Inhibition of in-vitro simvastatin metabolism in rat liver microsomes by bergamottin, a component of grapefruit juice

Pharmacokinetics and pharmacodynamic interaction of bergamottin with atorvastatin in rats

1. The pharmacokinetics and pharmacodynamic of concomitant administration of atorvastatin with bergamottin were investigated perspectives to reveal the potential herb-drug interaction between these two drugs.2. The hyperlipidaemia-induced Wistar rats received atorvastatin with or without bergamottin (2.5 mg/kg). The concentration of atorvastatin in the rats' serum was determined using an established HPLC/MS/MS method. The pharmacokinetic parameters were calculated using DAS software. Lipid levels were determined.3. Bergamottin increases the C_max (from 48 ± 5 ng/mL to 89 ± 7 ng/mL), AUC_0-∞ (from 176 ± 27 to 552 ± 131 h∗μg/L), and the elimination half-life of atorvastatin (t_1/2) of atorvastatin. Co-administration of atorvastatin with bergamottin decreased total cholesterol (by 14%), low-density lipoproteins-cholesterol (by 20%), and triglyceride (by 12%), but increased thigh-density lipoprotein-cholesterol, when compared with atorvastatin alone.4. Co-administration of bergamottin and atorvastatin alters both pharmacokinetics and pharmacodynamics of atorvastatin. This study provides pre-clinical information evidence that bergamottin could potentiate the therapeutic efficacy of atorvastatin or increase its accumulation and adverse effects.

Bergamottin a CYP3A inhibitor found in grapefruit juice inhibits prostate cancer cell growth by downregulating androgen receptor signaling and promoting G0/G1 cell cycle block and apoptosis

Prostate cancer is the second leading cause of cancer related death in American men. Several therapies have been developed to treat advanced prostate cancer, but these therapies often have severe side effects. To improve the outcome with fewer side effects we focused on the furanocoumarin bergamottin, a natural product found in grapefruit juice and a potent CYP3A inhibitor. Our recent studies have shown that CYP3A5 inhibition can block androgen receptor (AR) signaling, critical for prostate cancer growth. We observed that bergamottin reduces prostate cancer (PC) cell growth by decreasing both total and nuclear AR (AR activation) reducing downstream AR signaling. Bergamottin’s role in reducing AR activation was confirmed by confocal microscopy studies and reduction in prostate specific antigen (PSA) levels, which is a marker for prostate cancer. Further studies revealed that bergamottin promotes cell cycle block and accumulates G0/G1 cells. The cell cycle block was accompanied with reduction in cyclin D, cyclin B, CDK4, P-cdc2 (Y15) and P-wee1 (S642). We also observed that bergamottin triggers apoptosis in prostate cancer cell lines as evident by TUNEL staining and PARP cleavage. Our data suggests that bergamottin may suppress prostate cancer growth, especially in African American (AA) patients carrying wild type CYP3A5 often presenting aggressive disease.

Biomolecular Targets of Oxyprenylated Phenylpropanoids and Polyketides

Oxyprenylated secondary metabolites (e.g. phenylpropanoids and polyketides) represent a rare class of natural compounds. Over the past two decades, this group of phytochemicals has become a topic of intense research activity by several teams worldwide due to their in vitro and in vivo pharmacological activities, and to their great therapeutic and nutraceutical potential for the chemoprevention of acute and chronic diseases affecting humans. Such investigations have provided evidence that oxyprenylated secondary metabolites are able to interact with several biological targets at different levels accounting for their observed anticarcinogenic, anti-inflammatory, neuroprotective, immunomodulatory, antihypertensive, and metabolic effects. The aim of the present contribution is to provide a detailed survey of the so far reported data on the capacities of selected oxyprenylated phenylpropanoids and polyketides to trigger receptors, enzymes, and other types of cellular factors for which they exhibit a high degree of affinity and therefore evoke specific responses. With respect to the rather small amounts of these compounds available from natural sources, their chemical synthesis is also highlighted.

From traditional Ayurvedic medicine to modern medicine: identification of therapeutic targets for suppression of inflammation and cancer

Cancer is a hyperproliferative disorder that involves transformation, dysregulation of apoptosis, proliferation, invasion, angiogenesis and metastasis. Extensive research during the last 30 years has revealed much about the biology of cancer. Drugs used to treat most cancers are those that can block cell signalling, including growth factor signalling (e.g., epidermal growth factor); prostaglandin production (e.g., COX-2); inflammation (e.g., inflammatory cytokines: NF-kappaB, TNF, IL-1, IL-6, chemokines); drug resistance gene products (e.g., multi-drug resistance); cell cycle proteins (e.g., cyclin D1 and cyclin E); angiogenesis (e.g., vascular endothelial growth factor); invasion (e.g., matrix metalloproteinases); antiapoptosis (e.g., bcl-2, bcl-X(L), XIAP, survivin, FLIP); and cellular proliferation (e.g., c-myc, AP-1, growth factors). Numerous reports have suggested that Ayurvedic plants and their components mediate their effects by modulating several of these recently identified therapeutic targets. However, Ayurvedic medicine requires rediscovery in light of our current knowledge of allopathic (modern) medicine. The focus of this review is to elucidate the Ayurvedic concept of cancer, including its classification, causes, pathogenesis and prevention; surgical removal of tumours; herbal remedies; dietary modifications; and spiritual treatments.