Therapeutic targets of medicinal plants of Western Ghats, India

Drugs derived from natural resources represent a significant segment of the pharmaceutical market. Traditional systems of medicines like Ayurveda, Traditional Chinese Medicine (TCM) or the European phytotherapy assumed synergistic approach wherein all ingredients of the plants could bring about maximum therapeutic efficacy. Due to the escalated cost of development of pre-clinical synthetic drugs, there has been a Worldwide demand for phytopharmaceuticals. The modern therapy applies more and more combinatorial approach in treatment of diseases like cancer, cardiovascular or rheumatic diseases. High-throughput methods are available to investigate complex mixtures of whole plant extracts and establish synergistic effects for multi-therapeutic target treatments. Demands are increasing to establish open access data banks in a multidisciplinary effort for medicinal plant research with the aim to develop a common standard molecular/therapeutic "bar codes" for characterization of medicinal plants. In the present chapter an attempt has been made to compile information on medicinal plant extracts with respect to their pharmacological attributes to promote wider acceptance and use of these plant-based drugs in main stream of medicine. The mode of action of phytopharmaceuticals as assessed by up/down-regulation of therapeutic target molecules with respect to anti-cancer, anti-inflammatory, anti-hypertensive, anti-viral, anti-obesity, antidiabetic and pro-gynecological properties complying with multi-target therapy will be described. This approach further helps scientific validation of plant extracts/bioactive molecules that are already being used in traditional medicine

β-Amino butyric acid-induced resistance in pearl millet to downy mildew is associated with accumulation of defence-related proteins

Earlier studies had indicated that β-amino butyric acid (BABA) treatment of pearl millet seeds influenced seedling vigor and protected seedlings from downy mildew disease caused by the oomycetous biotrophic fungus Sclerospora graminicola. Application of 50mMBABAreduced disease severity and offered protection against S. graminicola of ∼74%. The protection induced was durable and operative during the vegetative and reproductive growth periods of the crop. In the present study an attempt was made to understand the biochemical basis for this protection. A close association was found between BABA-induced protection and increased accumulation of defence-related proteins like phenylalanine ammonia lyase, peroxidase, β-1,3-glucanase and cell wall hydroxyproline-rich glycoproteins (HRGP). Isoelectric focusing of β-1,3-glucanases indicated the presence of several isoforms, of which isoforms of pI 9.6 and 8.8 were markedly increased in BABA-treated seedlings upon S. graminicola infection. Increased accumulation of hydroxyproline-rich glycoproteins was also observed at 9 h after inoculation in these samples. Western blots with MAC 265, a monoclonal antibody against pea HRGP identified a 17-kDa HRGP molecule that significantly increased in concentration in BABA-treated pearl millet seedlings as a response to S. graminicola infection. The postinfectional protection offered by BABA involved induction of defence responses which were comparable to the highly resistant cultivar

Cytotoxic effect of p-coumaric acid on neuroblastoma, n2a cell via generation of reactive oxygen species leading to dysfunction of mitochondria inducing apoptosis and autophagy

p-Coumaric acid (p-CA), an ubiquitous plant phenolic acid, has been proven to render protection against pathological conditions. In the present study, p-CA was evaluated for its capacity to induce cytotoxic effect to neuroblastoma N2a cells and we report here the possible mechanism of its action. p-CA at a concentration of 150 mu mol/L, upon exposure for 72 h, stimulated 81.23 % of cells to apoptosis, as evidenced by flow cytometer studies mediated through elevated levels of ROS (7.5-fold over control). Excess ROS production activated structural injury to mitochondrial membrane, observed as dissipation of its membrane potential and followed by the release of cytochrome c (8.73-fold). Enhanced generation of intracellular ROS correlated well with the decreased levels (similar to 60 %) of intracellular GSH. Sensitizing neuroblastoma cells for induction of apoptosis by p-CA identified p53-mediated upregulated accumulation of caspase-8 messenger RNA (2.8-fold). Our data report on autophagy, representing an additional mechanism of p-CA to induce growth arrest, detected by immunoblotting and fluorescence, correlated with accumulation of elevated levels (1.2-fold) of the LC3-II protein and acridine orange-stained autophagosomes, both autophagy markers. The present study indicates p-CA was effective in production of ROS-dependent mitochondrial damage-induced cytotoxicity in N2a cells

Cloning, expression and purification of resistance gene analogue RGPM 301 from pearl millet in Escherichia coli

Plants combat their pathogens with an array of defense responses. One of the key mechanisms involves products of resistance (R) genes which are responsible for recognition of effector molecules from pathogens and subsequent triggering of defense responses. Resistance gene analogues (RGAs) containing the specific conserved domains of R-genes are isolated from various plants using degenerate oligonucleotide primer based PCR approach. In an earlier study, RGPM 301 an RGA from pearl millet shown to be involved in resistance mechanism against downy mildew disease was isolated and characterized. In the present study, RGPM 301 containing an open reading frame (ORF) of 992 amino acids was cloned into pRSET A expression vector and expressed in Escherichia coli as a Hig-tag fusion protein. The recombinant RGA RGPM 301 was purified to near homogeneity using the Nickel-CL agarose column. Its molecular mass was found to be 120 kDa when separated on the SDS-PAGE which was confirmed by western blotting analysis using the anti-His antibody. The purified protein was subjected to in-gel trypsin digestion followed by mass spectrometric analysis for the confirmation of its identity. These findings facilitate further studies on the exact role of this RGA in the pearl millet downy mildew host pathogen system

Bioactive potential of medicinal plants from Western Ghats Region, India

Methanol extracts of Elaeocarpus, E. serratus, E. tuberculatus (Elaeocarpaceae), Catunaregam uliginosa, C. spinosa (Rubiaceae), Elaeagnus conferta (Elaeagnaceae), Evodia lunu-ankenda (Rutaceae), Glycosmis arborea (Rutaceae), Melastoma malabathricum. (Melastomataceae), and Smilax zeylanica (Liliaceae) leaves were screened for antioxidant, anti-inflammatory, and cytotoxicity to Vero cell lines. 1,1-diphenyl-2-picrylhydrazyl and 2-2�-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid radical scavenging capacities were identified C. spinosa and E. tuberculatus. Anti-inflammatory capacity with lipoxygenase and human cyclooxygenase-2 inhibition for E. tuberculatus and E. serratus was recorded. The extracts prevented DNA damage by hydroxyl radicals produced by Fenton reagent. Cell cytotoxicity studies revealed S. zeylanica and E. tuberculatus with potent cytotoxicity to Vero cells

Accumulation of hydroxyproline-rich glycoproteins in pearl millet seedlings in response to Sclerospora graminicola infection

Hydroxyproline-rich glycoproteins (HRGPs) are important plant cell wall structural components that are known to be induced in response to pathogen attack. In the present study, accumulation of HRGPs in pearl millet seedlings in response to Sclerospora graminicola, the incitant of downy mildew disease was monitored by estimation of hydroxyproline (Hyp) in the hydrolyzed cell wall samples. In 2-day-old seedlings of a highly resistant cultivar of pearl millet inoculated with S. graminicola, a marked increase in Hyp content was observed in the coleoptiles as early as 2h compared to that in a highly susceptible cultivar. A correlation was observed between the amount of Hyp induced in coleoptiles of different cultivars of pearl millet to S. graminicola infection and the host resistance. Electrophoretic separation of the acid-ethanol extracted proteins from these coleoptiles followed by periodic acid Schiff staining revealed three glycoproteins of molecular masses 27, 17 and 14 kDa. These three glycoproteins also reacted positively on western blots with MAC 265, a monoclonal antibody against pea HRGP. indicating that they are HRGPs. The 17 kDa HRGP was markedly increased in highly resistant cultivar to S. graminicola infection compared to highly susceptible cultivar. The 14 kDa HRGP was exclusively present in the highly resistant cultivar and not in highly susceptible cultivar. Histological studies showed cross-linking of proteins in the cell walls of only highly resistant cultivar against S. graminicola infection. In addition. immunocytochemical studies using MAC 265 antibodies recognized these cross-linked proteins to be HRGPs. These findings indicated that accumulation of HRGPs in cell walls of highly resistant pearl millet seedlings is a component of defense reaction against downy mildew pathogen S. graminicola. (C) 2004 Elsevier Ireland Ltd. All rights reserved

Identification and characterization of Memecylon species using isozyme profiling

Background: The protein/isozyme fingerprint is useful in differentiating the species and acts as a biochemical marker for identification and systematic studies of medicinal plant species. Objective: In the present study, protein and isozyme profiles for peroxidase, esterase, acid phosphatase, polyphenol oxidase, alcohol dehydrogenase, and alkaline phosphatase of five species of Memecylon (Melastomataceae), Memecylon umbellatum, Memecylon edule, Memecylon talbotianum, Memecylon malabaricum, and Memecylon wightii were investigated. Materials and Methods: Fresh leaves were used to prepare crude enzyme extract for analyzing the five enzymes isozyme variations. Separation of isozymes was carried out using polyacrylamide gel electrophoresis (PAGE) and the banding patterns of protein were scored. Pair-wise comparisons of genotypes, based on the presence or absence of unique and shared polymorphic products, were used to regenerate similarity coefficients. The similarity coefficients were then used to construct dendrograms, using the unweighted pair group method with arithmetic averages. Results: A total of 50 bands with various Rf values and molecular weight were obtained through PAGE analysis. Among the five Memecylon species, more number of bands was produced in M. wightii and less number of bands was observed in M. edule. The results of similarity indices grouped M. malabaricum and M. wightii in one cluster with 98% similarity and M. umbellatum, M. edule, and M. talbotianum are grouped in another cluster with 79% similarity showing close genetic similarities which is in accordance with the morphological identification of Memecylon species. Conclusion: The protein/isozyme fingerprint is useful in differentiating the species and acts as a biochemical marker for identification of Memecylon species. Abbreviations Used: SDS-PAGE: Sodium docecyl sulfate polyacrylamide gel electrophoresis; NTSYS PC2: Numerical taxonomy system, version 2.2 for Windows XP, Vista, Win7, Win 8 and Win10 including 64 bi

Potential anti-inflammatory bioactives from medicinal plants of Western Ghats, India

Natural products have long been a thriving source for the discovery of new drugs because of their chemical diversity. With increased use of herbal remedies, traditionally used medicinal plants are receiving increased attention from scientific and pharmaceutical communities. The newer work on medicinal plants is mostly the rediscovery of traditional effects at cellular and molecular levels. Development of standardized, safe and effective herbal formulations as multi-target therapeutics and prophylaxis could be a tenable approach for the future. Hundreds of plant metabolites are reported to have many pharmacological activities although most of these reports are of academic interest and very few find entry at clinical trials. Compilation of the information would help promote wider acceptance and use of these plant based drugs in main stream of medicine. The present review is directed towards compilation of the pharmacological attributes of medicinal plants of Western Ghats, India in the drug discovery and development process as it could be a driving force to identify lead molecules providing an attractive strategy for novel and improved therapeutics