Antioxidant,anticholinesterase and antibacterial activities of Stachys guyoniana and Mentha aquatica

Context: Stachys guyoniana Noë ex. Batt. and Mentha aquatica L. are two Algerian Lamiaceae used in folk medicine.

Objective: To investigate their antioxidant, anticholinesterase and antibacterial activities.

Material and methods: n-Butanol (BESG), ethyl acetate (EESG) and chloroform (CESG) extracts of S. guyoniana and methanol (MEMA) and chloroform (CEMA) aerial part extracts of M. aquatica and methanol (MERMA) and acetone (AERMA) roots extracts of M. aquatica were evaluated for their antioxidant activity by the β-carotene-linoleic acid, DPPH^? and ABTS^?+?scavenging, CUPRAC and metal chelating assays. The anticholinesterase activity was tested against AChE and BChE. The antibacterial activity was assessed by MICs determination against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella heidelberg, Klebsiella pneumoniae, Enterobacter aerogenes and Morganella morganii strains.

Results: In the β-carotene test, the CESG (IC₅₀: 2.3?±?1.27?μg/mL) exhibited the highest activity. The BESG was the best scavenger of DPPH^? (IC₅₀: 2.91?±?0.14?μg/mL). In the ABTS test, AERMA was the most active (IC₅₀: 4.21?±?0.28?μg/mL). However, with the CUPRAC, the BESG exhibited the best activity (A_0.50: 0.15?±?0.05?μg/mL) and was active in metal chelating assay with 48% inhibition at 100?μg/mL. The BESG was the best AChE inhibitor (IC₅₀: 5.78?±?0.01?μg/mL) however, the AERMA showed the highest BChE inhibitory activity (IC₅₀: 19.23?±?1.42?μg/mL). The tested extracts exhibited a good antibacterial activity.

Conclusion: This study demonstrated good antioxidant, anticholinesterase and antibacterial potential of S. guyoniana and M. aquatica, which fits in well with their use in folk medicine.     

LC-MS–MS and GC-MS analyses of biologically active extracts and fractions from Tunisian Juniperus phoenice leaves

Context: Despite some studies related to Juniperus phoenicea L. (Cupressaceae), phytochemical and biological investigations of this plant remain unexplored.

Objective: This work is the first report dealing with the identification and characterization of volatile components and flavonoids in hexane and methanol extracts from J. phoenicea leaves

Materials and methods: Antioxidant activity of hexane, and methanol extracts from J. phoenicea leaves were determined by DPPH-radical scavenging assay. α-Amylase inhibitory activity was evaluated by enzyme inhibition using in vitro assay (each extract was dissolved in DMSO to give concentrations of 50, 100 and 200?mg/mL). The chemical composition of fractions (Fr1-Fr3) from methanol extract was determined by high-performance liquid chromatography coupled with mass spectroscopy (HPLC-MS) analysis.

Results and discussion: The hexane extract was analyzed by GC-MS technique which allowed the identification of 32 compounds. The main constituents were α-humulene (16.9%), pentadecane (10.2%) and α-cubebene (9.7%). Fraction Fr 2 exhibited a strong DPPH radical-scavenging activity (IC_50?=_?20.1?μg/mL) compared to that of BHT as well as the highest α-amylase inhibitory activity (IC_50?=_?28.4?μg/mL). Three flavonoids were identified in these fractions using HPLC-MS analysis: Quercetin 3-O-glucoside, isoscutellarein 7-O-pentoside and quercetin 3-O-pentoside. In addition, the more active fraction (Fr 2) was purified with semi-preparative HPLC affording one pure compound (amentoflavone) using ¹H NMR analysis. This compound exhibited powerful DPPH radical-scavenging (IC_50?=_?14.1?μg/mL) and α-amylase inhibition (IC_50?=_?20.4?μg/mL) effects.

Conclusion: This study provides scientific support to some medicinal uses of J. phoenicea found in North Africa.     

Phytochemical analysis,antiproliferative and antioxidant activities of Chrozophora tinctoria: a natural dye plant

Context: Chrozophora tinctoria (L.) A. Juss. (Euphorbiaceae) is known as ‘dyer’s-croton’ and used to obtain dye substances. Recently, natural antioxidants and colorants have been of interest because of their safety and therapeutic effects.

Objective: This study investigates the antiproliferative and antioxidant activities of the various extracts and fractions from C. tinctoria and analyzes their phytochemical contents.

Materials and methods: The aerial parts of C. tinctoria were extracted with water, ethyl acetate, n-butanol, and methanol/chloroform. Phenolic compounds and other constituents of the extracts were analyzed by HPLC/TOF-MS. The ethyl acetate extract (EA) was fractionated by flash chromatography. The extracts, fractions, and major phenolic compounds were investigated for their antiproliferative activities on human cervical adenocarcinoma (HeLa) cell line at the concentrations of 5–100?μg/mL by using BrdU ELISA assay during 24?h of incubation. DPPH radical scavenging activities (5–150?μg/mL) and total phenolic contents of the samples were also evaluated.

Results: 4-Hydroxybenzoic acid (268.20?mg/kg), apigenin-7-glucoside (133.34?mg/kg), and gallic acid (68.92?mg/kg) were the major components of EA. CT/E-F6 (IC₅₀?=?64.59?±?0.01?μg/mL) exhibited the highest antiproliferative activity. CT/E-F2 (IC₅₀=?14.0?±?0.0?μg/mL) and some fractions displayed higher radical scavenging activity compared to synthetic antioxidant BHT (IC_50?=_?23.1?±?0.0?μg/mL). Among the main phenolics, gallic acid exhibited the highest antiproliferative and radical scavenging abilities (IC_50?<_?5?μg/mL).

Conclusion: In this study, we have determined the biologically active fractions and their high effects may be attributed to the presence of gallic acid.     

Antiprotozoal screening of the Cuban native plant Scutellaria havanensis

Context: Scutellaria havanensis Jacq. (Lamiaceae) is a native medicinal herb with a history of use in Cuba.

Objective: This study screens the antiprotozoal activity of S. havanensis.

Materials and methods: Chloroform and methanol extracts from leaves and stems were evaluated in vitro at doses between 0.015 and 200?μg/mL against protozoan parasites: Plasmodium berghei, Trichomonas vaginalis and Leishmania amazonensis. Chloroform and methanol extracts were characterized by GC/MS. Cytotoxicity against mouse peritoneal macrophages was tested in parallel.

Results: Scutellaria havanensis extracts exhibited IC₅₀ values between 7.7 and 32.2?μg/mL against trophozoites of P. berghei and T. vaginalis; while the extracts were inactive against L. amazonensis promastigotes. Trichomonicidal activity of methanol extract exhibited the best selectivity but chloroform extract showed the highest antiplasmodial, trichomonicidal and cytotoxic activity. The majority of compounds in the chloroform extract were hydroxy and/or methoxyflavones (77.96%), in particular, wogonin (48.27%). In methanol extract, wogonin (5.89%) was detected. Trichomonicidal effect of wogonin was moderate (IC_50?=_?56?μM) and unspecific with respect to macrophages (SI?=?2). On the contrary, antiplasmodial activity of wogonin were particularly active (IC_50?=_?15?μM) demonstrating a higher selectivity index (SI?=?7.4).

Conclusions: Wogonin is an active principle compound of the chloroform extract of S. havanensis against P. berghei and T. vaginalis trophozoites, whereas the methanol extract of S. havanensis should be investigated more deeply as a trichomonicide. Our findings suggest that wogonin is potentially useful for the development of antimalarial alternative treatments.     

Phytochemical screening and evaluation of in vitro antioxidant and antimicrobial activities of the indigenous medicinal plant Albizia odoratissima

Context: Albizia odoratissima (L. f.) Benth has been used in Indian folk medicine to treat numerous inflammatory pathologies, such as leprosy, ulcers, burns and asthma.

Objective: To evaluate the antioxidant and antimicrobial properties of A. odoratissima.

Materials and methods: Dried leaves of A. odoratissima were extracted in organic solvents (hexane, chloroform, ethyl acetate, and methanol). The total phenolic content (TPC) and total flavonoid content (TFC) were determined using the Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. The antioxidant activity was examined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H₂O₂), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), and ferric reducing antioxidant power (FRAP) assays. The antibacterial activity was examined using minimum inhibitory concentration (MIC) and the minimum bacterial concentration (MBC), determined by broth microdilution method against Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Proteus vulgaris) and Gram-positive bacterium (Staphylococcus aureus).

Results: The TPC ranged from 4.40?±?1.06 to 1166.66?±?31.85?mg GAE/g of dry weight (DW), and the TFC ranged from 48.35?±?3.62 to 109.74?±?1.84?mg QE/g of DW. The IC₅₀ values of the ethyl acetate extract for DPPH, ABTS, and H₂O₂ were 10.96?±?0.40, 4.35?±?0.07, and 163.82?±?1.52?μg/mL, respectively. Both methanol and ethyl acetate extracts demonstrated effective antibacterial activity with MICs and MBCs values ranging 136–546?μg/mL and 273–1093?μg/mL, respectively, against the tested pathogenic species.

Conclusions: The leaves of A. odoratissima showed potent free radical scavenging property and antimicrobial activity.     

HPLC-DAD phenolic profile,cytotoxic and anti-kinetoplastidae activity of Melissa officinalis

Context Melissa officinalis subsp. inodora Bornm. (Lamiaceae) has been used since ancient times in folk medicine against various diseases, but it has not been investigated against protozoa.

Objective To evaluate the activities of M. officinalis against Leishmania braziliensis, Leishmania infantum and Trypanosoma cruzi as well as its cytotoxicity in fibroblast cell line.

Materials and methods The fresh leaves were chopped into 1?cm² pieces, washed and macerated with 99.9% of ethanol for 72?h at room temperature. Antiparasitic activity of M. officinalis was accessed by direct counting of cells after serial dilution, while the cytotoxicity of M. officinalis was evaluated in fibroblast cell line (NCTC929) by measuring the reduction of resazurin. The test duration was 24?h. High-performance liquid chromatography (HPLC) was used to characterise the extract.

Results The extract at concentrations of 250 and 125?μg/mL inhibited 80.39 and 54.27% of promastigote (LC_50? value?=_?105.78?μg/mL) form of L. infantum, 80.59 and 68.61% of L. brasiliensis (LC₅₀ value _?=_?110.69?μg/mL) and against epimastigote (LC₅₀ value _?=_?245.23?μg/mL) forms of T. cruzi with an inhibition of 54.45 and 22.26%, respectively, was observed. The maximum toxicity was noted at 500?μg/mL with 95.41% (LC_50? value?=_?141.01?μg/mL). The HPLC analysis identified caffeic acid and rutin as the major compounds.

Discussion The inhibition of the parasites is considered clinically relevant (<?500?μg/mL). Rutin and caffeic acids may be responsible for the antiprotozoal effect of the extract.

Conclusion The ethanol extract of M. officinalis can be considered a potential alternative source of natural products with antileishmania and antitrypanosoma activities.     

Inter-species comparative antioxidant assay and HPTLC analysis of sakuranetin in the chloroform and ethanol extracts of aerial parts of Rhus retinorrhoea and Rhus tripartita

Context: Extensive research on Rhus (Anacardiaceae) shows their antioxidant potential, which warrants further evaluation of its other species.

Objective: To perform a comparative antioxidant assay on extracts of R. retinorrhoea and R. tripartita, including sakuranetin quantification by a validated HPTLC method.

Materials and methods: In vitro antioxidant assay was performed on chloroform and ethanol extracts of R. retinorrhoea Steud. ex Oliv. (RRCE and RREE) and R. tripartita (Ucria) Grande (RTCE and RTEE) by DPPH radical scavenging (at 31.25, 62.5, 125, 250 and 500?μg/mL concentrations) and β-carotene-linoleic acid bleaching methods at 500?μg/mL concentration. Densitometric HPTLC method was developed and validated using toluene: ethyl acetate: methanol (8:2:0.2; v/v/v) as mobile phase, executed on glass-backed silica gel F₂₅₄ plate and scanned at 292?nm.

Results: Antioxidant activity of Rhus extracts tested by the two methods (DPPH/BCB) was found in order of RTEE?>?RREE?>?RTCE?>?RRCE with IC₅₀ 118.67/256.26, 315.75/82.35, 827.92/380.0 and 443.69/292.75, respectively. Scanning of the HPTLC plate provided an intense peak of sakuranetin at R_f =?0.59. The estimated sakuranetin content in the dry weight of the extracts was highest in RREE (27.95?μg/mg) followed by RRCE (25.22?μg/mg), RTEE (0.487?μg/mg) and RTCE (0.0?μg/mg). Presence of sakuranetin in RREE, RRCE and RTEE supported the highest antioxidant property of the two Rhus species. Nonetheless, low sakuratenin in R. tripartita indicated the presence of other bioactive constituents responsible for synergistic antioxidant activity.

Conclusion: The developed HPTLC method therefore guarantees its application in quality control of commercialized herbal drugs and formulations containing sakuranetin.     

Unlocking the in vitro anti-inflammatory and antidiabetic potential of Polygonum maritimum

Context: Several Polygonum species (Polygonaceae) are used in traditional medicine in Asia, Europe and Africa to treat inflammation and diabetes.

Objective: Evaluate the in vitro antioxidant, anti-inflammatory and antidiabetic potential of methanol and dichloromethane extracts of leaves and roots of the halophyte Polygonum maritimum L.

Material and methods: Antioxidant activity was determined (up to 1?mg/mL) as radical-scavenging activity (RSA) of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), copper (CCA) and iron (ICA) chelating activities and iron reducing power (FRAP). NO production was measured in lipopolysaccharide (LPS)-stimulated macrophages for 24?h at concentrations up to 100?μg/mL and antidiabetic potential was assessed by α-amylase and α-glucosidase inhibition (up to 10?mg/mL) assays. The phytochemical composition of the extracts was determined by gas chromatography-mass spectrometry (GC-MS).

Results: The methanol leaf extract had the highest activity against DPPH? (IC₅₀ =?26?μg/mL) and ABTS⁺? (IC₅₀ =?140?μg/mL), FRAP (IC₅₀ =?48?μg/mL) and CCA (IC₅₀ =?770?μg/mL). Only the dichloromethane leaf extract (LDCM) showed anti-inflammatory activity (IC₅₀ =?48?μg/mL). The methanol root (IC₅₀ =?19?μg/mL) and leaf (IC₅₀ =?29?μg/mL) extracts strongly inhibited baker’s yeast α-glucosidase, but LDCM had higher rat’s α-glucosidase inhibition (IC₅₀ =?2527?μg/mL) than acarbose (IC₅₀ =?4638?μg/mL). GC-MS analysis identified β-sitosterol, stigmasterol, 1-octacosanol and linolenic acid as possible molecules responsible for the observed bioactivities.

Conclusions: Our findings suggest P. maritimum as a source of high-value health promoting commodities for alleviating symptoms associated with oxidative and inflammatory diseases, including diabetes.     

Trypanocidal and leishmanicidal activities of flavonoids isolated from Stevia satureiifolia var. satureiifolia

Context Chagas’ disease and leishmaniasis produce significant disability and mortality with great social and economic impact. The genus Stevia (Asteraceae) is a potential source of antiprotozoal compounds.

Objective Aerial parts of four Stevia species were screened on Trypanosoma cruzi. Stevia satureiifolia (Lam.) Sch. Bip. var. satureiifolia (Asteraceae) dichloromethane extract was selected for a bioassay-guided fractionation in order to isolate its active compounds. Additionally, the antileishmanial activity and the cytotoxicity of these compounds on mammalian cells were assessed.

Materials and methods The dichloromethane extract was fractionated by column chromatography. The isolated compounds were evaluated using concentrations of 0–100?μg/mL on T. cruzi epimastigotes and on Leishmania braziliensis promastigotes for 72?h, on trypomastigotes and amastigotes of T. cruzi for 24?h and 120?h, respectively. The compounds’ cytotoxicity (12.5–500?μg/mL) was assessed on Vero cells by the MTT assay. The structure elucidation of each compound was performed by spectroscopic methods and HPLC analysis.

Results The dichloromethane extracts of Stevia species showed significant activity on T. cruzi epimastigotes. The flavonoids eupatorin (1.3%), cirsimaritin (1.9%) and 5-desmethylsinensetin (1.5%) were isolated from S. satureiifolia var. satureiifolia extract. Eupatorin and 5-desmethylsinensetin showed IC₅₀ values of 0.2 and 0.4?μg/mL on T. cruzi epimastigotes and 61.8 and 75.1?μg/mL on trypomastigotes, respectively. The flavonoid 5-desmethylsinensetin showed moderate activity against T. cruzi amastigotes (IC_50? value?=_?78.7?μg/mL) and was the most active compound on L. braziliensis promastigotes (IC_50? value?=_?37.0?μg/mL). Neither of the flavonoids showed cytotoxicity on Vero cells, up to a concentration of 500?μg/mL.     

Antioxidant,antimutagenic and antiproliferative activities in selected seaweed species from Sinaloa,Mexico

Context Seaweeds from the Mexican Pacific Ocean have not been evaluated as a source of chemoprotectants.

Objective The objective of this study is to evaluate chemopreventive activities of the seaweeds Phaephyceae – Padina durvillaei (Dictyotaceae) – Rodhophyceae – Spyridia filamentosa (Spyridiaceae), Gracilaria vermiculophylla (Gracilariaceae) – and Chlorophyceae – Ulva expansa (Ulvaceae), Codium isabelae (Codiaceae), Rhizoclonium riparium (Cladophoraceae) and Caulerpa sertularioides (Caulerpaceae).

Materials and methods Methanol, acetone and hexane seaweed extracts were assessed at 30 and 3?mg/mL on antioxidant capacity (DPPH and ABTS assays), 0.003–3.0?mg/plate on antimutagenic activity against AFB₁ using Salmonella typhimurium TA98 and TA100 tester strains in Ames test, and 12.5 to 100?μg/mL on antiproliferative activity on Murine B-cell lymphoma. Phenols, flavonoids and pigments content were also assessed as antioxidant compounds.

Results Extraction yield was higher in methanol than in acetone and hexane extracts (6.4, 2.7 and 1.4% dw). Antioxidant capacity was higher in brown and green than in red seaweed species, particularly in P. durvillaei extracted in acetone (EC_50? value=_?16.9 and 1.56?mg/mL for DPPH and ABTS). Flavonoids and chlorophylls were identified as mainly antioxidant components; particularly in hexane extracts, which were correlated with the antioxidant capacity. Highest mutagenesis inhibition (>?40%) occurred in R. riparium at the lowest concentration assayed (0.003?mg/plate), while highest antiproliferative inhibition (37 and 72% for 12.5 and 25?μg/mL) occurred in C. sertularioides.

Discussion and conclusion Flavonoids and chlorophylls explained the chemopreventive activities assessed in S. filamentosa, R. riparium and C. sertularioides. These seaweeds have a high potential as a source of novel chemoprotectants.     

Protective activity of Hertia cheirifolia extracts against DNA damage,lipid peroxidation and protein oxidation

Context: Hertia cheirifolia L. (Asteraceae), a perennial shrub widely distributed in Northern Africa, is traditionally used to treat inflammatory disorders.

Objective: The protective effect of methanol (Met E) and aqueous (Aq E) extracts of Hertia cheirifolia against DNA, lipid and protein oxidation was investigated.

Materials and methods: Different concentrations (50–1000?μg/mL) of Hertia cheirifolia aerial part extracts were examined against DNA, lipid and protein oxidation induced by H₂O_2?+?UV, FeSO₄, and Fe³⁺/H₂O₂-ascorbic acid, respectively. The DPPH^?, metal ion chelating, reducing power and β-carotene bleaching tests were conducted.

Results: Both extracts were rich in polyphenols, flavonoids and tannins, and were able to scavenge DPPH^? with IC₅₀ values of 138 and 197?μg/mL, respectively. At 300?μg/mL, Aq E exerted stronger chelating effect (99%) than Met E (69%). However, Met E reducing power (IC_50?=_?61?μg/mL) was more than that of Aq E (IC_50?=_?193?μg/mL). Both extracts protected from β-carotene bleaching by 74% and 94%, respectively, and inhibited linoleic acid peroxidation. The inhibitory activity of Aq E extract (64%) was twice more than that of Met E (32%). Interestingly, both extracts protected DNA against the cleavage by about 96–98%. At 1?mg/mL, Met E and Aq E restored protein band intensity by 94–99%.

Conclusions: Hertia cheirifolia exhibits potent antioxidant activity and protects biomolecules against oxidative damage; hence, it may serve as potential source of natural antioxidant for pharmaceutical applications and food preservation. This is the first report on the protective activity of this plant against biomolecule oxidation.     

Anti-cryptococcal activity of ethanol crude extract and hexane fraction from Ocimum basilicum var. Maria bonita: mechanisms of action and synergism with amphotericin B and Ocimum basilicum essential oil

Context: Ocimum basilicum L. (Lamiaceae) has been used in folk medicine to treat headaches, kidney disorders, and intestinal worms.

Objective: This study evaluates the anti-cryptococcal activity of ethanol crude extract and hexane fraction obtained from O. basilicum var. Maria Bonita leaves.

Materials and methods: The MIC values for Cryptococcus sp. were obtained according to Clinical and Laboratory Standards Institute in a range of 0.3–2500?μg/mL. The checkerboard assay evaluated the association of the substances tested (in a range of 0.099–2500?μg/mL) with amphotericin B and O. basilicum essential oil for 48?h. The ethanol extract, hexane fraction and associations in a range of 0.3–2500?μg/mL were tested for pigmentation inhibition after 7?days of treatment. The inhibition of ergosterol synthesis and reduction of capsule size were evaluated after the treatment with ethanol extract (312?μg/mL), hexane fraction (78?μg/mL) and the combinations of essential oil?+?ethanol extract (78?μg/mL?+?19.5?μg/mL, respectively) and essential oil?+?hexane fraction (39.36?μg/mL?+?10?μg/mL, respectively) for 24 and 48?h, respectively.

Results: The hexane fraction presented better results than the ethanol extract, with a low MIC (156?μg/mL against C. neoformans T₄₄₄ and 312?μg/mL against C. neoformans H99 serotype A and C. gattii WM779 serotype C). The combination of the ethanol extract and hexane fraction with amphotericin B and essential oil enhanced their antifungal activity, reducing the concentration of each substance needed to kill 100% of the inoculum. The substances tested were able to reduce the pigmentation, capsule size and ergosterol synthesis, which suggest they have important mechanisms of action.

Conclusions: These results provide further support for the use of ethanol extracts of O. basilicum as a potential source of antifungal agents.     

Anti-acetylcholinesterase activity and antioxidant properties of extracts and fractions of Carpolobia lutea

Context: There is an unmet need to discover new treatments for Alzheimer’s disease. This study determined the anti-acetylcholinesterase (AChE) activity, DPPH free radical scavenging and antioxidant properties of Carpolobia lutea G. Don (Polygalaceae).

Objective: The objective of this study is to quantify C. lutea anti-AChE, DPPH free radical scavenging, and antioxidant activities and cell cytotoxicity.

Materials and methods: Plant stem, leaves and roots were subjected to sequential solvent extractions, and screened for anti-AChE activity across a concentration range of 0.02–200?μg/mL. Plant DPPH radical scavenging activity, reducing power, and total phenolic and flavonoid contents were determined, and cytotoxicity evaluated using human hepatocytes.

Results: Carpolobia lutea exhibited concentration-dependent anti-AChE activity. The most potent inhibitory activity for the stem was the crude ethanol extract and hexane stem fraction oil (IC₅₀?=?140?μg/mL); for the leaves, the chloroform leaf fraction (IC₅₀?=?60?μg/mL); and for roots, the methanol, ethyl acetate and aqueous root fractions (IC₅₀?=?0.3–3?μg/mL). Dose-dependent free radical scavenging activity and reducing power were observed with increasing stem, leaf or root concentration. Total phenolic contents were the highest in the stem: ～632?mg gallic acid equivalents/g for a hexane stem fraction oil. Total flavonoid content was the highest in the leaves: ～297?mg quercetin equivalents/g for a chloroform leaf fraction. At 1?μg/mL, only the crude ethanol extract oil was significantly cytotoxic to hepatocytes.

Discussion and conclusions: Carpolobia lutea possesses anti-AChE activity and beneficial antioxidant capacity indicative of its potential development as a treatment of Alzheimer’s and other diseases characterized by a cholinergic deficit.     

Antimicrobial activity of Buchenavia tetraphylla against Candida albicans strains isolated from vaginal secretions

Context: Buchenavia tetraphylla (Aubl.) RA Howard (Combretaceae: Combretoideae) is an ethnomedicinal plant with reported antifungal action.

Objective: This study evaluates the antimicrobial activity of B. tetraphylla leaf extracts against clinical isolates of Candida albicans. The morphological alterations, combinatory effects with fluconazole and the cytotoxicity of the active extract were analyzed.

Materials and methods: Extracts were obtained using different solvents (hexane: BTHE; chloroform: BTCE; ethyl acetate: BTEE; and methanol: BTME). Antimicrobial activity was determined by the broth microdilution method using nine strains of C. albicans isolated from vaginal secretions and one standard strain (UFPEDA 1007).

Results: All extracts showed anti-C. albicans activity, including against the azole-resistant strains. The MIC values ranged from 156 to 2500?μg/mL for the BTHE; 156 to 1250?μg/mL for the BTCE; 625 to 1250?μg/mL for the BTME and 625?μg/mL to 2500?μg/mL for the BTEE. BTME showed the best anti-C. albicans activity. This extract demonstrated additive/synergistic interactions with fluconazole. Scanning electron microscopy analysis suggested that the BTME interferes with the cell division and development of C. albicans. BTME showed IC₅₀ values of 981 and 3935?μg/mL, against J774 macrophages and human erythrocytes, respectively. This extract also enhanced the production of nitric oxide by J774 macrophages.

Discussion and conclusion: Buchenavia tetraphylla methanolic extract (BTME) is a great source of antimicrobial compounds that are able to enhance the action of fluconazole against different C. albicans strains; this action seems related to inhibition of cell division.     

Studies on phytochemical,antioxidant, anti-inflammatory,hypoglycaemic and antiproliferative activities of Echinacea purpurea and Echinacea angustifolia extracts

Context: Echinacea (Asteraceae) is used because of its pharmacological properties. However, there are few studies that integrate phytochemical analyses with pharmacological effects.

Objective: Evaluate the chemical profile and biological activity of hydroalcoholic Echinacea extracts.

Materials and methods: Density, dry matter, phenols (Folin–Ciocalteu method), flavonoids (AlCl₃ method), alkylamides (GC-MS analysis), antioxidant capacity (DPPH and ABTS methods), antiproliferative effect (SRB assay), anti-inflammatory effect (paw oedema assay, 11 days/Wistar rats; 0.4?mL/kg) and hypoglycaemic effect (33 days/Wistar rats; 0.4?mL/kg) were determined in three Echinacea extracts which were labelled as A, B and C (A, roots of Echinacea purpurea L. Moench; B, roots, leaves, flowers and seeds of Echinacea purpurea; C, aerial parts and roots of Echinacea purpurea and roots of Echinacea angustifolia DC).

Results: Extract C showed higher density (0.97?g/mL), dry matter (0.23?g/mL), phenols (137.5?±?2.3 mEAG/mL), flavonoids (0.62?±?0.02 mEQ/mL), and caffeic acid (0.048?mg/L) compared to A and B. A, B presented 11 alkylamides, whereas C presented those 11 and three more. B decreased the oedema (40%) on day 2 similar to indomethacin. A and C showed hypoglycaemic activity similar to glibenclamide. Antiproliferative effect was only detected for C (IC₅₀ 270?μg/mL; 8171?μg/mL; 9338?μg/mL in HeLa, MCF-7, HCT-15, respectively).

Discussion and conclusion: The difference in the chemical and pharmacological properties among extracts highlights the need to consider strategies and policies for standardization of commercial herbal extracts in order to guarantee the safety and identity of this type of products.     

Evaluation of the antileishmanial potency,toxicity and phytochemical constituents of methanol bark extract of Sterculia villosa

Context: Visceral leishmaniasis is a protozoan disease caused by Leishmania donovani parasite. The genus Sterculia (Malvaceae) possesses ethnobotanical potential against this protozoan infection.

Objective: Determining the potential role of methanol bark extracts from Sterculia villosa Roxb (SVE) and its phytoconstituents against Leishmania donovani promastigotes.

Materials and methods: SVE was analysed by TLC, UV–Vis, IR spectroscopy and biochemical assays. Antileishmanial potential of SVE (0.5–130?μg/mL for 72?h) was characterized by MTT assay. Fluorescent microscopy was performed to validate the IC₅₀ dose. To determine the effect of SVE on promastigotes, reactive oxygen species (ROS) and superoxide generation, lipid peroxidation and DNA fragmentation assays were performed. Molecular aggregation of compounds was determined by atomic force microscopy (AFM). Extent of cytotoxicity of SVE at IC₅₀ dose was determined against RAW 264.7 macrophages, peritoneal macrophages and murine RBCs. In vivo cytotoxicity of SVE was evaluated in BALB/c mice.

Result: SVE exhibited reverse dose dependent antileishmanial activity when 130–0?μg/mL doses were tested against promastigotes. The IC₅₀ and IC₇₀ values were found to be 17.5 and 10?μg/mL, respectively. SVE at IC₅₀ dose demonstrated elevated level of ROS, superoxide, lipid peroxidation and DNA fragmentation against promastigotes with no cytotoxicity. AFM analysis suggested increasing size of molecular aggregation (31.3?nm Discussion and conclusions: The study elucidates the antileishmanial potential of SVE against Leishmania donovani promastigotes by exerting oxidative stress and DNA damage. In sum, SVE can be explored as an immunotherapeutic candidate against leishmaniasis and other infectious diseases.     

In vitro antimicrobial and anti-proliferative activities of plant extracts from Spathodea campanulata,Ficus bubu,and Carica papaya

Context African medicinal plants represent a prominent source of new active substances. In this context, three plants were selected for biological investigations based on their traditional uses.

Objective The antimicrobial and anti-proliferative features of three plants used for medicinal purpose were evaluated.

Materials and methods The antimicrobial activities of methanol extracts of Ficus bubu Warb. (Moraceae) stem bark and leaves, of Spathodea campanulata P. Beauv. (Bignoniaceae) flowers, as well as those of Carica papaya Linn. (Caricaceae) latex, were determined using the microbroth dilution method against a set of bacteria and fungi pathogens including: Enterococcus faecalis, Staphylococcus aureus, S. saprophyticus, S. epidermididis, Escherichia coli, Klebsiella pneumonia, Salmonella typhimurium, Candida albicans, and Trichophyton rubrum. The tested concentrations of extracts ranged from 2500.0 to 2.4?μg/mL and MIC values were evaluated after 24?h incubation at 37?°C. Subsequently, MTT assay was used to estimate anti-proliferative activity of these methanol extracts and of F. bubu latex on three human cancer cell lines (U373 glioblastoma, A549 NSCLC, and SKMEL-28 melanoma).

Results The methanol extract of F. bubu stem bark exhibited the highest antimicrobial activity against C. albicans with a MIC value of 9.8?μg/mL, while the F. bubu latex and the methanol extract of F. bubu leaves induced significant anti-proliferative activity against lung (IC₅₀ values of 10 and 14?μg/mL, respectively) and glioma (IC₅₀ values of 13 and 16?μg/mL, respectively) cancer cells.

Conclusion These results indicate that effective drugs could be derived from the three studied plants.     

Cytotoxicity and anti-Leishmania amazonensis activity of Citrus sinensis leaf extracts

Context: Leishmania amazonensis is the main agent of diffuse cutaneous leishmaniasis, a disease characterized by lesional polymorphism and the commitment of skin surface. Previous reports demonstrated that the Citrus genus possess antimicrobial activity.

Objective: This study evaluated the anti-L. amazonensis activity of Citrus sinensis (L.) Osbeck (Rutaceae) extracts.

Materials and methods: Citrus sinensis dried leaves were subjected to maceration with hexane (CH), ethyl acetate (CEA), dichloromethane/ethanol (CD/Et – 1:1) or ethanol/water (CEt/W – 7:3). Leishmania amazonensis promastigotes were treated with C. sinensis extracts (1–525?μg/mL) for 120?h at 27?°C. Ultrastructure alterations of treated parasites were evaluated by transmission electron microscopy. Cytotoxicity of the extracts was assessed on RAW 264.7 and J774.G8 macrophages after 48-h treatment at 37?°C using the tetrazolium assay. In addition, Leishmania-infected macrophages were treated with CH and CD/Et (10–80?μg/mL).

Results: CH, CD/Et and CEA displayed antileishmanial activity with 50% inhibitory activity (IC₅₀) of 25.91?±?4.87, 54.23?±?3.78 and 62.74?±?5.04?μg/mL, respectively. Parasites treated with CD/Et (131.2?μg/mL) presented severe alterations including mitochondrial swelling, lipid body formation and intense cytoplasmic vacuolization. CH and CD/Et demonstrated cytotoxic effects similar to that of amphotericin B in the anti-amastigote assays (SI of 2.16, 1.98 and 1.35, respectively). Triterpene amyrins were the main substances in CH and CD/Et extracts. In addition, 80?μg/mL of CD/Et reduced the number of intracellular amastigotes and the percentage of infected macrophages in 63% and 36%, respectively.

Conclusion: The results presented here highlight C. sinensis as a promising source of antileishmanial agents.     

In vitro assessment of selected Korean plants for antioxidant and antiacetylcholinesterase activities

Context: Antiacetylcholinesterase (AChE) drugs have been a main therapeutic treatment for Alzheimer’s disease because increased AChE levels play a key role in reducing neurotransmission.

Objectives: Extracts from 35 Korean plants were selected and screened for antioxidant and anti-cholinesterase activity to explore new sources derived from Korean natural resources that could be used as AD therapeutic agents.

Materials and methods: The antioxidant effect of extracts from 35 selected Korean plants was determined using two most common free radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS). Additionally, the effect of extracts, identified as antioxidants, on acetylcholinesterase inhibition was assessed by an acetylcholinesterase assay kit.

Results: Out of 36 extracts of 35 plants tested, Oenothera biennis L. (9.09?μg/mL), Saururus chinensis (Lour.) Baill. (9.52?μg/mL) and Betula platyphylla var. japonica (9.85?μg/mL) showed strong DPPH scavenging activity. Twelve other extracts also exerted moderate free radical scavenging activities with IC₅₀ values ranging from 10 to 50?μg/mL. Antioxidant capacity detected by ABTS assay was only significant in O. biennis (23.40?μg/mL), while the other extracts were weak or unable to reduce the production of ABTS. Based on the antioxidant activities of these plant extracts, 19 extracts with IC₅₀ values less than 100?μg/mL in DPPH assay were selected for further AChE inhibition assay. Among the extracts tested, the IC₅₀ value for Prunella vulgaris var. lilacina NAKAI (18.83?μg/mL) in AChE inhibitory activity was the lowest, followed by O. biennis (20.09?μg/mL) and Pharbitis nil Chosy (22.79?μg/mL).

Conclusions: Considering complex multifactorial etiology of AD, the extracts of P. vulgaris var. lilacina (aerial part), O. biennis (seed) and P. nil (seed) may be safe and ideal candidates for future AD modifying therapies.     

Antioxidant and anti-cholinesterase activity of Sargassum wightii

Abstract

Context. Sargassum has been used in traditional Chinese medicine since the eighth century AD to treat goiter. Sargassum wightii Greville (Sargassaceae) is a major source of alginic acid used widely in food and drug industries.

Objective: To evaluate the anti-Alzheimer potential of S. wightii through evaluation of antioxidant and cholinesterase inhibitory activities.

Materials and methods: Successive extraction was done using solvents of varying polarity. Solvent extracts (100–500?µg/mL) were employed for all the antioxidant assays. Free radical scavenging activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl, OH?, H₂O₂ radical scavenging assay. The reducing power of the seaweed was evaluated by ferric reducing antioxidant power and reducing power assay. Cholinesterase (ChE) inhibitory activity was evaluated and the Km, Vmax and Ki were calculated. Further, compound characterization was done by GC-MS analysis.

Results: The non-polar extracts were found to possess significant antioxidant activity. At 100?μg/mL, petroleum ether, hexane, benzene and dichloromethane extracts showed significant ChE inhibitory activity with IC₅₀ values of 19.33?±?0.56, 46.81?±?1.62, 27.24?±?0.90, 50.56?±?0.90?µg/mL, respectively, for AChE, and 17.91?±?0.65, 32.75?±?1.00, 12.98?±?0.31, 36.16?±?0.64?µg/mL, respectively, for BuChE. GC-MS reveals that 1,2-benzenedicarboxylic acid, diisooctyl ester is the major compound present in dichloromethane extract of S. wightii. The mode of inhibition exhibited by dichloromethane extract against the cholinesterases was found to be competitive type.

Discussion and conclusion: The presence of high amount of terpenoids could be the possible reason for its potential antioxidant and ChE inhibitory activity.