Antioxidant activity of alkyl gallates and glycosyl alkyl gallates in fish oil in water emulsions: Relevance of their surface active properties and of the type of emulsifier

The antioxidant activity of gallic acid and a series of alkyl gallates (C4-C18) and glycosylated alkyl gallates (C4-C18) on fish oil-in-water emulsions was studied. Three types of emulsifiers, lecithin, Tween-20 and sodium dodecyl sulphate (SDS) were tested. A nonlinear behavior of the antioxidant activity of alkyl gallates when increasing alkyl chain length was observed for emulsions prepared with lecithin. Medium-size alkyl gallates (C6-C12) were the best antioxidants. In contrast, for emulsions prepared with Tween-20, the antioxidants seem to follow the polar paradox. Glucosyl alkyl gallates were shown previously to be better surfactants than alkyl gallates. Nevertheless, they exhibited a worse antioxidant capacity than their corresponding alkyl gallates, in emulsions prepared with lecithin or Tween-20, indicating the greater relevance of having three OH groups at the polar head in comparison with having improved surfactant properties but just a di-ortho phenolic structure in the antioxidant

Influence of oxidized oils on digestibility of caseins in O/W emulsions

The impact of lipid oxidation on protein modifications in emulsions and the consequences on protein digestibility remains unclear. In this study, this impact is evaluated in casein (6 mg mL(-1)) based emulsions containing oxidized soybean or fish oil (3%) in presence (0.3%) or absence of the emulsifier Tween 20. Emulsions are prepared using oils at three oxidation levels and subsequently the impact on protein digestibility is evaluated after 24 h incubation at 4 degrees C. Remarkably, protein digestibility increases in emulsions containing medium and highly oxidized fish oil: 70 +/- 0.4% and 73 +/- 0.4% of the proteins are digested, respectively, whereas protein digestibility in emulsions containing low oxidized fish oil amounted to 63 +/- 0.4%. Protein digestibility in emulsions containing soybean oil stabilized by Tween 20 is not influenced by the oxidation level of the oil used. A remarkable tendency is observed for the malondialdehyde content of the emulsions depending on the presence of Tween 20. For soybean oil based emulsions, malondialdehyde concentrations are consistently higher in the presence of Tween 20. On the other hand, for the fish oil based emulsions an opposite trend is observed, except at the highest oxidation level evaluated, for which no significant differences can be detected. It is concluded that the composition of the interface in emulsions depends strongly upon the degree of oil oxidation and the presence of other emulsifiers. If the oil is more oxidized, less protein is present in the interface restricting the impact of lipid oxidation products on the proteins and hence their digestibility

The effect of different concentrations of tween-20 combined with rice husk silica on the stability of o/w emulsion: A kinetic study

Emulsion is a thermodynamically unstable system which undergoes destabilization with time. The destabilization kinetics of "food grade" oil-in-water (O/W) emulsions in the presence of both tween-20 and rice husk silica as emulsifiers were studied. Rice husk silica concentration of 2.5% was combined with various concentrations of tween-20 from 0.1 to 1%. Oil phase fraction was 20% relative to the aqueous phase. Emulsification was conducted using a rotor-stator homogenizer at 20,000 rpm. The emulsions tended to destabilize with time. Their destabilization rates were studied using zero order and first order kinetic models. In general, the kinetics of O/W emulsion destabilization followed first order model. Different concentrations of tween-20 combined with rice husk silica influenced the destabilization rate of o/w emulsions. Destabilization rates of emulsions stabilized using mixed emulsifiers of 1% tween-20 and 2.5% silica were ~50 times and ~3 times lower compared to those stabilized using silica alone and tween-20 alone, respectively

Neem oil nanoemulsions: characterisation and antioxidant activity

The aim of the present work is to develop nanoemulsions (NEs), nanosized emulsions, manufactured for improving the delivery of active pharmaceutical ingredients. In particular, nanoemulsions composed of Neem seed oil, contain rich bioactive components, and Tween 20 as nonionic surfactant were prepared. A mean droplet size ranging from 10 to 100nm was obtained by modulating the oil/surfactant ratio. Physicochemical characterisation was carried out evaluating size, f-potential, microviscosity, polarity and turbidity of the external shell and morphology, along with stability in simulated cerebrospinal fluid (CSF), activity of Neem oil alone and in NEs, HEp-2 cell interaction and cytotoxicity studies. This study confirms the formation of NEs by Tween 20 and Neem oil at different weight ratios with small and homogenous dimensions. The antioxidant activity of Neem oil alone and in NEs was comparable, whereas its cytotoxicity was strongly reduced when loaded in NEs after interaction with HEp-2 cells

Prostaglandin H synthase kinetics in the two-phase aqueous-micellar system

AbstractReaction mixture for PGHS (prostaglandin-H-synthase) is a two-phase system including micellar hydrophobic phase and hydrophilic aqueous phase. Reagents added to the mixture are distributed between phases, thus concentrations of reagents dissolved in phases can differ significantly from their overall contents.Using dynamic light scattering we found that the hydrophobic phase produced by tween-20 consists of micelles, which radius (4–5nm) does not depend on either tween-20 overall content (0.1%–1% v/v) or arachidonic acid (AA) addition (10–1000μM) or PGHS addition (1μM).Tween-20 overall content changing from 0.1% to 2% v/v dramatically affected COX kinetic, but accounting AA distribution between phases allowed us to estimate “true” parameters, independent of the tween-20 overall content and the concentration of another substrate: KMOx equals 9.8μM O2 in the aqueous phase or 0.0074bar in the gaseous phase, KMAA equals 5400μM AA in the phase of tween-20 micelles and 5400/PμM AA in the aqueous phase (P is the distribution ratio for the AA between the aqueous phase and the hydrophobic phase (P≫1000)). This approach allowed to evaluate PS, the distribution ratio for the AA between the hydrophobic phase and the PGHS active center (PS ~310). This coefficient indicates the AA selectivity toward the cyclooxygenase active center

In vitro modulation of inflammatory cytokine and IgG levels by extracts of Perna canaliculus

BACKGROUND: Inflammation is a predominant characteristic of autoimmune diseases which is characterized by the increased expression of pro-inflammatory cytokines. Soon to be published work from our laboratory has shown that ingestion of Perna canaliculus prevents the development of autoimmune diseases such as Systemic Lupus Erythematosus and rheumatoid arthritis in laboratory animals. The current paper attempts to illustrate how Perna can alleviate inflammation by modulating inflammatory cytokines, cyclooxygenase enzymes and Immunoglobulin-G (IgG) levels. METHODS: In the present study, hydrochloric acid [HCl] and Tween-20 were used to develop extracts of Perna. These extracts were assayed for protein content. Increasing concentrations of these extracts were then tested in cell culture for modulation of inflammatory cytokine, cyclooxygenase enzymes and IgG levels. Parallel tests were run using an available glycogen extract of Perna as a comparison to our in-house laboratory preparations. RESULTS: Tween-20 Perna extracts were found to be more stable and less toxic in cell culture than HCl digest of Perna. They also assayed higher in protein content that HCl extracts. Although both extracts inhibited IgG production in V2E9 hybridomas, Tween-20 extracts were more consistent in IgG suppression than HCl extracts. Overall Tween-20 extracts effectively decreased levels of TNF-α, IL-1, IL-2 and IL-6 as observed using cytokine bioassays. Twenty micrograms of Tween-20 Perna extracts induced such significant decreases in inflammatory cytokine production that when tested on sensitive cell lines, they very nearly abolished the decrease in viability induced by these cytokines. Tween-20 extracts effectively inhibited both COX-1 and COX-2 cyclooxygenase activity. As a comparison, the glycogen extract also demonstrated a similar though weaker effect on COX-1 and COX-2 enzymes. The active components of both extracts (Tween-20 and glycogen) were observed to possess molecular weights above 100 kDa. Although the anti-cytokine activity of the Tween-20 extract was destroyed by Proteinase-K treatment, the anti-COX-1 and anti-COX-2 activity of both the extracts were not sensitive to protease treatment. CONCLUSION: We have successfully demonstrated modulation in the levels of inflammatory cytokines, cyclooxygenase enzymes and immunoglobulins by our in-house laboratory preparations of Perna canaliculus, whereby suggesting an immunomodulatory role of Perna canaliculus in regulating inflammation

Effect Of Surfactant Chain Length Difference In Mixed Surfactant Systems On Self Emulsification Of Poorly Soluble Drug

In the present investigation the effect of chain length difference (Δn) of different surfactant mixtures was evaluated on self emulsifying capability of self emulsifying drug delivery system of aceclofenac. Three surfactants of Tween series namely Tween 20, Tween 40 and Tween 80 were used for the study. The lipid carrier used was almond oil. Surfactant mixtures were prepared by combining Tween 20 and Tween 80 (Δn=6), Tween 20 and Tween 40 (Δn=4), Tween 40 and Tween 80 (Δn=2) in definite proportion. Pseudoternary diagram study was carried out to determine the surfactant mixture which provides the largest microemulsifying region. The pseudoternary diagram study revealed that the microemulsifying region increases as the difference in chain length increases. So, Tween 80 and Tween 20 were selected for formulation development, the proportion of which is further optimized by simplex lattice design. The formulations were prepared and subjected to different evaluation parameters. The optimized formulation has a particle size of 68.95 nm and zeta potential of -15.3 mV

Effect of the surfactants tween 20 and CTAB on fluoranthene and anthracene degradation by P. putida

The effect of a nonionic and a cationic surfactant, Tween 20 and CTAB, on the biodegradation rate of fluoranthene and anthracene by a P. putida strain was investigated. Tween 20 had a positive effect on the biodegradation rate of anthracene. However, it did not affect significantly fluoranthene oxidation. The cationic surfactant CTAB inhibited the oxidation of both PAHs, fluoranthene and anthracene

Effect of Nonionic Surfactants on the Crystallinity and Thermal Stability of Poly(vinyl alcohol) Film

In this study, poly(vinyl alcohol) (PVA)/surfactant films were prepared by casting technique. Two nonionic surfactants with different alkyl chain lenghts (Tween 20 and Tween 40) were used. PVA/Tween 20 and PVA/Tween 40 films were characterized by means of Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). FTIR spectra of PVA/Tween films indicated the presence of hydrogen bond interactions between the Tween surfactants and PVA. XRD results showed that the incorporation of Tween 20 and 40 into the PVA film decreased the crystallinity of PVA.TGA curves revealed an increase in the thermal stability of PVA film in the presence of the surfactants. DOI: http://dx.doi.org/10.17807/orbital.v12i4.151

Development of Microemulsion Dermal Products Based on Avocado Oil for Topical Administration

The research described in this study aimed at developing microemulsions for dermal application using avocado oil. Due to its composition, avocado oil helps maintaining the barrier function of the skin. It has a nutritional effect on the skin, and it reduces the intensity of the process of skin peeling. Various surfactant:cosurfactant systems were tested in the conducted studies. There were no significant differences between the diagrams generated by Tween 20 and the surfactant:cosurfactant system, Tween 20:PEG400, at a ratio of 1:1. Six formulations were selected from the dilution line 7 of the ternary phase diagrams obtained by using as a surfactant Tween 20 and Tween 20:PEG 400, respectively. The formulations were characterized by determining physicochemical properties specific. In the next phase of study, these six formulations were used as a vehicle for incorporating erythromycin in order to develop erythromicyn incorporated formulations for topical administration. The quality control of microemulsions with erythromycin was performed by evaluating the physical chemical, organoleptic and sensorial properties. Microemulsions were pharmacotechnically characterized by assessing the in vitro and ex vivo release kinetics of erythromycin