Evaluation of the antioxidant and antibacterial properties of ethanol extracts from berries,leaves and stems of Hedera pastuchovii Woron. ex Grossh

This study was designed to examine the total phenolic and flavonoid contents, radical scavenging and antibacterial activity of the ethanolic extracts from leaves, berries and stems of Hedera pastuchovii Woron. ex Grossh. The berry extract, which contained the highest phenolic and flavonoid compounds, showed an appreciable DPPH^√ scavenging ability in comparison with leaf and stem extracts. The various extracts exhibited moderate to good activity against both Gram-negative and Gram-positive bacteria, and the effectiveness of leaf extract was higher for all tested bacteria.     

Antibacterial and antioxidant activity of naphthofuranquinones from the twigs of tropical mangrove Avicennia officinalis

Abstract

Mangrove plants are endowed with various biologically active compounds which have potent antibacterial and antioxidant properties. In present study, a bioactivity-guided fractionation for antibacterial and antioxidant active metabolites from the twigs of Avicennia officinalis collected from Kuala Selangor Nature Park, Selangor, Malaysia gave 13 major fractions. The antibacterial activity of A. officinalis fractions using well-diffusion showed strong selectivity on the Gram-positive bacteria (Staphylococcus epidermidis, S. aureus and Bacillus subtilis) with minimum inhibition concentration (MIC) values of 0.156-5.00?mg/mL. However, no antibacterial activities were observed on the Gram-negative bacteria (Vibrio cholera, Enterobacter cloacae and Escherichia coli). The active antibacterial fractions were further isolated using several chromatographic techniques to give two naphthofuranquinones, namely, avicenol C (1) and stenocarpoquinone B (2). Meanwhile, the antioxidant activity of A. officinalis fractions were evaluated using DPPH radical scavenging assay exhibited low antioxidant activities. Molecular structure of the naphthofuranquinones was elucidated using 1?D and 2?D NMR spectroscopy.     

Tunisian Native Mentha pulegium L. Extracts: Phytochemical Composition and Biological Activities

Mint species (Lamiaceae family) have been used as traditional remedies for the treatment of several diseases. In this work, we aimed to characterize the biological activities of the total phenolic and flavonoid contents of Mentha pulegium L. extracts collected from two different regions of Tunisia. The highest amounts of total phenols (74.45 ± 0.01 mg GAE/g DW), flavonoids (28.87 ± 0.02 mg RE/g DW), and condensed tannins (4.35 ± 0.02 mg CE/g DW) were found in the Bizerte locality. Methanolic leaf extracts were subjected to HPLC-UV analysis in order to identify and quantify the phenolic composition. This technique allowed us to identify seven phenolic compounds: two phenolic acids and five flavonoid compounds, such as eriocitrin, hesperidin, narirutin, luteolin, and isorhoifolin, which were found in both extracts with significant differences between samples collected from the different regions (p < 0.05). Furthermore, our results showed that the methanolic extract from leaves collected from Bizerte had the highest antioxidant activities (DPPH IC₅₀ value of 16.31 μg/mL and 570.08 μmol Fe²⁺/g, respectively). Both extracts showed high radical-scavenging activity as well as significant antimicrobial activity against eight tested bacteria. The highest antimicrobial activities were observed against Gram-positive bacteria with inhibition zone diameters and MIC values ranging between 19 and 32 mm and 40 and 160 µg/mL, respectively. Interestingly, at 10 μg/mL, the extract had a significant effect on cell proliferation of U87 human glioblastoma cells. These findings open perspectives for the use of Mentha pulegium L. extract in green pharmacy, alternative/complementary medicine, and natural preventive therapies for the development of effective antioxidant, antibacterial, and/or antitumoral drugs.     

Screening and characterization of medicinal plants extracts with bactericidal activity against Streptococcus mutans

Abstract

The aim of the present study was to perform a screening of extracts obtained from 15 medicinal plants using water (at 25 and 90?°C) or ethanol (at 25?°C), to bactericidal activity against cariogenic S. mutans ATCC 25175, as well as to carry out the preliminary phytochemical characterization of the extracts and HPLC/MS assay for selected extracts. The extractions were carried out for 5?h at 400?rpm. Only five from 45 tested extracts were selected based on their antibacterial activity. The IC₅₀ varied from of 28?ppm for Quercus ilex up to 250?ppm for Jatropha dioica. Different polyphenolic and quinic acids, flavonoids, anthocyanin or tyrosol were identified by HPLC/MS in selected extracts from Rosa gallica L., Jatropha dioica Sessé, Mimosa tenuiflora (Willd.) Poir, Quercus ilex L., and Solanum nigrum. The obtained results confirm that selected extracts are good candidates to be used for cariogenic bacteria control.     

Chemical composition of essential oils from different parts of Protium heptaphyllum (Aubl.) Marchand and their in vitro antibacterial activity

Abstract

In Brazilian folk medicine, Protium heptaphyllum is used to treat inflammatory conditions and to hasten wound repair. This paper aims to investigate the chemical composition and the in vitro antibacterial effects of the essential oils (EOs) obtained from P. heptaphyllum leaves and ripe and unripe fruits against a representative panel of oral pathogens. The GC-FID and GC-MS analysis revealed that the major components determined in P. heptaphyllum essential oils were myrcene (59.0%), β-elemene (17.2%), limonene (12.9%), spathulenol (12.6%), α-cubebene (11.6%), germacrene D (10.6%), trans-nerolidol (9.8%), and α-cadinol (8.8%). The essential oils of the ripe and unripe fruits showed the strongest antibacterial activity against the anaerobic bacteria Prevotella nigrescens (MIC?=?50?µg/mL). The leaf essential oil displayed very promising activity against Streptococcus mutans (MIC?=?50?µg/mL) and Streptococcus mitis (MIC?=?62.5?µg/mL). The antibacterial activity of EOs against oral pathogens is also described for the first time.

     

Diorganotin(IV) carboxylates of 3-methylphenyl ethanoic acid: Synthesis,crystal structure,antibacterial, anticancer and molecular docking studies

Abstract

Di-n-butyl- (1) and diethyltin(IV) (2) derivatives of 3-methylphenylethanoic acid were synthesized and characterized by elemental analysis, atomic absorption, IR, ¹H and 13C NMR spectroscopy and mass spectrometry. The spectroscopic data and single crystal X-ray diffraction studies for complex 2 have confirmed a bidentate coordination mode of the carboxylate ligand and the presence of hexacoordinated tin atoms in the complexes. The complexes were screened for their in vitro antibacterial activity against selected gram positive and gram negative bacterial strains. The anticancer potential was assessed against prostate cancer cell lines. Both complexes have shown higher activities than the ligand acid. Complex 1 with an IC₅₀ value of 4.97?±?0.27?μg/mL was found to be better anti prostate cancer agent than complex 2 (IC₅₀ = 11.26?±?2.18?μg/mL). Molecular docking study has suggested antibacterial action of the complexes in terms of their ability to develop hydrogen bonding and hydrophobic interactions with vital residues of the target proteins like tyrosyl-tRNA synthase from Staphylococcus aureus (gram-positive bacteria) and undecaprenyl diphosphate synthase from Escherichia coli (gram-negative bacteria).     

Pyranocarbazoles from Murraya koenigii (L.) Spreng. as antimicrobial agents

The bioassay guided fractionation of methanolic extract of Murraya koenigii (L.) Spreng. leaves resulted in the isolation of seven pyranocarbazoles. These were evaluated against four bacterial strains and ten Candida sp. including two matched pair of fluconazole sensitive/resistant clinical isolates. Out of seven, three i.e. Koenine (mk279), Koenigine (mk309) and Mahanine (mk347) exhibited significant antibacterial activity MIC90 3.12–12.5 μg/mL against bacterial strains Streptococcus aureus and Klebsiella pneumonia compared with standard drug Kanamycin MIC90 12.5 μg/mL. However, only mk309 was found active against variety of Candida species MIC90 12.5–100 μg/mL. It was observed that hydroxylation at C-6 and C-7 positions in the studied pyranocarbazoles activate the bioactivity. Simultaneously, decrease in Log P value compares with ?H and ?O?CH3 substituted derivatives. The study is focused on selective antifungal and antibacterial activity of pyranocarbazoles on bacterial strains S. aureus, K. pneumonia and variety of Candida species with structure activity relationship observations.     

Antibacterial triterpenoids from the leaves of Ilex hainanensis Merr.

One new triterpenoid (1) and seven known analogues (2–8) were isolated from the leaves of Ilex hainanensis Merr.. Their structures were established by analysis of their MS, 1D and 2D NMR spectroscopic data and comparison with those in the literature. The antibacterial activity of compounds 1–8 were evaluated by determination of minimum inhibitory concentration using twofold microdilution broth method against Streptococcus mutans ATCC 25175 (Gram-positive) and Fusobacterium nucleatum ATCC 10953 (Gram-negative). Compounds 3 and 5 showed significant antibacterial activity against S. mutans in concentration of 9.7 μg/mL, while showed little antibacterial activity against F. nucleatum. On the contrary, the inhibitory activity of compounds 1, 2 and 6 against F. nucleatum were higher than them against S. mutans.     

Phytochemical profiling and evaluation of modified resazurin microtiter plate assay of the roots of Trillium govanianum

Abstract

Trillium govanianum Wall. ex D. Don (Melanthiaceae alt. Trilliaceae), is native to the Himalayas. The present study, for the first time, was undertaken to explore the antimicrobial potential, to determine the minimum inhibitory concentration (MIC) values of the methanol extract of the roots of Trillium govanianum and its solid phase extraction (SPE) fractions by using resazurin microtiter assay (REMA) against Gram positive and Gram negative bacterial registered strains and to carry out phytochemical analysis. The remarkable amount of gallic acid equivalent phenolic and quercetin equivalent flavonoid content was manifested by MeOH extract (20.27?±?3.03?mg GAE/g DW and 9.25?±?0.50?mg QE/g DW respectively). The GC/MS analysis revealed the presence saturated and unsaturated components. Considerable level of antibacterial potential against Gram-positive bacteria (MIC: 2.5-0.009?mg/mL) than against Gram-negative bacteria (MIC: 2.5-0.165?mg/mL) were observed. The use of microtiter plates has the advantage of lower cost, fast and quantitative results.     

Phenanthrenes from Arundina graminifolia and in vitro evaluation of their antibacterial and anti-haemolytic properties

Chemical investigation and activity test of Arundina graminifolia led to the isolation of six phenanthrenes: blestriarene A (1), shancidin (2), densiflorol B (3), ephemeranthoquinone (4), coelonin (5) and lusianthridin (6). The isolated compounds demonstrated antibacterial and anti-haemolytic activities. It was found that compounds 1 and 2 had medium antibacterial activity against Staphylococcus aureus, Bacillus subtilis and Escherichia coli, with MICs of 20–40 μg/mL and MBCs of 40–320 μg/mL. Bactericidal mechanisms were explored. Rupture of cell wall and membrane and leakage of nuclear mass were observed by transmission electron microscopy (TEM). Moreover, compounds 1–3 attenuated the erythrocyte damage. Compounds 1 and 2 showed significant anti-haemolytic activity with inhibition rate about 50% at 16 μg/mL.     

One new flavonoid from Oroxylum indicum

One new flavonoid, 5,6,7-trimethoxyflavone-8-O-β-d-glucopyranoside (1), along with six known compounds 2–7, was isolated from Oroxylum indicum. Their structures were determined on the basis of spectral data. The antibacterial activities of compounds 1–4 were studied. Compounds 1 and 3 showed medium antibacterial activity against Staphylococcus aureus with MIC/MBC at 32–128 μg/ml.     

Chemical constituents from leaves and trunk bark of Rinorea oblongifolia (Violaceae)

Abstract

Two new coruleoellagic acid derivatives, 3,4′,5,5′,-tetramethylcoruleoellagic acid (1); 3′,4,4′,5,5′-pentamethylcoruleoellagic acid (2) and a new friedelane-type triterpene derivative rinol (5), were isolated from leaves and trunk bark of Rinorea oblongifolia (Violaceae) along with seven known compounds including 3,3′,4,4′,5′-pentamethylcoruleoellagic acid (3), hexamethylcoruleoellagic acid (4), 28-hydroxyfriedelin (6), friedelin (7), friedelan-3-ol (8), scopoletin (9) and β-sitosterol-3-O-β-D-glucopyranoside (10). Their structures were elucidated by means of spectroscopic methods including IR, 1D and 2D NMR in conjunction with mass spectrometry. Crude extracts of leaves and trunk bark as well as compounds 1–4 were evaluated for their antibacterial activities against 7 pathogenic bacterial strains (Streptococcus pneumoniae ATCC49619, Staphylococcus aureus ATCC 43300, Klepsiella pneumoniae ATCC 700603, Haemophilus influenza ATCC 49247, Escherichia coli ATCC 25922, Pseudomonas aeruginosa HM601, Staphylococcus aureus BAA 977). Compound (3) displayed noteworthy activity against Haemophilus influenza with MIC value of 9.38?µg/mL.     

The Optimization of Extraction Process,Antioxidant, Whitening and Antibacterial Effects of Fengdan Peony Flavonoids

Flavonoids have important biological activities, such as anti-inflammatory, antibacterial, antioxidant and whitening, which is a potential functional food raw material. However, the biological activity of Fengdan peony flavonoid is not particularly clear. Therefore, in this study, the peony flavonoid was extracted from Fengdan peony seed meal, and the antioxidant, antibacterial and whitening activities of the peony flavonoid were explored. The optimal extraction conditions were methanol concentration of 90%, solid-to-liquid ratio of 1:35 g:mL, temperature of 55 °C and time of 80 min; under these conditions, the yield of Fengdan peony flavonoid could reach 1.205 ± 0.019% (the ratio of the dry mass of rutin to the dry mass of peony seed meal). The clearance of Fengdan peony total flavonoids to 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, hydroxyl radical and 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical could reach 75%, 70% and 97%, respectively. Fengdan peony flavonoid could inhibit the growth of the Gram-positive bacteria. The minimal inhibitory concentrations (MICs) of Fengdan peony flavonoid on S. aureus, B. anthracis, B. subtilis and C. perfringens were 0.0293 mg/mL, 0.1172 mg/mL, 0.2344 mg/mL and 7.500 mg/mL, respectively. The inhibition rate of Fengdan peony flavonoid on tyrosinase was 8.53–81.08%. This study intensely illustrated that the antioxidant, whitening and antibacterial activity of Fengdan peony total flavonoids were significant. Fengdan peony total flavonoids have a great possibility of being used as functional food materials.     

Chemical profile and biological activities of Peltigera horizontalis (Hudson) Baumg. thallus and apothecia extracts

Abstract

The aim of this study was to determine, for the first time, the chemical composition of Peltigera horizontalis thallus and apothecia extracts (ether, ethyl acetate, dichloromethane and acetone) by HPLC-UV and GC-MS, and evaluate activity of genotoxic, anticholinesterase, antioxidant and antibacterial potential of acetone extracts. Major constituents of thallus extracts were gyrophoric acid, and methyl gyrophorate while dominant component of apothecia extracts was tenuiorin. The predominant volatile compounds in extracts were methyl orsellinate, dodecyl acrylate, orcinol and orcinol monomethyl ether. The thallus acetone extract at concentration of 2.0 µg mL^?1 gave the greatest decrease in the micronuclei frequency (22.4%) of all tested extracts. Apothecia extract showed stronger antioxidant activity as compared to thallus extract. Tested extracts at concentration of 10?mg mL^?1 exhibited inhibitory effect (16.5% for thallus and 12.8% for apothecia) on pooled human serum cholinesterase. P. horizontalis acetone extracts had no activity against the tested five bacteria strains.     

Chemical composition,antioxidant and antibacterial properties of Pteranthus dichotomus from Algerian Sahara

The phytochemical study of ethyl acetate and n-butanol extracts of Pteranthus dichotomus Forssk. led to the isolation and identification of 11 compounds, including three glycolipids 1–3, one lignan 4, three flavonoids 5–7 and four phytosterols 8–11. Structures of the isolated compounds have been elucidated by analysis of 1D and 2D NMR data, and mass spectrometry EI-MS and ESI-MS and by comparison with literature data. Furthermore, the ethyl acetate and n-butanol extracts were examined for their antioxidant and antibacterial activities. The results showed that both extracts (PDAC and PDBU) had a moderate antioxidant activity (IC50 = 375.514 μg/mL and 691.333 μg/mL) respectively.     

Phytochemical characterisation and bioprospection for antibacterial and antioxidant activities of Lippia alba Brown ex Britton & Wilson (Verbenaceae)

Ethanol extract and fractions obtained from fresh and dry aerial parts of Lippia alba were examined in order to determine their phytochemical composition, antioxidant capacity and antibacterial activities. The ethanol extracts and fractions exhibited an antioxidant effect by the DPPH assay, especially samples of fresh plant. HPLC analysis of the ethyl acetate fractions identified the presence of phenolic acids and flavonoids. The ethanol extract and fractions showed activity against reference and multidrug-resistant strains of Staphylococcus aureus and Enterococcus faecalis (MIC range 2000–250 μg/mL). The hexane and dichloromethane fractions of fresh plant showed better activity against reference strains of Escherichia coli (MIC of 250 and 125 μg/mL, respectively), but all extracts and fractions were less active against multidrug-resistant strains of all the Gram-negative species evaluated. The results showed that the extract and fractions of L alba aerial parts showed antibacterial activity, even against multidrug-resistant Gram-positive bacteria, and antioxidant effect (DPPH assay).     

An insight into chemical composition and bioactivity of 'Prokupac' red wine

Abstract

Autochthonous variety 'Prokupac' (Vitis vinifera L.) red wines with the addition of selected aromatic herbs (Artemisia absinthium, Cinnamomum zeylanicum, Glycyrrhiza glabra and Pimpinella anisum L.) were evaluated for chemical composition and biological activity. Furthermore, their polyphenolic profiles were determined by HPLC-DAD. While total phenolic (TPC) and flavonoid (TFC) contents, along with antioxidant activity, were significantly higher in all examined wine samples, the content of total anthocyanins was decreased, compared to a pure 'Prokupac' wine, used as the control one. On the other hand, 'Prokupac' wines with the addition of cinnamon (S. zeylanicum) and wormwood (A. absinthium) displayed highest antioxidant (EC₅₀, 0.021?±?0.001?mg/mL) and antibacterial (Enterococcus faecalis, MIC/MBC 15.63/62.50?μL/mL) activities, respectively. The study showed that 'Prokupac' wine with the addition of cinnamon was significantly enriched both with TPC and TFC, compared to control wine (p?<?0.05), which may contribute to its market potential.     

Synthesis of nitrogen-containing monoterpenoids with antibacterial activity

Abstract

Incorporation of the Beckmann rearrangement into the presented research resulted in the formation of nitrogen-containing terpenoid derivatives originating from naturally occurring compounds. Both starting monoterpenes and obtained derivatives were subjected to estimation of their antibacterial potential. In the presented study, Staphylococcus aureus was the most sensitive to examined compounds. The Minimal Inhibitory Concentration (MIC) experiments performed on S. aureus demonstrated that the (?)-menthone oxime (?)-8 and (+)-pulegone oxime (+)-13 had the best antibacterial activity among the tested derivatives and starting compounds. Their MIC₉₀ value was 100?µg/mL. The obtained derivatives were also evaluated for their inhibitory activity against bacterial urease. Among the tested compounds, three active inhibitors were found – oxime 14 and lactams (?)-15 and 16 limited the activity of Sporosarcina pasteurii urease with K_i values of 174.3?µM, 43.0?µM and 4.6?µM, respectively. To our knowledge, derivative 16 is the most active antiureolytic lactam described to date.     

Arylthio analogs of 5,8-quinolinedione: Synthesis,characterization, antibacterial,and antifungal evaluations

Abstract

A set of bis(arylthio) substituted 5,8-quinolinedione derivatives were synthesized and investigated for their in vitro antimicrobial effect. The antibacterial and antifungal activities of 6,7-bis(arylthio)-5,8-quinolinedione (4a–f) and 6,7-bis(arylthio)-2-methyl-5,8-quinolinedione (5a–f) were evaluated against four gram-negative bacteria, three gram-positive bacteria, and three fungi strains. The bis(methoxyarylthio) 5,8-quinolinedione analogs presented better activity against especially gram-positive bacteria compared to bis(halogenarylthio) 5,8-quinolinedione analogs. Bis(3-methoxyarylthio) 5,8-quinolinedione (4e) had the same activity of the reference drug against Staphylococcus aureus. Bis(2-methoxyarylthio) 5,8-quinolinedione (4f) showed two-and-a half-fold better activity with 89.69?μM against Enterococcus faecalis, and two-fold better activity with 11.20?μM against Staphylococcus epidermidis. Bis(2-methoxyarylthio)-2-methyl-5,8-quinolinedione 5f exhibited five-fold higher antibacterial activity with 43.44?μM against E. faecalis and also eight-fold activity of the reference drug with 2.71?μM against S. epidermidis.     

Investigation of antibacterial and cytotoxic potential of phenolics derived from Cistus incanus L. by means of thin-layer chromatography-direct bioautography and cytotoxicity assay

Cistus incanus L. (hairy rockrose) is a medicinal plant which belongs to the Cistaceae family and the Cistus genus, with a well established position in traditional medicine of the Mediterranean basin and the Middle East. It was the aim of this study to compare antibacterial activity of the phenolics derived from fourteen C. incanus samples of different origin (Turkey, Albania, Greece, and an unknown geographical location) obtained as herbal teas from a local market of diet supplements. This activity was assessed with the use of thin-layer chromatography–direct bioautography (TLC-DB) applied to crude extracts against the Gram negative naturally luminescent marine bacterium Aliivibrio fischeri and the Gram positive soil bacterium Bacillus subtilis as the test microorganisms. It was established that in spite of different origin of the investigated herbal samples, in qualitative terms their antibacterial activity was closely comparable and more strongly pronounced against the Gram positive than the Gram negative bacterium. Crude extract originating from one herbal specimen labelled A3 (sample no. 3 from Albania) underwent selective multi-step extraction of the phenolics, dividing them into six fractions (I to VI) that expectedly contain flavonoid aglycons, free phenolic acids, non-polar flavonoid glycosides, polar flavonoid glycosides, and phenolic acids obtained through the acidic and basic hydrolysis from the respective glycosides. Antibacterial activity of each A3 fraction was then assessed with the use of the same TLC-DB approach and it was established that the strongest effect was exerted by fractions I and II (flavonoid aglycons and free phenolic acids). Moreover, cytotoxic assay was performed for the crude C. incanus extracts against the human colon adenocarcinoma cells and a moderate yet well measurable cytotoxic effect was observed with all investigated C. incanus samples. In analogy to antibacterial activity, also in this case cytotoxic potential of all investigated crude C. incanus extracts was similar.