Backgrounds Colon cancer is the third most deadly and one of the most diagnosed diseases in the world. Although routine screening and early detection during last decades has improved the survival, colon cancer still claims hundreds of thousands lives each year worldwide. Surgery and chemotherapy is mainstay of current treatment, nevertheless toxicity associated with this treatment underscores the urgency of demand of a better therapeutics. Close to 50% of current chemotherapeutic drugs are direct or indirect descendants compounds isolated from medicinal plants, which indicate plants are great potential sources of novel therapeutics. In our literature review we found Eclipta alba to posses many pharmacological activities, including those with anticancer potentials. However, no study on anticancer activity of this kind has been reported. Methods Phytochemicals were extracted by maceration method from shade dried whole plant of Eclipta alba using methanol as a solvent. The anticancer effect of extract was investigated on various cancer cell lines like human colorectal carcinoma (HCT-116), human prostate cancer (PC-3), Michigan cancer foundation-breast cancer (MCF-7) and renal cell carcinoma (RCC-45). We have also studied the effects on normal human embryonic lung fibroblast cell (WI-38) using MTT (methyl thiazoldiphenyltetrazolium bromide) assay, clonogenic (colony formation) and migration assay. Finally obtained results were analyzed using ANNOVA and Dunnett’s test. Results Results obtained from MTT assay revealed that the methanolic extract of Eclipta alba carried significant (p < 0.005) specificity against HCT-116 cells as compared to the other cancer cells. This extract also showed minimal or nontoxicity to WI-38 cells. Migration as well as clonogenic assays also confirmed the anticancer potential of the extract against HCT-116 cells. Conclusion This is a unique finding of its kind because the specific anticancer effect with minimal toxicity on normal cells has not been reported on Eclipta alba extract. Finally this finding opens up a great possibility to develop a novel antitumor drug candidate against deadly colon cancer in the future.

Aggregation of proteins with the expansion of polyglutamine tracts in the brain underlies progressive genetic neurodegenerative diseases (NDs) like Huntington's disease and spinocerebellar ataxias (SCA). An insensitive cellular proteotoxic stress response to non-native protein oligomers is common in such conditions. Indeed, upregulation of heat shock factor 1 (HSF1) function and its target protein chaperone expression has shown promising results in animal models of NDs. Using an HSF1 sensitive cell based reporter screening, we have isolated azadiradione (AZD) from the methanolic extract of seeds of Azadirachta indica, a plant known for its multifarious medicinal properties. We show that AZD ameliorates toxicity due to protein aggregation in cell and fly models of polyglutamine expansion diseases to a great extent. All these effects are correlated with activation of HSF1 function and expression of its target protein chaperone genes. Notably, HSF1 activation by AZD is independent of cellular HSP90 or proteasome function. Furthermore, we show that AZD directly interacts with purified human HSF1 with high specificity, and facilitates binding of HSF1 to its recognition sequence with higher affinity. These unique findings qualify AZD as an ideal lead molecule for consideration for drug development against NDs that affect millions worldwide.

Huntington's disease (HD) is an autosomal dominantly inherited neurodegenerative disorder caused by expansion of CAG repeats in the coding area of huntingtin gene. In the HD brain, mutant huntingtin protein goes through proteolysis, and its amino-terminal portion consisting of polyglutamine repeats accumulate as inclusions that result in progressive impairment of cellular protein quality control system. Here, we demonstrate that partial rescue of the defective protein quality control in HD model mouse by azadiradione (a bioactive limonoids found in the seed of Azadirachta indica) could potentially improve the disease pathology. Prolonged treatment of azadiradione to HD mice significantly improved the progressive deterioration in body weight, motor functioning along with extension of lifespan. Azadiradione-treated HD mice brain also exhibited considerable decrease in mutant huntingtin aggregates load and improvement of striatal pathology in comparison with age-matched saline-treated HD controls. Biochemical analysis further revealed upregulation and activation of not only HSF1 (master regulator of protein folding) but also Ube3a (an ubiquitin ligase involved in the clearance of mutant huntingtin) in azadiradione-treated mice. Our results indicate that azadiradione-mediated enhanced folding and clearance of mutant huntingtin might underlie improved disease pathology in HD mice and suggests that it could be a potential therapeutic molecule to delay the progression of HD.

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