Junaid Aslam

Catharanthus roseus alkaloids: application of biotechnology for improving yield

Catharanthus roseus (L.) G. Don. is a well known medicinal plant. It produces several phyto-compounds many of which show anticancerous properties. The yields of these compounds are however, very low. In this present article, the current development of secondary metabolite synthesis in C. roseus involving biotechnology has been reviewed keeping in mind the various basic factors that influence yield. The importance of cell culture, the role of culturing conditions and other approaches aiming at higher production of alkaloids have been discussed. The genes encoding important enzymes, proteomics, expressed sequence tag and transcription factors in relation to alkaloid yield have also been summarized in order to understand the regulatory mechanisms of C. roseus.

Cultural conditions affect somatic embryogenesis in Catharanthus roseus L. (G.) Don

We established an efficient plant regeneration system for Catharanthus roseus L. (G.) Don through somatic embryogenesis. Embryogenic callus was induced from hypocotyl of seed germinated in vitro. Somatic embryogenesis in Catharanthus has been categorized into three distinct stages: (1) initiation and proliferation of embryo; (2) maturation, and; (3) germination or plantlet conversion. Beside plant growth regulators, various stages of embryogenesis were screened for their response to a wide variety of factors (pH, gelrite, light, sugar alcohols, polyethyleneglycol and amino acids), which affect embryogenesis. All of the tested factors had a small to marked influence on embryogeny and eventual conversion to plantlets. The plantlets were acclimatized successfully in a greenhouse. To our knowledge, this is the first report describing a detailed study of various cultural factors which regulate embryogenesis in C. roseus. The results discussed in this paper may be used in mass propagation to produce medicinal raw material, and the embryo precursor cells could be used in genetic modification programmes that aim to improve the alkaloid yield as well.

Influence of freezing and non-freezing temperature on somatic embryogenesis and vinblastine production in Catharanthus roseus (L.) G. Don.

Catharanthus roseus (L.) G. Don. (Apocynaceae) is an important dicotyledonous medicinal plant. It produces vinblastine and vincristine, two alkaloids that are being used against a variety of cancers. In the present study, the freezing (−196, 4, 15°C) and non-freezing (25°C) temperature was imposed on embryogenic cultures, and later in vitro embryogeny and vinblastine production in C. roseus was studied. Somatic embryo (SE) production was maximum at 15°C, but the SE maturation was high at 4°C. The SEs, grown at 25°C, showed highest germination and plantlet conversion. Quantitative estimation of vinblastine was carried out using high-performance liquid chromatography in various in vitro raised tissues (embryogenic callus), embryo stages (proliferated, matured and germinated embryos)], and SE-derived plantlets (leaf, shoot, root and whole plant) after various freezing- and non-freezing temperature treatments. Vinblastine synthesis was temperature dependent in C. roseus that has been discussed in this present article.

In vitro Production of Secondary Metabolites Using Elicitor in Catharanthus roseus : A Case Study

Secondary metabolites are mainly derived from plants and are used by humans from time immemorial. A plant cell, tissue, and organ culture has an inherent capacity to manufacture valuable chemical compounds as the parent plant does in nature. In vitro plant materials are one of the good sources for the production of secondary metabolite and elicitation can be used as one of the important tool in order to improve the synthesis of these compounds. In a variety of plant cell cultures, elicitors have increased production of terpenoid indole alkaloids, isoflavonoid phytoalexins, serquiterpenoid phytoalexin, coumarins etc. Although elicitation has been carried out in large number of medicinal plants, we extensively studied it in Catharanthus roseus, because it is an important source of anticancer compounds Vinblastine (VLB) and Vincristine (VCR). The use of elicitor is also important in order to meet the market demands, for reducing production costs and for in-depth investigation of biochemical and metabolic pathways. This information helps us in manipulation of biosynthetic pathways which can be used as a powerful tool to make natural product-like compounds.

Plant Tissue Culture: A Useful Measure for the Screening of Salt Tolerance in Plants

Soil salinity is one of the most important problems worldwide, which has decreased crop production to a great extent. The major or deleterious effects of salinity on plant growth and development are associated with low osmotic potential of soil solution, nutritional imbalance etc. Consequently these can ultimately lead to plant death because of growth arrest and molecular damage. Salt stress affects all the major processes such as photosynthesis, protein synthesis, lipid metabolism etc. The use of plant cell and tissue culture offers a means to focus on those physiological and biochemical processes inherent to cell which contribute to the adaptation to salt stress. The response depends on the species and the genotype, the length and the severity of the salt stress, the age and stage of development, the organ and cell type. In this article, various in vitro strategies have been made for salt tolerance. Effect of salinity on biochemical and antioxidant properties of plants have also been highlighted. The chapter also covers the role of genetic transformation for the development of salt tolerance in plants.

Pharmacognosy, Phytochemistry Pharmacological and Biotechnogical approaches of Catharanthus roseus (L.) G. Don

Catharanthus roseus is an important medicinal plant, mentioned in Ayurveda, an ancient Indian Sanskrit literature and has traditionally been used to treat many diseases including cancer and diabetes. More than 130 types of alkaloids (mostly monoterpene indole alklaloids) are reported from the plant and some proved effective in treating various types of cancers like breast and lung cancer, uterine cancer, melanomas, and Hodgkin’s and non-Hodgkin’s lymphoma. Two main alkaloids vincristine and vinblastine reported used in cancer treatment. Considering the medicinal value of this plant which already been shown to have, we evaluated the various in vitro biotechnological and biochemical approaches (viz. effect media composition, plant growth regulators, pH of the culture medium, temperature, light, aeration, elicitors, mutagenesis, high cell density culture, selection of superior cell lines, bioreactor and immobilization methods, hairy root culture, somatic embryogenesis, biosynthesis of alkaloids, metabolic and genetic engineering in alkaloids biosynthesis, coupling method for alkaloids biosynthesis, cellular compartmentation etc.); which directly concerning with the in vitro micropropagation and the enhancement of important secondary metabolites present in Catharanthus and being used in the treatment of various diseases.