A straightforward method to determine the cytocidal and cytopathic effects of the functional groups of gallic acid

Method development and validation for quantification of six bioactive compounds (andrographolide, columbin, piperine, gallic, paracoumaric and oleanolic acids) by HPTLC

OBJECTIVES

During the spread of pandemic diseases, immunity boosting herbal drugs are taken as a preventive medicine. Kapacurak Kuṭinīr Cūraṇam is a Siddha drug used for flu like viral infections, cold and fever. Developing an analytical method to estimate the content of active phytoconstituents in such antiviral immune boosting drug will be useful in the phyto pharmaceutical industry.

METHODS

A precise, reliable and sensitive ordinary phase high performance thin layer chromatography (HPTLC) method has been developed and validated for identification and simultaneous estimation of six bioactive components namely like andrographolide, columbin, gallic acid, ρ-coumaric acid, piperine and oleanolic acid from any Indian traditional medicine, medicinal plant, drugs and food materials etc. The separation was achieved on silica gel 60F₂₅₄ TLC plates using toluene: ethyl acetate: formic acid (7:3:0.5, v/v) as mobile phase. The gallic acid, ρ-coumaric acid, piperine markers were estimated using the densitometric scanning in absorption mode at 254 nm. The densitometric scanning was done after derivatization (vanillin-sulphuric acid reagent) at λ=520 nm for andrographolide, columbin and oleanolic acid.

RESULTS

The linear regression analysis data for the calibration plots showed a correlation coefficient in the concentration range 1-5 μg per band for the bioactive markers with respect to area. The method was validated for accuracy, precision, limit of detection (LOD), and quantitation of limit (LOQ).

CONCLUSIONS

Developed method was accurate, precise and fast to ensure the quality of Kapacurak Kuṭinīr Cūraṇam.

Enhanced antibacterial efficacy and mechanism of octyl gallate/beta-cyclodextrins against Pseudomonas fluorescens and Vibrio parahaemolyticus and incorporated electrospun nanofibers for Chinese giant salamander fillets preservation

A series of alkyl gallates were evaluated for the antibacterial activity against two common Gram-negative foodborne bacteria (Pseudomonas fluorescens and Vibrio parahaemolyticus) associated with seafood. The length of the alkyl chain plays a pivotal role in eliciting their antibacterial activities and octyl gallate (OG) exerted an excellent inhibitory efficacy. To extend the aqueous solubility, stability, and bactericidal properties of octyl gallate (OG), an inclusion complex between OG and β-cyclodextrin (βCD), OG/βCD, was prepared and identified with various methods including X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared spectroscopy (FTIR). Furthermore, the enhanced inhibitory effect and potential antibacterial mechanism of OG/βCD against two Gram-negative and Gram-positive foodborne bacteria were comprehensively investigated. The results show that OG/βCD could function against bacteria through effectively damaging the membrane, permeating into cells, and then disturbing the activity of the respiratory electron transport chain to cause the production of high-level intracellular hydroxyl radicals. Moreover, the reinforced OG/βCD-incorporated polylactic acid (PLA) nanofibers were fabricated using the electrospinning technique as food packaging to extend the Chinese giant salamander fillet's shelf life at 4 °C. This research highlights the antibacterial effectiveness of OG/βCD in aqueous media, which can be used as a safe multi-functionalized food additive combined with the benefits of electrospun nanofibers to extend the Chinese giant salamander fillets shelf life by 15 d at 4 °C.

Effect of gallic acid on the reproduction of adolescent male Brandt’s voles (Lasiopodomys brandtii)

Gallic acid (GA), a phenol that is present in various plants, potentially contains antioxidant properties. This study aimed to investigate the effects of GA on the reproduction of adolescent male Brandt’s voles (Lasiopodomys brandtii (Radde, 1861)). Antioxidant levels and apoptosis in the testis, as well as reproductive physiology, were evaluated in adolescent males treated with GA. The results showed that a low dose of GA enhanced relative epididymis mass and the sperm density in the epididymis, increased the mRNA levels of steroidogenic acute regulatory protein in the testis, and reduced the percentages of abnormal and dead sperm. In addition, a low dose of GA significantly increased the levels of superoxide dismutase, catalase, and glutathione peroxidase, and decreased the level of malondialdehyde in the testis, as well as the mRNA and protein levels of the apoptosis-related gene, caspase-3. However, a high dose of GA sharply reduced the mean diameter of the seminiferous tubules compared with a low dose. Collectively, these findings demonstrate that GA treatment during puberty affects the reproductive responses of male Brandt’s voles in a dose-dependent manner by regulating antioxidant levels and apoptosis.

Dendrimer Nanodevices and Gallic Acid as Novel Strategies to Fight Chemoresistance in Neuroblastoma Cells

Human neuroblastoma (NB), a pediatric tumor inclined to relapse, after an initial response to therapy, usually develops resistance. Since several chemotherapeutics exert anticancer effect by increasing reactive oxygen species (ROS), NB cells overproduce antioxidant compounds becoming drugs-resistant. A strategy to sensitize NB cells to chemotherapy involves reducing their antioxidant defenses and inducing ROS overproduction. Concerning this, although affected by several issues that limit their clinical application, antioxidant/pro-oxidant polyphenols, such as gallic acid (GA), showed pro-oxidant anti-cancer effects and low toxicity for healthy cells, in several kind of tumors, not including NB. Herein, for the first time, free GA, two GA-dendrimers, and the dendrimer adopted as GA reservoir were tested on both sensitive and chemoresistant NB cells. The dendrimer device, administered at the dose previously found active versus sensitive NB cells, induced ROS-mediated death also in chemoresistant cells. Free GA proved a dose-dependent ROS-mediated cytotoxicity on both cell populations. Intriguingly, when administered in dendrimer formulations at a dose not cytotoxic for NB cells, GA nullified any pro-oxidant activity of dendrimer. Unfortunately, due to GA, nanoformulations were inactive on NB cells, but GA resized in nanoparticles showed considerable ability in counteracting, at low dose, ROS production and oxidative stress, herein induced by the dendrimer.

Reshaped as polyester-based nanoparticles, gallic acid inhibits platelet aggregation, reactive oxygen species production and multi-resistant Gram-positive bacteria with an efficiency never obtained

Natural polyphenols such as Gallic Acid (GA) form an important class of bioactive chemical entities that, having innumerable biological properties, could represent a safer alternative to common drugs against several disorders, including platelet aggregation, radical oxygen species (ROS) hyperproduction, oxidative stress (OS) and bacterial infections. Unfortunately, their clinical uses are limited by pharmacokinetics drawbacks and high sensitivity to environmental factors. In order to overcome these problems and to exploit the GA curative potentials, it has been linked to a biodegradable nanospherical dendrimer matrix, capable of protecting it, thus obtaining a GA-enriched nanosized dendrimer (GAD) endowed with a strong antioxidant capacity. GAD activity as an inhibitor of platelet aggregation and ROS accumulation and its antibacterial efficiency are evaluated here and compared to those of free GA, obtaining outcomes never achieved. Regarding platelet aggregation induced by thrombin and collagen, the GAD proved to be stronger by 7.1 and 7.3 times, respectively. Furthermore, the GAD showed a ROS inhibitory activity higher than that of GA by 8.1 (thrombin) and 6.9 (collagen) times. Concerning the antibacterial activities, evaluated on eleven multi-resistant Gram-positive strains of clinical relevance, the GAD is far more potent than GA, by exerting a growth inhibitory activity at MIC (μM) concentrations lower by factors in the range 12-50.

Gallic and carnosic acids improve quality of frozen-thawed ram spermatozoa

The objective was to determine effects of gallic acid (GA) and carnosic acid (CA), present in carob pods and rosemary extract respectively, on frozen-thawed ram spermatozoa. Thirty ejaculates were collected from five Merino rams, pooled, diluted in Tris-based extender and divided into five equal portions containing: 0.05 or 2 mM of GA; 0.05 or 0.2 mM of CA; or no additive (control). Extended semen was equilibrated at +4°C, loaded into straws, held 5 cm above liquid nitrogen for 12 min then plunged. Computer-aided sperm analysis was used to assess motility, whereas flow cytometry was used to assess high mitochondrial membrane potential (HMMP) and percentages of spermatozoa with plasma membrane and acrosome integrity (PMAI). Spermatozoa supplemented with 2 mM GA had greater total motility than control spermatozoa (39.9 ± 3.01 vs. 29.2 ± 1.31%, mean ± SEM, p < .05). The PMAI was greatest in 0.2 mM CA (13.3 ± 0.68%), whereas HMMP was highest in 0.05 mM CA but lowest in control (22.9 ± 4.95 and 11.4 ± 3.64% respectively; p < .05). In conclusion, for cryopreservation of ram semen in Tris-based extender, supplementation with 2 mM GA increased post-thaw motility, whereas supplementation with 0.05 mM CA enhanced mitochondrial function.

Morphometric Evaluation of the Seminiferous Tubules and the Antioxidant Protective Effects of Gallic Acid and Quercetin in the Testis and Liver of Butyl Phthalate Treated Rats

The antioxidant protective effects of gallic acid (GAL) and quercetin (QUE) against oxidative stress induced by di-butyl phthalate (DnBP) in the liver and testis of rats were evaluated in this study. Adult albino Wistar rats (180-225 g) were treated with QUE or GAL (50 mg/kg) alone or in combination with DnBP (1 mL/kg) for 15 days. After treatment, tissue samples were taken for determination of glutathione and malondialdehyde levels, and superoxide dismutase and catalase activities. Serial sections of the testis and liver were stained with haematoxylin and eosin for microscopy and seminiferous tubular morphometry. As expected, DnBP induced oxidative stress was evident by increased malondialdehyde level in both organs. Co-treatment with GAL or QUE reversed the malondialdehyde by 45.42, 37.44 and 37.57%, 23.32% and catalase by 52.21, 70.15 and 85%, 38.14% in the testis and liver respectively whereas superoxide dismutase activity and glutathione level were differently modulated parallel to histopathological improvement in both tissues. The seminiferous tubular diameter, epithelial height, epithelial germ cell count and tubular length were significantly decreased by 11.09, 51.91, 40.65 and 11.10% respectively versus control values after DnBP treatments and were attenuated on co-treatment with GAL or QUE. Co-treatment with GAL afforded better protective effects in both tissues but QUE treatment alone appeared more effective than GAL on the investigated morphometric data. It seems likely that GAL or QUE prevented the tissue damage but the antioxidant profiles of the liver and testis are different in response to the oxidative stress.

Transcriptome analysis reveals GA induced apoptosis in HCT116 human colon cancer cells through calcium and p53 signal pathways

Gallic acid (GA) is a polyphenol widely found in numerous fruits and vegetables that has been reported to exert anticancer effects, including apoptosis, against cancer cell lines. However, little is known about the induction of apoptotic effects and the underlying mechanism. We used RNA-seq to examine differentially expressed genes in human colon cancer HCT116 cells after 12 h and 24 h exposure to GA. A total of 792 and 911 genes with known functions showed significantly different expression levels in 12 h and 24 h GA-treated HCT116 cells, respectively. KEGG enrichment analysis showed that the identified genes were involved in pathways such as cholinergic synapse, circadian entrainment, calcium signal processing and transport, arachidonic acid metabolism and the p53 signal pathway. Real-time quantitative PCR was used to validate the reliability of the results obtained by RNA-seq. The results of this study indicate that GA triggers apoptosis in HCT116 cells through obstructing the growth of cells in the early phase treatment by down-regulation of calcium channels and then up-regulation of the intrinsic p53 signal pathway through activation of apoptosis caspases, finally leading to the mitochondrial apoptosis pathway.

Gallic acid (GA) is a polyphenol widely found in plants that induced apoptosis in human colon cancer cells through calcium and p53 signal pathways.

Medicinal importance of gallic acid and its ester derivatives: a patent review

Gallic acid and its derivatives have a large number of applications in various fields of science. In nature, these compounds are widely distributed in plants and fruits, and thus they are being used as food stuffs, preservatives, etc. directly or indirectly by human community. They have also been implicated as anticarcinogenic, antimicrobial, antimutagenic, antiangiogenic and anti-inflammatory agents besides their use in treating critical diseases like depression, cancer, microbial infections, lipid-related diseases, etc. Herein, an attempt has been made to summarize the important uses of gallic acid derivatives which have extensively been disclosed particularly in various patents. This review would certainly create a great interest of the scientific community toward the developments and uses of gallic acid based compounds in the future.

Gallic acid as a selective anticancer agent that induces apoptosis in SMMC-7721 human hepatocellular carcinoma cells

Gallic acid (3,4,5-trihydroxybenzoic acid; GA) is a naturally occurring plant polyphenol, isolated from water caltrop, which has been reported to exert anticancer effects. The present study investigated the antiproliferative effects of GA on the HepG2 and SMMC-7721 human hepatocellular carcinoma (HCC) cell lines using MTT and colony formation assays. In particular, the underlying mechanism of GA-induced apoptosis in SMMC-7721 cells was studied in vitro by flow cytometry and western blotting. The results of the present study indicated that GA was capable of inhibiting the proliferation of HepG2 and SMMC-7721 cells in a time- and dose-dependent manner, as well as inducing the apoptosis of SMMC-7721 cells. GA induced caspase-3, caspase-9 and reactive oxygen species activity, elevated the expression of apoptosis regulator Bcl-2-like protein 4 and reduced the mitochondrial membrane potential in SMMC-7721 cells. When compared with HL-7702 normal human hepatocytes, GA demonstrated selective toxicity for HCC cells. In conclusion, GA is able to induce apoptosis in SMMC-7721 cells in vitro via mitochondrial-mediated pathways, and may possess the potential to be a novel therapeutic compound for use in the treatment of HCC.

Plant derived and dietary phenolic antioxidants: anticancer properties

In this paper, a review of the literature on the phenolic compounds with anticancer activity published between 2008 and 2012 is presented. In this overview only phenolic antioxidant compounds that display significant anticancer activity have been described. In the first part of this review, the oxidative and nitrosative stress relation with cancer are described. In the second part, the plant-derived food extracts, containing identified phenolic antioxidants, the phenolic antioxidants isolated from plants and plant-derived food or commercially available and the synthetic ones, along with the type of cancer and cells where they exert anticancer activity, are described and summarized in tables. The principal mechanisms for their anti-proliferative effects were also described. Finally, a critical analysis of the studies and directions for future research are included in the conclusion.

Combined administration of curcumin and gallic acid inhibits gallic acid-induced suppression of steroidogenesis, sperm output, antioxidant defenses and inflammatory responsive genes

In this study, we investigated the effects of administration of gallic acid (Gal) with or without curcumin (Cur) on the sperm output, steroid level and antioxidant defenses in rat testis in vivo and the expression of inflammatory responsive genes in vitro. Male Wistar rats were divided randomly into four groups and given oral Gal (100mg/kg/day) and Cur (100mg/kg/day) alone or in combination for four weeks. The sperm quality was impaired following Gal treatment, while Cur prevented this and also improved the sperm count as well as the efficiency of sperm production (DSP/gm testis). The inhibitory effects of Gal on plasma testosterone level, glutathione levels, activities of glutathione peroxidase, catalase, superoxide dismutase and steroidogenic enzymes, 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-HSD in the rat testis was blocked by Cur. Interestingly, the level of testosterone and the activities of the steroidogenic enzymes were significantly increased after treatment with Cur alone. Malondialdehyde concentration was unchanged following Gal treatment, while a significant decrease in malondialdehyde level was observed following treatment with Cur alone or in combination with Gal. We further analyzed the effects of Cur and Gal (25-100 μM) on the 93RS2 Sertoli cell-lines and observed that Cur blocked the Gal-induced suppression of inflammatory mediators such as TNF-α and IL-6, while Gal blocked the suppressive effect of Cur on IL-1α expression. Furthermore, the stimulatory or inhibitory effects of Gal on the expressions Tgf-β1 and CD-14 was concentration-dependent and could be blocked by Cur. When cultures of primary Sertoli cells were exposed to both Cur and Gal for 24h, p-JNK/SAPK expression remain stable, whereas Gal-induced p-p65 (NF-κB) expression and IκBα degradation was seen to be blocked by Cur but not Gal-induced expression of pERK1/2. Overall, Cur has stimulatory reproductive effects and could protect the testis from the toxic effects of Gal by mechanisms that could not be explained by its effects on the expressions of inflammatory cytokines but by its anti-oxidant properties.