Anthocyanins: Factors Affecting Their Stability and Degradation

Anthocyanins are secondary metabolites and water-soluble pigments belonging to the phenolic group, with important functions in nature such as seed dispersal, pollination and development of plant organs. In addition to these important roles in plant life, anthocyanins are also used as natural pigments in various industries, due to the color palette they can produce from red to blue and purple. In addition, recent research has reported that anthocyanins have important antioxidant, anticancer, anti-inflammatory and antimicrobial properties, which can be used in the chemoprevention of various diseases such as diabetes, obesity and even cancer. However, anthocyanins have a major disadvantage, namely their low stability. Thus, their stability is influenced by a number of factors such as pH, light, temperature, co-pigmentation, sulfites, ascorbic acid, oxygen and enzymes. As such, this review aims at summarizing the effects of these factors on the stability of anthocyanins and their degradation. From this point of view, it is very important to be precisely aware of the impact that each parameter has on the stability of anthocyanins, in order to minimize their negative action and subsequently potentiate their beneficial health effects.

Phenolic Profile and Antioxidant Capacity of Selected Medicinal and Aromatic Plants: Diversity upon Plant Species and Extraction Technique

Phenolic content and antioxidant capacity (AC) was evaluated in extracts of bay, sage and thyme leaves, myrtle leaves and berries, and sea buckthorn berries obtained by conventional (CE) and advanced extraction techniques [ultrasound-assisted (UAE) and accelerated solvent extraction (ASE)] using 80% acetone (v/v) as extraction solvent. Extracts were analyzed for phenolic content using UPLC/ESI MS2 and AC by ORAC method. Results indicated the variations in the phenolic composition and concentrations among analyzed plant species and applied extraction methods. Flavonoids showed to be the predominant phenolic group represented by flavonols kaemferol-3-O-hexoside (182.58–321.45 mg 100−1 g dm) and quercetin-3-glucoside (253.05–315.67 mg/100 g dm) in bay leaves, by flavonol isorhamnetine-3-O-hexoside (27.76–45.16 mg/100 g dm) in sea buckthorn berries and by flavone luteolin-7-O-glucoside (470.27–781.78 mg/100 g dm) in sage leaves. Among the phenolic acids, hydroxybenzoic acids and their derivates were the predominant phenolic group in thyme leaves and myrtle. Statistical analysis showed that ASE contributed to the highest content of total flavonols, flavones, hydroxycinnamic and hydroxybenzoic acids as well as AC. CE was more efficient method for the extraction of total flavan-3-ols, while UAE showed the highest efficiency in extraction of total anthocyanins. Analyzed plant extracts proved to be a rich source of various phenolics and results indicated suitable extraction methods for target phenolic compounds characteristic for certain plant species.

Low-Dimensional Architectures in Isomeric cis-PtCl2{Ph2PCH2N(Ar)CH2PPh2} Complexes Using Regioselective-N(Aryl)-Group Manipulation

The solid-state behaviour of two series of isomeric, phenol-substituted, aminomethylphosphines, as the free ligands and bound to PtII, have been extensively studied using single crystal X-ray crystallography. In the first library, isomeric diphosphines of the type Ph2PCH2N(Ar)CH2PPh2 [1a–e; Ar = C6H3(Me)(OH)] and, in the second library, amide-functionalised, isomeric ligands Ph2PCH2N{CH2C(O)NH(Ar)}CH2PPh2 [2a–e; Ar = C6H3(Me)(OH)], were synthesised by reaction of Ph2PCH2OH and the appropriate amine in CH3OH, and isolated as colourless solids or oils in good yield. The non-methyl, substituted diphosphines Ph2PCH2N{CH2C(O)NH(Ar)}CH2PPh2 [2f, Ar = 3-C6H4(OH); 2g, Ar = 4-C6H4(OH)] and Ph2PCH2N(Ar)CH2PPh2 [3, Ar = 3-C6H4(OH)] were also prepared for comparative purposes. Reactions of 1a–e, 2a–g, or 3 with PtCl2(η4-cod) afforded the corresponding square-planar complexes 4a–e, 5a–g, and 6 in good to high isolated yields. All new compounds were characterised using a range of spectroscopic (1H, 31P{1H}, FT–IR) and analytical techniques. Single crystal X-ray structures have been determined for 1a, 1b∙CH3OH, 2f∙CH3OH, 2g, 3, 4b∙(CH3)2SO, 4c∙CHCl3, 4d∙½Et2O, 4e∙½CHCl3∙½CH3OH, 5a∙½Et2O, 5b, 5c∙¼H2O, 5d∙Et2O, and 6∙(CH3)2SO. The free phenolic group in 1b∙CH3OH, 2f∙CH3OH,2g, 4b∙(CH3)2SO, 5a∙½Et2O, 5c∙¼H2O, and 6∙(CH3)2SO exhibits various intra- or intermolecular O–H∙∙∙X (X = O, N, P, Cl) hydrogen contacts leading to different packing arrangements.

Identification and Quantification of Naphthoquinones and Other Phenolic Compounds in Leaves, Petioles, Bark, Roots, and Buds of Juglans regia L., Using HPLC-MS/MS

The present study was designed to identify and quantify the major phenolic compounds in different Juglans regia L. (common walnut) tissues (leaves, petioles, bark, roots, buds), to define the compositions and contents of phenolic compounds between these tissues. A total of 91 individual phenolic compounds were identified and quantified, which comprised 8 hydroxycinnamic acids, 28 hydroxybenzoic acids, 11 flavanols, 20 flavonols, 22 napthoquinones, and 2 coumarins. Naphthoquinones were the major phenolic group in leaves, petioles, bark, and buds, as >60% of those identified, while hydroxybenzoic acids were the major phenolic group in side roots, as ~50% of those identified. The highest content of phenolic compounds was in the J. regia main root, followed by side roots and buds, leaves, and 1-year-old bark; the lowest content was in petioles and 2-year-old bark. Leaves, roots, and buds of J. regia represent a valuable source of these agro-residues.

An In Vitro Study on Inhibiting Pathogenic Activity by Biosynthesized Silver Nanoparticles using Dioscorea Pentaphylla

Development of biologically stimulated experimental processes for the biosynthesis of nanoparticles is an essential branch of nanobiotechnology. Biocompatible silver nanoparticles have acknowledged significant notice in recent years because of their capable applications in bioimaging, biosensors, biolabels, and biomedicine. This study reports a green chemistry approach for the biological synthesis of silver nanoparticles by using the rhizomes extract of Dioscorea Pentaphylla. The properties of synthesis nanoparticles were characterized by UV-Visible spectroscopy, FT-IR, SEM, TEM and EDS. Surface Plasmon Resonance (SPR) spectrum for silver nano-particles is obtained at 426 with dark brown color. FT-IR spectroscopy revealed that silver nanoparticles were functionalized with bio- molecules that have primary amine group (NH2), carbonyl phenolic group (-OH) and other stabilizing functional groups. The Morphological studies revealed that the particles are spherical in shape and in the size ranged from 20 ± 1nm. The effects of silver nanoparticles concentration and extract concentration were investigated and DPR-AgNPs showed the better pharma- cological applications.

ESTIMATION OF TOTAL PHENOLIC CONTENT (TPC) OF SELECTED ALLIUM SPECIES OF GUJARAT USING DIFFERENT EXTRACTS

Plants are known as a vital source for so many drugs having different groups like anticancer, antimicrobials, antioxidant etc. Therefore, there are so many plants, which are used widely by the tribal people across the world. As we know that nature can cure everything by one or another way. According to Ayurveda, plants have been known to cure various diseases like cancer, heart diseases, asthma etc. Now-a-days researchers are focusing on estimation and characterization of various plants and their constituents which are responsible for curing so many diseases according to traditional use of plants given in the Ayurveda. As we know plants are capable to produce secondary metabolites and the most important group is phenolic group. Phenolic compounds work as defense mechanism of plants against herbivores and pathogens. The present study represents the estimation of total Phenolic content of medicinally useful plants Allium cepa L. (Onion) and Allium sativum L. (Garlic) in its different extracts of bulb from selected districts of Gujarat. Chloroform was selected as non-polar solvent, acetone as polar protic and methanol and distilled water as polar protic solvent. The estimation of total phenolic content was conducted by using standard protocol. The data generated from this experiment provides basis for the advances in the pharmaceutical industries

Synthesis and Antioxidant of Some New Pyrazolo[1,5-a]pyrimidine, Pyrazolo[5,1-b]quinazoline and Imidazo[1,2-b]pyrazole Derivatives Incorporating Phenylsulfonyl Moiety

The synthesis and antioxidant of some new pyrazole analogs were described. It is achieved by the reaction of phenyl-4-(phenylsulfonyl)-1H-pyrazole-3,5-diamine (3) with different bifunctional reagents. The free radical-induced damage and the protective effects of the newly synthesized pyrazoles were studied. These new compounds inhibit the free radical-induced oxidative hemolysis of red blood cells effectively. It was found that these compounds effectively inhibit the free radical-induced oxidative hemolysis of red blood cells. Compound 5, which contain phenolic group, and 17, which bear sulfur, nitrogen atoms, and benzothiazole ring, respectively displayed high antioxidant activity. Analogs 15, 11, 10, and 9 were proved to exhibit antioxidative activity. Structures of new pyrazoles were confirmed by spectroscopic and elemental analyses and have been screened for their antioxidant activity.

EXPLORING THE POTENTIAL OF Α-ARBUTIN AS THE INHIBITOR OF NEURODEGENERATIVE DISORDERS

Tyrosinase is an enzyme involved in generation of dopamine-quinones, which has an important role in oxidative stress associated with the Parkinson’s disease. It is also a common molecular target for the design of novel anti-melanogenic agents. The inhibition of tyrosinase might be responsible for the experimentally observed intracellular antioxidant activity of α-arbutin. Moreover, intrinsic radical scavenging capacity of α-arbutin should also be considered. The binding mode of α-arbutin into the active site of Bacillus megaterium tyrosinase is predicted using AutoDock Vina 1.1. To map the thermodynamic feasibility of HAT and SET-PT mechanisms of the intrinsic antioxidant capacity α-arbutin, bond dissociation enthalpies (BDEs) and ionization potential (IP) are calculated using DFT with B3LYP functional and 6-31+g(d,p) basis set. α-Arbutin fitted well into the active site of tyrosinase, with the calculated binding affinity of -17.5 kcal/mol. The phenolic moiety is located deep into the binding pocket, interacting with His residues around Cu2+ ion. The binding mode of α-arbutin is stabilized via HBD interactions with His231, His42, His60, Arg209, Gly216, and Asn205, HBA interaction with Arg209 at the outer part of active site, and hydrophobic interactions with His208, Val218 and Ala221. The calculated IP of α-arbutin is 175.18 kcal/mol, and BDE of phenolic group is 79.85 kcal/mol. The spin densities of radical-cation and hydroxyl radical are delocalized on the aglycone moiety. The results of this study provide valuable structural insights into the molecular mechanisms of biological action of α-arbutin, and might be exploited for the design of more potent analogues.