In vitro modulation of oxidative burst via release of reactive oxygen species from immune cells by extracts of selected tropical medicinal herbs and food plants

Department of Health Sciences, Faculty of Science, University of Mauritius, Reduit, Mauritius.
Asian Pacific Journal of Tropical Medicine (Impact Factor: 0.93). 06/2012; 5(6):440-7. DOI: 10.1016/S1995-7645(12)60075-3
Source: PubMed


To evaluate in vitro immunomodulating properties and potential cytotoxicity of six tropical medicinal herbs and food plants namely Antidesma madagascariense (Euphorbiaceae) (AM), Erythroxylum macrocarpum (Erythroxylaceae) (EM), Faujasiopsis flexuosa (Asteraceae) (FF), Pittosporum senacia (Pittosporaceae) (PS), Momordica charantia (Cucurbitaceae) (MC) and Ocimum tenuiflorum (Lamiaceae) (OT).
Initially, the crude water and methanol extracts were probed for their capacity to trigger immune cells' NADPH oxidase and MPO-dependent activities as measured by lucigenin- and luminol-amplified chemiluminescence, respectively; as compared to receptor-dependent (serum opsonised zymosan- OPZ) or receptor-independent phorbol myristerate acetate (PMA).
Preliminary screening on whole human blood oxidative burst activity showed significant and concentration-dependent immunomodulating properties of three plants AM, FF and OT. Further investigations of the fractions on isolated human polymorphonuclear cells (PMNs) and mice monocytes using two different pathways for activation of phagocytic oxidative burst showed that ethyl acetate fraction was the most potent extract. None of the active samples had cell-death effects on human PMNs, under the assay conditions as determined by the trypan-blue exclusion assay. Since PMA and OPZ NADPH oxidase complex is activated via different transduction pathways, these results suggest that AM, FF and OT does not affect a specific transductional pathway, but rather directly inhibit a final common biochemical target such as the NADPH oxidase enzyme and/or scavenges ROS.
Our findings suggest that some of these plants extracts/fractions were able to modulate significantly immune response of phagocytes and monocytes at different steps, emphasizing their potential as a source of new natural alternative immunomodulatory agents.

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Available from: Ahmed M Mesaik, Oct 08, 2015
    • "Spices are basic ingredients in most of the dishes in Mauritius. Also, to treat minor ailments, several kinds of extracts from several endemic, exotic and indigenous plants are sold as decoctions or 'tisanes' in the Mauritian markets [4] . There is at present increasing interest both in the industry and in scientific research for spices and aromatic herbs because of their strong antioxidant and antimicrobial properties, which exceed many currently used natural and synthetic antioxidants. "
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    ABSTRACT: Objective: To investigate the in vitro antioxidant and antimicrobial activities along with phytochemical screening of organic and aqueous extracts of spices used in Mauritian foods. Methods: Antioxidant activity of the crude extracts was evaluated in terms of total antioxidant capacity, total phenol content and total flavonoid content. The antimicrobial activity of the spices was determined by the agar well diffusion method against a gram positive and a gram negative bacteria. The qualitative and quantitative phytochemical screening were carried out by standard biochemical assays. Results: All six spices were found to possess alkaloids, coumarins, flavonoids, saponins, steroids, tannins and phenols. Total phenolic content of the extracts varied between 177 and 1 890 mg GAE/g DW while the total flavonoid content varied between 2.8 and 37.6 mg QE/g DW. All six spices were found to possess strong antioxidant properties as well. Highest value was obtained for cinnamon [(24.930±0.198) μmol Fe2+/g DW] whilst turmeric showed the lowest antioxidant activity [(5.980±0.313) μmol Fe2+/g DW] (P<0.05). All extracts showed promising activity against Staphylococcus aureus and Escherichia coli. The size of the inhibition zones ranged between (11.20±0.23) mm to (26.10±2.09) mm (P<0.05) with turmeric and cinnamon being the most effective against Staphylococcus aureus while garlic was least effective against both E. coli and S. aureus. Conclusions: The present study reveals the presence of potential antioxidant and antimicrobial properties in the extracts of the spices which could be further exploited.
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    • "Considering the wealth of literature available that have linked the antioxidant properties of plants to their therapeutic and protective effects in many diseases as well as in the stimulation of the immune system against infectious attacks (Arthan et al., 2002; Mahomoodally et al., 2012 and Djoukeng et al., 2005), the marked antioxidant activity of PM extract would further substantiate the use of this plant in the local pharmacopeia in the treatment of common infectious diseases in terms of a stimulator of the immune system. "
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    ABSTRACT: Several plants of the Mauritian flora alleged to possess anti-infective properties were studied against different strains of pathogenic bacteria and fungi. The grounded dried plant materials were extracted with different extractants and screened for anti-microbial activity using the disk diffusion and the micro-dilution techniques. Preliminary screening revealed that the methanol extracts were most active. Salmonella enteritidis, Enterobacter cloacae and Bacillus subtilis were the three test organisms, which were found to be susceptible to all the crude methanolic extracts of the different plants investigated (100% susceptibility), followed by Escherichia coli (57.1%) and Pseudomonas aeruginosa (57.1%), and Staphylococcus aureus (28.6%). The lowest minimum inhibitory concentration recorded for the different crude methanol extracts against Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Enterobacter cloacae, Bacillus subtilis and the mould fungus Candida albicans were 500, 1000, 125, 250, 1000 and 125 g/ml, respectively. Bioautography using Cladosporium cucumerinum revealed that dichloromethane (DCM) extracts had the highest activity against the phytopathogenic fungus. It was also noted that the DCM extracts of Michelia champaca and Antidesma madagascariense yielded the maximum number of growth inhibiting compounds against Cladosporium cucumerinum. Activity of the different crude extracts was also investigated against several phytopathogenic filamentous fungi, Colletotrichum glocosporoides, Rhizoctonia solani, Sclerotinia sclerotium, Guignardia sp. and Fusarium oxysporum. It was found that crude hexane extracts as well as crude DCM extracts exhibited marked activity against several strains of fungi, especially Colletotrichum glocosporoides, Sclerotinia sclerotium and Guignardia sp.
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    ABSTRACT: We investigated a physiological function by fermenting a medicinal mushroom, (Cudrania tricuspidata fruit). A fermentation using lactic acid bacteria and the extracts isolated from 70% ethanol fractionation was included in cultured mouse spleen cells for cytokine secretion. As a result, total polyphenol content improved by 47% by organic acid fermentation. This was regarded as immune activity in fermented C. tricuspidata fruits, as the levels of interleukin (IL)-2 and IL-4 secretion increased. In addition, when the extracts were treated with a stimulant lipopolysaccharide, the secretion of helper T (Th) 1 cytokines IL-2, IL-12, and tumor necrosis factor- was suppressed, while the secretion of Th2 cytokines IL-4, IL-5, IL-6, and IL-10 significantly increased. Therefore, this study suggests that fermentative C. tricuspidata fruit extracts can contribute to the suppression of cellular immune reactions induced by the expression of Th1 cells and activation of the expression of Th2 cells inducing humoral immune reactions associated with the antibody generation by B lymphocytes.
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