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Secondary metabolites from numerous plant sources have been developed as anti-cancer reagents and compounds such as resveratrol, podophyllotoxin and zerumbone are of particular importance in this regard. Since their de novo chemical synthesis is both arduous and commercially expensive, there has been an impetus to develop viable, biotechnological methods of production. Accordingly, this review focuses on recent developments in the field, highlighting the use of micropropagation, cell suspension cultures, callus cultures, hairy root cultures, recombinant microbes and genetically modified higher plants. Optimization of media and culture conditions, precursor feeding, immobilization and the use of chemical or physical elicitation in various protocols has lead to increase in resveratrol and podophyllotoxin production. Heterologous gene transformation of higher plants with stilbene synthase derived from Arachis hypogaea or Vitis vinifera lead to resveratrol production with the concomitant increase in resistance to plant pathogens. Interestingly, genetic transformation of Podophyllum hexandrum and Linum flavum with Agrobacterium rhizogenes resulted in Ri-T-DNA gene(s)-mediated enhancement of podophyllotoxin production. Zerumbone yields from tissue cultured plantlets or from suspension cultures are generally low and these methods require further optimization. In microbes lacking the native resveratrol or zerumbone biosynthesis pathway, metabolic engineering required not only the introduction of several genes of the pathway, but also precursor feeding and optimization of gene expression to increase their production. Data pertaining to safety and toxicity testing are needed prior to use of these sources of anti-cancer compounds in therapy.

BackgroundHedychium coronarium Koen. (Zingiberaceae) is traditionally used as medicine in countries such as India, China, and Vietnam for treatment of various ailments including cancer. However, in spite of its implied significance in cancer treatment regimes, there are no reports so far involving the anticancerous attributes of H, coronarium ethanol extract (HCEE) on cancer cells and a more comprehensive study on its mechanism is still lacking.Materials and methodsThe cytotoxicity of HCEE was evaluated by MTT and clonogenic survival assay. Annexin V/propidium iodide (PI), Hoechst 33342 staining, and TUNEL assay were performed to detect apoptosis. Cell cycle analysis was performed using PI staining. JC-1 and 2′,7′-dichlorodihydrofluorescein diacetate assay were used to check the levels of MMP and ROS, respectively. Western blot analysis was carried out to measure the expression levels of proteins. Migration and invasion activity were assessed by wound healing and Transwell membrane assay, respectively.ResultsAntiproliferative effect of HCEE was investigated in various cancerous and normal cell lines. Among these, HCEE significantly inhibited the survival of HeLa cells without affecting the viability of normal human umbilical vein endothelial cells. Annexin V/PI, Hoechst staining, and TUNEL assay showed HCEE induced apoptosis in HeLa cells in a dose-dependent manner. HCEE promoted cell cycle arrest at G1 phase in HeLa cells by upregulating the levels of p53 and p21 and downregulating the levels of cyclin D1, CDK-4, and CDK-6. Moreover, HCEE treatment upregulated the expression of Bax and downregulated the expression of Bcl-2. Additionally, HCEE activated the caspase cascade by increasing the activities of caspase-9, caspase-8, and caspase-3. The expression levels of Fas ligand and Fas were also upregulated. Further, HCEE inhibited the migratory potential of HeLa cells by downregulating MMP-2 and MMP-9 expression levels.ConclusionOur results indicate H. coronarium exerts antiproliferative and apoptotic effects against HeLa cells, and therefore may be used for treatment against cervical cancer.

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