Release of antimicrobial actives from microcapsules by the action of axillary bacteria

Volatile Components and Preliminary Antibacterial Activity of Tamarillo (Solanum betaceum Cav.)

Tamarillo is a nutrient-dense fruit with a unique aroma from its volatile compounds (VCs). In this study, we aimed to compare the volatile profiles: (i) of fresh and freeze-dried tamarillo; (ii) detected using Thermal Desorption–Gas Chromatography–Mass Spectrometry (TD–GC–MS) and Solid-Phase MicroExtraction–Gas Chromatography-Mass Spectrometry (SPME–GC–MS); (iii) of freeze-dried pulp and peel of New Zealand grown tamarillo. The possible antibacterial activity of freeze-dried tamarillo extracts was also investigated. We show that freeze-drying maintained most of the VCs, with some being more concentrated with the loss of water. The most abundant VC in both fresh and freeze-dried tamarillo was hexanoic acid methyl ester for pulp (30% and 37%, respectively), and (E)-3-Hexen-1-ol for peel (36% and 29%, respectively). With the use of TD–GC–MS, 82 VCs were detected for the first time, when compared to SPME–GC–MS. Methional was the main contributor to the overall aroma in both peel (15.4 ± 4.2 μg/g DW) and pulp (118 ± 8.1 μg/g DW). Compared to water as the control, tamarillo extracts prepared by water and methanol extraction showed significant antibacterial activity against E. coli, P. aeruginosa, and S. aureus with zone of inhibition of at least 13.5 mm. These results suggest that freeze-dried tamarillo has a potential for use as a natural preservative to enhance aroma and shelf life of food products.

Characterization of (2E,6E)-3,7,11-Trimethyldodeca-2,6,10-Trien-1-Ol with Antioxidant and Antimicrobial Potentials from <i>Euclea Crispa</i> (Thunb.) Leaves

(2E,6E)-3,7,11-Trimethyldodeca-2,6,10-trien-1-ol or farnesol is a natural isoprenoid possessing a range of beneficial biological activities as anti-candidiasis, anti-tumor and anti-hyperglycaemia. The present study, for the first time, isolated and identified farnesol from Euclea crispa leaves’ extract, subsequently, validated its antioxidant and antimicrobial potentials. The isolated compound was confirmed by spectroscopic techniques including ultraviolet-visible (UV/Vis), fourier-transform infrared (FTIR), and 1H and 13C magnetic resonance (NMR) spectroscopies. By in vitro investigations, farnesol exhibited a considerable antioxidant activity with IC50 values of 113.79, 109.59, and 116.65 µg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and nitric oxide radical scavenging assays, respectively. Additionally, farnesol performed a potent reducing power capacity which was in line with ascorbic acid, an outstanding antioxidant. By the disc-diffusion assay, farnesol exposed the superior antimicrobial activity against various disease-causing microorganisms. Significantly, at the concentration of 50 µg/mL, the compound effectively inhibited the growth of Escherichia coli and Aspergillus niger with inhibition zones of 12 and 11 mm, respectively. Findings from this research suggest that E. crispa leaf is a potential source of farnesol, a powerful antioxidant and antimicrobial agent.

Characterization of (2E,6E)-3,7,11-Trimethyldodeca-2,6,10-Trien-1-Ol with Antioxidant and Antimicrobial Potentials from <i>Euclea Crispa</i> (Thunb.) Leaves

(2E,6E)-3,7,11-Trimethyldodeca-2,6,10-trien-1-ol or farnesol is a natural isoprenoid possessing a range of beneficial biological activities as anti-candidiasis, anti-tumor and anti-hyperglycaemia. The present study, for the first time, isolated and identified farnesol from Euclea crispa leaves’ extract, subsequently, validated its antioxidant and antimicrobial potentials. The isolated compound was confirmed by spectroscopic techniques including ultraviolet-visible (UV/Vis), fourier-transform infrared (FTIR), and 1H and 13C magnetic resonance (NMR) spectroscopies. By in vitro investigations, farnesol exhibited a considerable antioxidant activity with IC50 values of 113.79, 109.59, and 116.65 µg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and nitric oxide radical scavenging assays, respectively. Additionally, farnesol performed a potent reducing power capacity which was in line with ascorbic acid, an outstanding antioxidant. By the disc-diffusion assay, farnesol exposed the superior antimicrobial activity against various disease-causing microorganisms. Significantly, at the concentration of 50 µg/mL, the compound effectively inhibited the growth of Escherichia coli and Aspergillus niger with inhibition zones of 12 and 11 mm, respectively. Findings from this research suggest that E. crispa leaf is a potential source of farnesol, a powerful antioxidant and antimicrobial agent.

Sesquiterpenes in grapes and wines: Occurrence, biosynthesis, functionality, and influence of winemaking processes

Grapes are an important global horticultural product, and are mainly used for winemaking. Typically, grapes and wines are rich in various phytochemicals, including phenolics, terpenes, pyrazines, and benzenoids, with different compounds responsible for different nutritional and sensory properties. Among these compounds, sesquiterpenes, a subcategory of the terpenes, are attracting increasing interest as they affect aroma and have potential health benefits. The characteristics of sesquiterpenes in grapes and wines in terms of classification, biosynthesis pathway, and active functions have not been extensively reviewed. This paper summarizes 97 different sesquiterpenes reported in grapes and wines and reviews their biosynthesis pathways and relevant bio-regulation mechanisms. This review further discusses the functionalities of these sesquiterpenes including their aroma contribution to grapes and wines and potential health benefits, as well as how winemaking processes affect sesquiterpene concentrations.

Photocontrolled Cargo Release from Dual Cross-Linked Polymer Particles

Burst release of a payload from polymeric particles upon photoirradiation was engineered by altering the cross-linking density. This was achieved via a dual cross-linking concept whereby noncovalent cross-linking was provided by cyclodextrin host-guest interactions, and irreversible covalent cross-linking was mediated by continuous assembly of polymers (CAP). The dual cross-linked particles (DCPs) were efficiently infiltrated (∼80-93%) by the biomacromolecule dextran (molecular weight up to 500 kDa) to provide high loadings (70-75%). Upon short exposure (5 s) to UV light, the noncovalent cross-links were disrupted resulting in increased permeability and burst release of the cargo (50 mol % within 1 s) as visualized by time-lapse fluorescence microscopy. As sunlight contains UV light at low intensities, the particles can potentially be incorporated into systems used in agriculture, environmental control, and food packaging, whereby sunlight could control the release of nutrients and antimicrobial agents.

Controlled stimulation-burst targeted release by smart decentered core-shell microcapsules in gravity and magnetic field

By combining gravity and magnetic force, we have developed a versatile and facile microfluidic method for forming magnetic decentered core-shell microcapsules in which the directions of the oil core and the magnetic nanoparticles are either opposed or the same. When the temperature rises above the LCST of the PNIPAm, the shell shrinks rapidly and the core targets burst release towards the converse or the same direction as the magnet. By adjusting the direction of the magnet, the release direction of the active substance could be correspondingly accurately controlled.

Chemical profiling of Elaeocarpus serratus L. by GC-MS

OBJECTIVE

To determine the possible bioactive components of the ethanolic extract of leaves of Elaeocarpus serratus (E. serratus).

METHODS

The present research was carried out by using GC-MS analysis, while mass spectra of the compounds found in the extract was matched with the National Institute of Standards and Technology and Wiley library.

RESULTS

Thirty components from leaves of the above said plant were identified. The active principles with their retention time, molecular formula, molecular weight and concentration (%) in the ethanol extracts of leaf of E. serratus are obtained.

CONCLUSIONS

This is the first report of documentation of active constituents from leaves of E. serratus. The research reveals the potential of E. serratus leaves as a good source of bioactive compounds such as fatty acid esters, alcohols, hydrocarbons, aldehydes, alkenes, fatty acids and amides that justify the use of this plant for its various ailments by traditional practitioners.

Release behavior of trans,trans-farnesol entrapped in amorphous silica capsules

Farnesol, a compound widely found in several agro-food by-products, is an important bioactive agent that can be exploited in cosmetics and pharmaceutics but the direct bioapplication of this compound is limited by its volatility. Here the entrapment of farnesol in silica capsules was investigated to control the release of this bioactive compound in the vapor phase and in ethanol solutions. The preparation of silica capsules with oil cores was obtained by employing a sol-gel method using O/W/O multiple emulsions. Two distinct chemical vehicles for farnesol have been investigated, retinol and oleic acid, that afterwards have been emulsified as internal oil phases. The volatile release of farnesol from the as-prepared SiO2 capsules was investigated by headspace solid phase microextraction (HS-SPME) followed by gas chromatographic analysis (GC), and the release to ethanol was carried out by direct injection of the ethanolic fraction into the GC system. It is demonstrated that these capsules are efficient for the long controlled release of farnesol and that the respective profiles depend on the chemical parameters employed in the synthesis of the capsules.