Jayabalan Shilpha

In vitro mass propagation and conservation of Nilgirianthus ciliatus through nodal explants: A globally endangered, high trade medicinal plant of Western Ghats

Abstract Nilgirianthus ciliatus is a globally endangered aromatic slender shrub of Western Ghats with extensive applications in Ayurveda. It is endangered due to its indiscriminate collection and overexploitation to meet the requirements of the pharmaceuticals. This study deals with the preservation of this endangered plant through in vitro nodal culture. Nodal explants were initially cultured on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BA) or 6-furfurylaminopurine individually for primary shoot induction. For multiple shoot induction, primary shoots were transferred onto MS medium containing BA individually or in combination with auxins. Clusters of multiple shoots (up to 24.3) occurred with highest frequency (93.2%) on MS medium fortified with BA (3 mg l−1) and indole-3-acetic acid (0.1 mg l−1). In vitro regenerated plantlets were rooted on half-strength MS medium with maximum rooting frequency (82.2%) obtained in the presence of indole-3-butyric acid (1.0 mg l−1). The rooted plantlets were acclimatized to soil with 100% survival rate. Results of this study allowed us to develop an efficient regeneration system that will permit to carry out restoration programmes of N. ciliatus in Western Ghats. In future, this protocol will be an invaluable tool to produce synthetic seeds for cryopreservation and long-term conservation.

Analysis of genetic variation in sorghum (Sorghum bicolor (L.) Moench) genotypes with various agronomical traits using SPAR methods

Genetic variation among 45 genotypes of sorghum (Sorghum bicolor L.) representing seven subpopulations was assessed using three single primer amplification reaction (SPAR) methods viz., inter-simple sequence repeat (ISSR), random amplified polymorphic DNA (RAPD) and directed amplification of minisatellite-region DNA (DAMD). Totally 15 ISSR, 8 RAPD and 7 DAMD primers generated 263 amplification products, accounting for 84.6% polymorphism across all the genotypes. The Mantels test of correlation revealed the best correlation between ISSR and cumulative data with a correlation coefficient (r) of 0.84. Assessment of population diversity indicated that the maximum intra population genetic diversity was recorded among high FeZn lines (HFL) having maximum values of Neis genetic diversity (h) (0.244), Shannon information index (I) (0.368) and the percentage of polymorphic loci (Pp) (72.65%) while the corresponding lowest values of 0.074, 0.109 and 17.95% respectively were observed among the members of MDT subpopulation. The mean coefficient of gene differentiation (GST) and the gene flow (Nm) between populations were observed to be 0.396 and 0.7680 respectively. The analysis of molecular variance (AMOVA) suggested that maximum genetic variation exists within populations (95%) than among populations (5%). Thus the information obtained from this study could be utilized in sorghum breeding programmes for the development of varieties with improved nutrition and agronomic values in future.

Recent Advancements in the Clinical Evaluation of Plant-Derived Anticancer Compounds

Cancer is a chief global health burden and the leading cause of human death worldwide next to heart diseases. The alarming rise in the mortality rate owing to cancer has driven the chase for anticancer agents to effectively combat this disease. Searching for novel and efficient compounds of natural origin has been a major aspect of concerns because they exhibit less toxic side effects. Numerous secondary metabolites from plants and their semisynthetic analogs have been identified as an excellent, novel lead structures in developing promising anticancer agents. In the current scenario, several successful anticancer drugs and their derivatives have been obtained from plant sources, and many of them are in clinical trials. Phytocompounds such as vinca alkaloids, taxanes, podophyllotoxin, camptothecin, homoharringtonine, and their derivatives have appreciably influenced cancer research on many facets. Likewise, some of the other plant-derived anticancer agents including omacetaxine mepesuccinate, ingenol mebutate, β-lapachone, flavopiridol, curcumin, etc. are currently being under phase I and II clinical trials, either individually or in concert with other anticancer agents for the treatment of a broad range of tumors like lymphomas, leukemias, and solid tumors. Customary anticancer drug discovery has targeted mainly on the cytotoxic agents that hamper metabolic pathways critical to cell division. However, during recent years, several molecular target-based compounds have been emerged concentrating on other cellular process of cancer cells such as apoptosis, metastasis, angiogenesis, etc. Hence, the present anticancer drug discovery involves high-throughput screening of phytocompounds against a series of such molecular targets. The present chapter discusses the clinical evidences of some important phytocompounds of anticancer plants, overview of their current clinical status, and recent advances in their molecular mechanism of action.