Evaluation of surface-active and antioxidant effect of olive oil endogenous compounds on the stabilization of water-in-olive-oil nanoemulsions

Process Optimization of Tinospora cordifolia Extract-Loaded Water in Oil Nanoemulsion Developed by Ultrasound-Assisted Homogenization

Nanoemulsions are gaining interest in a variety of products as a means of integrating easily degradable bioactive compounds, preserving them from oxidation, and increasing their bioavailability. However, preparing stable emulsion compositions with the desired characteristics is a difficult task. The aim of this study was to encapsulate the Tinospora cordifolia aqueous extract (TCAE) into a water in oil (W/O) nanoemulsion and identify its critical process and formulation variables, like oil (27-29.4 mL), the surfactant concentration (0.6-3 mL), and sonication amplitude (40% to 100%), using response surface methodology (RSM). The responses of this formulation were studied with an analysis of the particle size (PS), free fatty acids (FFAs), and encapsulation efficiency (EE). In between, we have studied a fishbone diagram that was used to measure risk and preliminary research. The optimized condition for the formation of a stable nanoemulsion using quality by design was surfactant (2.43 mL), oil concentration (27.61 mL), and sonication amplitude (88.6%), providing a PS of 171.62 nm, FFA content of 0.86 meq/kg oil and viscosity of 0.597 Pa.s for the blank sample compared to the enriched TCAE nanoemulsion with a PS of 243.60 nm, FFA content of 0.27 meq/kg oil and viscosity of 0.22 Pa.s. The EE increases with increasing concentrations of TCAE, from 56.88% to 85.45%. The RSM response demonstrated that both composition variables had a considerable impact on the properties of the W/O nanoemulsion. Furthermore, after the storage time, the enriched TCAE nanoemulsion showed better stability over the blank nanoemulsion, specially the FFAs, and the blank increased from 0.142 to 1.22 meq/kg oil, while TCAE showed 0.266 to 0.82 meq/kg.

Enhanced efficacy of β-carotene loaded solid lipid nanoparticles optimized and developed via central composite design on breast cancer cell lines

β-carotene is obtained from both plants and animals and has been the subject of intense research because of its provitamin-A, antioxidant, and anticancer effects. Its limited absorption and oxidative degradation significantly reduce its antitumor efficacy when taken orally. In our study, we utilize a central composite design to develop "bio-safe and highly bio-compatible" solid lipid nanoparticles (SLNs) by using only the combination of palmitic acid and poloxamer-407, a block co-polymer as a surfactant. The current research aim to develop and characterize SLNs loaded with β-carotene to improve their bioavailability and therapeutic efficacy. In addition, the improved cytotoxicity of solid lipid nanoparticles loaded with β-carotene was screened in-vitro in human breast cancer cell lines (MCF-7). The nanoparticles exhibits good stability, as indicated by their mean zeta potential of -26.3 ± 1.3 mV. The particles demonstrated high drug loading and entrapment capabilities. The fabricated nanoparticle's prolonged release potential was shown by the in-vitro release kinetics, which showed a first-order release pattern that adhered to the Higuchi model and showed a slow, linear, and steady release over 48 h. Moreover, a diffusion-type release mechanism was used to liberate β-carotene from the nanoparticles. For six months, the nanoparticles also showed a notable degree of physical stability. Lastly, using the MTT assay, the anti-cancer properties of β-carotene-loaded solid lipid nanoparticles were compared with intact β-carotene on MCF-7 cell lines. The cytotoxicity tests have shown that the encapsulation of β-carotene in the lipid bilayers of the optimized formulation does not interfere with the anti-cancer activity of the drug. When compared to standard β-carotene, β-carotene loaded SLNs showed enhanced anticancer efficacy and it is a plausible therapeutic candidate for enhancing the solubility of water-insoluble and degradation-sensitive biotherapeutics like β-carotene.

Formulation and Biomedical Activity of Oil-in-Water Nanoemulsion Combining Tinospora smilacina Water Extract and Calophyllum inophyllum Seeds Oil

Introduction

Tinospora smilacina is a native plant used in traditional medicine by First Nations peoples in Australia to treat inflammation. In our previous study, an optimised Calophyllum inophyllum seed oil (CSO) nanoemulsion (NE) showed improved biomedical activities such as antimicrobial, antioxidant activity, cell viability and in vitro wound healing efficacy compared to CSO.

Methods

In this study, a stable NE formulation combining T. smilacina water extract (TSWE) and CSO in a nanoemulsion (CTNE) was prepared to integrate the bioactive compounds in both native plants and improve wound healing efficacy. D-optimal mixture design was used to optimise the physicochemical characteristics of the CTNE, including droplet size and polydispersity index (PDI). Cell viability and in vitro wound healing studies were done in the presence of CTNE, TSWE and CSO against a clone of baby hamster kidney fibroblasts (BHK-21 cell clone BSR-T7/5).

Results

The optimised CTNE had a 24 ± 5 nm particle size and 0.21± 0.02 PDI value and was stable after four weeks each at 4 °C and room temperature. According to the results, incorporating TSWE into CTNE improved its antioxidant activity, cell viability, and ability to promote wound healing. The study also revealed that TSWE has >6% higher antioxidant activity than CSO. While CTNE did not significantly impact mammalian cell viability, it exhibited wound-healing properties in the BSR cell line during in vitro testing. These findings suggest that adding TSWE may enhance CTNE's potential as a wound-healing treatment.

Conclusion

This is the first study demonstrating NE formulation in which two different plant extracts were used in the aqueous and oil phases with improved biomedical activities.

Optimisation of Calophyllum inophyllum seed oil nanoemulsion as a potential wound healing agent

Background

Efficient delivery systems of Calophyllum inophyllum seed oil (CSO) in the form of nanoemulsion were optimised to enhance its stability and ensure its therapeutic efficiency as a potential agent for various biomedical applications.

Method

Response Surface Methodology (RSM) was used to determine the effects of independent variables (oil, surfactant, water percentage and homogenisation time) on physicochemical characteristics, including droplet size, polydispersity index and turbidity.

Results

The optimised CSO nanoemulsion (CSONE) has a 46.68 nm particle size, 0.15 Polydispersity index value and 1.16 turbidity. After 4 weeks of storage at 5 ± 1 °C and 25 ± 1 °C, the CSONE was physically stable. The optimised CSO nanoemulsion showed enhancement in cell viability and wound healing in baby hamster kidney a clone BHK-21 (BSR) cells as compared to the CSO. The wound healing property of CSONE was higher than CSO.

Conclusion

Thus, our in vitro wound healing results demonstrated that CSO in the nanoemulsion form can promote wound healing by enhancing the proliferation and migration of epidermal cells.

Graphical Abstract

The coarse emulsion of Calophyllum inophyllum seed oil nano emulsion was prepared using high shear homogeniser techniques. The optimised CSONE with the droplet size of 46.68 nm was prepared from a mixture of CSO, Tween 80, and high pure water (HPW), then used for the biological investigation. The in vitro cell monolayer scratch assay revealed that CSONE in the lowest concentration of CSO resulted in 100% wound closure after 48 hrs. The optimised CSO nanoemulsion was found to be a promising and effective approach in the treatment of wounds by boosting the proliferation and migration of epidermal cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03751-6.

Enhancement of physicochemical and encapsulation stability of O1/W/O2 multiple nanoemulsions loaded with coenzyme Q10 or conjugated linoleic acid by incorporating polyphenolic extract

Multiple O1/W/O2 nanoemulsions and O1/W nanoemulsions fortified with CLA or CoQ10 were produced using extra virgin olive or olive pomace oil and were also incorporated with polyphenols extracted from olive kernel to enhance their kinetic and chemical stability. They were prepared using a high-speed ultrasonic homogenizer. Specifically, nanoemulsions with 6 wt% lipid phase and 6 wt% non-ionic emulsifier (Tween 40) were produced and they demonstrated a droplet diameter >200 nm and high encapsulation stability during 30 days of storage at 4 °C or 25 °C. The incorporation of CLA or CoQ10 and polyphenolic compounds facilitated the homogenization of emulsions, reducing the droplet size and enhancing their chemical stability, and their bioactive retention values were >79%. O1/W/O2 nanoemulsions were produced using a mixture of non-ionic emulsifiers (Span 20 and Tween 40) and the O1/W enriched nanoemulsion as the dispersed phase. All multiple emulsions showed a bimodal droplet size distribution and Newtonian behavior while polyphenols facilitated their homogenization. Both vegetable oils resulted in samples with high kinetic and chemical stability; the bioactive retention values were found to be >80% at the end of 30 days of storage at 4 °C or 25 °C. Extra virgin olive oil resulted in more stable nanoemulsions in regards to kinetic and chemical stability at 4 °C, showing limited creaming and sedimentation boundary. Multiple nanoemulsions with the lowest initial droplet size presented the lowest droplet diameter growth and phase separation and the highest retention values. By comparing O1/W nanoemulsions and O1/W/O2 nanoemulsions, we noted that the reduction in the total phenolic content and antioxidant activity during storage was higher in the O1/W type. However, both delivery systems protected CLA and CoQ10 presenting high retention during storage. FTIR spectra before and after ultrasonic homogenization indicated that the sonication process did not significantly affect the lipid phase of O1/W/O2 nanoemulsions.

Novel Processes for the Extraction of Phenolic Compounds from Olive Pomace and Their Protection by Encapsulation

Olive pomace, the solid by-product derived from olive oil production consists of a high concentration of bioactive compounds with antioxidant activity, such as phenolic compounds, and their recovery by applying innovative techniques is a great opportunity and challenge for the olive oil industry. This study aimed to point out a new approach for the integrated valorization of olive pomace by extracting the phenolic compounds and protecting them by encapsulation or incorporation in nanoemulsions. Innovative assisted extraction methods were evaluated such as microwave (MAE), homogenization (HAE), ultrasound (UAE), and high hydrostatic pressure (HHPAE) using various solvent systems including ethanol, methanol, and natural deep eutectic solvents (NADESs). The best extraction efficiency of phenolic compounds was achieved by using NADES as extraction solvent and in particular the mixture choline chloride-caffeic acid (CCA) and choline chloride-lactic acid (CLA); by HAE at 60 °C/12,000 rpm and UAE at 60 °C, the total phenolic content (TPC) of extracts was 34.08 mg gallic acid (GA)/g dw and 20.14 mg GA/g dw for CCA, and by MAE at 60 °C and HHPAE at 600 MPa/10 min, the TPC was 29.57 mg GA/g dw and 25.96 mg GA/g dw for CLA. HAE proved to be the best method for the extraction of phenolic compounds from olive pomace. Microencapsulation and nanoemulsion formulations were also reviewed for the protection of the phenolic compounds extracted from olive pomace. Both encapsulation techniques exhibited satisfactory results in terms of encapsulation stability. Thus, they can be proposed as an excellent technique to incorporate phenolic compounds into food products in order to enhance both their antioxidative stability and nutritional value.

Veiled Extra Virgin Olive Oils: Role of Emulsion, Water and Antioxidants

This review traces the current knowledge on the effects of various factors and phenomena that occur at interface, and the role of dispersed phase on the physicochemical, sensorial and nutritional characteristics of veiled extra virgin olive oil (VVOO). Since 1994 there have been numerous articles in the literature regarding the peculiar characteristic of unfiltered olive oil, so-called veiled or cloud virgin olive oil. It is a colloidal system (emulsion–sol), where the continuous lipidic phase dispreads mini droplets of milling water, fragments of cells and biotic fraction obtained from oil processing. During storage, the dispersed phase collapses and determines the quality of the virgin olive oil (VOO). The observed phenomena lead to worsening the quality of the product by causing defects such as oxidation of phenols, triacylglycerols hydrolysis and off-flavor formation. The addition of bioactive compounds, such as vitamins, on product based on VVOO, must take into account the eventual synergistic effect of individual substances. The role of the interphase is crucial to the synergic activity of bioactive molecules in improving oxidative stability, sensorial and health characteristics of VVOO.

Preparation and Characterization of Syringic Acid-Loaded TPGS Liposome with Enhanced Oral Bioavailability and In Vivo Antioxidant Efficiency

In this study, syringic acid-loaded TPGS liposome (SA-TPGS-Ls) was successfully prepared to improve oral bioavailability of syringic acid (SA). SA is a natural and notable antioxidant activity compound with its limited bioavailability ascribable to its poor aqueous solubility and fast elimination. Recently, TPGS has become a perfect molecular biomaterial in developing several carrier systems with sustained, controlled, and targeted the drug delivery. SA-TPGS-Ls was prepared via thin-film dispersion method and characterized in terms of particle size, stability, morphology, and encapsulation efficiency (EE). The results showed that SA-TPGS-Ls had regular spherical-shaped nanoparticles with EE of 96.48 ± 0.76%. The pharmacokinetic studies demonstrated a delayed MRT and prolonged t_1/2, while relative oral bioavailability increased by 2.8 times. Tissue distribution showed that SA-TPGS-Ls maintained liver drug concentration while delayed elimination was also observed in the kidney. In CCl₄-induced hepatotoxicity study, the activities of hepatic T-AOC, GSH-Px, CAT, GSH, and SOD were greatly elevated, while serum biological markers ALT, AST, and AKP were reduced after treatment of mice with SA-TPGS-Ls. Histopathological studies confirmed that SA-TPGS-Ls could remarkably improve the status of hepatic tissues. Collectively, SA-TPGS-Ls significantly improved the drug encapsulation efficiency, stability coupled with bioavailability of SA, hence increasing in vivo antioxidant activity of the drug.

Optimization of mixed surfactants-based β-carotene nanoemulsions using response surface methodology: An ultrasonic homogenization approach

In the present study, food grade mixed surfactant-based β-carotene nanoemulsions were prepared without using any co-surfactant. Response surface methodology (RSM) along with central composite design (CCD) was used to investigate the effect of independent variables (surfactant concentration, ultrasonic homogenization time and oil content) on response variables. RSM analysis results revealed that experimental results were best fitted into a quadratic polynomial model with regression coefficient values of more than 0.900 for all responses. Optimized preparation conditions for β-carotene nanoemulsions were 5.82% surfactant concentration, 4 min ultrasonic homogenization time and 6.50% oil content. The experimental values at optimized preparation conditions were 119.33 nm droplet size, 2.67p-Anisidine value and 85.63% β-carotene retention. This study will be helpful for the fortification of aqueous products with β-carotene.