Gallic Acid-Phospholipid Complex: Drug Incorporation and Physicochemical Characterization

Development of cellulose nanowhisker-gallic acid antioxidant bioconjugate via covalent conjugation and supramolecular interactions: A comparative study

A new supramolecular antioxidant bioconjugate based on cellulose nanowhisker (CNW) and gallic acid (GA) was developed by grafting β-CD on the surface of CNW and then employing host- guest chemistry to involve GA. Our challenge was to explore the effect of supramolecular conjugation of antioxidant molecules versus their covalent binding on the CNW backbone on the antioxidant activity. The synthesis of these products was confirmed using Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC) analyses. The antioxidant activity of gallic acid (GA) containing products, both products including its non-covalent interactions with CNW-g-β-CD and covalent bonding with CNW were experimentally evaluated using DPPH test. Theoretical calculations using Gaussian software and the density functional theory (DFT) method were also performed. The results showed that GA's antioxidant activity increased in non-covalent conjugated form. Hydrogen atom transfer (HAT) was used to predict the antioxidant activity of GA in computational methods. These findings not only expand our understanding of the structure-activity relationships in antioxidant systems but also provide valuable insights that can aid in the design and development of novel biopolymer-based antioxidants with improved properties.

Biosynthesis of gallic acid fabricated tellurium nanoparticles (GA-Te NPs) for enhanced antibacterial, antioxidant, and cytotoxicity applications

The development of antibiotic resistance and the onset of diverse forms of cancer necessitate the utilization of innovative multifunctional biocompatible materials. The synthesis of metal and metalloid nanoparticles through eco-friendly means demonstrates promising potential in therapeutic and diagnostic domains. Among these materials, Tellurium (Te) exhibits exceptional characteristics and finds application in numerous fields; nevertheless, its usage in biological applications has been somewhat limited, primarily due to its inherent toxicity. Furthermore, nanomaterials developed from Te have not garnered adequate research attention. Conversely, nanomaterials fashioned using biomolecules augment their biological efficacy and applicability. Therefore, the present work focuses on synthesizing the tellurium nanoparticles (Te NPs) using the antioxidant molecule gallic acid (GA) and evaluating their biological activity and toxicity for the first time. The study evidenced that GA-Te NPs are spherical and monodispersed, with an average size of 19.74 ± 5.3 nm. XRD analysis confirmed a hexagonal crystalline structure for GA-Te NPs, and FTIR analysis evidenced the capping of GA on Te NPs. GA-Te NPs (MIC: 1.56 μg/mL) strongly reduce the growth and biofilm formation of S. aureus, E. coli, and S. enterica. Additionally, GA-Te NPs at a concentration of 50 μg/mL cause a significant level of toxicity in BT474 breast cancer cells but not in NIH3T3 cells. Unexpectedly, GA-Te NPs at concentrations <250 μg/mL do not cause hemolysis in red blood cells (RBC) Besides, the way of utilizing the lower concentrations of therapeutics could result in ecological safety. Therefore, the study concludes that GA-Te NPs could be used as potential multifunctional agents.

Development of gallic acid-loaded ethylcellulose fibers as a potential wound dressing material

In this study, novel fibers were designed based on ethylcellulose (EC), loaded with different concentrations of gallic acid (GA) using the electrospinning technique, in order to investigate the potential of these materials as wound dressings. The chemical structure and morphology, along with the antimicrobial and biocompatibility tests of the EC_GA fibers were investigated. To observe the chemical interactions between the components, fourier transform infrared spectroscopy (FTIR) was used. The morphological analyzes were performed using scanning electron microscope (SEM). The uniaxial tensile test machine was used to obtain mechanical performance of the fibers. MTT assay was applied to get the biocompatibility properties of the fibers and antimicrobial test was applied to obtain the antimicrobial activity of the fibers. Based on the obtained results, the highest viability value of 67.4 % was obtained for 10%EC_100GA on the third day of incubation, demonstrating that with the addition of a higher concentration of GA, the cell viability increases. The antimicrobial tests, evaluated against Staphylococcus (S.) aureus, Escherichia (E.) coli, Pseudomonas (Ps.) aeruginosa and Candida (C.) albicans, showed a >90 % microbial reduction capacity correlated with a logarithmic reduction ranging from 0.63 to 1, for 10%EC_100 GA. In vitro release tests of GA from the fibers showed that GA was totally released from 10%EC_100 GA fibers after 2880 min, demonstrating a controlled release profile. These findings demonstrated that EC_GA fibers may be suitable for application in biomedical fields such as wound dressing materials. However, further studies should be performed to increase the biocompatibility properties of the fibers.

Effects of potential allelochemicals in a water extract of Abutilon theophrasti Medik. on germination and growth of Glycine max L., Triticum aestivum L., and Zea mays L

BACKGROUND

Velvetleaf (Abutilon theophrasti Medik.), primarily a cropland weed, exerts adverse impacts on the productivity of various crops, including soybean (Glycine max L.), wheat (Triticum aestivum L.), and maize (Zea mays L.), by hindering their vegetative growth. However, the interference mechanism of velvetleaf on the three crops remains unclear.

RESULTS

The inhibitory effect of velvetleaf water extract on the germination and growth of soybean, wheat, and maize was determined in pot experiments and field trials. Four phenolic acids were identified as allelochemicals: protocatechuic acid (PA), gallic acid (GA), chlorogenic acid (CHA), and vanillic acid (VA). These allelochemicals were detected in different parts (leaves, roots, and stems) of velvetleaf, and in the rhizosphere soil of tested crops over the range of 1.19-556.23 μm kg^-1 . These allelochemicals were administered in approximate concentrations as in velvetleaf roots and rhizosphere soil, and their effects varied with crop species and velvetleaf parts. The allelochemicals generally had low-dose stimulation and high-dose inhibition effects on the growth of soybean, wheat, and maize. Furthermore, the biomass distribution of these crops was affected by allelochemicals in the soil. In field trials, the allelochemicals significantly (P < 0.05) inhibited the growth of all tested crops over the whole growth period, and PA showed a significant (P < 0.05) inhibitory effect on the yield of soybean, wheat, and maize.

CONCLUSION

GA, PA, CHA, and VA in velvetleaf aqueous extracts were identified as allelochemicals that play an inhibitory role on three crops. © 2022 Society of Chemical Industry.

Co-assembling of natural drug-food homologous molecule into composite hydrogel for accelerating diabetic wound healing

Diabetic wound healing is a major clinical challenge due to its vulnerability to bacterial infection and the prolonged inflammation in the wound. Traditional dressings for the healing of diabetic wounds are often suffered from unsatisfactory efficacy and frequent dressing changes which may cause secondary damage. Therefore, it is necessary to find a wound dressing that balances material functionality, degradation, safety, and tissue regeneration. Our recent studies demonstrated that gallic acid (GA) could spontaneously form supramolecular hydrogels at a relatively high concentration. However, a single network of GA hydrogel is prone to degradation, poor adhesion, and poor swelling, and may not be suitable for wound healing dressings. In this study, a composite hydrogel (GAK) was constructed by introducing konjac glucomannan (KGM) into the gel system of gallic acid (GA) and applied to promote diabetic wound healing. The composite hydrogel (GAK) with superior surface adhesion, stability, and swelling properties than the single-network of GA hydrogel. Moreover, in vitro experiments showed that GAK hydrogel had excellent biocompatibility and exhibited antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Additionally, the GAK hydrogel could significantly accelerate angiogenesis, collagen deposition, and re-epithelialization during wound healing in diabetic mice, reducing the expression of related inflammatory proteins interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), and cyclooxygenase-2 (COX-2), and improving the wound closure rate. The findings of this study suggest that this composite hydrogel (GAK) can be an ideal dressing material for accelerating diabetic wound healing.

In vitro evaluation of antioxidant activity and determination of total phenolic and flavonoids contents of ethanol-water extracts of Paeonia lactiflora and Calendula officinalis L. petals

In this study, the petals collected from peony hybrid Paeonia lactiflora "Bowl of beauty" and Calendula officinalis L. were extracted using ethanol-water mixture assisted with microwave and ultrasonic treatment. The isolation of Calendula officinalis L. essential oil was done by hydrodistillation as well. The total phenolic and flavonoids content in the extracts and oil were determined and their antioxidant activity was evaluated. The highest total phenolic content was found for the extracts of hybrid Paeonia lactiflora and Calendula officinalis L. obtained by ultrasound extraction (9.73 and 10.03 mg GA/mL RE, respectively), while the highest flavonoid content was obtained by microwave-assisted extraction (14.45 and 6.02 mg QE/mL RE, respectively). Antioxidant activity was assessed using standard antioxidant in vitro DPPH• and ABTS•+ assays. The highest antioxidant activity was obtained in DPPH• and ABTS•+ assay for the microwave-assisted extraction of hybrid Paeonia lactiflora (79% and 83%) and ultrasound-assisted extraction of Calendula officinalis L. (45% and 49%), respectively. In order to improve the antioxidative activity of both extract and essential oil the pectin films with gallic acid, using enzymatically assisted catalysis to attain covalent bonding to a carrier, were prepared. Optical microscopy and FTIR spectroscopy were used for the characterization of obtained materials. The films, with essential oil of Calendula officinalis L. and gallic acid, showed significantly increased percentage inhibition in DPPH• and ABTS•+ test (91% and 95%, respectively) after 10 minutes. The results, also, showed that all formulations of pectin biopolymer film, modified with gallic acid, can be successfully applied as a carrier for both types of ingredients.

In vitro evaluation of antioxidative activities of the extracts of petals of Paeonia lactiflora and Calendula officinalis incorporated in the new forms of biobased carriers

In this study, the petals collected from peony hybrid Paeonia lactiflora "Bowl of Beauty" and Calendula officinalis L. were extracted using an ethanol-water mixture assisted with microwave and ultrasonic treatment. The isolation of Calendula officinalis L. essential oil was done by hydrodistillation as well. The total phenolic and flavonoids content in the extracts and oil were determined and their antioxidant activity was evaluated. The highest total phenolic content was found for the extracts of hybrid P. lactiflora and C. officinalis L. obtained by ultrasound extraction (83.16 and 114.47 mg GA/g, respectively), while the flavonoid content obtained by microwave-assisted extraction was relatively high (123.48 and 65.29 mg QE/g, respectively). The highest antioxidant activity was obtained in DPPH• and ABTS•+ assay for the microwave-assisted extraction of hybrid P. lactiflora (79% and 83%) and ultrasound-assisted extraction of C. officinalis L. (45% and 49%), respectively. To improve antioxidant activity of both types of examined analytes (extracts and essential oil), the pectin biopolymer film (as a carrier) was prepared in the process of enzymatically assisted catalysis. Optical microscopy and FTIR spectroscopy were used for the characterization of obtained materials. The films, with essential oil of C. officinalis L. and gallic acid, showed significantly increased percentage inhibition in DPPH• and ABTS•+ test (91% and 95%, respectively) after 10 minutes. The results, also, showed that all formulations of pectin biopolymer film, modified with gallic acid, can be successfully applied as a carrier for both types of ingredients.

Chitosan and glyceryl monooleate nanostructures containing gallic acid isolated from amla fruit: targeted delivery system

Gallic acid, active constituent of amla fruit its natural abundance with beneficial multi actions in body make them attractive for clinical applications. In present study, we focused on extracting, separating and characterizing gallic acid from amla and further formulated into chitosan nanoparticles, so bring it to increase its aqueous solubility and thereby bioactivity. Gallic acid nanoparticles were prepared by using poloxamer 407, chitosan and Glyceryl Monooleate (GMO) using probe sonicator and high pressure homogenization method. Prepared nanoparticles were characterized by particle size, zeta potential, DSC, XRD, SEM, entrapment efficiency, loading content, in-vitro release and stability study. They showed approximately 76.80% encapsulation of gallic acid with average size of 180.8 ± 0.21 nm, and zeta potential +24.2 mV. The cumulative in vitro drug release upto 24 hrs 77.16% was achieved suggesting that from all our findings, it can be concluded that work will facilitate extraction, design and fabrication of nanoparticles for protection and sustained release of gallic acid particularly to colonic region.

Improved Anticancer Effect of Magnetite Nanocomposite Formulation of GALLIC Acid (Fe₃O₄-PEG-GA) Against Lung, Breast and Colon Cancer Cells

Lung cancer, breast cancer and colorectal cancer are the most prevalent fatal types of cancers globally. Gallic acid (3,4,5-trihydroxybenzoic acid) is a bioactive compound found in plants and foods, such as white tea, witch hazel and it has been reported to possess anticancer, antioxidant and anti-inflammatory properties. In this study we have redesigned our previously reported anticancer nanocomposite formulation with improved drug loading based on iron oxide magnetite nanoparticles coated with polyethylene glycol and loaded with anticancer drug gallic acid (Fe₃O₄-PEG-GA). The in vitro release profile and percentage drug loading were found to be better than our previously reported formulation. The anticancer activity of pure gallic acid (GA), empty carrier (Fe₃O₄-PEG) nanocarrier and of anticancer nanocomposite (Fe₃O₄-PEG-GA) were screened against human lung cancer cells (A549), human breast cancer cells (MCF-7), human colon cancer cells (HT-29) and normal fibroblast cells (3T3) after incubation of 24, 48 and 72 h using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) MTT assay. The designed formulation (Fe₃O₄-PEG-GA) showed better anticancer activity than free gallic acid (GA). The results of the in vitro studies are highly encouraging to conduct the in vivo studies.

Gallic acid-PAMAM and gallic acid-phospholipid conjugates, physicochemical characterization and in vivo evaluation

Gallic acid (GA) is a naturally occurring compound with valuable antioxidant activity. Its oral bioavailability is limited by its high metabolism and rapid clearance. In this paper, GA was conjugated with two different materials, phosphatidylcholine (PC) and polyamidoamine (PAMAM) dendrimer. The prepared conjugates were characterized by FTIR, DSC, and SEM. Also, they were tested for drug content and in vitro drug release. It was found that GA conjugation with both materials have significantly prolonged its release up to 12 h. In vivo hepatoprotective activity of free and conjugated GA was studied in rats after carbon tetrachloride (CCl4)-induced oxidative damage in rat liver through measurement of different liver marker enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT)), in addition to the total protein and albumin level in rat serum. Also, histopathological examination of liver cell of all rat groups was done. Results showed that both prepared conjugates have significantly reduced the hepatic marker enzymes accompanied by normalizing total protein and albumin levels in rat serum and with respect to CCl4-induced group (p < .05). Histopathological examination showed that pretreatment of rats with GA-PC or GA-PAMAM before CCL4 could reduce the induced cellular histopathological changes. It appears that conjugation of GA could enhance its bioavailability and increase its hepatoprotective effect.

Characterization of the Interaction between Gallic Acid and Lysozyme by Molecular Dynamics Simulation and Optical Spectroscopy

The binding interaction between gallic acid (GA) and lysozyme (LYS) was investigated and compared by molecular dynamics (MD) simulation and spectral techniques. The results from spectroscopy indicate that GA binds to LYS to generate a static complex. The binding constants and thermodynamic parameters were calculated. MD simulation revealed that the main driving forces for GA binding to LYS are hydrogen bonding and hydrophobic interactions. The root-mean-square deviation verified that GA and LYS bind to form a stable complex, while the root-mean-square fluctuation results showed that the stability of the GA-LYS complex at 298 K was higher than that at 310 K. The calculated free binding energies from the molecular mechanics/Poisson-Boltzmann surface area method showed that van der Waals forces and electrostatic interactions are the predominant intermolecular forces. The MD simulation was consistent with the spectral experiments. This study provides a reference for future study of the pharmacological mechanism of GA.

Cyclodextrin and phospholipid complexation in solubility and dissolution enhancement: a critical and meta-analysis

INTRODUCTION

Poor solubility and dissolution of drugs are the major challenges in drug formulation and delivery. In order to improve the solubility and dissolution profile of drugs, various methods have been investigated so far. The cyclodextrin (CD) complexation and phospholipid (PL) complexation are among the exhaustively investigated methods employed for more precise improvement of the solubility and dissolution of poorly water-soluble drugs.

AREAS COVERED

The article discusses the CD and PL complexation techniques of solubility and dissolution enhancement. Various studies reporting the CD and PL complexation as the potential approaches to improve the dissolution, absorption and the bioavailability of the drugs have been discussed. The article critically reviews the physicochemical properties of CDs and PLs, eligibility of drugs for both the complexation, thermodynamics of complexation, methods of preparation, characterization, advantages, limitation and the meta-analysis of some studies for both the techniques.

EXPERT OPINION

The CD and PL complexation techniques are very useful in improving solubility and dissolution (and hence the bioavailability) of biopharmaceutical classification system Class II and Class IV drugs. The selection of a particular kind of complexation can be made on the basis of eligibility criteria (of drugs) for the individual techniques, cost, stability and effectiveness of the complexes.

The gallic acid-phospholipid complex improved the antioxidant potential of gallic acid by enhancing its bioavailability

Gallic acid (GA) is well known for its antioxidant and hepatoprotective activity, though its effectiveness is restricted due to rapid metabolism and elimination. To overcome these problems, gallic acid-phospholipid complex was prepared and the effect of phospholipid complexation was investigated on carbon tetrachloride (CCl4)-induced oxidative damage in rat liver. The complex significantly reduced the hepatic marker enzymes in rat serum and restored the antioxidant enzyme levels with respect to CCl4-induced group (P < 0.05 and P < 0.01). Also, the complex improved the pharmacokinetics of GA by increasing the relative bioavailability and elimination half-life. The study therefore suggests that phospholipid complexation has enhanced the therapeutic efficacy of GA which may be due to its improved absorption and increased bioavailability in rat serum.