Correlation between the major components of Phyllanthus amarus and Phyllanthus urinaria and their inhibitory effects on phagocytic activity of human neutrophils

Abstract

BackgroundRecently, we have highlighted the immunomodulatory activity of the standardized extracts of Phyllanthus amarus and P. urinaria. The present study was carried out to correlate between the prevalent constituents of the herbs and their inhibitory effects on phagocytic activity of human neutrophils.MethodsThe compounds, gallic acid, ellagic acid, corilagin, geraniin, phyllanthin and hypophyllanthin were identified and quantitatively analyzed in the extracts of Phyllanthus amarus and P. urinaria obtained from Malaysia and Indonesia by using a validated reversed phase high performance liquid chromatography (RP-HPLC) method. The standardized extracts and the pure compounds were evaluated for their effects on chemotaxis, β2 integrin (CD18) expression, phagocytosis and chemiluminescence of human phagocytes. Chemotactic activity was assessed using the Boyden chamber technique, inhibition of CD18 expression and phagocytic ability were tested with the aid of flow cytometry, while effect on the respiratory burst was investigated using a luminol-based chemiluminescence assay.ResultsAll plant extracts strongly inhibited migration of the phagocytes with the Malaysian P. amarus depicting the highest inhibitory activity. Amongst the compounds tested, geraniin demonstrated the strongest inhibitory activity on chemotaxis of polymorphonuclear leukocytes (PMNs) and monocytes with IC50 values of 1.09 and 1.69 μM, respectively, which were lower than that of ibuprofen. All plant extracts and pure compounds exhibited high inhibitory activity on the oxidative burst of zymosan and PMA stimulated leukocytes. Geraniin and corilagin exhibited exceptionally strong inhibition on the reactive oxygen species (ROS) activity with IC50 values lower than aspirin. The plant extracts exhibited moderate inhibition of E. coli uptake by monocytes but weak effect on PMNs. Of all the compounds, phyllanthin at 50 μg/mL exhibited the highest engulfment inhibitory activity with percentage of phagocytizing cells of 14.2 and 27.1% for PMNs and monocytes, respectively. All plants and compounds tested possessed weak effect on CD18 expression on leukocytes except for hypophyllanthin and phyllanthin which exhibited significant inhibitory effect.ConclusionThe strong inhibition of the extracts on the phagocytic activity of neutrophils was due to the presence of their major constituents especially geraniin, corilagin, phyllanthin and hypophllanthin which were able to modulate the innate response of phagocytes at different steps.

Inhibitory Effects of the Standardized Extract of Phyllanthus amarus on Cellular and Humoral Immune Responses in Balb/C Mice

“…The lignans and phenolic compounds in the 80% ethanol extract of P. amarus including phyllanthin, hypophyllanthin, gallic acid, ellagic acid, corilagin and geraniin were identified and quantified by reversed phase HPLC method as previously reported (Jantan et al 2014). Representative HPLC chromatograms of P. amarus for identification of the lignans and phenolic compounds are shown in Fig.…”

“…In addition to HPLC analysis, phyllanthin and hypophyllanthin were also isolated and identified spectroscopically. -2014- -MAY-2015. During the experiment, animals were housed in a well-ventilated controlled room on a 12 h light/12 h dark schedule at room temperature.…”

“…A voucher specimen (No UKMB 30078) of the plants was authenticated by Dr Abdul Latif Mohamad of Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM) and deposited at the UKM herbarium. The 80% ethanol extract was prepared as described previously (Jantan et al, 2014). The extract was resuspended in 5% Tween 20 solution before being orally administered to mice.…”

“…In our previous study, it was established that the standardized extract of P. amarus and their major constituents including phyllanthin, hypophyllanthin, gallic acid, geranin, corilagin and ellagic acid suppressed the in vitro chemotactic migration as well as phagocytic ability of phagocytes and suppressed the release of reactive oxygen species (ROS) by granulocytes (Jantan et al, 2014). We also observed that the 80% ethanol extract of P. amarus was able to inhibit migration and phagocytosis of leukocyte and Mac-1 expression in granulocytes isolated from treated Wistar-Kyoto rats.…”

4,5,4′-Trihydroxychalcone, 8,8′-(ethene-1,2-diyl)-dinaphtalene-1,4,5-triol and rutin from Gynura segetum inhibit phagocytosis, lymphocyte proliferation, cytokine release and nitric oxide production from phagocytic cells

“…PMNs was isolated from the whole blood by Ficoll gradient separation whereas the isolation of peripheral blood monocytes (PBMCs) and peripheral blood lymphocytes were performed by using lymphoprep as described previously [13, 14]. Then, number of monocytes and lymphocytes were adjusted to 5 × 10 5 cells/mL whereas PMNs was adjusted to 1 × 10 6 cells/mL.…”