Gallic Acid Derivatives Research Articles

In Vitro Antineoplastic and Antiviral Activity and In Vivo Toxicity of Geum urbanum L. Extracts

This study evaluated the in vitro antineoplastic and antiviral potential and in vivo toxicity of twelve extracts with different polarity obtained from the herbaceous perennial plant Geum urbanum L. (Rosaceae). In vitro cytotoxicity was determined by ISO 10993-5/2009 on bladder cancer, (T-24 and BC-3C), liver carcinoma (HEP-G2) and normal embryonic kidney (HEK-293) cell lines. The antineoplastic activity was elucidated through assays of cell clonogenicity, apoptosis induction, nuclear factor kappa B p65 (NFκB p65) activation and total glutathione levels. Neutral red uptake study was applied for antiviral activity. The most promising G. urbanum extract was analyzed by UHPLC–HRMS. The acute in vivo toxicity analysis was carried out following OEDC 423. The ethyl acetate extract of aerial parts (EtOAc-AP) exhibited the strongest antineoplastic activity on bladder cancer cell lines (IC50 = 21.33–25.28 µg/mL) by inducing apoptosis and inhibiting NFκB p65 and cell clonogenicity. EtOAc and n-butanol extracts showed moderate antiviral activity against human adenovirus type 5 and human simplex virus type I. Seventy four secondary metabolites (gallic and ellagic acid derivatives, phenolic acids, flavonoids, etc.) were identified in EtOAc-AP by UHPLC–HRMS. This extract induced no signs of acute toxicity in liver and kidney specimens of H-albino mice in doses up to 210 mg/kg. In conclusion, our study contributes substantially to the detailed pharmacological characterization of G. urbanum, thus helping the development of health-promoting phytopreparations.

Gallic Acid Derivatives Propyl Gallate and Epigallocatechin Gallate Reduce rRNA Transcription via Induction of KDM2A Activation.

We previously reported that lysine-demethylase 2A (KDM2A), a Jumonji-C histone demethylase, is activated by gallic acid to reduce H3K36me2 levels in the rRNA gene promoter and consequently inhibit rRNA transcription and cell proliferation in the breast cancer cell line MCF-7. Gallic acid activates AMP-activated protein kinase (AMPK) and increases reactive oxygen species (ROS) production to activate KDM2A. Esters of gallic acid, propyl gallate (PG) and epigallocatechin gallate (EGCG), and other chemicals, reduce cancer cell proliferation. However, whether these compounds activate KDM2A has yet to be tested. In this study, we found that PG and EGCG decreased rRNA transcription and cell proliferation through KDM2A in MCF-7 cells. The activation of both AMPK and ROS production by PG or EGCG was required to activate KDM2A. Of note, while the elevation of ROS production by PG or EGCG was limited in time, it was sufficient to activate KDM2A. Importantly, the inhibition of rRNA transcription and cell proliferation by gallic acid, PG, or EGCG was specifically observed in MCF-7 cells, whereas it was not observed in non-tumorigenic MCF10A cells. Altogether, these results suggest that the derivatization of gallic acid may be used to obtain new compounds with anti-cancer activity.

Liquid Chromatographic/Mass Spectrometric Study on the Role of Beech (Fagus sylvatica L.) Wood Polyphenols in Red Heartwood Formation

The present research focused on the analysis of European beech (Fagus sylvatica L.) wood polyphenols in respect to red heartwood formation, which is a significant color and technological defect of the species. For the first time, high-performance liquid chromatography/tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) were applied for the investigation of the structure and the radial distribution of polyphenols. Altogether 125 compounds were characterized by their MSn spectra, of which 71 were tentatively identified, including procyanidins (dimers to pentamers), flavonoids (taxifolin, naringenin, isorhamnetin, (epi)afzelechin), (+)-catechin, (−)-epicatechin) and their glycoside conjugates, phenolic acids (gallic acid, vanillic acid, syringic acid) and their glycosides as well as gallic acid derivatives, many of which were identified for the first time in beech wood. It was found that the concentration of many compounds increased at the color boundary. In situ polyphenol synthesis and metabolism were clearly evidenced at the color boundary. Red heartwood contained only free aglycones (syringic acid, taxifolin, naringenin, isorhamnetin, naringenin, syringic acid). Contrary to earlier assumptions, the MALDI-TOF analysis did not indicate the presence of oxidized high-molecular-weight polymeric polyphenols in the red heartwood tissues. The role of individual compounds in the formation of the red heartwood chromophores are discussed.

Effect of pulsed ultrasound assisted extraction and aqueous acetone mixture on total hydrolysable tannins from pomegranate peel

Pomegranate peels are disposed of as waste even though it is an eminent source of total hydrolysable tannins (THT) and possesses a great worth for recycling. The present study was carried out with the hypothesis that pulsed system ultrasound-assisted extraction (PSUAE) technique optimization would aid in retaining high extract yield and THT recovery yield from pomegranate peel extract (PPE) with enhanced antioxidant potential. The extraction was performed at various conditions regarding solvent concentration (30–90% of acetone), solvent-feed ratio (10–30 mL/g), extraction time (10–20 min), and ultrasound amplitude (40–80%) for maximum extract yield, THT and antioxidant activity (AA). To model and optimize the process conditions tools namely response surface methodology (RSM) and artificial neural network (ANN) were applied. For solvent concentration, solvent-feed ratio, extraction time, and amplitude the optimal conditions attained with aid of RSM and ANN were: 56%, 26.5 mL/g, 15 min, 55%, and 45%, 23 mL/g, 15 min, 50% respectively. The extract yield and THT content determined with RSM and ANN optimized values were 51.2%, 86.4 mg TAE/g, and 62%, 98.1 mg TAE/g, respectively. The mean square error value displayed the minimum and R2 exhibited maximum value in case of ANN compared to RSM model. PSUAE significantly augmented the AA of PPE to 77.2 ± 0.50% compared to 49.7 ± 0.35% of conventional extraction. FTIR and HPLC analysis established that PPE produced from PSUAE contains a significant amount of THT compounds (gallic acid and tannic acid derivative). SEM elucidated that the sonication effect resulted in peel cell wall disruptions ensuing in elevated extraction of THT. Therefore, this pulsed mode of ultrasound extraction could be regarded as an easy, cost-effective, and competent technique for the extraction of preferred natural THT from pomegranate peels that possess high prospective to be applied in food and nutraceutical formulations.

New Horizons in Microbiological Food Safety: Ultraefficient Photodynamic Inactivation Based on a Gallic Acid Derivative and UV-A Light and Its Application with Electrospun Cyclodextrin Nanofibers.

An excellent bactericidal effect of octyl gallate (OG)-mediated photodynamic inactivation (PDI) against foodborne pathogens (Escherichia coli and Staphylococcus aureus) was evaluated in relation to the mode of action. UV-A irradiation (wavelength, 365 nm; irradiance, 8.254 ± 0.18 mW/cm2) of the bacterial suspension containing 0.15 mM OG could lead to a >5-log reduction of viable cell counts within 30 min for E. coli and only 5 min for S. aureus. Reactive oxygen species (ROS) formation was considered the main reason for the bactericidal effect of OG + UV-A light treatment because toxic ROS induced by OG-mediated PDI could attack the cellular wall, proteins, and DNA of microbes. Moreover, the bactericidal effect, as well as the yields of ROS, depended on OG concentrations, irradiation time, and laser output power. Furthermore, we prepared an edible photodynamic antimicrobial membrane comprising electrospun cyclodextrin nanofibers (NFs) by embedding OG. The resultant OG/HPβCD NFs (273.6 μg/mL) under UV-A irradiation for 30 min (14.58 J/cm) could cause a great reduction (>5-log) of viable bacterial counts of E. coli. The in situ photodynamic antibacterial activity of OG/HPβCD NF-based packaging was evaluated during the Chinese giant salamander storage. Overall, this research highlights the dual functionalities (antibacterial and photodynamic properties) of OG as both an antibacterial agent and photosensitizer and the effectiveness of electrospun NFs containing OG as an active antibacterial packaging material for food preservation upon UV light illumination.

Gallic Acid and Diabetes Mellitus: Its Association with Oxidative Stress

Diabetes mellitus (DM) is a severe chronic metabolic disease with increased mortality and morbidity. The pathological progression of DM is intimately connected with the formation and activation of oxidative stress (OS). Especially, the involvement of OS with hyperglycemia, insulin resistance, and inflammation has shown a vital role in the pathophysiological development of DM and related complications. Interestingly, accumulating studies have focused on the exploration of natural antioxidants for their improvement on DM. Of specific interest is gallic acid (GA), which is rich in many edible and herbal plants and has progressively demonstrated robust antioxidative and anti-inflammatory effects on metabolic disorders. To provide a better understanding of its potential therapeutic impacts and enhancement of human health care, the available research evidence supporting the effective antidiabetic properties of GA and relevant derivatives are needed to be summarized and discussed, with emphasis on its regulation on OS and inflammation against DM. This review aims to highlight the latest viewpoints and current research information on the role of OS in diabetes and to provide scientific support for GA as a potential antihypoglycemic agent for DM and its complications.

Gallic acid analogues with antibreast cancer and antioxidant action: synthesis and pharmacological assessment

Breast cancer is one of the important public health problems today and recent treatments have not been found to be very effective for advanced-stage metastatic disease of the breast. In the present study ten 3,4,5- trihydroxybenzohy- drazone derivatives (AR 01- AR 10) were synthesized by two different methods viz. reflux and stirring. It was observed that compounds synthesized by stirring method acquire good yield and require less time in comparison to reflux method. Further cytotoxicity activity performed on two breast cancer cell lines viz. MDA-MB-468 and MCF-7 revealed moderate activity in all compounds at 40 μg/mL and 80 μg/mL which has the highest in samples AR 01 and AR 10 for both cell lines. Considerably all compounds have shown potent antioxidant activity at 50 μg/mL and above concentrations. Tumor in mice treated with compound AR 01 was found to be smaller in comparison to control and AR 10. Findings revealed that compound having electron donating group showed more potent activity against breast cancer cell lines both in vitro and in vivo. Cytotoxicity activity also corelates with QSAR study and showed that compounds having donating group showed positive contribution towards the toxicity. These findings suggest that gallic acid derivatives were potent cytotoxic against breast cancer cell lines and may provide potent therapeutic effects against breast cancer.

Metabolites of Siberian Raspberries: LC-MS Profile, Seasonal Variation, Antioxidant Activity and, Thermal Stability of Rubus matsumuranus Phenolome.

Rubus matsumuranus H. Lev. & Vaniot, a famous Siberian shrub of the Rosaceae family, is used in the folk medicine of nomads (Buryats, Yakuts, Soyots, and Mongols) as a remedy for the treatment of diseases of the respiratory and hepatobiliary systems. The lack of scientific information on R. matsumuranus leaves contributed to the investigation of the metabolomic profile and biological activity of this plant. In this study, metabolites of R. matsumuranus leaves in three stages (active growth, flowering, and fruiting) were characterised using high-performance liquid chromatography with photodiode array and electrospray ionisation triple quadrupole mass spectrometric detection (HPLC-PDA-ESI-tQ-MS). In total, 63 compounds were identified, including gallic acid derivatives, hydroxycinnamates, catechins, procyanidins, flavonols, and ellagitannins. Lambertianin C (57.11 mg/g of dry weight, DW), miquelianin (39.63 mg/g DW), and kaempferol-3-O-glucuronide (31.18 mg/g DW) were the major compounds in R. matsumuranus leaves. As a result of the HPLC-PDA-based assay to determine the antioxidant activity, it was revealed that lambertianin A, sanguiin H6, lambertianin C, and sanguiin H11 were effective scavengers of free radicals (2,2-diphenyl-1-picrylhydrazyl, DPPH•) and possessed Fe2+-chelating activity. After an investigation of the phenolic content in infusions and decoctions obtained by extraction with water at different temperatures, it was revealed that a hot infusion (80 °C) is a phenolic-rich preparation of R. matsumuranus leaves. Our research suggests that R. matsumuranus leaves are a rich source of phenolic compounds with high antioxidant properties and that this could be a prospective plant for new functional products.

Front Cover: Preparative isolation of antioxidative gallic acid derivatives from Saxifraga tangutica using a class separation method based on medium‐pressure liquid chromatography and reversed‐phase liquid chromatography

DOI: 10.1002/jssc.202100361 The cover picture shows the discovery of antioxidative natural products from traditional Chineses medicines (TCMs) or traditional Tibetan medicines (TTMs). Firstly, the TCMs or TTMs extract underwent the sample pretreatment process with medium pressure liquid chromatography (part A, red labeled Part A). Second, the preprocessed fractions should be screened the DPPH inhibitors using the on-line RPLC-DPPH system and the active chromatographic peaks (DPPH inhibitors) can be recognized (part B, red labeled Part B). Then, the active compounds (DPPH inhibitors or antioxidative natural products) contained in the active chromatographic peaks were separated by the off-line two-dimensional (RPLC×HILIC in this manuscript) preparative liquid chromatography (part C, red labeled Part C). Lastly, through analysis of MS and NMR spectra, the structures of antioxidative natural products (part D, red labeled Part D) were identified.

Potential Health Benefits of a Pomegranate Extract, Rich in Phenolic Compounds, in Intestinal Inflammation

Background: Pomegranate is a fruit rich in bioactive compounds such as punicalagins, gallic acid, and ellagic acid derivatives. It has been widely used since ancient times in traditional medicine for a wide variety of diseases. It has been reported that bioactive compounds, such as polyphenols, are able to induce the expression of cytoprotective enzymes, including HO-1. The contribution of HO-1 activity to the prevention of intestinal inflammation has been shown in different models of Inflammatory bowel diseases (IBD). Objective: Aim of the present research was to investigate the molecular mechanisms involved in the beneficial effects of a pomegranate extract (PE), rich in bioactive compounds in intestinal inflammation. Methods: Caco-2 cells exposed to LPS and DSS induced colitis were chosen as convenient experimental models of intestinal inflammation. Results: Results obtained in our experimental conditions showed that PE in vitro was able to induce HO-1 and to reduce cellular damage and oxidative stress through an increase of GSH levels. Moreover, PE was able to decrease the pro-inflammatory marker IL-8 levels and activate TIGAR pathway. The results obtained in vivo, in agreement with the data obtained in vitro, highlighted the ability of PE to reduce intestinal inflammation, preserve the colon length and histological features and reduce IL-6 levels compared to the DSS treated group. Conclusion: PE, rich in bioactive compounds, could contribute, as a supportive therapy, to enhance the effects of the conventional therapeutic strategies on the management of IBD.

Preparative isolation of antioxidative gallic acid derivatives from Saxifraga tangutica using a class separation method based on medium-pressure liquid chromatography and reversed-phase liquid chromatography.

Saxifraga tangutica is widely used as a medicinal herb to treat hepatic diseases. Here, we developed a class separation method to separate gallic acid derivatives 1,1-diphenyl-2-picrylhydrazyl inhibitors from the methanol extract of Saxifraga tangutica. Firstly, an MCI GEL CHP20P medium-pressure liquid chromatography was used to pretreat the crude extract from Saxifraga tangutica (500g) and the target sample (fraction Fr1, 1.7g) was obtained. Then, an online reversed-phase liquid chromatography-1,1-diphenyl-2-picrylhydrazyl assay was employed for recognizing potential 1,1-diphenyl-2-picrylhydrazyl inhibitors and six 1,1-diphenyl-2-picrylhydrazyl inhibitors fractions were recognized from fraction Fr1. Subsequently, the six 1,1-diphenyl-2-picrylhydrazyl inhibitors fractions were isolated via a ReproSil-Pur C18 AQ preparative column. During the separation process, the hydrophilic liquid chromatography was used to enrich the target compounds (Fr1-3-1-1 and Fr1-3-1-2) from the fraction Fr1-3, which were hardly isolated only by one step reversed-phase liquid chromatography. Finally, six gallic acid derivatives were obtained and identified as gallic acid (Fr1-1-1), gallic acid 3-O-β-D-glucoside (Fr1-1-2), protocatechuic acid (Fr1-2), 4-O-galloyl-(-)-shikimic acid (Fr1-3-1-1), 5-O-galloyl-(-)-shikimic acid (Fr1-3-1-2), and 3-O-galloyl-shikimic acid (Fr1-4), respectively. Thus, the present study indicated that this method was highly efficient for the preparative separation of gallic acid derivatives 1,1-diphenyl-2-picrylhydrazyl inhibitors from natural products.

Rapid identification of chemical constituents of Rhodiola crenulata using liquid chromatography-mass spectrometry pseudotargeted analysis.

Rhodiola crenulata (R. crenulata), is a famous traditional Chinese medicine, with observable effects such as anti-high-altitude illness and fatigue resistance. Nevertheless, comprehensive and systematic structural identification of its components remains a challenge. In this study, a pseudotargeted analytical method, involving key fragment filtering by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry and ultra-high performance liquid chromatography-linear ion trap-Orbitrap mass spectrometry, was developed for rapid detection and identification of the chemical constituents of R. crenulata. The process consists of three steps: (i) acquiring sufficient mass spectral data, (ii) constructing a key fragments schedule and discovering the substructures rapidly by pseudotargeted key fragment filtering, and (iii) further identification of the compound structures based on accurate masses, fragment ions, related literatures, and authentic standards. As a result, 104 compounds were identified and divided into five categories, among which three potentially new and 59 ones were reported for the first time in R. crenulata. These results indicated that the major types of components are flavanols and gallic acid derivatives, organic acids, alcohols and their glycosides, flavonoids and their glycosides. This study enhances the understanding of R. crenulata and provides a reference for rapid and comprehensive identification of constituents in other herbal medicines.

Polyhydroxybenzoic acid derivatives as potential new antimalarial agents.

With more than 200 million cases and 400,000 related deaths, malaria remains one of the deadliest infectious diseases of 2021. Unfortunately, despite the availability of efficient treatments, we have observed an increase in people infected with malaria since 2015 (from 211 million in 2015 to 229 million in 2019). This trend could partially be due to the development of resistance to all the current drugs. Therefore, there is an urgent need for new alternatives. We have, thus, selected common natural scaffolds, polyhydroxybenzoic acids, and synthesized a library of derivatives to better understand the structure-activity relationships explaining their antiplasmodial effect. Only gallic acid derivatives showed a noticeable potential for further developments. Indeed, they showed a selective inhibitory effect on Plasmodium (IC50 ~20 µM, SI > 5) often associated with interesting water solubility. Moreover, this has confirmed the critical importance of free phenolic functions (pyrogallol moiety) for the antimalarial effect. Methyl 4-benzoxy-3,5-dihydroxybenzoate (39) has, for the first time, been recognized as a potential lead for future research because of its marked inhibitory activity against Plasmodium falciparum and its significant hydrosolubility (3.72 mM).

LC-ESI-QTOF-MS/MS Analysis, Cytotoxic, Antiviral, Antioxidant, and Enzyme Inhibitory Properties of Four Extracts of Geranium pyrenaicum Burm. f.: A Good Gift from the Natural Treasure.

This study focused on the biological evaluation and chemical characterization of Geranium pyrenaicum Burm. f. Different solvent extracts (hexane, ethyl acetate, methanol, and water extracts) were prepared. The phytochemical profile, antioxidant, and enzyme inhibitory activity were investigated. Cytotoxicity was assessed using VERO, FaDu, HeLa and RKO cells. The antiviral activity was carried out against HSV-1 (Herpes simplex virus 1) propagated in VERO cell line. The aqueous extract, possessing high phenolic content (170.50 mg gallic acid equivalent/g extract), showed the highest reducing capacity (613.27 and 364.10 mg Trolox equivalent/g extract, for cupric reducing antioxidant capacity and ferric reducing antioxidant power, respectively), radical scavenging potential (469.82 mg Trolox equivalent/g extract, against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), metal chelating ability (52.39 mg ethylenediaminetetraacetic acid equivalent/g extract) and total antioxidant capacity (3.15 mmol Trolox equivalent/g extract). Liquid chromatography-electrospray ionization-quadrupole time-of-flight-mass spectrometry (LC-ESI-QTOF-MS/MS) alloved to tentatively identify a total of 56 compounds in the extracts, including ellagitannins, gallic acid and galloyl derivatives amongst others. The ethyl acetate extracts substantially depressed cholinesterase enzymes (4.49 and 12.26 mg galantamine equivalent/g extract against AChE and BChE, respectively) and α-amylase enzyme (1.04 mmol acarbose equivalent/g extract). On the other hand, the methanolic extract inhibited tyrosinase (121.42 mg kojic acid equivalent/g extract) and α-glucosidase (2.39 mmol acarbose equivalent/g extract) activities. The highest selectivity towards all cancer cell lines (SI 4.5–10.8) was observed with aqueous extract with the FaDu cells being the most sensitive (CC50 40.22 µg/mL). It can be concluded that the presence of certain bioactive antiviral molecules may be related to the high anti HSV-1 activity of the methanolic extract. This work has generated vital scientific data on this medicinal plant, which is a prospective candidate for the creation of innovative phyto-pharmaceuticals.

Programmable binary crystallization behaviors assisted by hydrogen bond on HOPG surface

Crystallization behaviors of 1,3,5-tri(1H-benzo[d]imidazol-2-yl) benzene (BTIB), gallic acid derivative (A10), and their hydrogen-bonded complex BTIB/A10 on Highly Oriented Graphite(HOPG) surface were studied by scanning tunneling microscope (STM) in combination with density functional theory (DFT) calculations. Single component BTIB self-assembled into porous and linear nanostructures, and A10 aggregated into linear nanostructure. Induced by the intermolecular interactions, an ordered BTIB/A10 nanostructure with the molecular ratio of 1:3 was in situ obtained and identical to the bulk assembly structure. When 1,3,5-Tris(4-carboxyphenylethynyl) benzene (H3BTE) or 1,3,5-tris(10-carboxydecyloxy)-benzene (TCDB) instead of A10 was adopted, porous nanostructure with the molar ratio of 1:1 was in situ prepared in BTIB/H3BTE and BTIB/TCDB system respectively, which indicated the regulatory effect of the number of aromatic acids’ carboxyl groups on the co-assemblies of BTIB and aromatic acids. Simultaneously, the flexible connection groups between the three carboxyl groups and the central benzene ring in TCDB resulted in the formation of another co-assembly nanostructure in BTIB/TCDB system, which was different from the BTIB/H3BTE system. These results would be contributed to deepening the understanding of the interfacial crystal behaviors and probably providing an efficient pathway of regulating the structures of binary hydrogen-bonded crystals.

Synthesis of water-soluble ester-linked ursolic acid–gallic acid hybrids with various hydrolytic stabilities

To obtain derivatives of ursolic acid with improved water solubility and antioxidant activity, new ester-linked hybrids of ursolic acid and gallic acid were synthesized. In the reaction of methyl gallate with ursoloyl chloride acetate, both mono- and diacylation products were obtained. To prepare mono-alkylated and mono-acylated derivatives of gallic acid, 4,5-O-methoxymethylene-protected methyl gallate was used. It was found that ursolic-gallic acid hybrids containing phenolic ester linkage readily underwent hydrolysis at C-28 of triterpenoid. The dioxolane protection allowed selective hydrolysis of the methyl ester at the aromatic moiety of the hybrid compound leaving intact the labile C-28 ester at the triterpenoid moiety. The hybrids possessing an ester–ether linker (terpenoid-COO–CH2CH2–O-aryl) are stable to the hydrolysis. The majority of the obtained ursolic–gallic acid hybrids containing free phenolic hydroxyl groups possess excellent antioxidant activity. Notable water solubilities (∼0.5 mg/mL) of novel hybrids containing both carboxyl group and hydroxyls at aromatic moiety were found.

HPLC-PDA-ESI-MS/MS Profiling and Anti-Biofilm Potential of Eucalyptussideroxylon Flowers.

The development of multidrug-resistant bacterial strains is a worldwide emerging problem that needs a global solution. Exploring new natural antibiofilm agents is one of the most important alternative therapies in combating bacterial infections. This study aimed at testing the antimicrobial potential of Eucalyptus sideroxylon flowers extract (ESFE) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans prior to testing the antibiofilm activity against S. aureus, P. aeruginosa and C. albicans. ESFE demonstrated antimicrobial activity and promising inhibition activity against methicillin-resistant S. aureus (MRSA) biofilm formation up to 95.9% (p < 0.05) at a concentration of 0.05 mg/mL and eradicated C. albicans biofilm formation up to 71.2% (p < 0.05) at a concentration of 0.7 mg/mL. LC-MS analysis allowed the tentative identification of eighty-three secondary metabolites: 21 phloroglucinol, 18 terpenes, 16 flavonoids, 7 oleuropeic acid derivatives, 7 ellagic acid derivatives, 6 gallic acid derivatives, 3 phenolic acids, 3 fatty acids and 2 miscellaneous. In conclusion, E. sideroxylon is a rich source of effective constituents that promote its valorization as a promising candidate in the management of multidrug-resistant bacterial infections.

Insight into the Secondary Metabolites of Geum urbanum L. and Geum rivale L. Seeds (Rosaceae).

The present study aimed at the identification and quantitation of phenolic compounds, fatty acids, and further characteristic substances in the seeds of Geum urbanum L. and Geum rivale L. For this purpose, individual components of extracts recovered with MeOH, CH2Cl2, and by cold-pressing, respectively, were characterized by HPLC-DAD/ESI-MSn and GC/MS and compared with reference compounds. For both Geum species, phenolic compounds, such as flavonoids and gallic acid derivatives, and triterpenes, such as saponins and their aglycones, were detected. Surprisingly, both Geum species revealed the presence of derivatives of the triterpenoid aglycons asiatic acid and madecassic acid, which were characterized for the first time in the genus Geum. Furthermore, the fatty acids of both species were characterized by GC–MS after derivatization. Both species showed a promising fatty-acid profile in terms of nutritional properties because of high proportions of unsaturated fatty acids. Linoleic acid and linolenic acid were most abundant, among other compounds such as palmitic acid and stearic acid. In summary, the present study demonstrates the seeds of G. urbanum and G. rivale to be a valuable source of unsaturated fatty acids and bioactive phenolics, which might be exploited for nutritional and cosmetic products and for phytotherapeutic purposes.

A sensitive analytical method for the determination of SG-SP1 in rat plasma by HPLC-MS/MS and its application to a pharmacokinetic study

SG-SP1, a newly synthesised gallic acid derivative, blocks histamine release by reducing calcium influx in mast cells and inhibits inflammatory cytokine expression. This derivative has promising anti-allergic potential. Our research was designed to establish a quantitative determination method for SG-SP1 in rat plasma using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS), to validate the analytical method including stability and to characterise its pharmacokinetic behaviour in rats. After simple protein precipitation with acetonitrile including an internal standard, SG-SP1 was eluted on a reversed-phase column using a mobile phase of water and acetonitrile (2:8 v/v, including 0.1 % formic acid). The protonated precursor ion [M+H]+ and major fragment ion were confirmed at m/z 588.2 and 180.1, respectively. The substance was stable under bench and storage conditions. The analytical method met the criteria of FDA-validated bioanalytical methods and was successfully applied to a pharmacokinetic study for the first time. SG-SP1 decayed in a biphasic pattern with terminal half-life of 5.1 h and clearance of about 3.2 L/h/kg. Double peaks were observed following oral administration, and the absolute oral bioavailability was ∼1 %.

Effectiveness of henna leaves extract and its derivatives as green corrosion inhibitors of reinforcement steel exposed to chlorides

In this work, Henna leaves extract (HLE) and its principal derivatives of Lawsone and Gallic acid are examined as green corrosion inhibitors. Our contribution is to quantify the effectiveness of HLE, Lawsone and Gallic acid on the corrosion inhibition of steel in simulated concrete pore solution (SCPS) containing 0.5 M NaCl, using electrochemical methods as open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, environmental scanning electron microscopy, coupled to the energy dispersive X-ray microanalysis, was performed to investigate the morphology of the steel surface immersed in SCPS containing green inhibitors. Results highlight a synergistic effect with the formation of a protective layer on the steel surface by forming inhibitor-metal complexes. The HLE and Gallic acid act as anodic corrosion inhibitors and Lawsone behaves as a mixed type. These inhibitors are adsorbed on the steel surface by chemisorption according to the adsorption isotherm of Langmuir. The maximal inhibition efficiency is about 93% obtained at 0.2 g/L of HLE, which represents the higher effectiveness compared to Lawsone and Gallic acid.