Immunomodulatory effects and structure-activity relationship of botanical pentacyclic triterpenes: A review.

Botanical pentacyclic triterpenes possessed a broad range of pharmacological activities such as anti-oxidant, anti-tumor, anti-microbial and anti-inflammatory activities. It is believed that the mechanisms involved in these bioactivities are due to the modulation of immune system. Recently, the pharmacological validation on immunomodulatory of pentacyclic triterpenes derived from higher plants is very limited and several existence review papers related for this group of compound have not been focused for this activity. In this review, we have highlighted several studies on immunomodulatory potential of botanical pentacyclic triterpenes isolated from wide array of different species of medicinal plants and herbs based on various preclinical in vitro and animal models. This review also attempts to discuss on bioactivities of compouns related with their structure-activity relationship. Hence, the evaluation of pentacyclic triterpenes offers a great opportunity to discover adjuvants and novel therapeutic agents that presented beneficial immunomodulatory properties.

Inhibition of chemiluminescence and chemotactic activity of phagocytes in vitro by the extracts of selected medicinal plants.

The methanol extracts of 20 selected medicinal plants were investigated for their effects on the respiratory burst of human whole blood, isolated human polymorphonuclear leukocytes (PMNs) and isolated mice macrophages using a luminol/lucigenin-based chemiluminescence assay. We also tested the effect of the extracts on chemotactic migration of PMNs using the Boyden chamber technique. The extracts of Curcuma domestica L., Phyllanthus amarus Schum & Thonn and C. xanthorrhiza Roxb. were the samples producing the strongest oxidative burst of PMNs with luminol-based chemiluminescence, with IC(50) values ranging from 0.5 to 0.7 µg/ml. For macrophage cells, the extracts which showed strong suppressive activity for luminol-based chemiluminescence were C. xanthorrhiza and Garcinia mangostana L. Among the extracts studied, C. mangga Valton & Vazsjip, Piper nigrum L. and Labisia pumila var. alata showed strong inhibitory activity on lucigenin-amplified oxidative burst of PMNs, with IC(50) values ranging from 0.9 to 1.5 µg/ml. The extracts of Zingiber officinale Rosc., Alpinia galangal (L.) Willd and Averrhoa bilimbi Linn showed strong inhibition on the chemotaxic migration of cells, with IC(50) values comparable to that of ibuprofen (1.5 µg/ml). The results suggest that some of these plants were able to modulate the innate immune response of phagocytes at different steps, emphasizing their potential as a source of new immunomodulatory agents.