Screening of selected medicinal plants for their hepatoprotective activity

Food and medicine have been the inseparable companions of mankind from the beginning of man’s existence and man had to contend with diseases that affected his life. Among the different sources of medicines, plants have been widely used for their healing abilities and have provided mankind with a large variety of potent drugs to alleviate suffering from various diseases. The ancient traditional Indian system of medicine, Ayurveda, is predominantly plant based, making use of native plants in spite of powerful contemporary modern medicine. The first chapter has been studied under different parts. The first part deals with the usefulness of plants to mankind, a brief introduction to herbal drugs where plants and phytoconstituents have been suggested as good alternatives to synthetic drugs. The next part deals with liver and its functions, liver disorders, reasons for liver disorders and finally the experimental models for the evaluation of antihepatotoxic activity. The last part is about reviews on plants used in general as hepatoprotectants to cure liver disorders and antioxidant activity of plants. The second chapter of the thesis explains the scope and objective of the present investigation in detail with the name of the plants selected to evaluate for their hepatoprotective activity. The plan of work in brief has also been explained in this chapter. The next chapter deals with the plant profile, ethnomedical/tribal literature information, chemical and pharmacological reviews of the selected two plants of my study. The subsequent experimental or materials and methods chapter of the thesis has been broadly divided into three sections. a) Pharmacognostical studies b) Chemical studies c) Pharmacological studies. The first section deals with collection, authentication, drying and powdering of the plant Cuscuta reflexa and Cassytha filiformis. The two plant materials were collected from different parts of Chennai, Tamil Nadu and authenticated. The dried and powdered plant materials were extracted with suitable solvents. The extraction procedures like cold maceration done for the powdered plant materials and standardisation of plant extracts had also been explained. Fresh plant materials were used for morphological and microscopical evaluation. The next part of the work was carried out in various phases, which includes pharmacognostical evaluation in order to establish the identity and to standardize the plant materials. Morphological and microscopical characters were also studied. Physicochemical parameters like total ash, acid insoluble ash, water soluble ash, sulphated ash values, alcohol soluble extractive and water soluble extractive values were determined. Fluorescence analysis was carried out for the plant powder and their extracts by treating with several reagents. The colour changes were observed under UV and visible lights. In the micro chemical analysis, the plant powders were treated with several reagents, and the colour changes were observed under microscope. Estimation of total phenolic and flavanoid content was done for all the extracts of both the plant materials. The preliminary phytochemical analysis of the plant powders and extracts were carried out. The section b of materials and methods deals with the isolation of phytoconstituents from the plant extracts using column chromatography by gradient elution method with solvents like n-hexane, petroleum ether, chloroform, ethyl acetate and methanol. The plant extracts were subjected to TLC and HPTLC analysis using several solvent systems. An in vitro antioxidant activity studies were also done for various extracts by different methods. The final section c of the chapter deals with the pharmacological investigation such as selection of animals and dose, acute toxicity studies, experimental model to damage liver with hepatotoxicant d-galactosamine, experimental design for screening of the plant extracts for in vivo hepatoprotective activity, their biochemical, histopathological parameters and finally statistical analysis for the biochemical parameters. The following chapter of the thesis deals with the results and discussion pertaining to the present study have been elaborated separately under corresponding sections of the previous chapter such as 5a, 5b and 5c supported by tables and figures. Finally I would like to conclude that my present study throws immense light on two angiosperm-parasitic taxa with reference to pharmacognostical, phytochemical and biological aspects enriching with new vistas