Antiproliferation of human prostate cancer cells by ethanolic extracts of Brazilian propolis and its botanical origin

Abstract

Abstract. Propolis is a resinous substance collected by bees (Apis mellifera) from various tree buds which they then use to coat hive parts and to seal cracks and crevices in the hive. Propolis, a known ancient folk medicine, has been extensively used in diet to improve health and to prevent disease. In the present study, we have evaluated the effects of ethanolic extracts of Brazilian propolis group l2 and bud resins of botanical origin (B. dracunculifolia), and propolis group 3 on proliferation of metastasis (DU145 and PC-3) and primary malignant tumor (RC58T/h/SA#4)-derived human prostate cancer cells. The strongest inhibition was observed in propolis group 3 (sample #3) extracts whereas moderate growth inhibition was observed in human prostate epithelial cells. In the RC58T/h/SA#4 cells, resins of botanical origin of propolis group 12 (sample #1) and propolis group 12 (sample #2) induced growth inhibition that was associated with S phase arrest whereas propolis group 3 (sample #3) induced growth inhibition that was associated with G2 arrest. The mechanisms of cell cycle effects of propolis were investigated. The resins of botanical origin of propolis group 12 and propolis group 12 showed similar inhibition of cyclin D1, CDK4 and cyclin B1 expression. Propolis group 3 showed higher induction of p21 expression but no inhibition of cyclin D1, CDK4 and cyclin B1 expression. The results obtained here demonstrate that the Brazilian propolis extracts have significant inhibitory effect on proliferation of human prostate cancer cells. Inhibition was achieved through regulation of protein expression of cyclin D1, B1 and cyclin dependent kinase (CDK) as well as p21. Our results indicate that the Brazilian propolis extracts show promise as chemotherapeutic agents as well as preventive agents against prostate cancer. IntroductionProstate cancer is the most common male cancer in USA and other Western countries, and the second leading cause of male cancer death in USA (1). Despite its pervasive impact, the etiology of prostate cancer and the factors that promote its progression are not well understood. To date, there is no secure way to tell whether prostate cancer, once found, should receive treatment. Although prostatectomy, radiation therapy and hormone therapy have been used for curing prostate cancer patients, recurrence and metastasis of prostate cancer are major problems in prostate cancer therapy. Current available treatment often has troubling side-effects such as urinary incontinence and erectile dysfunction. There is no effective treatment modality once the cancer has evolved into the hormone refractory stage. Preventive strategies are currently emerging. These is an increase in the usage of nutritional supplements such as soybeans, garlic, green tea and Vitamin D3 etc., to augment the prescribed anticancer therapies.Propolis is a resinous substance collected by Apis mellifera from various tree buds which they then use to coat hive parts and to seal cracks and crevices in the hive (2). Propolis has been used as ...

Analysis of chemical composition and bioactive property evaluation of Indian propolis

“…The results obtained are in agreement with the results of propolis collected from China [21] . Ethanolic extract of Brazilian propolis showed potent cytotoxicity and apoptosis inducing ability against prostate cancer cell lines also supported our results [22] .…”

Comparative antiproliferation of human prostate cancer cells by ethanolic extracts of two groups of Brazilian propolis

“…When the cells were growing in the serum free medium (KGM), propolis groups 12 and 13 showed similar inhibition against the growth of RC-58T/h/SA#4 (LI et al, 2007) and PrEC cells, but group 13 demonstrated higher growth inhibition than group 12, as shown in Figure 3, and two propolis samples showed higher inhibitory efficiency in malignant cells (RC-58T/h/SA#4) than normal prostate epithelial (PrEC). The 50% growth inhibition (GI50) of propolis was 5 μg.mL -1 for propolis group 12 and 2.75 μg.mL -1 for group 13 in RC-58T/h/SA#4 cell, but 8.75 and 3.25 μg.mL -1 in PrEC cell, as shown in Table 2.…”

“…After treatment for 48 hours, detection reagents (MTS) were added, and cells were incubated for 1 hour. The absorbance was measured at 492 nm in 96-well plate reader (LI et al, 2007). …”

“…Telomerase-immortalized primary human prostate cancerderived cell line (RC-58T/h/SA#4) and primary human prostate epithelial cells (PrEC) (Cambrex Bioproducts, Walkersville, MD) were grown and maintained in the keratinocyte serum free medium (K-SFM) supplemented with bovine pituitary extract and recombinant epidermal growth factor (KGM) (Life Technologies, Inc. Gaithersburg, MD) (LI et al, 2007).…”

Growth inhibitory activity of ethanol extracts of Chinese and Brazilian propolis in four human colon carcinoma cell lines

“…These include flavonoids, polyphenols, phenolic aldehydes, terpenoids, coumarines, amino acids, steroids and inorganic compounds (2). Propolis products originating from Europe and China contain many types of flavonoids and phenolic acid esters (21), whereas propolis of Brazilian origin is composed mainly of artepillin C, terpenoids and prenylated derivatives of p-coumaric acid (22,23). Benzyl caffeate and phenethyl caffeate isolated from the methanol extract of Chinese propolis do exert antiproliferative activity in murine colon carcinoma cells (21).…”