Chemical composition, antioxidant effects and antimicrobial activities of some spices’ essential oils on food pathogenic bacteria

Thymus vulgaris, Cinnamomum zeylanicum and Ocimum gratissimum are spices widely used as aroma enhancers and food preservatives. This work assessed the chemical composition, antioxidant and antimicrobial effect of their essential oils on some food pathogenic bacteria, namely, Staphylococcus aureus, Citrobacter freundii, Enterobacter cloacae, Morganella morganii, Escherichia coli, Salmonella typhimurium, Proteus vulgaris and Shigella flexineri. After chemical analyses of the essential oils by gas chromatography and gas chromatography coupled to mass spectroscopy, the antimicrobial effects were subsequently assessed by disk and microdilution methods, while the antioxidant evaluations were performed by free radical scavenging activity. T. vulgaris essential oil composed of p-cymene (45.90%) and thymol (23.72%) which exhibited the highest inhibitory diameters of 20.33±0.58 and 18.00±1 mm, respectively, on the growth of S. aureus and C. freundii. O. gratissimum essential oil with thymol as major compound (47.11%) was more active to inhibit the growth of C. freundii and S. flexineri with respective inhibitory diameters of 18±1.73 and 16±2 mm. Essential oil from dry leaves of C. zeylanicum containing cinnamaldehyde (82.23%) and linalool (12.12%) was found to have the lowest values for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) (≤3.53 mg/mL)considering the growth of S. flexineri, C. freundii and E. cloacae. Regarding the antioxidant effect, C. zeylanicum and T. vulgaris essential oil showed the most scavenging effect with half-maximal DPPH scavenging concentration (SC50) of 2.5 × 10-5 and 6.5 × 10-5 mg/ml, respectively. Their antioxidant effects were higher than conventionally used antioxidants in food products, butylhydroxyltoluene (BHT) and vitamin C.Key words: Spices, essential oils, chemical composition, antibacterial and antioxidant effects

Effect of Four Essential Oils on Cells Release Membrane and Biofilm Formation of Clinical Bacterial Isolated From Oral Infection

Background: Bacterial biofilms forming are current resistant bacterial form to the treatment of oral diseases that colonizes in the gingival and sub-gingival regions of the mouth. The present study aims to screen the anti-biofilm potential and evaluate the effect of four essential oils on cells release membrane. Methods: Seven type isolate bacteria obtained during previous work were screen to select those who had ability to form biofilm using Congo Red Agar method, tube method and crystal violet method. The inhibitory parameter of biofilm forming was determine using microtiter plate method. The effect of essential oil on cell membrane release of each selected bacterial was put in evidence by measuring cellular material that absorb at 260 nm and 280 nm after 0 min, 30 min and 60 min of exposure and confirm by measuring DNA, RNA and proteins release by treated cells on extracellular medium using Nanodrop 1000 spectrophotometer. Results: The crystal violet method shows twelve (12) strong, five (05) moderate and five (05) weak biofilm forming bacteria. The anti-biofilm activity against the oral bacteria who shown that most of essentials oils have activity on different biofilm formation and the MICs ranged from 0.31 mg/mL to 1.25 mg/mL. Concentration of intracellular material released in extracellular medium ranged from 186,56 ± 2,35 ng/µL to 766,6 ± 2,84 ng/µL for DNA, 158,06 ± 1,87 ng/µL to 628,53 ± 2,05 ng/µL for RNA and 695,9 ± 2,11ng/µL to 1125,23 ± 2,15 ng/µL for proteins. Conclusion: This study demonstrates that the selected EOs have a significant anti-biofilm activity, acting on the cell surface and causing the disruption of the bacterial membrane. These EOs are interesting alternative to conventional antimicrobials for the control of oral microorganisms. Keywords: Anti-biofilm activity, Biofilm, oral disease

Activité antioxydante des extraits méthanoliques de Phragmanthera capitata (Loranthaceae) récoltée sur Citrus sinensis

Objectif : Évaluer les teneurs en phénols totaux et l’activité antioxydante in vitro des extraits méthanoliques de Phragmanthera capitata (Loranthaceae) utilisé traditionnellement pour le traitement de nombreuses maladies liées au stress oxydatif chez l’homme.Méthodologies et résultats : La teneur en phénols totaux a été déterminée par la méthode de Folin-Ciocalteu et l’activité antioxydante par deux méthodes : le piégeage des radicaux libres du DPPH et la réduction du fer FRAP. L’extrait méthanolique des tiges contient une teneur plus élevée en phénols totaux (445,2 mg EAA/g ES) suivi de l’haustorium (138,1 mg EAA/g ES) et des feuilles (78,6 mg EAA/g ES). La capacité de piégeage du DPPH de l’extrait des feuilles est moins active que ceux de l’haustorium et des tiges. Le pouvoir réducteur de l’extrait des tiges est élevé comparé à celui des feuilles et de l’haustorium.Conclusions et applications : L’activité antioxydante des extraits de P. capitata récoltée sur citrus sinensis mis en évidence dans cette étude pourrait justifier les usages traditionnels de cette plante afin de développer de nouveaux composés bioactifs.Mots clés : Phragmanthera capitata, phénols totaux, DPPH, FRAP, activité antioxydante, Loranthacea

Chemical composition of essential oils of Eugenia caryophylla and Mentha sp cf Piperita and their in vitro antifungal activities on six human pathogenic fungi

Background: Many fungal infections are responsible for human skin damages, to control their negative action, some aromatic and medicinal plants are traditionally used by local population in Cameroon. The present study was carried out to determine the chemical composition of essential oils of Eugenia caryophylla and Mentha sp cf piperita and their antifungal activity on some human pathogenic fungi.Materials and methods: Essential oils from Eugenia caryophylla and Mentha sp cf piperita were extracted by steam distillation using Clevenger apparatus and the antifungal activity was evaluated on six human pathogenic fungal strains; two yeasts (Candida albicans 1 and Candida albicans 2) and four dermatophytes (Tricophyton rubrum 1, T. rubrum 2, T. violaceum, and T. soudanensis) using modified broth microdilution method M27-A3 and M38-A respectively.Results: The essential oils obtained yielded of 5.9 for Eugenia caryophylla and 0.2% Mentha sp cf piperita respectively. The chemical composition was assigned by GC and GC/SM and showed that E. caryophylla was mainly composed of eugenol (80.0 %), E-caryophyllene (8.3%), and eugenol acetate (6.7%) while Mentha sp cf piperita was characterized by piperitone (67.5 %), menthol (10.0 %) and ß-phellandrene (5.8%). The result showed that essential oil of E. caryophylla exhibit the highest antifungal activity with MICs and MFC of 0.25μL/mL and 0.125μL/mL for filamentous fungi and MIC of 0.5 μL/mL for both yeast strains while MFC value was 1 μL/mL for one yeast strain and not determined for the second. MFCs Mentha sp cf piperita essential oil showed a weak activity with a MIC of 2.5 μL/mL on Tricophyton strains while no activity was exhibited on Candida albicans strains.Conclusion: The results of this work can be used to confirm their traditional uses and can also be proposed as natural ingredients to some industries to treat superficial infections.Keys words: Essential oil, Eugenia caryophylla, Mentha sp cf piperita, antifungal activity, Human pathogenic strains, fungistatic and fungicide

Identification and phytochemical screening of Endophytic fungi from stems of Phragmanthera capitata (Sprengel) S. Balle (Loranthaceae)

Objective: The purpose of this study was to identify some endophytic fungi, which were associated with the stems of Phragmanthera capitata (Loranthaceae), and to determine the phytochemical composition of their extracts.Methodology and results: The isolation of endophytic fungi was made on PDA medium (Potato dextrose agar) and the identification was based on macroscopic and microscopic observations of the different strains isolated and using identification keys. The qualitative phytochemical analysis of acetate ethyl extracts of the endophytes was carried out using standard procedures. Eleven fungi species belonging to 4 genera were isolated: Aspergillus (06 species), Penicillium (03), Trichoderma (01) and Fusarium (01). The phytochemical analysis revealed the presence of flavonoids, anthroquinones, tannins, phenols, steroids, coumarins and terpenoids and absence of alkaloids and saponins in all the extracts.Conclusion and application of results: The study shows that endophytic fungi of P. capitata could be a potential source of new bioactive compounds, which can be used in the fields of health and agriculture

The anti-arthritic and anti-inflammatory activities of aqueous extract powder bark of Anthocleista schweinfurthii Gilg (Loganiaceae)

  Aqueous extract bark of Anthocleista schweinfurthii (ASE) was investigated for anti-arthritic, anti-inflammatory activities and phytochemicals screening. Phytochemical screening was carried out according, to LC-MS procedures, the anti-inflammatory effect of ASE was evaluated in vitro inhibition of 15-lipoxygenase (15-LOX) enzyme and  proteinase inhibiting action assays. The anti-arthritic activity was performed according to the Bovine Serum Albumin (BSA) test. The chemical composition of ASE showed that it was mainly composed of isocyanate, biphenyltriol, methoxyflavanone, soscoparin and glucopyroside. In the anti-inflammatory assays, ASE showed selective inhibition of 15-lipooxygenase with IC50 value of and moderate activity against the inhibition of proteinase action with IC50 value of L. Both the methods  showed that the ASE posses good anti-inflammatory activity. ASE had strong in vitro anti-arthritic activity with IC50 of , the positive control Diclofenac had IC50 value of  The result of this study justified the use of this plant in traditional Cameroonian medicine in the treatment of inflammation. ASE may offer a new source of potential therapeutic agents for the effective treatment of arthritis and inflammation.    Keywords: Anthocleista schweinfurthii, phytochemical screening, anti-arthritic activity, anti-inflammatory activity,    &nbsp

IN VITRO ANTIOXIDANT AND ANTI-INFLAMMATORY ACTIVITIES OF ALCHORNEA CORDIFOLIA (SCHUMACH AND THONN.) MULL. ARG. AND ANTROCARYON KLAINEANUM PIERRE EXTRACTS

Objective: This study aims to evaluate the in vitro antioxidant, anti-inflammatory activities of the aqueous and hydroethanolic extracts recipe of Alchornea cordifolia and Antrocaryon klaineanum. A preliminary phytochemical screening was carried out. Methods: The total phenols content was determined by the Folin Ciocalteu reagent method, while the antioxidant activity of both extracts was characterized by the 2-2diphenyl-1-picrilhidrazil (DPPH) and β-carotene assays. The anti-inflammatory activity of the extracts was evaluated as the inhibition of Bovine Serum Albumin (BSA) denaturation and antiproteinase activity. Results: The aqueous extracts of Alchornea cordifolia and Antrocaryon klaineanum contained more polyphenols [270 mg Ascorbic acid equivalent (AAE)/g dry weight (dw)] than the hydroethanolic recipe extract (262.41 mg AAE/g dw) at the same concentration level. On the other hand, the aqueous and hydroethanolic recipe extract had the same radical scavenging activity with the antiradical power of 0.851 and 0.830, respectively. Similarly, the recipe extract had the same reducing activity with reducing the power of 94.2±2.03 mg EAA/g dw and 97.4±4.16 mg EAA/g dw for the aqueous and hydroethanolic recipe extract of Alchornea cordifolia and Antrocaryon klaineanum respectively. For the anti-inflammatory activity it was observed that both extracts possess the same activity as Diclofenac® with an IC50 of 50.21 μg/ml. The phytochemical screening of the extracts revealed the presence of alkaloids, flavonoids, carbohydrates, phenols and tannins, which may account for their activities. Conclusion: The plant recipe extract studied possess antioxidant and anti-inflammatory potentials, which may be beneficiary to its consumers

Antidiarrheal Activity of Dissotis multiflora

The present work was undertaken to evaluate antidiarrheal activity of ethanolic leaf extract of Dissotis multiflora (Sm) Triana (D. multiflora) on Shigella flexneri-induced diarrhea in Wistar rats and its subacute toxicity. Diarrhea was induced by oral administration of 1.2 × 109 cells/mL S. flexneri to rats. Antidiarrheal activity was investigated in rats with the doses of 111.42 mg/kg, 222.84 mg/kg, and 445.68 mg/kg. The level of biochemical parameters was assessed and organs histology examined by 14 days’ subacute toxicity. S. flexneri stool load decreased significantly in dose-dependent manner. The level of ALT increased (p<0.05) in male rats treated with the dose of 445.68 mg/kg while creatinine level increased in rats treated with both doses. In female rats, a significant decrease (p<0.05) of the level of AST and creatinine was noted in rats treated with the dose of 222.84 mg/kg of D. multiflora. Histological exams of kidney and liver of treated rats showed architectural modifications at the dose of 445.68 mg/kg. This finding suggests that D. multiflora leaf extract is efficient against diarrhea caused by S. flexneri but the treatment with doses lower than 222.84 mg/kg is recommended while further study is required to define the exact efficient nontoxic dose

Studies on dyeing and bacterial resistance of Dacryodes macrophylla extract on woollen fabric

The dyeing of wool fabric using a natural dye extracted from Dacryodes macrophylla has been studied using both conventional as well as ultrasonic dyeing methods. Natural dye was extracted using water as solvent by Soxhlet extraction method. The extracted color was characterized by spectroscopic studies like UV/Visible and further tested for antimicrobial activity (against Vibrio cholerae (MTCC3906), Salmonella enterica serotype typhi (MTCC733), Shigella flexneri (MTCC1457), Escherichia coli (MTCC119), Listeria monocytogenes (MTCC657) and Staphylococcus aureus (MTCC 96). It was observed that the water extract of D. macrophylla showed antimicrobial activities against S. enterica. The effect of mordants on the dyeing outcome in terms of colour depth as well as fastness properties of the dyeing was investigated.&nbsp; It has been found that employing all the three techniques of dyeing i.e., conventional dyeing at 100 oC and 80 oC as well as ultrasonicated dyeings conducted at 80 oC, the mordanted samples were deeper in depth than their unmordanted counterparts. The results of fastness properties of the dyed fabrics were fair to good. Depths of the shade and fastness properties in case of ultrasonic dyeing were found to be better compared to conventional dyeing. Dacryodes macrophyllaextract&nbsp; was found to enhance microbial resistance of wool as well as was itself as a good source of coloration. These textiles dyed with the natural dyes can be very useful in developing clothing for infants, elderly and infirm people to protect them against common infections

BIOACTIVITY OF ESSENTIAL OILS FROM MEDICINAL PLANTS OF CAMEROON AND THEIR COMBINATION AGAINST INFANT DIARRHEA INDUCED BY BACTERIA

Background: In Cameroon, one of the most common childhood illnesses after malaria is diarrhea, which generally has a bacterial origin. In rural areas, plant utilization is often one of the first ways of treatment though, with no scientific bases. Therefore, the aim of this work was to evaluate the antibacterial activities of nine essential oils (EOs) of Cameroonian plants and their combinations against some strains responsible for diarrhea. Material and Methods: To determine the bacterial species generally involved in childhood diarrheal infections, a retrospective study was done. The EOs of Eucalyptus globulus, Cymbopogon citratus, Xylopia aethiopica, Thymus vulgaris, Ocimum canum, Cananga odorata, Citrus medica, Citrus paradisi and Citrus reticulata were screened against the most incriminated bacterial species using the spot-on-agar test and microdilution methods. Some of the EOs with good antibacterial activity were analyzed by Gas Chromatography and Gas Chromatography/Mass Spectrometry. According to their composition, Thymus vulgaris and Eucalyptus globulus EOs were combined with that of Cymbopogon citratus using the ratios 2/1; 1/1; 1/2 (w/w) and tested against on bacterial growth. Results: The retrospective study showed that 10.8% of infant diarrhea was caused by Escherichia coli, Salmonella typhimurium and Salmonella paratyphimurium. The Minimum inhibition Concentrations (MIC) of single EOs was between 0.78 and 25 mg/mL which were observed to be greater than those of their combinations which ranged between 0.195 and 6.52 mg/mL. The active essential oils contained mainly hydrocarbonated and oxygenated monoterpens. Conclusion: The good antibacterial effects of two Thymus combinations Th1 and Th2 observed on Salmonella typhimurium and Salmonella paratyphimurium suggest their used in aromatherapy to cure bacterial diarrhea