Effect of bioclimatic area on the composition and bioactivity of Tunisian Rosmarinus officinalis essential oils

The chemical composition of eight Tunisian Rosmarinus officinalis L. populations (A–H) from different bioclimatic areas has been examined by gas chromatography (GC) and GC-mass spectrometry. The essential oils are characterised by high amounts of oxygenated monoterpenes (58.2–71.7%) followed by monoterpene hydrocabons (15.1–26.7%). 1,8-Cineole, camphor, α-pinene and borneol are the main representative components. The antioxidant activity was investigated by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing ability power assay and β-carotene bleaching test. Samples showed antiradical activity by inhibiting DPPH radical with IC₅₀ values ranging from 375.3 to 592.8 μg mL^? 1 for samples F and A, respectively. Sample A also showed the most promising activity in β-carotene bleaching test (IC₅₀ of 31.9 μg mL^? 1). The essential oils were also screened for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity. Sample G showed the highest activity against AChE (IC₅₀ of 64.7 μg mL^? 1) while sample D (IC₅₀ of 29.5 μg mL^? 1) exhibited the most potent activity against BChE.     

Comparative study on the antioxidant activities of extracts of Coreopsis tinctoria flowering tops from Kunlun Mountains,Xinjiang, north-western China

Coreopsis tinctoria flowering tops (CTFs) from the Kunlun Mountains in Xinjing (north-western China) have been used for tea production for about a century. This study aims to assess the antioxidant activities and total phenolic, flavonoid and proanthocyanidin contents of various solvent extracts of CTF. CTF was extracted using n-hexane, chloroform, ethyl acetate, n-butanol, 75% aqueous ethanol (AEE) and water. The antioxidant activities of the CTF extracts were investigated through DPPH, ABTS, ^*OH, ^*O₂^? , total antioxidant capacity and reducing power assays. The results showed that n-butanol extract showed the highest contents of total phenols and flavonoids, with DPPH, ABTS and ^*OH radical-scavenging activities with IC₅₀ values of 134, 90.72 and 13.8 μg mL^? 1, respectively. The AEE demonstrated the strongest DPPH and ABTS radical-scavenging activities, with IC₅₀ values of 103 and 75.16 μg mL^? 1, respectively. Given its high antioxidant effect, CTF is a good source of natural antioxidants or functional food materials.     

Composition and antioxidant activity of Senecio nudicaulis Wall. ex DC. (Asteraceae): a medicinal plant growing wild in Himachal Pradesh,India

The composition of essential oil isolated from Senecio nudicaulis Wall. ex DC. growing wild in Himachal Pradesh, India, was analysed, for the first time, by capillary gas chromatography (GC) and GC–mass spectrometry. A total of 30 components representing 95.3% of the total oil were identified. The essential oil was characterised by a high content of oxygenated sesquiterpenes (54.97%) with caryophyllene oxide (24.99%) as the major component. Other significant constituents were humulene epoxide-II (21.25%), α-humulene (18.75%), β-caryophyllene (9.67%), epi-α-cadinol (2.90%), epi-α-muurolol (2.03%), β-cedrene (1.76%), longiborneol (1.76%), 1-tridecene (1.16%) and citronellol (1.13%). The oil was screened for antioxidant activity using DPPH, ABTS and nitric oxide-scavenging assay. The oil was found to exhibit significant antioxidant activity by scavenging DPPH, ABTS and nitric oxide radicals with IC₅₀ values of 10.61 ± 0.14 μg mL^? 1, 11.85 ± 0.28 μg mL^? 1 and 11.29 ± 0.42 μg mL^? 1, respectively.     

Chemical composition,N-nitrosamine inhibition and antioxidant and antimicrobial properties of essential oil from Coreopsis tinctoria flowering tops

Coreopsis tinctoria flowering (CTF) tops from the Kunlun Mountains in Xinjing (north-western China) have been used for tea production for about a century. This study was to assess antioxidant, nitrite-scavenging and N-nitrosamine inhibitory and antimicrobial activities of the essential oil extracted from CTF tops. The essential oil was extracted through hydrodistillation and its chemical compositions were analysed by GC–MS. Seventy compounds of the oil were identified, representing 81.87% of total oil. The antioxidant capacities of the oil with IC₅₀ values for scavenging DPPH and ABTS were 287.66 ± 12.60 and 1.251 ± 0.127 μg mL^? 1, respectively. The nitrite-scavenging and N-nitrosamine inhibitory activities (IC₅₀) were 0.3912 ± 0.0127 and 0.6564 ± 0.036 μg mL^? 1, respectively. The oil has a certain antimicrobial capacity, but its capacity was weaker than that of penicillinG (24 μg mL^? 1). The oil showed antioxidant and antimicrobial capacities and had a stronger nitrite-scavenging and N-nitrosamine inhibitory properties.     

Antimicrobial substances from the rare actinomycete Nonomuraea rhodomycinica NR4-ASC07T

Nonomuraea rhodomycinica NR4-ASC07^T is a rare actinomycete isolated from soil in Sirindhorn peat swamp forest. The crude extract of its culture broth exhibited antimicrobial and anticancer against diverse human pathogens and cancer cells. The chemical investigation of the crude extract led to the isolation of two new metabolites named nonomuric acid (1) and 3-hydroxy deoxydaunorubicinol aglycone (2), along with two known bioactive compounds [ε-rhodomycinone (3) and 7-deoxy-13-dihydrocarminomycinone (4)]. Compounds 1 and 3 showed antimalarial activity with the half maximal inhibitory concentration (IC₅₀) of 8.00 and 8.88 μg mL^?1, respectively. Compound 4 inhibited growth of Mycobacterium tuberculosis and Bacillus cereus at the minimum inhibitory concentrations of 50.0 and 12.50 μg mL^?1, respectively. Every compound exhibited cytotoxicity against cancer cells tested at IC₅₀ ≥ 6.34 μg mL^?1. These finding are the first report of bioactive metabolites produced by strain NR4-ASC07^T, suggesting that rare actinomycetes are yet promising sources for novel drug discovery.     

Chemical composition and antioxidant activity of essential oil from aerial parts of Teucrium flavum L. subsp. flavum growing spontaneously in Tunisia

The objectives of this study were to chemically characterise and evaluate the antioxidant potential of the essential oil from Teucrium flavum L. subsp. flavum growing spontaneously in Tunisia. The volatile oil was extracted by hydrodistillation of the aerial parts in a Clevenger type apparatus. Forty constituents were identified via GC and GC-MS analysis. β-caryophyllene (32.5%) and α-humulene (17.8%) were the most abundant components. The evaluation of free radical scavenging activity using stable DPPH free radical showed that the volatile oil exhibits a moderate antioxidant activity and reduces DPPH to 50% at EC₅₀ value of 1230 μg mL^? 1.     

Evaluation of antioxidant activities of the edible and medicinal Acacia albida organs related to phenolic compounds

This study compared phenolic contents and antioxidant activity in different organs of Acacia albida (leaves and bark) and focuses on identification of phenolic compounds of leaves by HPLC-DAD. The analysed organs exhibited differences in total polyphenol contents (100 and 59.5 mg GAE g^? 1 DW). Phenolic contents of leaves were two times higher than those in bark. Ethanolic extracts exhibited good antioxidant activities with IC₅₀ = 26 μg mL^? 1 for DPPH and EC₅₀ = 50 μg mL^? 1 for FRAP. Identification by HPLC-DAD revealed the presence of nine phenolic compounds known for their high antioxidant activity. The results suggested that this species can be used as source of natural antioxidants.     

In vitro cytotoxicity of some Narcissus plants extracts

This study compares the chloroform extracts of bulbs and roots of Narcissus papyraceus Ker Gawl. and Narcissus tazetta L. The cytotoxicity of the plant extracts was evaluated against human hepatocellular carcinoma cell line (HEPG2) and colon carcinoma cell line (HCT116) in comparison to doxorubicin. The extracts from the after-flowering (AF) bulbs of N. tazetta L. and N. papyraceus exhibited strong cytotoxic activity against HEPG2 (IC₅₀: 2.2, 3.5 μg mL^? 1) and HCT116 (IC₅₀: 4.2, 3.9 μg mL^? 1) cell lines, respectively. N. tazetta L. bulbs exhibited the least cell viability percentage in HepG-2 cell line (5.32%), while the AF root extracts of N. papyraceus exhibited the least cell viability percentage in HCT116 cell line (4.93%), when applied at a concentration of 50 μg mL^? 1, thereby being more active than doxorubicin at the same concentration.     

New Ni(II) complexes involving symmetrical bidentate N,O-donor Schiff base ligands: synthesis at ambient temperature,crystal structures,electrochemical study,antioxidant and cytotoxic activities

A new series of Ni(II) complexes, [Ni(L¹)₂] (1), [Ni(L²)₂] (2), [Ni(L³)₂] (3), and [Ni(L⁴)₂] (4), were synthesized at ambient temperature. The bidentate Schiff base ligands HL^1?4 have been obtained by the condensation reaction of 2-hydroxybenzaldehyde, 5-bromo-2-hydroxybenzaldehyde, 3-methoxy-2-hydroxy-benzaldehyde, and 4-methoxy-2-hydroxy-benzaldehyde, respectively, with 2-methoxyethylamine. The newly synthesized complexes were characterized by elemental analyses, FT-IR and UV–vis spectroscopy. The crystal structures of mononuclear Ni(II) complexes 2 and 3 were determined by the single-crystal X-ray diffraction technique. Electrochemical properties of the complexes were investigated in acetonitrile. The antioxidant properties of the Schiff base ligands and complexes were evaluated by two in vitro tests, DPPH radical scavenging and reducing power. The compounds were screened for their in vitro anticancer potential using gastric cancer cell lines by MTT assay. All ligands and complexes showed considerable cytotoxic activity against cancer cell lines (IC₅₀ = 0.2516–5.468 μg·mL^?1). The most promising result was achieved for complex 1 with the best IC₅₀ value of 0.2516 μg·mL^?1. It was found that the proliferation rate of MKN-45 cells decreased after treatment with the complexes in a dose-dependent way.     

The corrected structure of depressoside,an antioxidative iridoid glucoside extracted from the flowers of Gentiana urnula Harry Sm.

Three known iridoid glucosides (gentiournoside A, gentiournoside E and depressoside) were isolated from the flowers of Gentiana urnula Harry Sm. through activity-guided fractionations with a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. All three compounds exhibited excellent DPPH radical scavenging activities (IC₅₀: 10–20 μmol L^?1) comparable to that of ascorbic acid and Trolox. However, examination of the NMR data revealed that the reported chemical structure of depressoside, previously isolated from the leaves of G. depressa, needed correcting due to incorrect elucidation around C-7 of the iridane skeleton, and was corrected to 6-β-(2,3-dihydroxyphenyl)-d-glucosyl 7-O-(2,3-dihydroxybenzoyl)-loganate. Depressoside exhibited a much higher scavenging activity against superoxide radicals (IC₅₀: 45.5 μmol L^?1) than the other two extracted compounds (IC₅₀: more than 900 μmol L^?1) due to the crucial presence of a pyrogallyl unit.     

Antioxidant potential of indigenous cyanobacterial strains in relation with their phenolic and flavonoid contents

Antioxidant activities of eight indigenous cyanobacterial strains belonging to the genera Oscillatoria, Chroococcidiopsis, Leptolyngbya, Calothrix, Nostoc and Phormidium were studied in relation with their phenolic and flavonoid contents, ranging 3.9–12.6 mg GAE g^?1 and 1.7–3.44 mg RE g^?1. The highest activities were shown by Leptolyngbya sp. SI-SM (EC₅₀ = 63.45 and 67.49 μg mL^?1) and Calothrix sp. SI-SV (EC₅₀ = 65.79 and 69.38 μg mL^?1) calculated with ABTS and DPPH assays. Significant negative correlations were seen between total phenolic and flavonoid contents and the antioxidant activities in terms of EC₅₀ values. Furthermore, HPLC detected 15 phenolic compounds with total concentrations ranging from 277.3 to 829.7 μg g^?1. The prevalent compounds in most of the strains were rutin, tannic acid, orcinol, phloroglucinol and protocatechuic acid. Cyanobacterial strains showed high potential as a good source of phenolic compounds with potent antioxidative potential which could be beneficial for food, cosmetic and pharmaceutical industries.     

Online antioxidant activity and ultra-performance LC-electrospray ionisation-quadrupole time-of-fight mass spectrometry for chemical fingerprinting of Indian polyherbal formulations

A HPLC–DAD–DPPH method was developed for evaluating the 1, 1-diphenyl-2-picryl hydrazyl free radical scavenging activity of ethylacetate extracts of different polyherbal formulations (draksarista, draksava, lohasava and arvindasava) by using RP-18e column. The ethylacetate extract from polyherbal, ‘draksarista’ exhibited maximum free radical scavenging activity (99.9 ± 0.38%) followed by draksava (99.8 ± 0.34%), lohasava (98.5 ± 0.30%) and arvindasava (42.3 ± 0.34%) at 100 μg mL^? 1. Simultaneously, ultra-performance liquid chromatography coupled with electrospray ionisation-quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS) was used to study chemical composition of the ethylacetate extracts of formulations. The characteristic electrospray mass ionisation reveals the dominance of polyphenols and their glycosides in the four polyherbal formulations.     

Identification of Iridoids,Flavonoids and Triterpenes from the Methanolic Extract of Melampyrum bihariense A. Kern. and the Antioxidant Activity of the Extract

Melampyrum bihariense A. Kern. (Scrophulariaceae), a plant species used in traditional medicine for the treatment of rheumatic disorders and skin infections, was investigated with regard to its antioxidant activity and identification of its bioactive chemical constituents. The crude methanolic extract of the aerial parts of M. bihariense was examined by the spectrophotometric DPPH (1,1-diphenyl-2-picrylhydrazyl) and ferric reducing antioxidant power methods. The free radical scavenging capacity (SC₅₀) of the extract was found by the DPPH method to be 27.10 mg mL⁻¹, and the ferric reducing ability equivalent to ascorbic acid at 50 mg mL⁻¹ was 0.709 μg mL⁻¹. The chemical composition of this highly effective in the methanolic extract was analysed, and the main compounds were isolated through solvent–solvent partition, and multiple chromatographic separations, including column chromatography, vacuum liquid chromatography, centrifugal planar chromatography and preparative thin-layer chromatography. The structures were established by one- and two-dimensional NMR and liquid chromatography-mass spectrometry. The iridoids aucubin (1), 8-epi-loganin (2) and mussaenoside (3), the flavones apigenin and luteolin and the triterpene acids ursolic acid and oleanolic acid were identified; components 2, 3, ursolic acid and oleanolic acid for the first time in this species. The present study reveals that M. bihariense exerts antioxidant activity, and the iridoids, flavonoids and triterpene acids may be the main bioactive constituents of its methanolic extract.

     

α-glucosidase inhibitors isolated from Mimosa pudica L.

The aim of the study was to isolate digestive enzymes inhibitors from Mimosa pudica through a bioassay-guided fractionation approach. Repeated silica gel and sephadex LH 20 column chromatographies of bioactive fractions afforded stigmasterol, quercetin and avicularin as digestive enzymes inhibitors whose IC₅₀ values as compared to acarbose (351.02 ± 1.46 μg mL^?1) were found to be as 91.08 ± 1.54, 75.16 ± 0.92 and 481.7 ± 0.703 μg mL^?1, respectively. In conclusion, M. pudica could be a good and safe source of digestive enzymes inhibitors for the management of diabetes in future.     

In vitro biological activity of aromadendrin-4′-methyl ether isolated from root extract of Ventilago madraspatana Gaertn with relevance to anticandidal activity

In this study, antimicrobial and antioxidant activities of the hexane extract of the root of Ventilago madraspatana were evaluated. Based on the significant bioactivity of crude hexane extract, an active compound was purified from the root extract. The active compound was further purified and identified as aromodendrin-4′-methyl ether by the ¹H NMR spectrum. The isolated compound significantly inhibited Staphylococcus epidermidis with the lowest MIC and MBC at 78 μg/mL (P < 0.05). The compound also exhibited significant anticandidal activity with MIC and MBC values of 312 and 625 μg/mL, respectively. The radical scavenging activity of aromodendrin-4′-methyl ether was evident by its lower IC₅₀ values of 60 μg/mL for DPPH scavenging and 3.2 μg/mL for ABTS scavenging. The compound also exhibited ferrous ion chelation and H₂O₂ scavenging activities. The study is an attempt to increase the industrial utility of V. madrasapatana.     

Antimalarial and cytotoxic constituents of Xylaria cf. cubensis PK108

Xylaria cf. cubensis PK108 was identified by its distinctive morphological characteristics and its internal transcribed spacers sequence analysis. The chromatographic separation and structural elucidation based on spectroscopic analysis of fungal crude extracts led to 10 compounds; tryptoquivaline L (1), fiscalin C (2), epi-fiscalin C (3), cytochalasin D (4), ergosterol (5), ergosterol peroxide (6), chevalone C (7), xylaranol B (8), helvolic acid (9) and cyclo-(l-Pro-l-Leu) (10). The bioassay screening showed that 4 displayed cytotoxicity against KB and NCI-H187 cancer cell lines with IC₅₀ values of 3.25 and 5.95 μg mL^? 1. 6 exhibited cytotoxicity against NCI-H187 with an IC₅₀ value of 5.81 μg mL^? 1. 7 and 9 showed antimalarial activity with IC₅₀ values of 25.00 and 6.25 μg mL^? 1, respectively. This result establishes Xylaria as broad spectrum bioactive compound producers.     

Identification of Iridoids,Flavonoids and Triterpenes from the Methanolic Extract of Melampyrum bihariense A. Kern. and the Antioxidant Activity of the Extract

Melampyrum bihariense A. Kern. (Scrophulariaceae), a plant species used in traditional medicine for the treatment of rheumatic disorders and skin infections, was investigated with regard to its antioxidant activity and identification of its bioactive chemical constituents. The crude methanolic extract of the aerial parts of M. bihariense was examined by the spectrophotometric DPPH (1,1-diphenyl-2-picrylhydrazyl) and ferric reducing antioxidant power methods. The free radical scavenging capacity (SC₅₀) of the extract was found by the DPPH method to be 27.10 mg mL^?1, and the ferric reducing ability equivalent to ascorbic acid at 50 mg mL^?1 was 0.709 μg mL^?1. The chemical composition of this highly effective in the methanolic extract was analysed, and the main compounds were isolated through solvent–solvent partition, and multiple chromatographic separations, including column chromatography, vacuum liquid chromatography, centrifugal planar chromatography and preparative thin-layer chromatography. The structures were established by one- and two-dimensional NMR and liquid chromatography-mass spectrometry. The iridoids aucubin (1), 8-epi-loganin (2) and mussaenoside (3), the flavones apigenin and luteolin and the triterpene acids ursolic acid and oleanolic acid were identified; components 2, 3, ursolic acid and oleanolic acid for the first time in this species. The present study reveals that M. bihariense exerts antioxidant activity, and the iridoids, flavonoids and triterpene acids may be the main bioactive constituents of its methanolic extract.     

New dammarane and ursane-type triterpenoids from the flower of Ixora coccinea Linn.

Two new esters of dammarane triterpenoids ixorene isovalerate (1), ixorene 3′,8′-dimethyloctanoate (2) and a new ursane-type triterpenoids Ixoroid acid (3) were isolated from the methanolic extract of flowers of Ixora coccinea Linn., along with the three known constituents. The structures of compounds 1 and 3 were elucidated on the basis of extensive 1D,2D NMR studies and mass spectrometry as 17β-dammara-12,20-diene-3β-isovelarate and 3β-hydroxy-18β-urs-12ene-29β-oic acid, respectively, whereas 2 was identified as 17β-dammara-12,20-diene-3β-3′,8′-dimethyloctanoate through ¹H NMR and mass spectral data. Compounds 1, 2, 4 and 5 were evaluated for their in vitro cytotoxic activity, which exhibited weak activity against the 3T3, PC3 and HeLa cell lines with the IC₅₀ value >30 μM. Antioxidant results of 1 – 5 revealed that only compound 5 showed antioxidant activity in DPPH radical scavenging inhibition with the IC₅₀ 1.31 × 10^? 6 ± 0.005 μm mL^? 1. Both activities are the first records of these isolated compounds from the flowers of Ixora coccinea Linn.     

Evaluation of pigments from methanolic extract of Tagetes erecta and Beta vulgaris as antioxidant and antibacterial agent

The Total Phenolic Content (TPC), antioxidant and antibacterial activities of methanolic extract of Marigold flower (MF) (Tagetes erecta) and Beet root (BR) (Beta vulgaris) were examined. The present work reveals that MF contained greater amount of TPC (42.5 mg/g GAE) as compared to BR (39.4 mg/g GAE). Methanolic extract of MF exhibited excellent DPPH free radical scavenging power (IC₅₀ 0.0716 mg/mL) and reducing power at 1 mg/mL concentration. Similar results have been obtained in FTC and TBA method. The results of antibacterial test indicated that the methanolic extract of MF and BR is significantly effective against both type of Gram-negative (Escherichia coli, Shigella dysenteriae) and Gram-positive (Bacillus subtilis, Staphylococcus aureus) bacterial strains. Therefore, the present study suggests that the Marigold and BR are promising source of herbal medicinal products with noteworthy antioxidant and antibacterial activity.     

Crystal structures and in vitro anticancer studies on new unsymmetrical copper(II) Schiff base complexes derived from meso-1,2-diphenyl-1,2-ethylenediamine: a comparison with related symmetrical ones

Two new unsymmetrical copper(II) Schiff base complexes, [CuLⁿ(py)]ClO₄ (n = 1, 2) in which Lⁿ represents a tridentate N₂O type Schiff base ligand, were synthesized. Lⁿs were derived from monocondensation of meso-1,2-diphenyl-1,2-ethylenediamine with salicylaldehyde or 3-methoxysalicylaldehyde. The reaction between [CuLⁿ(py)]ClO₄ and other salicylaldehyde derivatives resulted in new N₂O₂ unsymmetrical tetradentate Cu^II complexes, CuL^3–6. Crystal structures of [CuL¹(py)]ClO₄, CuL⁴, and CuL⁵ were obtained. These new complexes as well as a series of related symmetrical ones (i.e. CuL^7–12) were tested for their in vitro anticancer activity against human liver cancer cell line (Hep-G2) by MTT and apoptosis assay. All of the complexes showed considerable cytotoxic activity against tumor cell lines (IC₅₀ = 5.13–16.24 μg mL^?1). The symmetrical CuL⁷ was the most potent anticancer derivative (IC₅₀ = 5.13 μg mL^?1) compared to the control drug 5-FU (IC₅₀ = 5.4 μg mL^-1, p < 0.05). Flow cytometry experiments showed that the copper derivatives especially [CuL²(py)]ClO₄ and CuL⁷ induced more apoptosis on Hep-G2 tumor cell lines compared to 5-FU.