LC-MS Analysis and Antioxidant Activity of the Hydro-alcoholic Extract of Melissa Officinalis L. from Algeria

The present work focuses on evaluation of the chemical composition and antioxidant activity of the hydro-methanolic extract of Melissa officinalis from Algeria. The liquid chromatography-mass spectrometry analysis allowed the identification of six compounds: caffeic acid, caftaric acid, hydroxyjasmonic acid glucoside, caftaric acid glucoside, rosmarinic acid and sagerinic acid. The in-vitro antioxidant activity of the hydro-methanolic extract was evaluated by using four different methods including: radical scavenging assay (DPPH), scavenging activity (ABTS), cupric reducing antioxidant capacity, and ferric reducing power assay. The extract exhibited a relatively strong antioxidant activity compared to the synthetic antioxidants. The highest radical scavenging activity was registered using DPPH and ABTS methods, IC50= 20.53±2.64 μg/mL and 22.50±0.67 μg/mL, respectively. These results suggest that Melissa officinalis L. could be considered a potential source of natural antioxidants with potential interest in the agrochemical and pharmaceutical industries

PHYTOCHEMICAL CONSTITUENTS, PHENOLIC CONTENTS, AND ANTIOXIDANT ACTIVITY OF CRATAEGUS AZAROLUS EXTRACTS

 Objective: The aim of this study was the isolation and identification of secondary metabolites from Crataegus azarolus (L.) and the antioxidant evaluation of its extracts and compounds.Methods: The air-dried powdered parts of the plant were extracted with 70% methanol and fractionated by chloroform, ethyl acetate, and n-butanol. The n-butanol extract was separated using polyamide SC6 column and silica gel TLC. In addition, a fraction of silica gel column of the CHCl3 extract was analyzed by gas chromatography–mass spectrometer (GC–MS). The total phenolic and total flavonoid contents of CHCl3 and n-butanol extracts were estimated. Furthermore, the antioxidant activities of CHCl3, n-butanol extracts, and two flavonoids were evaluated according to five different methods.Results: Eight compounds were identified in CHCl3 and n-butanol extracts, among them, five volatile compounds identified by GC–MS for the 1st time from the species, as well as three known flavonol glycosides identified by spectral analysis (ultraviolet,1H-nuclear magnetic resonance [NMR], and13C-NMR) and by comparison with literature data. The n-butanol extract showed the higher content of polyphenols (307.33 ± 2.33 mg (gallic acid equivalents)/g extract) and flavonoids (143.0 ± 2.12 mg QE/g extract) and it proves the highest antioxidant activity with all assays used.Conclusion: Five volatile compounds were identified for the 1st time from the C. azarolus and the antioxidant potential of plant extracts was measured using five different methods

Chemical composition, antioxidant, anticholinesterase, and alpha-glucosidase activity of Stevia rebaudiana Bertoni extracts cultivated in Algeria

peer reviewedStevia rebaudiana Bertoni is an endemic species to Paraguay famous for its sweetening power and therapeutic potential for various diseases such as diabetes. The present work evaluates the chemical composition and antioxidant, anticholinesterase, and α-glucosidase activities of S. rebaudiana. The essential oil (EO) of dry Stevia leaves was analyzed by GC/MS and detected the presence of 33 components. Caryophyllene oxide (24.28%), spathulenol (12.31%) and nerolidol (11.8%), and manool oxide (7.36%) were identified as the major ones. The antioxidant activity was evaluated by four complementary methods: DPPH (2,2 diphenylpicrylhydrazyl, ABTS (2, 2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid) free radicals scavenging, Cupric reducing antioxidant capacity (CUPRAC), and reducing power. The crude methanolic extract and its fractions showed a variable antioxidant activity and strongly correlated with the content of quantified bioactive compounds. The ethyl acetate fraction showed a very high antioxidant activity close to the tested standards, while EO was active only in the CUPRAC assy. The petrol ether and chloroform fractions showed the best butyrylcholinesterase (BChE) inhibitory activity with IC50 values: 123.7 ± 1.78 and 170.1 ± 0.78 μg/mL, respectively. On the other hand, EO and chloroform revealed a moderate inhibitory activity against acetylcholinesterase (AChE). The in vitro inhibitory effect of the extracts on α-glucosidase indicated that EO effectively inhibited the enzyme with an IC50: 74.9 ± 6.4 µg/mL, better than the standard acarbose. The EO of Stevia has a significant anti-diabetic potential

PHYTOCHEMICAL CONSTITUENTS, PHENOLIC CONTENTS, AND ANTIOXIDANT ACTIVITY OF CRATAEGUS AZAROLUS EXTRACTS

 Objective: The aim of this study was the isolation and identification of secondary metabolites from Crataegus azarolus (L.) and the antioxidant evaluation of its extracts and compounds.Methods: The air-dried powdered parts of the plant were extracted with 70% methanol and fractionated by chloroform, ethyl acetate, and n-butanol. The n-butanol extract was separated using polyamide SC6 column and silica gel TLC. In addition, a fraction of silica gel column of the CHCl3 extract was analyzed by gas chromatography–mass spectrometer (GC–MS). The total phenolic and total flavonoid contents of CHCl3 and n-butanol extracts were estimated. Furthermore, the antioxidant activities of CHCl3, n-butanol extracts, and two flavonoids were evaluated according to five different methods.Results: Eight compounds were identified in CHCl3 and n-butanol extracts, among them, five volatile compounds identified by GC–MS for the 1st time from the species, as well as three known flavonol glycosides identified by spectral analysis (ultraviolet,1H-nuclear magnetic resonance [NMR], and13C-NMR) and by comparison with literature data. The n-butanol extract showed the higher content of polyphenols (307.33 ± 2.33 mg (gallic acid equivalents)/g extract) and flavonoids (143.0 ± 2.12 mg QE/g extract) and it proves the highest antioxidant activity with all assays used.Conclusion: Five volatile compounds were identified for the 1st time from the C. azarolus and the antioxidant potential of plant extracts was measured using five different methods

Crystal structures and antioxidant capacity of (E)-5-benzyloxy-2-{[(4-chlorophenyl)imino]methyl}phenol and (E)-5-benzyloxy-2-({[2-(1H-indol-3-yl)ethyl]iminiumyl}methyl)phenolate

The title Schiff base compounds, C20H16ClNO2 (I) and C24H22N2O2 (II), were synthesized via the condensation reaction of 2-amino-4-chlorophenol for (I), and 2-(2,3-dihydro-1H-indol-3-yl)ethan-1-amine for (II), with 4-benzyloxy-2-hydroxybenzaldehyde. In both compounds, the configuration about the C=N imine bond is E. Neither molecule is planar. In (I), the central benzene ring makes dihedral angles of 49.91 (12) and 53.52 (11)° with the outer phenyl and chlorophenyl rings, respectively. In (II), the central benzene ring makes dihedral angles of 89.59 (9) and 72.27 (7)°, respectively, with the outer phenyl ring and the mean plane of the indole ring system (r.m.s. deviation = 0.011 Å). In both compounds there is an intramolecular hydrogen bond forming an S(6) ring motif; an O—H...O hydrogen bond in (I), but a charge-assisted N+—H...O− hydrogen bond in (II). In the crystal of (I), molecules are linked by C—H...π interactions, forming slabs parallel to plane (001). In the crystal of (II), molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers. The dimers are linked by C—H...O hydrogen bonds, C—H...π interactions and a weak N—H...π interaction, forming columns propagating along the a-axis direction. The antioxidant capacity of the synthesized compounds was determined by cupric reducing antioxidant capacity (CUPRAC) for compound (I) and by 2,2-picrylhydrazyl hydrate (DPPH) for compound (II)

Crystal structure, Hirshfeld surface analysis and antioxidant capacity of 2,2′-{(1E,1′E)-[1,2-phenylenebis(azanylylidene)]bis(methanylylidene)}bis(5-benzyloxy)phenol

The whole molecule of the title Schiff base compound, C34H28N2O4, is generated by mirror symmetry, with the mirror bisecting the central benzene ring. It was synthesized via the condensation reaction of 1,2-diaminebenzene with 4-benzyloxy-2-hydroxybenzaldehyde. The molecule is V-shaped and there are two intramolecular O—H...N hydrogen bonds present forming S(6) ring motifs. The configuration about the C=N imine bonds is E. The central benzene ring makes dihedral angles of 41.9 (2) and 43.6 (2)° with the phenol ring and the outer benzyloxy ring, respectively. The latter two rings are inclined to each other by 84.4 (2)°. In the crystal, molecules are linked by C—H...π interactions, forming layers lying parallel to the ab plane. The Hirshfeld surface analysis and the two-dimensional fingerprint plots confirm the predominance of these interactions in the crystal structure. The antioxidant capacity of the compound was determined by the cupric reducing antioxidant capacity (CUPRAC) process

Anticholinesterase and antioxidant activities of foliar extract from a tropical species: Psidium guajava L. (Myrtaceae) grown in Algeria

Guava (Psidium guajava L.) is a fruit tree largely used in folk medicine in tropical and subtropical areas. This exotic species was introduced in a botanical garden in the northeast of Algeria in the 1950’s. The aim of this study is to estimate, for the first time, the antioxidant and anticholinesterase activities of chloroform, ethyl acetate and n-butanol extracts of P. guajava growing in Algeria. Six antioxidant assays were tested, results showed very important efficiency in free radical scavenging, reducing power and β-carotene bleaching of tested extracts. Values of IC50 or A0.5 of some samples were lower than those of standards. With regard to anticholinesterase activity, the inhibitory of both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) was investigated. The extracts exhibited interesting capacity to inhibit these enzymes with low values of IC50 and even less than that of galanthamine. These activities were correlated with total phenolic content which was more important compared to the one found in extracts from trees growing in tropical and subtropical region. This could be due to resistance and adaptation of P. guajava grown in Algeria. The data obtained suggest the use of bioactive compounds from P. guajava leaves as antioxidant and drugs for symptomatic treatment of Alzheimer disease