METHODS: Mice were initiated with single dose of 7,12-dimethylbenz[α]anthracene (DMBA) (390 nmol/100 μL) followed by, in subsequent week, repeated promotion (twice weekly; 22 weeks) with 12-O-tetradecanoylphorbol-13-acetate (TPA) (1.7 nmol/100 μL). Annonacin (85 nM) and curcumin (10 mg/kg; reference) were, respectively, applied topically to DMBA/TPA-induced mice 30 min before each TPA application for 22 weeks. Upon termination, histopathological examination of skin, liver and kidney as well as genes and proteins expression analysis were conducted to elucidate the potential mechanism of annonacin.
RESULTS: With comparison to the carcinogen control, Annonacin significantly increased the tumor latency period and reduced the tumor incidence, tumor burden and tumor volume, respectively. In addition, it also suppressed tumorigenesis manifested by significant reduction of hyperkeratosis, dermal papillae and number of keratin pearls on skin tissues. Annonacin also appeared to be non-toxic to liver and kidney. Significant modulation of both AKT, ERK, mTOR, p38, PTEN and Src genes and proteins were also observed in annonacin-targeted signaling pathway(s) against tumorigenesis.
CONCLUSIONS: Collectively, results of this study indicate that annonacin is a potential therapeutic compound targeting tumor promoting stage in skin tumorigenesis by modulating multiple gene and protein in cancer signaling pathways without apparent toxicity.
Materials and methods: Hepatotoxicity was induced with intraperitoneal injection of carbon tetrachloride (CCl4) (1 mL/kg b.wt.) once a week for 12 weeks. The hepato- and DNA protective effects of the extracts in different combinations were compared with that of a standard drug Clavazin (200 mg/kg b.wt.). Tissue alanine aminotransferase, alpha-fetoprotein, tumor necrosis factor alpha (TNF-α), isoprostanes-2α, malondialdehyde, and 8-hydroxydeoxyguanosine, the significant hallmarks of oxidative stress, were studied.
Results: Histopathological findings of the liver sections from the rat group which received CCl4+cabralealactone, solasodin, and salvadorin demonstrated improved centrilobular hepatocyte regeneration with moderate areas of congestion and infiltration comparable with Clavazin. For in silico study, the identified compounds were subjected to molecular docking with cyclooxygenase-2 and TNF-α followed by a molecular dynamics study, which indicated their potential as anti-inflammatory agents.
Conclusion: Cabralealactone, solasodin, and salvadorin confer some hepatoprotective and DNA-damage protective effects against CCl4-induced toxicity. They successfully restored the normal architecture of hepatocytes and have the potential to be used as inhibitor to main culprits, that is, cyclooxygenase-2 and TNF-α. They can combat oxidative stress and liver injuries both as mono and combinational therapies. However, combination therapy has more ameliorating effects.
METHODS AND RESULTS: Five groups of rats: normal control, cancer control, TPHE low dose, TPHE high dose and positive control (tamoxifen) were used for the in vivo study. Histopathological examination showed that TPHE significantly suppressed the carcinogenic effect of LA7 tumour cells. The tumour sections from TPHE-treated rats demonstrated significantly reduced expression of Ki67 and PCNA compared to the cancer control group. Using a bioassay-guided approach, the cytotoxic compound of TPHE was identified as a tricyclic sesquiterpene lactone, namely, 8β- hydroxyl- 4β, 15- dihydrozaluzanin C (HDZC). Signs of early and late apoptosis were observed in MCF7 cells treated with HDZC and were attributed to the mitochondrial intrinsic pathway based on the up-regulation of Bax and the down-regulation of Bcl-2. HDZC induced cell cycle arrest in MCF7 cells and increased the expression of p21 and p27 at the mRNA and protein levels.
CONCLUSION: This results of this study substantiate the anticancer effect of TPHE and highlight the involvement of HDZC as one of the contributing compounds that act by initiating mitochondrial-mediated apoptosis.