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Immunomodulatory principles of Pelargonium sidoides
Author(s) -
Kayser O.,
Kolodziej H.,
Kiderlen A. F.
Publication year - 2001
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.785
Subject(s) - leishmania , microbiology and biotechnology , biology , gallic acid , leishmania donovani , leishmania major , amastigote , pharmacology , biochemistry , visceral leishmaniasis , leishmaniasis , immunology , antioxidant , parasite hosting , world wide web , computer science
Extracts and isolated constituents (coumarins and phenols) of Pelargonium sidoides DC, a plant species used in folk medicine by the Southern African native population, were evaluated for their effects on nonspecific immune functions. Although this herbal medicine is also successfully employed in modern phytotherapy in Europe to cure infectious diseases of the respiratory tract, the scientific basis of its remedial effects is still unclear. Thus, functional bioassays including an in vitro model for intracellular infection with Leishmania parasites, an extracellular Leishmania growth assay, a fibroblast‐virus protection assay (IFN activity), a fibroblast‐lysis assay (TNF activity) and a biochemical assay for inorganic nitric oxides (iNO) were employed. None of the test samples revealed significant activity against extracellular, promastigote Leishmania donovani , the causative agent of human visceral leishmaniasis. In contrast, apart from the coumarin samples, all the Pelargonium extracts (EC 50 <0.1–3.3 μg/mL), gallic acid (EC 50 4.4 μg/mL) and its methyl ester (EC 50 12.5μg/mL) significantly reduced the intracellular survival of L. donovani amastigotes within murine macrophages. These data indicate that the samples acted indirectly on Leishmania parasites, possibly by activating leishmanicidal macrophage functions. Macrophage activation was confirmed by detection of tumour necrosis factor (TNF‐α) and inorganic nitric oxides (iNO) in supernatants of sample‐treated macrophage cultures. Synthesis of iNO is a well‐known effector mechanism of macrophages against microorganisms such as Leishmania . Interestingly, blocking iNO‐synthase with L‐NMMA had no substantial effect on sample‐induced intracellular Leishmania kill. From bioassay‐guided fractionation, gallic acid and its methyl ester present in large amounts in P. sidoides and in its active extracts, were identified as the prominent immunomodulatory principle for this herbal medicine. The results, when taken together with recent reported antibacterial activity, provide a rational basis for both the traditional and the present utilization of P. sidoides in the claimed conditions. Copyright © 2001 John Wiley & Sons, Ltd.