MSc.

Ginger (Zingiber officinale Rosc.) is an important spice crop with immense medicinal properties and health beneficial effects. Various bioactive compounds present in ginger are responsible for the medicinal properties. Gingerols are the most pharmacologically active compounds in ginger and posses anti-inflammatory, analgesic, antipyretic, gastro protective, cardiotonic and antihepatotoxic activities. Of the different gingerols, the most potent and pharmacologically bioactive compound is 6-gingerol and is now a target for drug development. Centre for Plant Biotechnoloy and Molecular Biology maintains a good collection of germplasm of ginger somaclones regenerated through direct/ indirect of organogenesis/ embryogenesis and in vitro mutagenesis.
The investigations on “Screening ginger (Zingiber officinale Rosc.) somaclones for gingerol content and validation of anticancerous properties of gingerol” were carried out at Centre for Plant Biotechnology and Molecular Biology and Distributed Information Centre, College of Horticulture, Kerala Agricultural University, Thrissur during August 2013 to June 2015. The objectives of the study were to screen ginger somaclones for gingerol content, to identify cancer targets for gingerols and shogoal using in silico tools and to validate anticancerous properties of gingerol.
Fifty somaclones of ginger derived from the cultivar Maran regenerated through direct /indirect methods of regeneration and in vitro mutagenesis were raised in field during 2013-14 season. Dry ginger was prepared from the harvested clones and oleoresin was extracted by solvent extraction. The content of pungent principles in fifty ginger somaclones were estimated using High Performance Liquid Chromatography. Accelry Discovery studio 4.0 software was used for molecular docking of four ginger ligands viz. 6-gingerol, 8-gingerol, 10-gingerol and 6–shogaol and other approved drugs with the selected targets for cancer. Different cell lines obtained from Amala Cancer Research Centre, Thrissur viz. HCT15 (colon cancer),
Raw 264.7 (mouse leukaemic monocyte macrophage) and L929 (murine fibro sarcoma) were used to study the anticancerous properties of 6-gingerol.
The somaclones studied showed variability in the content of pungency principles like 6-gingerol (3.33-13.83g/kg dry ginger powder), 8-gingerol (0.2 - 0.94g/kg), 10-gingerol (0.17-1.15g/kg) and 6-shogaol (0.61 - 2.33 g/kg) . Somaclones regenerated after in vitro mutagenesis recorded higher content of gingerol. Principle Component Analysis done for clustering somaclones based on quality parameters could locate five high gingerol yielding somaclones viz. Mse 20Gy 418, Mse 20Gy 175, Mse 20Gy 862, Mc 10Gy 330 and Mc 10Gy 168.
Molecular docking was attempted with four ginger ligands and eleven approved drugs with thirteen targets.In the molecular docking studies, ginger ligands showed good interactions with some of the cancer targets selected for all types of cancer. The Difference between C-Docker interaction energy and C-Docker energy was found minimum for the target c-Met (2.287) when 6-gingerol was docked. Minimum binding energy was recorded for 6-gingerol with targets Activator protein-1 (-138.2092) and Epidermal Growth Factor Receptor (-107.9914). Similary, for 8-gingerol, minimum binding energy was recorded with Activator protein-1 (-140.5949) and Oestrogen receptor (-100.0471), for 10-gingerol with Epidermal Growth Factor Receptor (-131.1699) and Ribosomal S6 kinase (-102.6721) and for 6- shogaol with Activator protein-1 (-117.683) and Epidermal Growth Factor Receptor (-107.9644). The maximum number of hydrogen bonds (5) for 6-gingerol were recorded with target follistatin. Studies on ADME/Toxicity properties showed that 6- gingerol was superior with respect to absorption, solubility and less neurotoxic effect as compared to other ginger ligands and approved drugs. Based on the results of docking and ADME/ Toxicity properties, 6-gingerol was selected for cell culture studies to validate the anticancerous properties.
The phytocompound 6-gingerol was found cytotoxic to all the three cancer cells lines studied. The cytotoxicity increased with increase in concentration of 6-
gingerol. The IC50 values recorded for different cancer cell lines, 24 h. after treatment (100 μM for HCT15, 102 μM for L929 and 102 μM for Raw 264.7) showed the uniform cytotoxicity in the three cell lines studied.
The investigations paved way to locate high gingerol yielding somaclones, to prove the effectiveness of 6-gingerol as an anticancerous phytochemical through molecular docking and cell culture studies and to highlight the potential of 6-gingerol for drug development. The study also gave an insight into the use of pungent phenolic compounds studied in ginger for other medicinal applications.