Phytosterol Pygeum africanum regulates prostate cancer in vitro and in vivo

A UPLC- MS/MS Method to Quantify β-Sitosterol and Ferulic Acid of Pygeum Africanum Extract in Bulk and Pharmaceutical Preparation

This study uses a liquid chromatography-electrospray ionization-tandem mass spectrometry method to determine β-Sitosterol and Ferulic acid in Pygeum africanum extract. Chromatographic separation of the two analytes was performed on an ACQUITY UPLC H-Class system coupled with Xevo TQD mass spectrometer and HSS T3 C18 column (2.1 X 50 mm, 1.8 μm). Mobile phase A consisted of an aqueous solution of 0.1% formic acid (v/v), and mobile phase B was 0.1% formic acid (v/v) in methanol pumped through a gradient elution mode. Mass spectrometer parameters were optimized using an electrospray ionization source in the positive and negative ionization modes. The quantification of the two analytes was performed using multiple reaction monitoring transitions. The method was fully validated per (FDA) guidelines regarding linearity, accuracy, precision, carryover and selectivity. The proposed method was applied successfully to determine the two investigated compounds in commercially available pharmaceutical products.

The African cherry: A review of the botany, traditional uses, phytochemistry, and biological activities of Prunus africana (Hook.f.) Kalkman

ETHNOPHARMACOLOGICAL RELEVANCE

Prunus africana (Hook.f.) Kalkman (Rosaceae), commonly known as "Pygeum" or "African cherry", occurs in mainland montane forests scattered across sub-Saharan Africa, Madagascar, and some surrounding islands. Traditionally, decoctions of the stem-bark are taken orally for the treatment of a wide variety of conditions, such as benign prostatic hyperplasia (BPH), stomach ache, chest pain, malaria, heart conditions, and gonorrhoea, as well as urinary and kidney diseases. The timber is used to make axe handles and for other household needs. The dense wood is also sawn for timber.

AIM

The fragmented information available on the ethnobotany, phytochemistry, and biological activities of the medicinally important P. africana was collated, organised, and analysed in this review, to highlight knowledge voids that can be addressed through future research.

MATERIALS AND METHODS

A bibliometric analysis of research output on P. africana was conducted on literature retrieved, using the Scopus® database. The trend in the publications over time was assessed and a network analysis of collaborations between countries and authors was carried out. Furthermore, a detailed review of the literature over the period 1971 to 2021, acquired through Scopus, ScienceDirect, SciFinder, Pubmed, Scirp, DOAJ and Google Scholar, was conducted. All relevant abstracts, full-text articles and various book chapters on the botanical and ethnopharmacological aspects of P. africana, written in English and German, were consulted.

RESULTS

A total of 455 documents published from 1971 to 2021, were retrieved using the Scopus search. Analysis of the data showed that the majority of these documents were original research articles, followed by reviews and lastly a miscellaneous group comprising conference papers, book chapters, short surveys, editorials and letters. Data were analysed for annual output and areas of intense research focus, and countries with high research output, productive institutions and authors, and collaborative networks were identified. Prunus africana is reported to exhibit anti-inflammatory, analgesic, antimicrobial, anti-oxidant, antiviral, antimutagenic, anti-asthmatic, anti-androgenic, antiproliferative and apoptotic activities amongst others. Phytosterols and other secondary metabolites such as phenols, triterpenes, fatty acids, and linear alcohols have been the focus of phytochemical investigations. The biological activity has largely been ascribed to the phytosterols (mainly 3-β-sitosterol, 3-β-sitostenone, and 3-β-sitosterol-glucoside), which inhibit the production of prostaglandins in the prostate, thereby suppressing the inflammatory symptoms associated with BPH and chronic prostatitis.

CONCLUSIONS

Many of the ethnobotanical assertions for the biological activity of P. africana have been confirmed through in vitro and in vivo studies. However, a disparity exists between the biological activity of the whole extract and that of single compounds isolated from the extract, which were reported to be less effective. This finding suggests that a different approach to biological activity studies should be encouraged that takes all secondary metabolites present into consideration. A robust technique, such as multivariate biochemometric data analysis, which allows for a holistic intervention to study the biological activity of a species is suggested. Furthermore, there is a need to develop rapid and efficient quality control methods for both raw materials and products to replace the time-consuming and laborious methods currently in use.

The use of African medicinal plants in cancer management

Cancer is the third leading cause of premature death in sub-Saharan Africa. Cervical cancer has the highest number of incidences in sub-Saharan Africa due to high HIV prevalence (70% of global cases) in African countries which is linked to increasing the risk of developing cervical cancer, and the continuous high risk of being infected with Human papillomavirus In 2020, the risk of dying from cancer amongst women was higher in Eastern Africa (11%) than it was in Northern America (7.4%). Plants continue to provide unlimited pharmacological bioactive compounds that are used to manage various illnesses, including cancer. By reviewing the literature, we provide an inventory of African plants with reported anticancer activity and evidence supporting their use in cancer management. In this review, we report 23 plants that have been used for cancer management in Africa, where the anticancer extracts are usually prepared from barks, fruits, leaves, roots, and stems of these plants. Extensive information is reported about the bioactive compounds present in these plants as well as their potential activities against various forms of cancer. However, information on the anticancer properties of other African medicinal plants is insufficient. Therefore, there is a need to isolate and evaluate the anticancer potential of bioactive compounds from other African medicinal plants. Further studies on these plants will allow the elucidation of their anticancer mechanisms of action and allow the identification of phytochemicals that are responsible for their anticancer properties. Overall, this review provides consolidated and extensive information not only on diverse medicinal plants of Africa but on the different types of cancer that these plants are used to manage and the diverse mechanisms and pathways that are involved during cancer alleviation.

Cell Culture-Based Assessment of Toxicity and Therapeutics of Phytochemical Antioxidants

Plant-derived natural products are significant resources for drug discovery and development including appreciable potentials in preventing and managing oxidative stress, making them promising candidates in cancer and other disease therapeutics. Their effects have been linked to phytochemicals such as phenolic compounds and their antioxidant activities. The abundance and complexity of these bio-constituents highlight the need for well-defined in vitro characterization and quantification of the plant extracts/preparations that can translate to in vivo effects and hopefully to clinical use. This review article seeks to provide relevant information about the applicability of cell-based assays in assessing anti-cytotoxicity of phytochemicals considering several traditional and current methods.

Root Extract of a Micropropagated Prunus africana Medicinal Plant Induced Apoptosis in Human Prostate Cancer Cells (PC-3) via Caspase-3 Activation

Prostate cancer is one of the major causes of cancer-related deaths among men globally. Medicinal plants have been explored as alternative treatment options. Herein, we assessed the in vitro cytotoxic effects of 70% ethanolic root extracts of six-month-old micropropagated Prunus africana (PIR) on PC-3 prostate cancer cells as an alternative to the traditionally used P. africana stem-bark extract (PWS) treatment. In vitro assays on PC-3 cells included annexin-V and propidium iodide staining, DAPI staining, and caspase-3 activity analysis through western blotting. PC-3 cells were exposed to PWS and PIR at different concentrations, and dose-dependent antiprostate cancer effects were observed. PC-3 cell viability was determined using CCK-8 assay, which yielded IC50 values of 52.30 and 82.40 μg/mL for PWS and PIR, respectively. Annexin-V and PI staining showed dose-dependent apoptosis of PC-3 cells. Significant (p < 0.001) percent of DAPI-stained apoptotic PC-3 cells were observed in PWS, PIR, and doxorubicin treatment compared with the negative control. PWS treatment substantially elevated cleaved caspase-3 levels in PC-3 cells compared with the PIR treatment. These results provide evidence for the antiprostate cancer potential of PIR and sets a basis for further research to enhance future utilization of roots of young micropropagated P. africana for prostate cancer treatment as an alternative to stem bark. Moreover, micropropagation approach may help provide the required raw materials and hence reduce the demand for P. africana from endangered wild population.

Antioxidant Potential of Red Palm-Pressed Mesocarp Olein

Oxidative stress occurs due to the imbalance amount of the free radicals and antioxidants in human body which often associated with numerous chronic diseases. The antioxidant properties of red palm-pressed mesocarp olein (PPMO) have not been widely studied. Therefore, antioxidant properties of PPMO relative to commercially available edible oils, namely red palm olein (RPO), palm olein (PO), extra virgin olive oil (OO) and extra virgin coconut oil (CNO) were studied. PPMO exhibited significant higher phytonutrients which more than 2-fold compared to the edible oils. Overall, antioxidant screening indicated that PPMO has significantly higher antioxidant activities than RPO, PO and CNO in term of DPPH, H₂O₂, NO scavenging and FIC; and significantly higher H₂O₂ and FIC than OO. The outcomes of this study reveal that PPMO is as good as commercially available edible oil, also a good source for food applications and dietary nutritional supplements. More importantly, the utilization of PPMO could mitigate oil palm waste problem and results in positive environmental impact.

Natural Products for the Management of Castration-Resistant Prostate Cancer: Special Focus on Nanoparticles Based Studies

Prostate cancer is the most common type of cancer among men and the second most frequent cause of cancer-related mortality around the world. The progression of advanced prostate cancer to castration-resistant prostate cancer (CRPC) plays a major role in disease-associated morbidity and mortality, posing a significant therapeutic challenge. Resistance has been associated with the activation of androgen receptors via several mechanisms, including alternative dehydroepiandrosterone biosynthetic pathways, other androgen receptor activator molecules, oncogenes, and carcinogenic signaling pathways. Tumor microenvironment plays a critical role not only in the cancer progression but also in the drug resistance. Numerous natural products have shown major potential against particular or multiple resistance pathways as shown by in vitro and in vivo studies. However, their efficacy in clinical trials has been undermined by their unfavorable pharmacological properties (hydrophobic molecules, instability, low pharmacokinetic profile, poor water solubility, and high excretion rate). Nanoparticle formulations can provide a way out of the stalemate, employing targeted drug delivery, improved pharmacokinetic drug profile, and transportation of diagnostic and therapeutic agents via otherwise impermeable biological barriers. This review compiles the available evidence regarding the use of natural products for the management of CRPC with a focus on nanoparticle formulations. PubMed and Google Scholar search engines were used for preclinical studies, while ClinicalTrials.gov and PubMed were searched for clinical studies. The results of our study suggest the efficacy of natural compounds such as curcumin, resveratrol, apigenin, quercetin, fisetin, luteolin, kaempferol, genistein, berberine, ursolic acid, eugenol, gingerol, and ellagic acid against several mechanisms leading to castration resistance in preclinical studies, but fail to set the disease under control in clinical studies. Nanoparticle formulations of curcumin and quercetin seem to increase their potential in clinical settings. Using nanoparticles based on betulinic acid, capsaicin, sintokamide A, niphatenones A and B, as well as atraric acid seems promising but needs to be verified with preclinical and clinical studies.

Ethiopian Medicinal Plants Traditionally Used for the Treatment of Cancer, Part 2: A Review on Cytotoxic, Antiproliferative, and Antitumor Phytochemicals, and Future Perspective

This review provides an overview on the active phytochemical constituents of medicinal plants that are traditionally used to manage cancer in Ethiopia. A total of 119 articles published between 1968 and 2020 have been reviewed, using scientific search engines such as ScienceDirect, PubMed, and Google Scholar. Twenty-seven medicinal plant species that belong to eighteen families are documented along with their botanical sources, potential active constituents, and in vitro and in vivo activities against various cancer cells. The review is compiled and discusses the potential anticancer, antiproliferative, and cytotoxic agents based on the types of secondary metabolites, such as terpenoids, phenolic compounds, alkaloids, steroids, and lignans. Among the anticancer secondary metabolites reported in this review, only few have been isolated from plants that are originated and collected in Ethiopia, and the majority of compounds are reported from plants belonging to different areas of the world. Thus, based on the available bioactivity reports, extensive and more elaborate ethnopharmacology-based bioassay-guided studies have to be conducted on selected traditionally claimed Ethiopian anticancer plants, which inherited from a unique and diverse landscape, with the aim of opening a way forward to conduct anticancer drug discovery program.

Phytosterols in Cancer: From Molecular Mechanisms to Preventive and Therapeutic Potentials

Cancer is the second leading cause of death worldwide. Compelling evidence supports the hypothesis that the manipulation of dietary components, including plant compounds termed as phytochemicals, demonstrates certain important health benefits in humans, including those in cancer. In fact, beyond their well-known cardiovascular applications, phytosterols may also possess anticancer properties, as has been demonstrated by several studies. Although the mechanism of action by which phytosterols (and derivatives) may prevent cancer development is still under investigation, data from multiple experimental studies support the hypothesis that they may modulate proliferation and apoptosis of tumor cells. Phytosterols are generally considered safe for human consumption and may also be added to a broad spectrum of food matrices; further, they could be used in primary and secondary prevention. However, few interventional studies have evaluated the relationship between the efficacy of different types and forms of phytosterols in cancer prevention. In this context, the purpose of this review was to revisit and update the current knowledge on the molecular mechanisms involved in the anticancer action of phytosterols and their potential in cancer prevention or treatment.

Are polyphenol antioxidants at the root of medicinal plant anti-cancer success?

ETHNOPHARMACOLOGICAL RELEVANCE

Given the severe side effects associated with most of the conventional cancer medications, as well as the expanding body of evidence indicating secondary toxicity of these drugs, individuals with cancer are increasingly turning to natural alternatives. Similarly, the pharmaceutical industry is in search of natural products to treat cancer. An understanding of the specific active components in plant products with which anti-cancer efficacy is achieved is required for this research to move forward.

AIM OF THE STUDY

To integrate data from cancer-relatestudies on plant-derived products or extracts, to elucidate whether these products may have similar active ingredients and/or mechanisms of action, that can explain their efficacy. This review also includes a discussion of the methodological complexities and important considerations involved in accurate isolation and characterisation of active substances from plant material.

CONCLUSIONS

From the literature reviewed, most plant products with consistently reported anti-cancer efficacy contains high levels of polyphenols or other potent antioxidants and their mechanisms of action correlate to that reported for isolated antioxidants in the context of cancer. This suggests that natural products may indeed become the panacea against this chronic disease - either as therapeutic medicine strategy or to serve as templates for the design of novel synthetic drugs. The recommendation is made that antioxidant activity of plant actives and especially polyphenols, should be the focus of anti-cancer drug discovery initiatives. Lastly, researchers are advised to exploit current techniques of chemical compound characterisation when investigating polyphenol-rich plants to enable the easy consolidation of research findings from different laboratories.

Kidney, skeletal muscle and myocardium as potential target sites of Pygeum africanum toxicity in Wistar rats

OBJECTIVE

Extract of Pygeum africanum (PAE) is commonly used herbal medication in the treatment of benign prostatic hyperplasia. In Montenegro and neighboring countries, PAE is primarily advertised as dietary supplement in the treatment of erectile dysfunction. The purpose of this study was to broaden the current cognition concerning its safety profile.

MATERIAL AND METHODS

Twenty-four adult male Wistar rats were used. The first control group (O) received water and second control group (OO) received olive oil for 30 days. The third and fourth groups (PA5 and PA10) were treated with PAE dissolved in olive oil (50 and 100mg/kg p.o. daily). The behavior of animals was observed continuously, bodyweight gain (BWG) was calculated weekly and the weight of selected organs was measured at the end of experiment. Total protein and glutathione content of the liver were analyzed. Standard biochemical analyses were also performed.

RESULTS

BWG was higher in PA5 compared to both controls at all measuring intervals. Liver weight/body weight ratio was significantly higher in PA10 in comparison with O. Prostate weight/body weight ratio was lower in both PA5 and PA10 compared to OO, achieving statistical significance in PA5. The value of creatinine was higher in PA5 and PA10 compared to both control groups, but achieving statistical significance in PA10 only. LDH was also increased in PA5 and PA10 compared to both controls.

CONCLUSIONS

Both dosage regimens of PAE, particularly PA10, caused some toxicological effects in Wistar rats after one month of application. Kidney, skeletal muscle and/or myocardium are suspected as target sites of PA toxicity most likely. In order to provide more reliable conclusion it is necessary to conduct an additional research on the basis of these findings.

A Review of the Potential of Phytochemicals from Prunus africana (Hook f.) Kalkman Stem Bark for Chemoprevention and Chemotherapy of Prostate Cancer

Prostate cancer remains one of the major causes of death worldwide. In view of the limited treatment options for patients with prostate cancer, preventive and treatment approaches based on natural compounds can play an integral role in tackling this disease. Recent evidence supports the beneficial effects of plant-derived phytochemicals as chemopreventive and chemotherapeutic agents for various cancers, including prostate cancer. Prunus africana has been used for generations in African traditional medicine to treat prostate cancer. This review examined the potential roles of the phytochemicals from P. africana, an endangered, sub-Saharan Africa plant in the chemoprevention and chemotherapy of prostate cancer. In vitro and in vivo studies have provided strong pharmacological evidence for antiprostate cancer activities of P. africana-derived phytochemicals. Through synergistic interactions between different effective phytochemicals, P. africana extracts have been shown to exhibit very strong antiandrogenic and antiangiogenic activities and have the ability to kill tumor cells via apoptotic pathways, prevent the proliferation of prostate cancer cells, and alter the signaling pathways required for the maintenance of prostate cancer cells. However, further preclinical and clinical studies ought to be done to advance and eventually use these promising phytochemicals for the prevention and chemotherapy of human prostate cancer.

Bioactive natural products for chemoprevention and treatment of castration-resistant prostate cancer

Prostate cancer (PCa), a hormonally-driven cancer, ranks first in incidence and second in cancer related mortality in men in most Western industrialized countries. Androgen and androgen receptor (AR) are the dominant modulators of PCa growth. Over the last two decades multiple advancements in screening, treatment, surveillance and palliative care of PCa have significantly increased quality of life and survival following diagnosis. However, over 20% of patients initially diagnosed with PCa still develop an aggressive and treatment-refractory disease. Prevention or treatment for hormone-refractory PCa using bioactive compounds from marine sponges, mushrooms, and edible plants either as single agents or as adjuvants to existing therapy, has not been clinically successful. Major advancements have been made in the identification, testing and modification of the existing molecular structures of natural products. Additionally, conjugation of these compounds to novel matrices has enhanced their bio-availability; a big step towards bringing natural products to clinical trials. Natural products derived from edible plants (nutraceuticals), and common folk-medicines might offer advantages over synthetic compounds due to their broader range of targets, as compared to mostly single target synthetic anticancer compounds; e.g. kinase inhibitors. The use of synthetic inhibitors or antibodies that target a single aberrant molecule in cancer cells might be in part responsible for emergence of treatment refractory cancers. Nutraceuticals that target AR signaling (epigallocatechin gallate [EGCG], curcumin, and 5α-reductase inhibitors), AR synthesis (ericifolin, capsaicin and others) or AR degradation (betulinic acid, di-indolyl diamine, sulphoraphane, silibinin and others) are prime candidates for use as adjuvant or mono-therapies. Nutraceuticals target multiple pathophysiological mechanisms involved during cancer development and progression and thus have potential to simultaneously inhibit both prostate cancer growth and metastatic progression (e.g., inhibition of angiogenesis, epithelial-mesenchymal transition (EMT) and proliferation). Given their multi-targeting properties along with relatively lower systemic toxicity, these compounds offer significant therapeutic advantages for prevention and treatment of PCa. This review emphasizes the potential application of some of the well-researched natural compounds that target AR for prevention and therapy of PCa.

Inhibition of Gli/hedgehog signaling in prostate cancer cells by "cancer bush" Sutherlandia frutescens extract

Sutherlandia frutescens is a medicinal plant, traditionally used to treat various types of human diseases, including cancer. Previous studies of several botanicals link suppression of prostate cancer growth with inhibition of the Gli/hedgehog (Gli/Hh) signaling pathway. Here we hypothesized the anti-cancer effect of S. frutescens was linked to its inhibition of the Gli/Hh signaling in prostate cancer. We found a dose- and time-dependent growth inhibition in human prostate cancer cells, PC3 and LNCaP, and mouse prostate cancer cell, TRAMP-C2, treated with S. frutescens methanol extract (SLE). We also observed a dose-dependent inhibition of the Gli-reporter activity in Shh Light II and TRAMP-C2QGli cells treated with SLE. In addition, SLE can inhibit Gli/Hh signaling by blocking Gli1 and Ptched1 gene expression in the presence of a Gli/Hh signaling agonist (SAG). A diet supplemented with S. frutescens suppressed the formation of poorly differentiated carcinoma in prostates of TRAMP mice. Finally, we found Sutherlandioside D was the most potent compound in the crude extract that could suppress Gli-reporter in Shh Light II cells. Together, this suggests that the S. frutescens extract may exert anti-cancer effect by targeting Gli/Hh signaling, and Sutherlandioside D is one of the active compounds.

A phytosterol enriched refined extract of Brassica campestris L. pollen significantly improves benign prostatic hyperplasia (BPH) in a rat model as compared to the classical TCM pollen preparation Qianlie Kang Pule'an Tablets

In Qinghai Province, the Brassica campestris L. pollen preparation Qianlie Kang Pule'an Tablet (QKPT) is traditionally used for BPH therapy. However, in QKPT the content of supposedly active phytosterols is relatively low at 2.59%, necessitating high doses for successful therapy. Therefore, a phytosterol enriched (4.54%) refined extract of B. campestris pollen (PE) was developed and compared with QKPT in a BPH rat model. Six groups of rats (n=8 each), namely sham-operated distilled water control, castrated distilled water control, castrated QKPT 2.0g/kg, castrated PE 0.1g/kg, castrated PE 0.2g/kg, and castrated PE 0.4g/kg, were intragastrically treated with the respective daily doses. Testosterone propionate (0.3mg/day) was administered to all castrated rats, while the sham-operated group received placebo injections. After 30 days, the animals were sacrificed and prostates as well as seminal vesicles excised and weighted in order to calculate prostate volume index (PVI) as well as prostate index (PI) and seminal vesicle index (SVI), defined as organ weight in g per 100g body weight. Compared with sham-operated controls, PI (p<0.01), PVI (p<0.01), and SVI (p<0.01) were all significantly increased in all castrated, testosterone treated rats. After treatment with PE at 0.4 and 0.2g/kg or QKPT at 2.0g/kg per day, both indices were significantly reduced (p<0.01) as compared to the castrated distilled water control. For PE at 0.1g/kg per day only PI was significantly reduced (p<0.05). At the highest PE concentration of 0.4g/kg per day both PI and SVI were also significantly reduced when compared to the QKPT group (p<0.05). Both PE and QKPT demonstrated curative effects against BPH in the applied animal model. In its highest dose at 0.4g/kg per day, PE was clearly superior to QKPT.

Anti-inflammatory effect and prostate gene expression profiling of steryl ferulate on experimental rats with non-bacterial prostatitis

Steryl ferulate (SF) is a bioactive mixture extracted from rice bran and shows higher inhibitory activity against inflammation than the corresponding free sterols.

The role and place of medicinal plants in the strategies for disease prevention

Medicinal plants have been used in healthcare since time immemorial. Studies have been carried out globally to verify their efficacy and some of the findings have led to the production of plant-based medicines. The global market value of medicinal plant products exceeds $100 billion per annum. This paper discusses the role, contributions and usefulness of medicinal plants in tackling the diseases of public health importance, with particular emphasis on the current strategic approaches to disease prevention. A comparison is drawn between the 'whole population' and 'high-risk' strategies. The usefulness of the common-factor approach as a method of engaging other health promoters in propagating the ideals of medicinal plants is highlighted. The place of medicinal plants in preventing common diseases is further examined under the five core principles of the Primary Health Care (PHC) approach. Medicinal plants play vital roles in disease prevention and their promotion and use fit into all existing prevention strategies. However, conscious efforts need to be made to properly identify, recognise and position medicinal plants in the design and implementation of these strategies. These approaches present interesting and emerging perspectives in the field of medicinal plants. Recommendations are proposed for strategising the future role and place for medicinal plants in disease prevention.

Cytotoxicity of herbal extracts used for treatment of prostatic disease on head and neck carcinoma cell lines and non-malignant primary mucosal cells

Previously, a growth inhibiting effect of PC-Spes on head and neck carcinoma cell lines had been demonstrated. In order to determine the toxic impact of particular herbs in the mixture, we exposed the head and neck cancer cell lines FADU, HLaC79 and its Paclitaxel-resistant subline HLaC79-Clone1 as well as primary mucosal keratinocytes to increasing concentrations of the herbal mixture Prostaprotect, which has a similar formulation as PC-Spes, as well as its single herbal components Dendranthema morifolium, Ganoderma lucidium, Glycyrrhiza glabra, Isatis indigotica, Panax pseudo-ginseng, Rabdosia rubescens, Scutellaria baicalensis and Pygeum africanum. Growth inhibition was measured using the MTT assay. Expression of P-glycoprotein (P-GP), multidrug resistance protein-1 (MRP-1), multidrug resistance protein-2 (MRP-2), breast cancer resistance protein (BCRP) and androgen receptor (AR) were examined by western blot analysis. Pygeum africanum extract clearly turned out as the main cytotoxic component of the Prostaprotect prescription mixture, and initated apoptosis in sensitive cell lines. All other extracts had only minor toxic effects. Western blot analysis revealed increased expression of P-GP in HLaC79-Clone1 cells, while HLaC79 and FADU cells were negative. All three cell lines were negative for MRP-1 and BCRP but positive for MRP-2. HLaC79 and its descendant HLaC79-Clone1 both expressed AR, as verified by western blotting and immunofluorescence staining. Primary mucosal keratinocytes were negative for all multidrug resistance markers as well as for AR. Growth inhibition rates of the single herbal extracts were compared with previously published results in prostate carcinoma cell lines. The relationship between expression levels of AR and multidrug resistance markers in relation to the measured toxicity of herbal extracts in our head and neck cancer cell system is critically discussed.

Estrogenic plant consumption predicts red colobus monkey (Procolobus rufomitratus) hormonal state and behavior

Numerous studies have examined the effects of anthropogenic endocrine disrupting compounds; however, very little is known about the effects of naturally occurring plant-produced estrogenic compounds (i.e., phytoestrogens) on vertebrates. To examine the seasonal pattern of phytoestrogen consumption and its relationship to hormone levels (407 fecal samples analyzed for estradiol and cortisol) and social behavior (aggression, mating, and grooming) in a primate, we conducted an 11-month field study of red colobus (Procolobus rufomitratus) in Kibale National Park, Uganda. The percent of diet from estrogenic plants averaged 10.7% (n=45 weeks; range: 0.7-32.4%). Red colobus fed more heavily on estrogenic Millettia dura young leaves during weeks of higher rainfall, and the consumption of this estrogenic item was positively correlated to both their fecal estradiol and cortisol levels. Social behaviors were related to estradiol and cortisol levels, as well as the consumption of estrogenic plants and rainfall. The more the red colobus consumed estrogenic plants the higher their rates of aggression and copulation and the lower their time spent grooming. Our results suggest that the consumption of estrogenic plants has important implications for primate health and fitness through interactions with the endocrine system and changes in hormone levels and social behaviors.

Aggressive prostate cancer is prevented in ERαKO mice and stimulated in ERβKO TRAMP mice

Previous evidence suggests soy genistein may be protective against prostate cancer, but whether this protection involves an estrogen receptor (ER)-dependent mechanism is unknown. To test the hypothesis that phytoestrogens may act through ERα or ERβ to play a protective role against prostate cancer, we bred transgenic mice lacking functional ERα or ERβ with transgenic adenocarcinoma of mouse prostate (TRAMP) mice. Dietary genistein reduced the incidence of cancer in ER wild-type (WT)/transgenic adenocarcinoma of mouse prostate mice but not in ERα knockout (KO) or ERβKO mice. Cancer incidence was 70% in ERWT mice fed the control diet compared with 47% in ERWT mice fed low-dose genistein (300 mg/kg) and 32% on the high-dose genistein (750 mg/kg). Surprisingly, genistein only affected the well differentiated carcinoma (WDC) incidence but had no effect on poorly differentiated carcinoma (PDC). No dietary effects have been observed in either of the ERKO animals. We observed a very strong genotypic influence on PDC incidence, a protective effect in ERαKO (only 5% developed PDC), compared with 19% in the ERWT, and an increase in the incidence of PDC in ERβKO mice to 41%. Interestingly, immunohistochemical analysis showed ERα expression changing from nonnuclear in WDC to nuclear in PDC, with little change in ERβ location or expression. In conclusion, genistein is able to inhibit WDC in the presence of both ERs, but the effect of estrogen signaling on PDC is dominant over any dietary treatment, suggesting that improved differential targeting of ERα vs. ERβ would result in prevention of advanced prostate cancer.

Biological effect of human serum collected before and after oral intake of Pygeum africanum on various benign prostate cell cultures

Pygeum africanum (Tadenan) is a popular phytotherapeutic agent used in the treatment of symptomatic benign prostatic hyperplasia. The active compounds of the drug have not been identified, and determining the plasma concentration of the drug is, therefore, not possible. Because there are conflicting results on the efficacy of this drug, we aimed to investigate its effect on prostate cell growth in vitro using human serum collected before and after Pygeum africanum intake. We used primary and organotypic cultures of human prostatic stromal myofibroblast cell line WPMY and prostatic epithelial cell line PNT2. We also used fresh benign prostatic tissue. The serum of a treated man induced decreases in the proliferation of primary cells, organotypic cells and WPMY cells but not PNT2 cells. We also analysed the effect of treated serum on the gene expression profile of WPMY cells. The transcriptome analysis revealed an upregulation of genes involved in multiple tumour suppression pathways and a downregulation of genes involved in inflammation and oxidative-stress pathways. The oral intake of Pygeum africanum resulted in serum levels of active substances that were sufficient to inhibit the proliferation of cultured myofibroblasts prostatic cells. This inhibition was associated with changes in the transcriptome.

The natural compounds atraric acid and N-butylbenzene-sulfonamide as antagonists of the human androgen receptor and inhibitors of prostate cancer cell growth

Extracts from the plant Pygeum africanum are widely used in the therapy of benign prostate hyperplasia (BPH) and in combinational therapy for prostate cancer, the second leading cause of cancer death and the mostly diagnosed form of cancer in men. The androgen receptor (AR) plays a crucial role in the development of the prostate as well as in prostate diseases. Even though the extracts from P. africanum are considered as beneficial for prostate diseases in clinical trials, and some active compounds for treatment of BPH could be identified, compounds responsible for AR inhibition and the molecular mechanism for inhibition of prostatitis need to be identified. Recently, atraric acid and N-butylbenzene-sulfonamide were isolated from a selective dichlormethane extract of P. africanum as two novel AR antagonistic compounds. The molecular mechanisms of AR inhibition were analyzed and are summarized here. Both compounds are the first known natural, complete and specific AR antagonist.

The natural compound atraric acid is an antagonist of the human androgen receptor inhibiting cellular invasiveness and prostate cancer cell growth

Extracts from Pygeum africanum are used in the treatment of prostatitis, benign prostatic hyperplasia and prostate cancer (Pca), major health problems of men in Western countries. The ligand-activated human androgen receptor (AR) supports the growth of the prostate gland. Inhibition of human AR by androgen ablation therapy and by applying synthetic anti-androgens is therefore the primary goal in treatment of patients. Here, we show that atraric acid (AA) isolated from bark material of Pygeum africanum has anti-androgenic activity, inhibiting the transactivation mediated by the ligand-activated human AR. This androgen antagonistic activity is receptor specific and does not inhibit the closely related glucocorticoid or progesterone receptors. Mechanistically, AA inhibits nuclear transport of AR. Importantly, AA is able to efficiently repress the growth of both the androgen-dependent LNCaP and also the androgen-independent C4-2 Pca cells but not that of PC3 or CV1 cells lacking AR. In line with this, AA inhibits the expression of the endogenous prostate specific antigen gene in both LNCaP und C4-2 cells. Analyses of cell invasion revealed that AA inhibits the invasiveness of LNCaP cells through extracellular matrix. Thus, this study provides a molecular insight for AA as a natural anti-androgenic compound and may serve as a basis for AA derivatives as a new chemical lead structure for novel therapeutic compounds as AR antagonists, that can be used for prophylaxis or treatment of prostatic diseases.

Antiproliferative and apoptotic effects of the herbal agent Pygeum africanum on cultured prostate stromal cells from patients with benign prostatic hyperplasia (BPH)

BACKGROUND

Previous reports show that the herbal agent Pygeum africanum (PA) used to treat benign prostatic hyperplasia (BPH) inhibits proliferation of prostate stromal cells from BPH tissues. To determine underlying mechanisms, we compared proliferative and apoptotic responses to PA between BPH and non-BPH prostate stromal cells with a focus on the specific reaction displayed by stromal cell subsets. An interaction of PA with growth factors and hormones was also investigated.

METHODS

Primary prostate stromal cells from BPH/LUTS patients undergoing open prostatectomy (n = 3) and patients without benign prostatic hyperplasia (BPH) undergoing cystectomy (n = 3) were treated with PA. Cells were characterized by immunofluorescence. Sensitivity to PA was determined using proliferation assays. Apoptosis, transforming growth factor B1 (TGFB1), fibroblast growth factor 2 (FGF2), vimentin, alpha smooth muscle actin (alphaSMA), and smoothelin expression were examined after PA treatment. Cell immunophenotype and proliferation were tested after incubating cells with PA plus either FGF2, TGFB1, vascular endothelial growth factor (VEGF), dihydrotestosterone (DHT) or 17beta-estradiol (E2).

RESULTS

Antiproliferative potency and apoptosis induced by PA on stromal cells were increased in BPH versus non-BPH cells. Apoptosis targeted alphaSMA+ cells, more abundant in BPH cells. Downregulation of TGFB1 expression was induced by PA. FGF2 increased cells sensitivity to PA. Incubation with other mitogenic factors like VEGF, DHT, and E2 decreased sensitivity to PA. Both TGFB1 and E2 blocked the antiproliferative activity of PA.

CONCLUSIONS

Results suggest that PA is antiproliferative and apoptotic on proliferative prostate fibroblasts and myofibroblasts but not on smooth muscle cells. Mechanisms of action include TGFB1 downregulation and inhibition of FGF2 specific signaling.

Common botanical compounds inhibit the hedgehog signaling pathway in prostate cancer

Many botanical compounds have been proposed to prevent cancer. We investigated the cancer treatment and prevention abilities of apigenin, baicalein, curcumin, epigallocatechin 3-gallate (EGCG), genistein, quercetin, and resveratrol both in vivo in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice as well as in vitro in prostate cancer cell lines. In our experiments, these seven compounds act similarly to the Hedgehog antagonist cyclopamine, a teratogenic plant alkaloid, which had been previously shown to "cure" prostate cancer in a mouse xenograft model. With IC(50) values ranging from <1 to 25 mumol/L, these compounds can inhibit Gli1 mRNA concentration by up to 95% and downregulate Gli reporter activity by 80%. We show that four compounds, genistein, curcumin, EGCG, and resveratrol, inhibit Hedgehog signaling as monitored by real-time reverse transcription-PCR analysis of Gli1 mRNA concentration or by Gli reporter activity. Three compounds, apigenin, baicalein, and quercetin, decreased Gli1 mRNA concentration but not Gli reporter activity. Our results show that these compounds are also able to reduce or delay prostate cancer in vivo in TRAMP mice. All seven compounds, when fed in combination as pure compounds or as crude plant extracts, inhibit well-differentiated carcinoma of the prostate by 58% and 81%, respectively. In vitro, we show that all seven compounds also inhibit growth in human and mouse prostate cancer cell lines. Mechanistically, we propose the Hedgehog signaling pathway to be a direct or indirect target of these compounds. These botanicals at pharmacologic concentrations are potentially safer and less expensive alternatives to cyclopamine and its pharmaceutical analogues for cancer therapy.