Anti-leukemic activity of Satureja bachtiarica occurs by apoptosis in human cells.

Failure of apoptosis contributes to leukemia progression. We investigated extracts of a native Iranian plant, Satureja bachtiarica, for possible anti-leukemia activity by induction of apoptosis and changes to the cell cycle. Growth inhibition caused by aqueous, butanol, dichloromethane and hexane extracts of S. bachtiarica on K562 and Jurkat leukemia cells was assessed using a colorimetric assay. Extracts were analyzed for induction of apoptosis and cell cycle arrest using flow cytometry and measurement of caspase-3 activity. Dichloromethane and hexane extracts inhibited leukemia cell proliferation in a dose-dependent manner. The IC50 values of these extracts were 22-33 µg/ml. Flow cytometric determination of annexinV/propidium iodide positive cells verified a significantly increased percentage of apoptotic cells compared to negative controls. Both 50 µg/ml dichloromethane and hexane extracts induced apoptosis in 89-97% of K562 and 94-97% of Jurkat cells 48 h after treatment. The effects of extracts on the cell cycle included significantly increased numbers of K562 and Jurkat cells in the subG1 phase and decreased numbers of cells in the G1, S and G2/M phases. After 24 h, we found increased levels of caspase-3 activation in cells treated with 25 µg/ml dichloromethane and hexane extracts compared to untreated cells. Our findings indicate the anti-leukemic effects of dichloromethane and hexane extracts of S. bachtiarica due to induction of apoptosis and inhibition of cell cycle progression.

Tumor Cell Death via Apoptosis and Improvement of Activated Lymphocyte Cytokine Secretion by Extracts from Euphorbia Hebecarpa and Euphorbia Petiolata.

Background: Immunomodulatory materials from natural herbs and the characterization of their immune enhancement effects may have tremendous potential as cancer treatment. The aim of the present study was to investigate the apoptosis-inducing activities of Euphorbia hebecarpa Boiss and Euphorbia petiolata Banks & Sol. plant extracts and their effects on cytokine secretion by lymphocytes. Materials and Methods: We assessed the apoptosis-inducing effect of the plants' hexane extracts on previously determined sensitive cell lines (HeLa for E. hebecarpa and K562 for E. petiolata) by flow cytometry and measurement of caspase 3 activation. The apoptosis-related gene expressions were examined by real-time PCR. The effects of the extracts on lymphocyte proliferation and cytokine secretion were examined. Results: Flow cytometry analysis showed that the inhibitory effect of the extracts on tumor cell growth was due to cell apoptosis. The plant extracts at the 100 µg/ml dose induced apoptosis in HeLa (98.5 ± 0.1%) and K562 (57.7 ± 1.9%) cells. The extracts increased caspase 3 activation (≈2-fold>control). Real-time PCR showed Fas and Bax gene upregulation and Bcl-2 downregulation, which resulted in an increased Bax/Bcl-2 expression ratio. The extracts increased lymphocyte proliferation and increased levels of IFN-γ production in the presence and absence of mitogen (p < 0.05). They significantly increased IL-4 and decreased IL-10 secretion by mitogen-stimulated lymphocytes. E. hebecarpa also increased IL-17 release. Conclusion: These results have shown that both extracts possess antitumor activity by inducing apoptosis, possibly through both intrinsic and extrinsic pathways. In addition, they induced secretion of different T helper subset related cytokines that are effective in the immune response against cancer.

Modulation of in vitro proliferation and cytokine secretion of human lymphocytes by Mentha longifolia extracts.

OBJECTIVE: Mentha longifolia L. Hudson has been used in folk medicine for various purposes especially for its anti-inflammatory effects. Lymphocytes play a central role in development of inflammation. In the present study, we investigated the immunomodulatory effects of different extracts of M. longifolia on human peripheral blood lymphocytes (PBLs), as main players in development of inflammation. MATERIALS AND METHODS: PBLs stimulated with phytohemagglutinin (PHA) were cultured in the presence of the plant extracts. The effects of the extracts on activation of cells were determined by BrdU assay. The viability of cells was examined by flow cytometry using propidium iodide staining. Also, IFN-γ (T helper 1, TH1) and IL-4 (TH2) secretion was measured by ELISA. RESULTS: Except for the water extract which had a weak inhibitory effect, treatment of cells with more than 1µg/ml of butanol, hexane, ethyl acetate and dichloromethane extracts resulted in strong inhibition of cells proliferation (IC50 4.6-9.9 µg/ml). Flow cytometry analysis showed that these extracts at ≤10µg/ml were non-cytotoxic. Dichloromethane and ethyl acetate extracts at 10 µg/ml decreased IFN-γ production in a dose-dependent manner from 919±91.1 pg/ml in PHA-only-treated cells to 568±22.6 pg/ml (in dichloromethane-treated cells) and 329±12.3 pg/ml (in ethyl acetate-treated cells) (p<0.001). At 10 µg/ml, the ethyl acetate extract increased IL-4 secretion compared to PHA-only-treated cells (p<0.05). The hexane extract decreased IFN-γ level but did not affectIL-4 production. CONCLUSION: Reduction of IFN-γ and augmentation of IL-4 secretion induced by the extracts suggested the potential of M. longifolia to inhibit TH1 inflammatory responses toward a TH2 dominant response.

Augmentation of lymphocytes activation and T cell modulation by the extracts from some Euphorbia species.

CONTEXT: Euphorbia is an important Euphorbiaceae genus that is traditionally being used for various infections, inflammation, and cancer. OBJECTIVE: The present study investigated the possible in vitro immunomodulatory effect of three species of Euphorbia genus including Euphorbia microciadia Boiss, Euphorbia osyridea Boiss, and Euphorbia heteradenia Jaub. & Sp. on lymphocyte activation and cytokine secretion. MATERIALS AND METHODS: Human lymphocytes were cultured in the presence of various concentrations (0.1-200 µg/ml) of the butanol/hexane extracts of the plants in the presence or absence of phytohemmagglutinin (PHA). The activation of lymphocytes after 48 h was determined by a proliferation assay. The release of T cell cytokines was studied to determine the dominant T cell subsets involved in the immune response. RESULTS: All three plant extracts increased the proliferation of PHA-treated lymphocytes (maximum; 132% of control). Extract treatment of lymphocytes in the absence of PHA resulted in an increased proliferation of the cells indicating their lymphocyte mitogenic activity (maximum at 10 µg/ml E. microciadia extract; 494.5 ± 42.2% of control, p < 0.01). The extracts of E. microciadia and E. osyridea could increase IL-4 and IL-10 secretion but not IFN-γ production showing their capacity to deviate immune response toward a Th2 pattern. Euphorbia heteradenia did not change the release of IL-4 and IFN-γ cytokines but increased IL-10 production. The three extracts stimulated lymphocytes to produce IL-17 which showed their possible effects on Th17 cells activation. CONCLUSION: The studied extracts had the ability to modulate T cell responses suggesting their possible beneficial effects on immune host defense.

Inhibition of nitric oxide production and proinflammatory cytokines by several medicinal plants.

BACKGROUND: A number of medicinal plants have been used to treat various immunological diseases. Nitric oxide (NO) has an important regulatory role in the various types of inflammatory processes. OBJECTIVE: To investigate the NO modulatory activity of the extracts of several medicinal plants native to Iran including Dracocephalum kotschyi, Linum persicum, Dionysia termeana, Salvia mirzayanii, Ferulago angulata and Euphorbia cheiradenia. METHODS: The methanolic extracts of the plants were prepared and examined for their effects on the NO production by lipopolysaccharide-stimulated mouse macrophages. The level of TNF-α and IL-1ß pro-inflammatory cytokines in the macrophage culture were detected using enzyme-linked immunosorbent assay. RESULTS: All the extracts at concentration of 50 µg/ml demonstrated a significant decrease in NO production (p<0.001) after a 24-hour treatment. This inhibitory effect was also seen after 48 hours. Among the extracts, L. persicum was the strongest extract in reducing the NO production at 1 µg/ml after both 24 and 48-hours (nearly 100% inhibition, p<0.001). S. mirzayanii extract with 66.2 ± 8% inhibition at 50 µg/ml, showed the mildest effects in 48 hour culture. In cytokine release determination, the extract of L. persicum significantly inhibited both TNF-α and IL-1ß cytokines production by stimulated macrophages (p<0.001). D. kotschyi, D. termeana and F. angulata decreased secretion of IL-1ß from the cells. CONCLUSION: These results indicate the presence of anti-inflammatory and macrophage inhibitory substances in these plants.

Inhibition of tumor cells growth and stimulation of lymphocytes by Euphorbia species.

Plants have been shown to possess a number of beneficial anticancer and immunomodulatory properties. In this study the possible in vitro antitumor activity and immunomodulatory effects of five species of Euphorbia, an important genus of Euphorbiaceae, including E. petiolata, E. hebecarpa, E. osyridea, E. microciadia, and E. heteradenia were investigated using cytotoxicity and cell proliferation assays. Among different tumor cell lines, the most sensitive cell line to methanolic extracts of the plants was determined as follows. Hela cervical cancer cells to E. hebecarpa and E. microciadia, K562 leukemia cells to E. petiolata and E. heteradenia, and Fen bladder cancer cells to E. osyridea. The methanolic extracts were then fractionated into hexane, n-butanol, ethyl acetate, and water and the effect of these fractions was tested for cytotoxic activity on the selected cell lines. The results indicated the significant stronger antiproliferatory effect of the hexane factions in all the plants when compared with other ones. The methanolic extracts of the plants were also studied for their effects on the activation of the lymphocytes. All of the extracts showed stimulatory effects on the proliferation of the lymphocytes at lower concentrations. After further fractionation of the extracts, the butanolic and hexane fractions showed the highest activity on the lymphocyte activation. In conclusion, all the plants studied had the capacity to inhibit proliferation of tumor cells with beneficial immunomodulatory effects on the lymphocytes. This dual effect of the plants indicates their value for further investigations as antitumor agents.