Anticancer activity of propolis.
Sawicka D, Car H, Halina, M et al. 2012. The anticancer activity of propolis. FoliaHistochem Cytobiol 50:1;25-37.
Propolis is a resinous substance produced by bees. The main components of propolis are fatty, aliphatic and aromatic acids, flavonoids, alcohols, terpenes, sugars and esters. It has been ascribed a number of therapeutic properties and this review aimed to summarise the mechanism of action for the active compounds of propolis in the apoptotic process and their influence on the proliferation of cancer cells.
The study of active compounds in propolis resulted in the extraction of CAPE and chrysin, which are believed to be mainly responsible for the antitumor therapeutic activities of propolis. The cancer inhibitory effects of CAPE and chrysin have been confirmed in a variety of culture cell lines.
CAPE exhibits strong antitumor effects in oral cancer cells: fibroblasts from oral submucous fibrosis (OSF), neck metastasis of gingiva carcinoma (GNM) and tongue squamous cell carcinoma. Previous studies have identified that CAPE inhibits colorectal cancer cells proliferation and induces cell cycle arrest by down regulation of b-catenin protein expression and activation of the cyclin-dependent kinase inhibitors which prevent pRb phosphorylation.
Chrysin (5,7-dihydroxyflavone) is a natural flavonoid found in plant extracts (e.g. Passiflora caerulea, Populus tremula), honey and propolis. It has antioxidant and anti-inflammatory effects and has been shown to influence the apoptotic process.
In vitro studies show different sensitivities of tumour cells to extracts of propolis in the context of apoptosis. Results from several studies indicate different degrees of sensitivity to water-soluble propolis extracts among cancer cells and normal fibroblasts. Ethanolic extracts of propolis have also demonstrated action on apoptosis of breast cancer cells in vitro. However the mechanism of propolis-induced apoptosis appears to be independent of the kind of cancer cells studied, but dependent on the concentration of propolis extract. The literature indicates that propolis induces apoptosis through the release of cytochrome c from mitochondria to the cytosol.
The results of the in vitro studies considered for review suggest that propolis, CAPE and chrysin have cytotoxic properties against cancer cells through the induction of apoptosis or cell division and cell growth arrest. The studies presented in this review suggest that propolis and its compounds, CAPE and chrysin, may inhibit cell cycle proliferation or induce apoptosis in tumor cells. The results of these studies also suggest the inhibition of NF-kB activation, the suppression of anti-apoptotic proteins, such as IAP, c-FLIP, Akt kinase, and the initiation of extrinsic pathway of apoptosis by induction of TRAIL and Fas receptor stimulation in cancer cells.
The researchers concluded that while many studies have shown the inhibitory effects of propolis and its compounds on growth and cancer cell proliferation, further work is warranted to investigate the efficiency and mechanism of their beneficial effects. More information would also be required to understand how that translates into clinical practice.
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|Publication:||Australian Journal of Herbal Medicine|
|Date:||Dec 1, 2012|
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