This study was carried out to assess the anticancer efficacy of linarin (LN), linarin acetate (LA) and acacetin (AC), the flavonoid compounds with the same flavone ring structure but different substitution, against human prostate cancer (PCA), LNCaP and DU145 cells. LN was isolated and purified from Chrysanthemum zawadskii; LA was chemically synthesized from LN, and AC obtained commercially. In each case, the cells were treated with these agents at 25-100 microM doses for 24-72 h. LN and LA showed moderate cell growth inhibition with different time kinetics as compared to AC. LN caused up to a 5-fold increase in cell death and LA enhanced cell death by up to 4-fold with the increase in treatment time in both cell lines. AC showed a time- as well as dose-dependent stronger cell growth inhibition (20-70%) accompanied by cell death as compared to LN and LA in both the cell lines. LN or LA did not show any profound effect on cell cycle arrest except for a moderate G1 arrest, whereas, AC showed a stronger G1 and/or G2-M arrest depending on the doses and treatment times. G1 arrest was associated with an increase in Cip1/p21 and a decrease in CDK2, CDK4 and CDK6 protein levels. G2-M arrest was associated with a decrease in Cdc25C, Cdc2/p34 and cyclin B1, which were more prominent in LNCaP compared to DU145 cells. LN, LA and AC induced cell death was associated with significant increase in apoptosis induction (up to 5-6-fold) accompanied by poly-(ADP-ribose) polymerase cleavage. Overall, AC showed more potent anticancer efficacy among these three flavonoids, which was diminished when its flavone ring was modified by disaccharide rhamnose substitution at C7 (LN) or acetylation of this substituted group (LA). These findings, for the first time, revealed the structural determinants in anticancer efficacy and mechanisms of these three flavonoids against human PCA cells.

BackgroundArctiin, isolated from Forsythia suspensa has been reported to have anti-inflammatory, anti-oxidant, antibacterial, and antiviral effects in vitro. However, there has been a lack of studies regarding its effects on immunological activity. The aim of this study is to investigate the anti-inflammatory potential and possible mechanisms of arctiin in LPS-induced macrophages.MethodsWe investigated the mRNA and protein levels of proinflammatory cytokines through RT-PCR and western blot analysis, followed by a FACS analysis for surface molecule changes.ResultsArctiin dose dependently decreased the production of NO and proinflammatory cytokines such as IL-1β, IL-6, TNF-α, and PGE2, and it reduced the gene and protein levels as determined by RT-PCR and western blot analysis, respectively. The expression of co-stimulatory molecules such as B7-1 and B7-2 were also inhibited by arctiin. Furthermore, the activation of the nuclear transcription factor, NF-κB in macrophages was inhibited by arctiin.ConclusionTaken together these results provide evidence of the bioactivity of arctiin in inflammatory diseases and suggest that arctiin may exert anti-inflammatory effect by inhibiting the pro-inflammatory mediators through the inactivation of NF-kB.

Betulinic acid (BA), a pentacyclic triterpene isolated from Lycopus lucidus, has been reported to be a selective inducer of apoptosis in various human cancer and shown anti-inflammatory and immunomodulatory properties. We postulated that BA modulates the immunomodulatory properties at least two groups of protein mediators of inflammation, interleukin-1beta (IL-1beta) and the tumor necrosis factor-alpha (TNF-alpha) on the basis of the critical role of the monocytes and tissue macrophages in inflammatory and immune responses. TNF-alpha and IL-1beta were produced by BA in a dose dependent manner at concentration of 0.625 and 10 microg/mL. The production of NO associated with iNOS was inhibited when treated with LPS at the concentration of 2.5 to 20 microg/mL of BA whereas COX-2 expression was decreased at 2.5 to 20 microg/mL. These modulations of inflammatory mediators were examined in LPS-stimulated RAW 264.7 cells and peritoneal macrophages. The morphology of macrophage was also examined and enhanced surface CD 40 molecule was expressed when treated BA at 0.625 to approximately 5 microg/mL with or without LPS. Furthermore, BA (20 microg/mL) enhanced apoptosis by producing DNA ladder in the RAW 264.7 cells. Our results indicated that BA induced activation of macrophage and pro-inflammatory cytokines. This may provide a molecular basis for the ability of BA to mediate macrophage, suppress inflammation, and modulate the immune response.

The herb, Chrysanthemum zawadskii var, latilobum commomly known as Gu-Jul-Cho in Korea, used in traditional medicine to treat pneumonia, bronchitis, cough, common cold, pharyngitis, bladder-related disorders, gastroenteric disorders, and hypertension. Linarin is the main active compound and the biological mechanisms of its activity are unclear. It is believed that effects of this herb may be exerted through the pluripotent effectors of linarin due to its ability to treat a variety of afflictions. In this study, the effects of linarin on the mouse macrophages cell line, RAW 264.7, were investigated. It was found that linarin could activate macrophages by producing cytokines. Monocytes and tissue macrophages produce at least two groups of protein mediators of inflammation, interleukin 1 (IL-1) and the tumor necrosis factor (TNF). Recent studies have shown that TNF and IL-1 modulate the inflammatory function of endothelial cells, leukocytes, and fibroblasts. TNF-alpha production by macrophages treated with linarin occured in a dose dependent manner. However, IL-1 production was largely unaffected by this natural product. This study demonstrated the ability of linarin to activate macrophages both directly and indirectly. Linarin also affect both cytokine production and nitric oxide inhibition, in addition to the expression of some surface molecules. Nitric oxide (NO), derived from L-argin-ine, is produced by two forms(constitutive and inducible) of nitric oxide synthase (NOS). The NO produced in large amounts by inducible NOS is known to be responsible for the vasodilation and hypotension observed in septic shock. Linarin was found to inhibit NO production in the LPS-activated RAW 264.7 cells. Linarin may be a useful candidate as a new drug for treating endotoxemia and the inflammation accompanied by NO overproduction. The linarin-treated total lymphocytes exhibited cytotoxicity in a dose dependent manner between 20 microg/ml and 40 microg/ml. These results suggest that linarin may function through macrophage activation.

We isolated a coumarin compound decursin (C19H20O5; molecular weight 328) from Korean angelica (Angelica gigas) root and characterized it by spectroscopy. Here, for the first time, we observed that decursin (25-100 μmol/L) treatment for 24 to 96 hours strongly inhibits growth and induces death in human prostate carcinoma DU145, PC-3, and LNCaP cells. Furthermore, we observed that decursinol [where (CH3)2-C=CH-COO- side chain of decursin is substituted with -OH] has much lower effects compared with decursin, suggesting a possible structure-activity relationship. Decursin-induced growth inhibition was associated with a strong G1 arrest (P < 0.001) in DU145 and LNCaP cells, and G1, S as well as G2-M arrests depending upon doses and treatment times in PC-3 cells. Comparatively, decursin was nontoxic to human prostate epithelial PWR-1E cells and showed only moderate growth inhibition and G1 arrest. Consistent with G1 arrest in DU145 cells, decursin strongly increased protein levels of Cip1/p21 but showed a moderate increase in Kip1/p27 with a decrease in cyclin-dependent kinases (CDK); CDK2, CDK4, CDK6, and cyclin D1, and inhibited CDK2, CDK4, CDK6, cyclin D1, and cyclin E kinase activity, and increased binding of CDK inhibitor (CDKI) with CDK. Decursin-caused cell death was associated with an increase in apoptosis (P < 0.05-0.001) and cleaved caspase-9, caspase-3, and poly(ADP-ribose) polymerase; however, pretreatment with all-caspases inhibitor (z-VAD-fmk) only partially reversed decursin-induced apoptosis, suggesting the involvement of both caspase-dependent and caspase-independent pathways. These findings suggest the novel anticancer efficacy of decursin mediated via induction of cell cycle arrest and apoptosis selectively in human prostate carcinoma cells.