Natural antioxidant fine particles recovery from Eucalyptus globulus leaves using supercritical carbon dioxide assisted processes

Microparticle Production of Active Pharmaceutical Ingredient Using Supercritical Antisolvent Process: A Case Study of Allopurinol

Allopurinol is a relatively water-insoluble drug and, consequently, its efficacy was frequently limited by the dissolution or solubility phenomena. The purpose of this study was to improve the solid-state properties and dissolution behavior of allopurinol via a supercritical antisolvent (SAS) process using CO2 as an antisolvent. The effects of operating parameters: temperature (35–55 °C), pressure (80–100 bar), solution concentration (8–15 mg/mL), CO2 flow rate (2–4 L/min), and solution flow rate (0.25–0.50 mL/min) were studied. Moreover, the physical properties of unprocessed and SAS-processed allopurinol were analyzed by SEM, FTIR, DSC, TGA, and PXRD. The dissolution rate of unprocessed and SAS-processed allopurinol was also investigated and compared. In this case study, allopurinol was effectively micronized from 15.3 μm to 1.35 μm at the optimal operating condition. The results verify that the solid-state properties and dissolution rate of allopurinol can be controlled and improved via the micronization process by using SAS technology.

The Synergistic Effect of Three Essential Oils against Bacteria Responsible for the Development of Lithiasis Infection: An Optimization by the Mixture Design

The present study aimed to determine the chemical composition and the synergistic effect of three plants' essential oils (EOs), Eucalyptus camaldulensis (ECEO), Mentha pulegium (MPEO), and Rosmarinus officinalis (ROEO), against three bacterial strains, Proteus mirabilis, Klebsiella pneumoniae, and Staphylococcus aureus, in order to increase the antimicrobial effectiveness by the use of a low dose of essential oils, consequently decreasing the toxicity and negative impact. For this reason, an augmented simplex-centroid mixture design was used to build polynomial models in order to highlight the synergy between the essential oils against bacterial strains. Antimicrobial effect screening was performed by the disc diffusion method and the minimal inhibitory concentrations (MIC) were also studied. The gas chromatography/mass spectrometry (GC-MS) results show the richness of these essential oils by terpenic compounds, especially 1,8-Cineole and P-Cymene for ECEO, Pulegone for MPEO, and α-Pinene and Camphene for ROEO. Moreover, a significant antibacterial effect has been demonstrated and the best values were revealed by MPEO and ECEO against P. mirabilis and K. pneumoniae, with inhibition zones (IZ) of 25 and 20 mm, respectively, and an MIC of 0.0391% (v:v) against K. pneumoniae. The optimal mixtures showed a synergistic effect of essential oils, and the lowest minimal inhibitory concentrations of the mixtures (MICm) were in the order of 29.38% of MPEO, 45.37% of ECEO, and 25.25% of ROEO against P. mirabilis and in the order of 60.61% of MPEO and 39.39% of ROEO against K. pneumoniae. These results indicate the antibacterial efficacy of the three essential oils combined and suggest their importance in the treatment of urinary tract infections caused by resistant bacterial strains.

Nano-zirconia - Evaluation of its antioxidant and anticancer activity

Bioactivity of nanomaterials largely depends on its size, shape and crystalline nature. In this work, the smaller sized spherical shaped nano-zirconia (ZrO₂ NPs) (of ~9 to 11nm) was fabricated and studied its biological activity especially antioxidant and cytotoxicity against human colon carcinoma (HCT-116) and human lung carcinoma (A-549) cell lines. To have its real applications in biological aspects readily available Eucalyptus globulus (E. globulus) leaf extract was used as an effective capping and reducing agent for its synthesis. The prepared ZrO₂ NPs was characterized by using different sophisticated instrumentations such as UV-visible spectrophotometer, XRD, FTIR, TEM, SAED, EDX, DLS and fluorescence spectroscopy. Cellular mitochondrial activity i.e. cell viability was measured by MTT assay and anti-oxidant activity was determined by DPPH assay. The smaller sized ZrO₂ NPs showed strong antioxidant activity as well as cytotoxicity on human cancer cell lines. Comparative cytotoxic studies were conducted on human cancerous cell lines using different techniques. Results confirmed the efficient anti-cancer activities of the fabricated ZrO₂ NPs towards the tested cell lines as well as efficient anti-oxidant activity. This is the first study in which E. globulus leaf extract was used to synthesize smaller spherical shaped ZrO₂ NPs for improved bioactivity i.e. antioxidant and cytotoxicity.