Investigation by response surface methodology of the combined effect of pH and composition of water-methanol mixtures on the stability of curcuminoids

Paenibacillus polymyxa Antagonism towards Fusarium: Identification and Optimisation of Antibiotic Production

An antibiotic produced by Paenibacillus polymyxa 7F1 was studied. The 7F1 strain was isolated from the rhizosphere of a wheat field. Response surface methodology was used to optimize the physicochemical parameters. The strain showed broad-spectrum activity against several plant pathogens. Identification of the strain was realized based on 16s rRNA gene and gyrB gene sequencing. The antibiotic was optimized by one-factor-at-a-time (OFAT) and response surface methodology (RSM) approaches. The suitable antibiotic production conditions were optimized using the one-factor-at-a-time method. The individual and interaction effects of three independent variables: culture temperature, initial pH, and culture time, were optimized by Box-Behnken design. The 16SrRNA gene sequence (1239 nucleotides) and gyrB gene (1111 nucleotides) were determined for strain 7F1 and shared the highest identities to those of Paenibacillus polymyxa. The results showed the optimal fermentation conditions for antibiotics produced by Paenibacillus polymyxa 7F1 were a culture temperature of 38 °C, initial pH of 8.0, and culture time of 8 h. The antibiotics produced by Paenibacillus polymyxa 7F1 include lipopeptides such as iturin A and surfactin. The results provide a theoretical basis for the development of bacteriostatic biological agents and the control of mycotoxins.

Simultaneous effect of different chromatographic conditions on the chromatographic retention of pentapeptide derivatives (HGRFG and NPNPT)

Introduction: Oligopeptides exhibit great prospects for clinical application and its separation is of great importance in new drug development. Methods: To accurately predict the retention of pentapeptides with analogous structures in chromatography, the retention times of 57 pentapeptide derivatives in seven buffers at three temperatures and four mobile phase compositions were measured via reversed-phase high-performance liquid chromatography. The parameters ( k H A , k A , and p K a ) of the acid-base equilibrium were obtained by fitting the data corresponding to a sigmoidal function. We then studied the dependence of these parameters on the temperature (T), organic modifier composition (φ, methanol volume fraction), and polarity ( P m N parameter). Finally, we proposed two six-parameter models with (1) pH and T and (2) pH and φ or P m N as the independent variables. These models were validated for their prediction capacities by linearly fitting the predicted retention factor k-value and the experimental k-value. Results: The results showed that log k H A and log k A exhibited linear relationships with 1 / T , φ or P m N for all pentapeptides, especially for the acid pentapeptides. In the model of pH and T, the correlation coefficient (R²) of the acid pentapeptides was 0.8603, suggesting a certain prediction capability of chromatographic retention. Moreover, in the model of pH and φ or P m N , the R² values of the acid and neutral pentapeptides were greater than 0.93, and the average root mean squared error was approximately 0.3, indicating that the k-values could be effectively predicted. Discussion: In summary, the two six-parameter models were appropriate to characterize the chromatographic retention of amphoteric compounds, especially the acid or neutral pentapeptides, and could predict the chromatographic retention of pentapeptide compounds.

Curcumin Hybrid Lipid Polymeric Nanoparticles: Antioxidant Activity, Immune Cellular Response, and Cytotoxicity Evaluation

Poor solubility and short biological half-life present a challenge that needs to be overcome in order to improve the recognized bioactivities of curcumin (CUR), the main phenolic compounds derived from the roots of Curcuma longa. However, drug delivery systems have proven to be an excellent strategy to improve and obtain greater bioavailability. Our previous studies on curcuminoid hybrid nanoparticles have shown promising results by significantly increasing the solubility of desmethoxycurcumin (DMC) and bisdemethoxycurcumin (BDM). In this contribution, we performed a detailed characterization of a CUR as well as in vitro and in vivo studies. The developed method produced CUR loaded nanoparticles with an average size of 49.46 ± 0.80. Moreover, the FT-IR analysis confirmed the encapsulation, and TEM images showed their spherical shape. The NP achieved an encapsulation efficiency greater than 99%. Further, the release studies found that the NPs obtained a significantly higher release than the pure compounds in water. In vivo delayed-type hypersensitivity (DTH) studies showed promising results by enhancing the immune activity response of CUR in NP compared to bulk CUR. Furthermore, we report a significant increase in antioxidant activity for CUR-NP in aqueous solution compared to free CUR. Finally, an important in vitro cytotoxic effect on gastric AGS and colon SW620 adenocarcinoma cell lines was found for CUR-NP while empty carrier nanoparticles are observed to exhibit low cytotoxicity, indicating the potential of these CUR-PLU NPs for further studies to assess their phytotherapeutic applications.

Bovine Serum Albumin-Based Nanoparticles: Preparation, Characterization, and Antioxidant Activity Enhancement of Three Main Curcuminoids from Curcuma longa

Bovine Serum Albumin (BSA) lipid hybrid nanoparticles are part of the new solutions to overcome low bioavailability of poor solubility drugs such as curcuminoids, which possess multiple biological advantages; however, they are counterbalanced by its short biological half-life. In this line, we prepared the three main curcuminoids: curcumin (CUR), desmethoxycurcumin (DMC), and bisdemethoxycurcumin (BDM)-loaded BSA nanoparticles. The three formulations were characterized by the average size, size distribution, crystallinity, weight loss, drug release, kinetic mechanism, and antioxidant activity. The developed method produced CUR-, DMC-, and BDM-loaded BSA nanoparticles with a size average of 15.83 ± 0.18, 17.29 ± 3.34, and 15.14 ± 0.14 nm for CUR, DMC, and BDM loaded BSA, respectively. FT-IR analysis confirmed the encapsulation, and TEM images showed their spherical shape. The three formulations achieved encapsulation efficiency upper to 96% and an exhibited significantly increased release from the nanoparticle compared to free compounds in water. The antioxidant activity was enhanced as well, in agreement with the improvement in water release, obtaining IC₅₀ values of 9.28, 11.70, and 15.19 µg/mL for CUR, DMC, and BDM loaded BSA nanoparticles, respectively, while free curcuminoids exhibited considerably lower antioxidant values in aqueous solution. Hence, this study shows promises for such hybrid systems, which have been ignored so far, regarding proper encapsulation, protection, and delivery of curcuminoids for the development of functional foods and pharmaceuticals.

Design of Hybrid Polymeric-Lipid Nanoparticles Using Curcumin as a Model: Preparation, Characterization, and In Vitro Evaluation of Demethoxycurcumin and Bisdemethoxycurcumin-Loaded Nanoparticles

Polymeric lipid hybrid nanoparticles (PLHNs) are the new generation of drug delivery systems that has emerged as a combination of a polymeric core and lipid shell. We designed and optimized a simple method for the preparation of Pluronic F-127-based PLHNs able to load separately demethoxycurcumin (DMC) and bisdemethoycurcumin (BDM). CUR was used as a model compound due to its greater availability from turmeric and its structure similarity with DMC and BDM. The developed method produced DMC and BDM-loaded PLHNs with a size average of 75.55 ± 0.51 and 15.13 ± 0.014 nm for DMC and BDM, respectively. An FT-IR analysis confirmed the encapsulation and TEM images showed their spherical shape. Both formulations achieved an encapsulation efficiency ≥ 92% and an exhibited significantly increased release from the PLHN compared with free compounds in water. The antioxidant activity was enhanced as well, in agreement with the improvement in water dissolution; obtaining IC₅₀ values of 12.74 ± 0.09 and 16.03 ± 0.55 for DMC and BDM-loaded PLHNs, respectively, while free curcuminoids exhibited considerably lower antioxidant values in an aqueous solution. Hence, the optimized PHLN synthesis method using CUR as a model and then successfully applied to obtain DMC and BDM-loaded PLHNs can be extended to curcuminoids and molecules with a similar backbone structure to improve their bioactivities.

Multivariate optimization of an analytical method for the analysis of Abruzzo white wines by ICP OES

An inductively coupled plasma-optical emission spectrometry (ICP OES) method was optimized and applied for determining the concentration of 14 elements (Ba, Ca, Co, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Sr, V, and Zn) in three representative white wines of the Abruzzo region (Italy). In order to optimise an ICP OES method a three level factorial design for three variables was used. The intensity of the emission lines for analytes was simultaneously maximised by using Derringer's desirability function. Using this approach, the optimal experimental conditions for wine analysis of 0.48 L min-1, 1.8 mL min-1 and 0.5 L min-1 for the nebulizer gas flow rate, sample uptake rate and auxiliary gas flow rate respectively were achieved. A total of 46 white wine samples of the three varieties were analysed by using the optimised experimental conditions. Linear Discriminant Analysis (LDA) and Partial Least Squares Linear Discriminant Analysis (PLS LDA) allowed an acceptable classification of the three varietal samples.

Preparation, chemical characterization and determination of crocetin's pharmacokinetics after oral and intravenous administration of saffron (Crocus sativus L.) aqueous extract to C57/BL6J mice

OBJECTIVES

To prepare a lyophilized saffron aqueous extract (SFE) and determine its chemical profile and serum and tissue pharmacokinetics after intravenous and oral administration to C57/Bl6J mice.

METHODS

Lyophilized SFE was prepared, characterized using semi-preparative HPLC and NMR analysis, and stability studies at room temperature, and was quantified for crocin content with an HPLC-PDA method. After intravenous and oral administration of SFE (60 mg/kg, reconstituted with water for injection) to C57/Bl6J mice, crocetin (derived from in vivo crocin hydrolysis) serum and tissue levels (unconjugated and total) were measured with an HPLC-PDA method and subjected to compartmental and non-compartmental PK analysis.

KEY FINDINGS

Saffron aqueous extract was rich in all-trans-crocin (27.8 ± 0.1% w/w) and stable for more than 15 months. One-compartment PK model described crocetin's (unconjugated) kinetics after intravenous administration of SFE, while a first-order kinetic parameter described the rate of crocetin biotransformation to crocetin metabolite (conjugated). Α οne-compartment PK model with first-order absorption described crocetin and crocetin's metabolite kinetics after SFE oral administration. Relative oral bioavailability was calculated at 1.17 for total crocetin. Tissue NCA PK analysis revealed extensive crocetin distribution to liver and kidneys.

CONCLUSIONS

SFE is a stable lyophilized extract rich in all-trans-crocin. The PK study allowed the estimation of basic PK parameters and the bioavailability of SFE's main bioactive component, crocetin, after peros administration.

Qualitative and Quantitative Analysis of C-glycosyl-flavones of Iris lactea Leaves by Liquid Chromatography/Tandem Mass Spectrometry

Iris lactea Pall. var. chinensis (Fisch.) Koidz. is a traditional medicinal plant resource. To make full use of the I. lactea plant resources, constituents of I. lactea leaves were determined by high performance liquid chromatography (HPLC)-quadrupole time-of-flight tandem mass spectrometry and 22 C-glycosylflavones were identified or tentatively identified. Optimal extraction of I. lactea leaves was established via single factor investigations combined with response surface methodology. Then, HPLC coupled with a diode array detector was used to quantitatively analyze the six main components of 14 batches of I. lactea leaves grown in different areas. The results showed the C-glycosylflavones were the main components of I. lactea leaves, and the total contents of detected components were relatively stable for the majority of samples. These results provide a foundation for the development and utilization of I. lactea leaves.

Combined optimization of N-terminal site-specific PEGylation of recombinant hirudin using response surface methodology and kinetic analysis

In this study, a combined optimization method was developed to optimize the N-terminal site-specific PEGylation of recombinant hirudin variant-2 (HV2) with different molecular weight mPEG-propionaldehyde (mPEG-ALD), which is a multifactor-influencing process. The HV2-PEGylation with 5 kDa mPEG-ALD was first chosen to screen significant factors and determine the locally optimized conditions for maximizing the yield of mono-PEGylated product using combined statistical methods, including the Plackett-Burman design, steepest ascent path analysis, and central composition design for the response surface methodology (RSM). Under the locally optimized conditions, PEGylation kinetics of HV2 with 5, 10, and 20 kDa mPEG-ALD were further investigated. The molar ratio of polyethylene glycol to HV2 and reaction time (the two most significant factors influencing the PEGylation efficiency) were globally optimized in a wide range using kinetic analysis. The data predicted by the combined optimization method using RSM and kinetic analysis were in good agreement with the corresponding experiment data. PEGylation site analysis revealed that almost 100% of the obtained mono-PEGylated-HV2 was modified at the N-terminus of HV2. This study demonstrated that the developed method is a useful tool for the optimization of the N-terminal site-specific PEGylation process to obtain a homogeneous mono-PEGylated protein with desirable yield.