The antimammary tumor effects of ethanolic extract of propolis from Adamawa region (Cameroon) are by apoptosis via reactive oxygen species-mediated mitochondrial pathway.

Identification of novel natural treatment to combat cancer is a current need. This study was aimed at assessing the anticancer effects of ethanol-extracted Cameroonian propolis (EEP). The antitumor effect of EPP was evaluated in vitro by measuring; cell viability, cell cycle, cell death mechanism, cell migration/invasion, reactive oxygen species (ROS), mitochondrial potential (ΔΨm), caspase activity, and apoptosis-regulating proteins (Bcl-2 and Bcl-XL) in cell lines. In vivo, the effect of EEP against 7,12 dimethylbenz(a)anthracene (DMBA)-induced breast tumorigenesis in rats was assessed. EEP was found to induce cytotoxicity against ER negative MDA-MB-231 breast cancer cells by activating apoptosis through ROS-mediated mitochondrial pathway. The extract equally triggered caspase-3 and caspase-9, increment of ROS level, disruption of ΔΨm and down-regulation of Bcl-XL and Bcl-2 proteins. Besides, EPP prevented migration and invasion activities by inhibiting MMP-2 activity. At all doses it prevented breast tumor incidence (20% in EEP 150 mg/kg vs 70% in DMBA) as well as tumor burden. Tumor sections from EEP-treated rats showed middle proliferation of mammary ducts with weak inflammatory responses. In summary, Cameroonian propolis exhibited antimammary tumor effects via the intrinsic pathway of apoptosis.

Ethanol-extracted Cameroonian propolis: Antiproliferative effects and potential mechanism of action in prostate cancer.

The present study was conducted to evaluate in vitro and in vivo antiproliferative potential of the Cameroonian propolis and to elucidate its underlying mechanism. In vitro, ethanol-extracted propolis (EEP) was tested on cell growth, cell proliferation, cell cycle, cell death mechanism and cell migration. The cell cycle- and apoptosis-regulating proteins were assessed by Western blotting. In vivo the testosterone-induced benign prostatic hyperplasia (BPH) in Wistar rat was used to evaluate the antiproliferative potential of EEP. EEP reduced DU145 and PC3 cell survival with an IC50 of 70 and 22 µg/ml respectively. It increased the number of late apoptotic cells, the amount of cells in G0/G1 phase in DU145 and PC3 cells at 50 µg/ml. Cell cycle proteins (cdk1, pcdk1 and their related cyclins A and B) were down-regulated in both DU145 and PC3 cells, while cdk2 and pcdk2 were down-regulated only in PC3 cells. The pro-apoptotic Bax protein was up-regulated, while the anti-apoptotic Akt and pAKT, and Bcl-2 proteins were down-regulated. It increased prostate cell adhesion and chemotaxis. EEP reduced prostate weight, volume and epithelial thickness in rats. We demonstrated for the first time that Cameroonian propolis is endowed with in vitro and in vivo antiproliferative properties in the prostate.

Ethanol-extracted Cameroonian propolis exerts estrogenic effects and alleviates hot flushes in ovariectomized Wistar rats.

BACKGROUND: Since the biological properties of propolis depend to the plants that can be found in a specific region, propolis from unexplored regions attracts the attention of scientists. Ethanolic extract of Cameroonian propolis (EEP) is used to treat various ailments including gynecological problems and amenorrhea. Since there were no scientific data to support the above claims, the present study was therefore undertaken to assess estrogenic properties of Cameroonian propolis. METHODS: To achieve our goal, the ability of EEP to induce MCF-7 cells proliferation in E-screen assay as well as to activate estrogen receptors α (ERα) and ß (ERß) in cell-based reporter gene assays using human embryonic kidney cells (HEK293T) transfected with ERs was tested. Further, a 3-day uterotrophic assay was performed and the ability of EEP to alleviate hot flushes in ovariectomized adult rats was evaluated. RESULTS: In vitro, EEP showed an antiestrogenic activity in both HEK293T ER-α and ER-ß cells. In vivo, EEP induced a significant increase in a bell shape dose response manner of the uterine wet weight, the total protein levels in the uterus, the uterine and vaginal epithelium height and acini border cells of mammary gland with the presence of abundant eosinophil secretions. Moreover, EEP induced a significant decrease in the total number, average duration as well as frequency of hot flushes after 3 days of treatment in rat (equivalent to a month in woman). The dose of 150 mg/kg exhibited the most potent estrogenic effects among all the tested doses. The UPLC-HRMS analysis showed the presence of caffeic acid derivatives and trirtepernoids in EEP, which are well known endowed with estrogenic properties. CONCLUSION: These results suggest that Ethanolic extract of Cameroonian propolis has estrogen-like effects in vivo and may alleviate some menopausal problems such as vaginal dryness and hot flushes. Ethanol-extracted Cameroobian propolis exhibited in vitro and in vivo estrogen-like effects. This extract may contain promising phytoestrogens.

Characterisation of triterpenes and new phenolic lipids in Cameroonian propolis.

Chemical investigation of a sample of propolis originating from North-Western Cameroon led to the isolation of thirteen alk(en)ylphenols (1-13) (inseparable mixture) along with α-amyrin (14), ß-amyrin (15), lupeol (16), cycloartenol (17), mangiferonic acid (18), ambonic acid (19), mangiferolic acid (20), ambolic acid (21), isomangiferolic acid (22) and nine alk(en)ylresorcinols (23-31) (inseparable mixture). All compounds were identified following analysis of their spectroscopic data and comparison with previously published reports. Compounds (8), (12), (13) and (30) are new natural products. GC-MS analysis carried out on the alk(en)ylphenol and alk(en)ylresorcinol mixtures (dimethyl disulphide trimethylsilyl derivatives) revealed the presence of saturated and mono-unsaturated compounds with side chain lengths ranging from C11 to C19 and C15 to C19, respectively. The position of the double bond in mono-unsaturated derivatives was established from the characteristic fragments resulting from the cleavage of the bond between the two methylthio-substituted carbons. The most abundant compound in each mixture was 3-(12'Z-heptadecenyl)-phenol (10) and 5-(12'Z-heptadecenyl)-resorcinol (29). This study is the first to report the presence of triterpenes (except for lupeol) and phenolic lipids, including eighteen compounds previously unreported in bee glue, in an African sample.