (thyme-1, oregano-1, lemongrass-1, and lemongrass-2 oils) observed strong inhibitory effects. The MAP results showed that 100% CO₂ gas packaging reduced significantly levels of total mesophilic microorganisms on cabbage and radish sprouts, and their reduction level was 1.55 and 2.26 log₁₀ CFU/g compared to control after 21 days of storage (p ≤ 0.05). Based on previous results, combined effects of EOs in vapor phase and MAP (100% CO₂) showed that lemongrass-2 oil with 20 discs showed complete inactivation by <1.0 log₁₀ CFU/g after 14 days of storage. These results could provide useful information for developing alternative preservation method to improve the freshness and shelf-life of fresh produce using natural antimicrobials.     

Optimization of supercritical CO2 extraction of dried Helichrysum italicum flowers by response surface methodology: GC-MS profiles of the extracts and essential oil

Supercritical (SC) CO₂ extraction of dried Immortelle flowers was performed at different process parameters. The optimal extraction conditions related to the yield were determined by response surface methodology (yield 4.09% at 20 MPa and 52°C). The extracts were analyzed by GC-MS and tremetone derivatives dominated: bitalin A, 12-acetoxytremetone, gnaphaliol, 1-[2-(2-methyl-2,3-dihydroxypropyl)-2,3-dihydro-1-benzofuran-5-yl]ethanone, isobutyl bitalin A, and 1-[2-(acetylprop-1-en-2-yl)-3-hydroxy-2,3-dihydro-1-benzofuran-5-yl]ethanone. Striking differences were found among the essential oil and SC-CO₂ extracts composition. The major oil compounds were γ-curcumene, α-pinene, β-selinene, α-selinene, and limonene. Mono- and sesquiterpene were found among minor constituents of the extracts. Neryl acetate was present in the extracts and essential oil.     

Daily Enteral DHA Supplementation Alleviates Deficiency in Premature Infants

Docosahexaenoic acid (DHA) is an essential fatty acid (FA) important for health and neurodevelopment. Premature infants are at risk of DHA deficiency and circulating levels directly correlate with health outcomes. Most supplementation strategies have focused on increasing DHA content in mother's milk or infant formula. However, extremely premature infants may not reach full feedings for weeks and commercially available parenteral lipid emulsions do not contain preformed DHA, so blood levels decline rapidly after birth. Our objective was to develop a DHA supplementation strategy to overcome these barriers. This double‐blind, randomized, controlled trial determined feasibility, tolerability and efficacy of daily enteral DHA supplementation (50 mg/day) in addition to standard nutrition for preterm infants (24–34 weeks gestational age) beginning in the first week of life. Blood FA levels were analyzed at baseline, full feedings and near discharge in DHA (n = 31) or placebo supplemented (n = 29) preterm infants. Term peers (n = 30) were analyzed for comparison. Preterm infants had lower baseline DHA levels (p < 0.0001). Those receiving DHA had a progressive increase in circulating DHA over time (from 3.33 to 4.09 wt% or 2.88 to 3.55 mol%, p < 0.0001) while placebo‐supplemented infants (receiving standard neonatal nutrition) had no increase over time (from 3.35 to 3.32 wt% or 2.91 to 2.87 mol%). Although levels increased with additional DHA supplementation, preterm infants still had lower blood DHA levels than term peers (4.97 wt% or 4.31 mol%) at discharge (p = 0.0002). No differences in adverse events were observed between the groups. Overall, daily enteral DHA supplementation is feasible and alleviates deficiency in premature infants.