Розмарин и рак Rosmarinus officinalis & cancer Научные исследования
Carnosol: Sources, Chemistry, and Synthesis
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- 4. Anti-oxidant Activity of Carnosol
- 5. Anti-inflammatory Activity of Carnosol
- 6. Anti-Cancer properties of Carnosol
- 6.2 Carnosol and Breast Cancer
- 6.3 Carnosol and Skin Cancer
- 6.4 Carnosol and Leukemia
- 6.5 Carnosol and Colon Cancer
3. Carnosol: Sources, Chemistry, and SynthesisMediterranean herbs including rosemary and sage have been used for culinary purposes and for their medicinal properties for millennia. Carnosol was first isolated from sage (Salvia carnosa) in 1942 and the chemical structure was first established in 1964 by Brieskorn et al [17]. Rosemary and sage have been known to contain a variety of polyphenols such as carnosol, carnosic acid, rosmanol, rosmarinic acid as well as others [18]. It has been estimated that approximately 5% of the dry weight of rosemary leaves contains carnosol and carnosic acid, however, this fraction is estimated to account for > 90% of the antioxidant activity [19]. Carnosol is an ortho-diphenolic diterpene with an abietane carbon skeleton (Figure 1) with hydroxyl groups at positions C-11 and C-12 and a lactone moiety across the B ring [20]. Carnosol is the product of oxidative degradation of carnosic acid (Figure 2) [21]. The most popular and expensive way to procure a highly purified form of carnosol is through extraction and purification from natural sources such as rosemary. Recently, a semi-synthetic process has been described using pisiferic acid (Figure 2) extracted from Sawara (Chamaecyparis pisifera) leaves, a cypress tree native to Japan, to synthesize carnosic acid and then to carnosol [22]. Carnosic acid was prepared through oxidation of pisfiric acid using three different methods: a) mCBPO, b) CAMCBP in CH2CL2, or c) IBX in CHCl2-CH3OH. The third semi-synthetic reaction developed had an overall yield of 72% while the first two had considerably lower yields as low as 10%. Carnosol was prepared from carnosic acid in the presence of silver oxide in CH2CL2 with a purified yield of 67%. Alternatively, carnosic acid in the presence of methanol for 1 week at room temperature will oxidize carnosic acid to carnosol [23,24]. 4. Anti-oxidant Activity of CarnosolThe health promoting properties of rosemary and sage have been attributed to the antioxidant activity of polyphenols present in these extracts [25–28]. Reactive oxygen species and depletion of antioxidant enzymes have been suggested to promote a variety of biological responses including nueurogenerative, inflammatory conditions, cardiovascular disease, and carcinogenesis of various tissues [29]. Rosemary extracts were prepared and shown by the DPPH (2,2-diphenyl-1-pycrilhydrazil hydrate) radical scavenging activity assay to have a radical scavenging activity up to 95.1% [25] with approximately 90% of the antioxidant activity attributed to the diterpenes carnosol and carnosic acid [19]. Carnosol has been shown to inhibit Cu2+ induced LDL oxidation and lipid free radicals in mouse liver microsomes [30] and are good scavengers of peroxyl radicals (CCl302) [19]. The antioxidant response element is believed to be activated through the catechol-hydroxyl groups of carnosol and is converted to a carnosol quinone [8]. This quinone derivative is the main anti-oxidation product of carnosol essentially voiding it of any antioxidant activity [31] and under appropriate conditions the antioxidant activity can be recovered [32]. The glutathione-S-transferase (GST) family of phase II detoxification enzymes catalyze the reaction of glutathione with electrophiles and have been a target of interest for cancer [33]. Carnosol by intraperitoneal administration has been shown to enhance the in vivo activity of GST and quinone reductase in the liver of the female rat [34]. Carnosol (100–400 mg/kg) increased GST activity by 1.6 to 1.9 fold increase. 5. Anti-inflammatory Activity of CarnosolDeregulated inflammatory signaling including excess nitric oxide (NO) produced by NO synthase (iNOS) occurs during inflammation and the multi-step process of carcinogenesis which has led to the search for agents that decrease inflammatory signaling pathways. Raw 264.7 cells treated with carnosol reduced LPS stimulated NO production with an IC50 of 9.4 uM [35]. This led to an inhibition of the NF-kB, p38 and p44/42 mitogen activated protein kinase (MAPK). In another study, carnosol was shown to activate the peroxisome proliferator-activated receptor gamma. Carnosol has also been shown to reduce the pro-inflammatory leukotrienes in intact polymorphonuclear leukocytes (PMNL), inhibit 5-lipoxygenase, antagonize the intracellular ca2+ mobilization, and inhibit the secretion of leukocyte elastase [6]. In addition, carnosol blocks protein kinase C signaling and inhibits the binding of AP-1 to the COX-2 promoter which should be noted is fundamentally different than the synthetic COX-2 inhibitors (e.g. celecoxib) that function as direct inhibitors of Cox-2 [36]. 6. Anti-Cancer properties of Carnosol6.1 Carnosol and Prostate CancerIn our laboratory, we are currently investigating the potential role of carnosol for the prevention and treatment of prostate cancer (PCa). Earlier we provided evidence that carnosol promotes G2 cell cycle arrest in PC3 cells decreasing cell viability [37]. The anti-cancer properties of carnosol were associated with a potential to modulate multiple signaling pathways such as the cell cycle related proteins, PI3K/AKT, and apoptotic related proteins [38]. To understand the effects of carnosol in PC3 cells we performed an antibody array that identified 36 proteins downregulated at least 50% and 24 proteins that were up-regulated at least 200% including a target within the 5’-AMP-activated protein kinase (AMPK) protein subunit. AMPK has been shown to regulate the growth and survival of cancer cells. We observed a dose dependent increase in the phosphorylated forms of AMPK-α (Thr172) which has been shown to be upstream of the mammalian target of rapamycin (mTOR). We were also able to show a decrease in the phosphorylation of mTOR (Ser2448) and related downstream targets. Recently, we have shown that carnosol has a unique property where it functions as a dual disruptor of both androgen and estrogen receptor α in PCa [9]. Using a TR-FRET assay we were able to show that carnosol is an antagonist at both the AR and ERα with no agonist properties. To our knowledge this is a unique property as several synthetic agents including fulvestrant, toremifene, and tamoxifen have been investigated as dual disruptors, however, through dose escalation it is not uncommon for these synthetic agents to display agonist properties at the AR [39–42]. Carnosol displayed minimal effects on non-tumorigenic prostate epithelial cells when treated with increasing concentrations and was similar in effect with what was observed with flutamide and tamoxifen. Interestingly, we observed an increase in protein expression of androgen receptor with tamoxifen and flutamide which was reversible with co-treatment with carnosol. In a xenograft study, athymic nude mice were implanted with 22Rv1 cells and treated with carnosol orally five days weekly. At the conclusion of the study mice treated with carnosol had a significant suppression in tumor growth by 36% (P = 0.028) and circulating PSA by 26% (P = 0.0042). 6.2 Carnosol and Breast CancerCarnosol and carnosic acid were investigated for their antimicrobial and anti-cancer properties in breast cancer [43]. Both carnosol and carnosic acid were shown to have cytotoxic activity against MCF-7 cells with an IC50 of 82 and 96 µM. We have observed similar results with carnosol decreasing the cell viability of MCF-7 cells [9], AU565, and MDA-MB-231 (unpublished results). Further studies are needed to determine if carnosol preferentially targets ER+ breast cancer cells versus ER− breast cancer cells. Carnosol was evaluated to determine the ability of carnosol to inhibit the formation of DMBA-DNA adduct formation and DMBA-induced mammary tumorigenesis in the female rat [44]. Intraperitoneal administration of rosemary and carnosol were shown to significantly inhibit mammary adduct formation by 44% and 40%, respectively. At week 20 post DMBA treatment carnosol (100 and 200 mg/kg) administration resulted in a significant inhibition of tumor formation was observed with decreases of 33% (P < 0.001) and 30% (p < 0.005), respectively. The role of carnosol in preventing DMBA-induced mammary tumorigenesis may be partially explained by carnosol inducing detoxification enzymes including GST and quinone reductase which carnosol has been shown to modulate in other studies [34,45]. Another consideration is the microsomal metabolism of endogenous estrogens. CD-1 mice were administered rosemary (2%) in their diet led to an increase in the oxidation and glucuronidation of estradiol and estrone inhibiting their uterotropic action [46]. Using mammary epithelial cells carnosol was shown to block the increased binding of AP-1 to the COX-2 promoter [36]. In addition, carnosol was shown to inhibit the activation of PKC, ERK1/2, p38, and c-jun NH2-terminal kinase mitogen activated protein kinase. Overexpression of c-jun inhibited the suppressive effects of carnosol.
The migration and invasion of B16/F10 mouse melanoma cells was shown to be inhibited by carnosol [47]. Carnosol treatment resulted in the decrease of MMP-9 mRNA and protein expression with an IC50 value for MMP-9 mRNA at 5 µM suggesting regulation at the transcriptional level. Several upstream regulators of MMP-9 including AKT, p38, and JNK and to a lesser extent Erk1/2 phosphorylation activities were modulated by carnosol. The activity of NF-kB was also inhibited by carnosol (10 µM). 6.4 Carnosol and LeukemiaCarnosol was shown to induce apoptosis by disrupting the mitochondrial membrane potential in three acute leukemia cell lines which included SEM, RS4:11, and MV4:11 [48]. At 18 µM carnosol did not induce cell death of peripheral blood mononuclear cells (PBMCs) isolated from healthy volunteers while the same dose in cell lines resulted in apoptosis. Apoptosis and alterations in mitochondrial membrane potential resulted from carnosol treatment. There is evidence to suggest that carnosol targets the anti-apoptotic members of the Bcl-2 family of proteins. A reduction in Bcl-2 protein expression ranged from 33 to 53% in the three cell lines. Several phytochemicals have been reported to have sensitizing properties when used in combination with chemotherapies in a variety of cancer cell lines. Interestingly, co-treatments of carnosol and AraC, or methotrexate, or vincristine resulted in a delay in chemotherapy induced DNA fragmentation [49]. Further studies are needed to understand how co-treatment of carnosol with chemotherapeutic agents delays DNA fragmentation. 6.5 Carnosol and Colon CancerUsing a model for colon tumorigenesis dietary administration of carnosol was observed to decrease intestinal multiplicity by 46% in the C57BL/6J/Min/+ (Min/+) mouse [50]. Mice were administered a diet with or without carnosol (0.1%). Carnosol was shown to restore E-cadherin and β-catenin to the enterocyte membranes producing a phenotype similar to the APC+/+ wild-type (WT) littermate. Inherited mutations in the APC tumor suppressor gene result in the generation of familial adenomatous polyposis coli with somatic mutations in >80% of sporadic colon cancers [51]. These results suggest that carnosol prevents Apc-associated tumorigenesis in a mouse model, however, further studies are needed. жүктеу/скачать 2.03 Mb. Достарыңызбен бөлісу:
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