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Introduction: There are limited studies on the anti-cancer and immunomodulatory effects of the fig fruit latex. In this study, we aimed to investigate the effect of fig fruit latex on several cancer cell lines as well as its effect on lymphocytes proliferation and cytokines secretion. Methods: After preparing a methanolic extract from fig latex, its effect on various cancer cell lines including Fen (bladder cancer), K562 (myeloid leukemia), Hela (cervix carcinoma), Jurkat (lymphoid leukemia) and Raji (lymphoma) was examined by MTT colorimetric assay. For evaluating the effects of extract on lymphocyte proliferation and viability, BrdU assay and flow cytometry staining were used. Cytokine secretion was measured by ELISA assay. Results: The extract showed the strongest activity against K562 cell line (IC50, 234 µg/ml) and the least activity against Hela cells (IC50 >1000 µg/ml). On evaluation of the immunomodulatory effect of fig by BrdU assay, a reduction in lymphocytes proliferation by increasing the concentration of the extract was observed; proliferation index from 1.2±0.06 at 0.1 µg/ml of the extract reached to 0.13±0.2 at 800 µg/ml. In flow cytometry analysis, a significant cytotoxic effect at concentrations ≥400 µg/ml was observed. The extract at 100 and 200µg/ml had the ability to reduce secretion of interferon (IFN)-γ and interleukin (IL)-4 cytokines. Conclusion: Fig latex extract showed cytotoxicity on different cells particularly K562 leukemia cells which implied its anticancer activity. This extract at lower concentrations reduced lymphocytes proliferation and cytokine production which showed its immunoinhibitory effects and suggested its possible beneficial in treatment of immune-mediated diseases.

Backgrounds & objectives: In addition to their genomic actions, thyroid hormones (THs) can modulate the immune responses through cell surface receptors. One of these is the antiviral effect of THs. Methimazole, as an anti-thyroid compound, is widely used to treat hyperthyroid patients. It also reduces blood leukocytes, granulocytes in particular, and thereby may affect the immune response. Recently, we reported that methimazole-induced hypothyroidism intensifies herpes simplex virus-1(HSV-1) infectivity. To determine whether the effect is mediated through alterations in circulating leukocytes, we assessed the HSV-1 infectivity and circulating leukocytes in methimazole-induced hypothyroid rat. Methods: Male Sprague Dawley rats received methimazole (200 μg/ml) in their drinking water for 2 weeks. Rats were then inoculated with a non-lethal single dose of HSV-1, and sacrificed 3 days later to harvest their spleen. Spleen extract was prepared, and virus yield was determined by evaluation of cytopathic effects (CPE) induced by the extract in a Vero cell culture system. For quantitative analysis, standard method of Reed-Muench was employed. The routine Wright’s staining protocol was used for blood leukocytes differential count. Results: The CPE development was significantly increased in the cell cultures exposed to the spleen extract of methimazole-treated animals (P < 0.05), indicating a higher virus yield and intensified virus infectivity. However, the effect of methimazole on blood leukocytes was minimal. Conclusion: Our data suggest that methimazole increases the susceptibility to HSV-1 infection, at least in part, by blocking THs synthesis but not alterations in circulating leukocytes.