Article

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

ABSTRACT 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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    • "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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    • "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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