Ivan Bašić

Immunomodulation by water-soluble derivative of propolis: a factor of antitumor reactivity

The antimetastatic efficacy of a water-soluble derivative of propolis (WSDP) was studied. Tumor was a transplantable mammary carcinoma of CBA mouse. Metastases in the lung were generated by 2 x 10(5) viable tumor cells i.v. WSDP was given intraperitoneally at doses of 50 or 150 mg/kg before or after tumor cell inoculation. Therapies reduced the number of metastases in the lung and tumor growth was suppressed significantly by WSDP. It is likely that antimetastatic activity of the WSDP is mainly mediated by immunomodulatory activity. Changes in several immunological parameters such as production of lymphocyte activating factor by peritoneal macrophages and the efficacy of those macrophages to kill tumor cell in vitro, responses of lymphocytes to mitogen, and weight and cellularity of spleen, respectively, correlated well with antimetastatic properties of the WSDP. Based on results we postulate that the antimetastatic activity of propolis includes a pronounced immunomodulatory activity mainly toward augmentation of nonspecific antitumor resistance in mice via macrophage activation.

Inhibition of mammary carcinoma cell proliferation in vitro and tumor growth in vivo by bee venom

The possible tumor growth- and metastasis-inhibiting effects of bee venom in mice and in tumor cell cultures were studied. The tumor was a transplantable mammary carcinoma (MCa) of CBA mouse. Intravenous administration of bee venom to mice significantly reduced the number of metastases in the lung. However, subcutaneous administration of bee venom did not reduce the number of lung metastases, indicating that the antitumor effect of the venom could be highly dependent on the route of injection as well as close contact between the components of the venom and the tumor cells, as was shown by in vitro studies on MCa cells. We also observed variations in immunological parameter induced by bee venom. We proposed that bee venom has an indirect mechanism of tumor growth inhibition and promotion of tumor rejection that is based on stimulation of the local cellular immune responses in lymph nodes. Apoptosis, necrosis, and lysis of tumor cells are other possible mechanisms by which bee venom inhibits tumor growth.

A royal jelly as a new potential immunomodulator in rats and mice

In order to study a possible immunomodulatory effect of the royal jelly (RJ) secreted by mandibular and hypopharingeal glands of the worker honeybee (Apis mellifera Linné.) we have used a well established rodent model. The CBA mice were given s.c. 0.1 ml of RJ, 7 days before, or immediately after, the immunization with sheep red blood cells (SRBC). The Y59 rats received i.m. 0.4 ml or i.v. 0.025 ml of RJ once or twice at 7 day intervals. Serum levels of total proteins and immunoglobulins in the rats that received RJ once or twice within a 2-week-period were significantly lower (P < or = 0.05) as compared with the nontreated animals. In mice which were immunized with 4 x 10(8) of SRBC 7 days after the application of RJ the number of plaque forming splenocytes was significantly higher (P < or = 0.05) than that in the controls. Both the weight of inguinal lymph node and the number of peripheral blood lymphocytes were increased (P < or = 0.05) in RJ-treated mice 3 or 5 days after the immunization, respectively. Neutrophils were decreased (P < or = 0.05) in the mice that were killed 5 or 10 days after the RJ treatment. Overall these results indicate that RJ exhibited immunomodulatory properties by stimulating antibody production and immunocompetent cell proliferation in mice or depressing humoral immune functions in rats. Both phenomena, though species-related in this model, could probably be reversed by changing the dose or the route of RJ application.

Radioprotective effects of propolis and quercetin in γ-irradiated mice evaluated by the alkaline comet assay

The radioprotective effects of ethanolic extract of propolis (EEP) and quercetin on the white blood cells of the whole-body irradiated CBA mice were investigated. Irradiation was performed using a gamma-ray source ((60)Co), and absorbed dose was 9 Gy. The efficiency of test components was evaluated when given intraperitoneally (ip) at a dose of 100 mg kg(-1) for 3 consecutive days before and/or after irradiation. Moreover, possible genotoxic effects of test components were also assessed on non-irradiated animals. For each experimental group leukocyte count was determined and the primary DNA damage in leukocytes was assessed using the alkaline comet assay. The higher efficiency of EEP and quercetin was observed when given preventively. The results suggest that propolis and quercetin given to mice before irradiation protect their white blood cells from lethal effects of irradiation and diminish primary DNA damage as confirmed by the alkaline comet assay. Positive results obtained on gamma-irradiated mice given EEP and quercetin, complementary with our earlier observations on survival of irradiated mice, indicate that these compounds could be considered effective non-toxic radioprotectors. The exact mechanisms of radioprotection by these compounds and their effects on DNA repair processes are still to be elucidated.

Influence of honey bee products on transplantable murine tumours

The effect of propolis [it is a water-soluble derivative (WSDP)] and related polyphenolic compounds of propolis (caffeic acid, caffeic acid phenethyl ester and quercetin), honey, royal jelly and bee venom on tumour growth, metastasizing ability and induction of apoptosis and necrosis in murine tumour models (mammary carcinoma and colon carcinoma) was investigated. WSDP and related polyphenolic compounds showed significant anti-metastatic effect (P < 0.01 and P < 0.001) given either before or after tumour-cell inoculation. Oral or systemic application of WSDP or caffeic acid significantly reduced subcutaneous tumour growth and prolonged the survival of mice. Honey also exerted pronounced anti-metastatic effect (P < 0.05) when applied before tumour-cell inoculation (peroral 2 g kg(-1) for mice or 1 g kg(-1) for rats, once a day for 10 consecutive days). Royal jelly did not affect metastasis formation when given intraperitoneally or subcutaneously. However, intravenous administration of royal jelly before tumour-cell inoculation significantly (P < 0.05) inhibited metastasis formation. When mice were given 10(5) tumour cells intravenously immediately after bee venom injection, the number of tumour nodules in the lung was significantly lower (P < 0.001) than in untreated mice or mice treated with bee venom subcutaneously. Local presence of bee venom in the tissue caused significant delay in subcutaneous tumour formation. These findings clearly demonstrate that anti-tumour and anti-metastatic effects of bee venom are highly dependent on the route of injection and on close contact between components of the bee venom and tumour cells. These data show that honey bee products given orally or systemically may have an important role in the control of tumour growth and tumour metastasizing ability.

Radioprotective Effects of Quercetin and Ethanolic Extract of Propolis in Gamma-Irradiated Mice

Radioprotective Effects of Quercetin and Ethanolic Extract of Propolis in Gamma-Irradiated Mice The aim of this study was to assess radioprotective effects of quercetin and the ethanolic extract of propolis (EEP) in CBA mice exposed to a single radiation dose 4 Gy (60Co). The mice were treated with 100 mg kg-1 quercetin or EEP a day for three consecutive days either before (pre-treatment) or after gamma-irradiation (therapy). Leukocyte count was determined in blood drawn from the tail vein, and DNA damage in leukocytes was assessed using the alkaline comet assay. Genotoxic effects of the test compunds were also evaluated in non-irradiated mice. The levels of radioprotection provided by both test compounds were compared with those established in mice that were given chemical radioprotector S-(2-Aminoethy1)isothiouronium bromide hydrobromide (AET). Mice that received pre-treatment were less sensitive to irradiation. Mice given the post-irradiation therapy showed a slight but not significant increase in total leukocyte count over irradiated negative control. Quercetin showed better protective properties than EEP in both pre-treatment and therapy, and activated a higher number of leukocytes in non-irradiated mice. The alkaline comet assay suggests that both natural compounds, especially when given as pre-treatment, protect against primary leukocyte DNA damage in mice. At tested concentrations, EEP and quercetin were not genotoxic to non-irradiated mice. AET, however, caused a slight but not significant increase in DNA damage. Although the results of this study show the radioprotective potential of the test compounds, further investigation is needed to clarify the underlying protection mechanisms. Primjena alkalnog kometnog testa u istraživanju radioprotektivnih učinaka alkoholnog ekstrakta propolisa i kvercetina na miševima ozračenim gama-zračenjem

Protection of mouse bone marrow by WR-2721 after fractionated irradiation☆

The ability of WR-2721 to protect mouse bone marrow after single or fractionated doses of radiation was assessed using both a clonogenic assay (survival of colony-forming units spleen (CFU) and a functional assay (lethality at 30 days) of stem cell survival. Cell survival curves and dose-response curves for radiation alone and drug with radiation were constructed over the dose range of .5 to 8 Gy and 1.5 to 15 Gy, respectively. The fractionated regimen consisted of four fractions ranging from 0.5 to 1.75 Gy given at 6-hr intervals for a total treatment time of 19.5 hr. WR-2721 was given 30 min before each fraction at a dose of 200 mg/kg. The protection factor was smaller after fractionated doses than after single doses for both assays, 1.3 (95% c.l., 1.0-1.6) vs. 2.3 (95% c.l., 2.0-2.6) for CFU survival and 1.34 vs. 1.8 for lethality at 30 days. No drug cytotoxicity could be demonstrated in the fractionated schedule. These data suggest that protection by WR-2721 is dependent on size of dose and will be less after clinically relevant, small dose fractions. However, some protection does remain even in the low dose range, where proportionally more damage is due to single-hit irreparable events.

Inhibitory Effect of Water-Soluble Derivative of Propolis and Its Polyphenolic Compounds on Tumor Growth and Metastasizing Ability: A Possible Mode of Antitumor Action

Polyphenolic compounds are widely distributed in the plant kingdom and display a variety of biological activities, including chemoprevention and tumor growth inhibition. Propolis is made up of a variety of polyphenolic compounds. We compared how the routes of administration of polyphenolic compounds deriving from propolis and of propolis itself affect the growth and metastatic potential of a transplantable mammary carcinoma (MCa) of the CBA mouse. The influence of tested compounds on local tumor growth was also studied. Metastases in the lung were generated by 2 × 105 tumor cells injected intravenously (IV). A water-soluble derivative of propolis (WSDP) and polyphenolic compounds (caffeic acid, CA, and CA phenethyl ester, CAPE) were given to mice per os (PO) or intraperitoneally (IP) before or after tumor cell inoculation. Tested compounds significantly decreased the number of lung colonies. When mice were inoculated with 105 MCa cells in the exact site of subcutaneous injection of different doses of WSDP, CA, or CAPE, tumor growth was inhibited, and survival of treated mice was prolonged. Antitumor activity, according to the results obtained, is mostly related to the immunomodulatory properties of the compounds and their capacity to induce apoptosis and necrosis. In conclusion, results presented here indicate that WSDP, CA, and CAPE could be potential useful tools in the control of tumor growth in experimental tumor models when administrated PO; because PO administration is the easiest way of introducing a compound used for prevention and/or cure of any disease, it is likely that this article has reached the goal of the investigation.

Peroral application of water-soluble derivative of propolis (WSDP) and its related polyphenolic compounds and their influence on immunological and antitumour activity.

Polyphenolic compounds are widely distributed in the plant kingdom and display a variety of biological activities, including chemoprevention and growth inhibition of tumours. Propolis contains a conglomerate of polyphenolic compounds. We investigated the effect of propolis and polyphenolic compounds, components of propolis, on the growth and metastatic potential of a transplantable mammary carcinoma (MCa) of the mouse. Metastases in the lung were generated by 2 x 10 tumour cells injected intravenously (i.v.). A water-soluble derivative of propolis (WSDP) and the polyphenolic compounds (caffeic acid (CA) and caffeic acid phenethyl ester (CAPE)) were given to mice perorally before or after tumour cell inoculation. WSDP, CA and CAPE reduced the number of metastases in the lung. This implies that the antitumour activities of the compounds used in these studies are mostly related to the immunomodulatory properties of the compounds, their cytotoxicity to tumour cells, and their ability to induce apoptosis and/or necrosis.

Evaluation of radioprotective effects of propolis and its flavonoid constituents: in vitro study on human white blood cells.

This in vitro study aimed to evaluate the possible radioprotective effects of the natural substances WSDP, caffeic acid, chrysin and naringin on γ‐irradiated human white blood cells. The effectiveness of tested compounds was evaluated using the alkaline comet assay, the analysis of structural chromosome aberration and the cytokinesis‐block micronucleus assay. The results obtained by the alkaline comet study indicate favourable toxicity profiles of propolis and its polyphenolic components, and confirmed the radioprotective abilities comparable to the chemical radioprotector AET. WSDP and its polyphenolic components were able to reduce the number of necrotic cells. None of tested compounds induced significant genotoxicity, but all of them offered a quite measurable protection against DNA damage. WSDP was found to be the most effective in diminishing the levels of primary and more complex cytogenetic DNA damage in white blood cells. Considering its complex composition, to undoubtedly explain the underlying mechanisms of cyto/radioprotective effects, further studies are needed. Copyright