Effects of triterpenes on the immune system.
BACKGROUND
Triterpenes, which comprise a broad chemical group of active principles, are implicated in the mechanisms of action and pharmacological effects of many medicinal plants used in folk medicine against diseases in which the immune system is implicated. They have been described as anti-inflammatory, antiviral, antimicrobial, and antitumoral agents, as well as being immunomodulator compounds. Several of them are implicated in the resolution of immune diseases, although their effects have not always been clearly correlated.


OBJECTIVE
The aim of this review is to compile relevant data on the mechanisms of action of triterpenes isolated from active ethnomedicinal plants and their role in the resolution of diseases in which the immune system is implicated to examine the mechanism by which they are useful as ethnopharmacological medicines.


METHODS
The selection of papers was made using the most relevant databases for the biomedical sciences on the basis of their ethnopharmacological use. We principally chose those studies that examined the resolution of allergic responses in vivo and those that studied the effects of the more relevant mediators implicated in the immune response in vitro.


RESULTS
The number of compounds actually studied is limited compared with the high number of principles that have been isolated and identified. Many studies focus on specific pathologies such cancer or inflammation, but in many cases they are clearly correlated with the immune response. Lanostanes, cucurbitanes, and oleananes are probably the most interesting groups; however, other compounds are also of potential importance.


CONCLUSIONS
Studies of specific mechanisms against mediators or transcription factors could be the objective for future research on ethnomedicinal plants used to combat immune diseases since the results obtained with cucurbitacins or derivatives of oleanolic acid support the use of different medicinal plants, thereby opening up a new frontier for future studies.
Ríos
José-Luis
JL
Departament de Farmacologia, Facultat de Farmàcia, Universitat de València, Av Vicent Andrés Estellés s/n 46100 Burjassot, Valencia, Spain. riosjl@uv.es
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D019380:Anti-HIV Agents / Q000494:pharmacology; D006801:Humans; D007107:Immune System / Q000187:drug effects*; D014157:Transcription Factors / Q000037:antagonists & inhibitors; D014315:Triterpenes / Q000494:pharmacology*
D000276:Adjuvants, Immunologic; D019380:Anti-HIV Agents; D014157:Transcription Factors; D014315:Triterpenes