Devendra Kumar Pandey

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimers disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Evaluation of antioxidant, antibacterial, and antidiabetic potential of two traditional medicinal plants of India: Swertia cordata and Swertia chirayita.

Background: Swertia cordata and Swertia chirayita are temperate Himalayan medicinal plants used as potent herbal drugs in Indian traditional systems of medicine (Ayurvedic, Unani and Siddha). Objective: Assessment of Antioxidant, antibacterial, and antidiabetic potential of Swertia cordata and Swertia chirayita. Materials and Methods: Phytochemicals of methanolic and aqueous extracts of the two Swertia species were analyzed. The antioxidant potential of all the extracts was assessed by measuring total phenolic content, total flavonoid content and free radical scavenging potential was assessed by 1,1-diphenyl-2-picrilhydrazyl (DPPH) assay, antibacterial activity was assessed against various pathogenic and nonpathogenic bacteria in vitro by Kirby-Bauer agar well diffusion method and antidiabetic activity was assessed by α-amylase inhibition. Results: Methanolic leaf extracts of both the species of Swertia contain significant antibacterial as well as anti-diabetic potential, whereas methanolic root extracts of both species were found to have potential antioxidant activity. However, Swertia chirayita showed better activities than Swertia cordata although both species have good reputation in traditional Indian medicine. Conclusion: Both the species are having high medicinal potential in terms of their antioxidant, antibacterial and antidiabetic activities. Studies are required to further elucidate antioxidant, anti-diabetic and antibacterial potentials using various in-vitro, in-vivo biochemical and molecular biology techniques.

HPTLC Method for Quantitative Evaluation of Seasonal Variation of Stigmasterol in Rauvolfia serpentina (L). Benth. ex Kurz.

Abstract Rauvolfia serpentina (L). Benth. ex Kurz. (Apocynaceae) occupies a prominent position in the ethno-therapeutics practiced in the Indian subcontinent. The plant is known to contain a number of bioactive secondary metabolites including indole alkaloids. The objective of our present study is to estimate the seasonal variation of stigmasterol content in the roots of the plant. Seasonal modulation in stigmasterol content in R. serpentina roots was analyzed by High Performance Thin Layer Chromatography (HPTLC) performed on Silica gel 60 F254 TLC plates with benzene-acetone 86:14 (v/v) as mobile phase. Densitometric analysis was carried out at λ=366 nm after derivatization with vanillin-10 % (v/v) sulphuric acid alcohol. In the root samples stigmasterol was present at Rf value of 0.44. Stigmasterol content was found to be the highest in roots harvested during summer and the lowest in winter and there was a gradual decrease from summer to winter through monsoon and autumn and from spring the hike was again found. Modulation in stigmasterol content during different seasons was noted which can be implicated to the popular notion of variation in secondary metabolites depending on temperature, ultraviolet radiation and other factors related to seasonal changes. Popular use of the plant in Indian ethnomedicine may be attributed to the presence of stigmasterol as one of the important constituents of the plant.

Impact of Furfural and Kerosene Co-exposure through Inhalation in Lungs of Rats

Furfural is being added to kerosene to check the adulteration of gasoline/high speed diesel oil. The possibility of a co-exposure of furfural and kerosene and the ability to exhibit the toxic effects of such a mixture were examined in view of the toxicity potential of the two alone and in combination with each other. A single inhalation exposure of rats to furfural was fully tolerated up to a concentration of 126 ppm. However, exposure to higher concentrations of furfural resulted in a dose dependent mortality. Exposure of rats to vapor of kerosene ranging from 426-1054 ppm did not show toxic signs and mortality up to a period of seven days. Simultaneous exposure of rats to furfural and kerosene vapors ranging in concentration from 35 ppm to 138 ppm showed a suppression of LC50 value of furfural. The LC50 was 105 ppm in rats exposed to furfural-kerosene vapors. Inhalation exposure of rats to ½ LC50 of furfural to 95 ppm, 1 hr daily, 5 days/week over a period of 28 days caused severe irritation of eyes and nose leading to lacrimation, perinasal and perioral wetness, labored breathing and mild nasal bleeding. Neither the body weight nor lung weight showed any change as compared to the control group. Activities of acid and alkaline phosphatase, glutamic pyruvic and glutamic oxaloacetic transaminases, succinic dehydrogenase, total sulfhydryl content and lactic acid content were evaluated.

A Stigmasterol Containing n-hexane Fraction of Rauvolfia serpentina Methanolic Extract Shows Tissue-Specific Variation of Biocidal and Antioxidant Activities

Tissue-specific variation of stigmasterol in Rauvolfia serpentina and the corresponding biocidal and antioxidant activities of the methanol extract were measured using high-performance thin-layer chromatography. Stigmasterol had the highest concentration in the roots. The highest radical scavenging activity was seen in the root extract (60.94%) at 1 mg.mL−1 DPPH gradient; highest total phenolics content in 1 mg.mL−1 of the root extract was 67 μg of Gallic acid equivalent mg−1 d.w.; highest flavonoids present in the extract was 275 μg of Quercetin equivalent mg−1 d.w. The antibacterial activity was correlated to the amount of stigmasterol, total phenolics, total flavonoids, and antioxidants present in the plant parts.

Comparative HPTLC Analysis of Antioxidant Compound Gallic Acid from in vitro and Naturally Grown Stevia rebaudiana

Abstract Stevia rebaudiana Bertoni (Asteraceae) is a perennial shrub of South America, produces diterpene glycosides used as low calorie sweeteners. Stevioside and extracts prepared from the leaves have been used widely all over the world as sweetening agents, taste modifiers and sugar substitutes. Gallic acid (GA) is reported for its anti-inflammatory, anticancer, antiviral and antimelanogenic activities and many of these are mediated by its antioxidative capacity. Presently a study has been conducted on the comparative High Performance Thin Layer Chromatography (HPTLC) analysis of gallic acid from the dried leaf powder of in-situ and in-vitro grown S. rebaudiana. Nodal explants of S. rebaudiana were cultured in vitro in MS media supplemented with 6-benzyladenine (BA; 8.5 mM) and indole-3-butyric acid (IBA; 9.2 mM). The quantitative determination of gallic acid was performed on silica gel 60 F254 HPTLC plates as stationary phase. The linear ascending development was carried out in a twin trough glass chamber saturated with a mobile phase consisting of chloroform: ethyl acetate: formic acid (5:4:1) at room temperature (22±2°C). CAMAG TLC scanner-3 equipped with CATS software (version: 1.4.4.6337) was used for spectrodensitometric scanning and analysis in the ultraviolet region at λ=280 nm. The method was validated for linearity, precision and accuracy. Correlation coefficient, limit of detection (LOD), limit of quantification (LOQ) as well as recovery values were found to be satisfactory. S. rebaudiana raised in vitro (0.042 %) was found to contain higher amount of GA than their naturally growing counterparts (0.022 %).

Biotechnological aspects of the production of natural sweetener glycyrrhizin from Glycyrrhiza sp.

Biotechnology as a frontline technology has been maneuvered in a myriad of ways on Glycyrrhiza glabra that has directly or indirectly benefited the mankind. The roots and stolons of licorice species have long been used worldwide as a herbal medicine and natural sweetener. The main ingredient responsible for sweetness is glycyrrhizin which is used as sweetener agent in many herbal and commercial products. Currently, tissue culture technology has enabled mass production of the elite population in lesser time, an achievement over conventional methods. Glycyrrhizin which is the most important constituent is enhanced by in vitro propagation, elicitation, genetic transformations and bioconversions. Identification and quantification of glycyrrhizin and its related compounds have been successful by high performance liquid chromatography (HPLC), capillary electrophoresis (CE), UV spectrometry, counter-current chromatography (HSCCC), thin layer chromatography (HPTLC). Advances in molecular markers have unraveled genetic diversity among plant populations and also species, identified specific genes, constructed genetic linkage maps and analyzed genetic relationships. There have been numerous contributions on genetic diversity assessment, mass production and in vitro production of glycyrrhizin in G. glabra in the recent past. Here we review on biotechnological advances in genetic diversity assessment of elite population and mass production and genetic improvement of G. glabra for enhanced production of glycyrrhizin.

Knowledge and intelligent computing techniques in bioinformatics

Knowledge-based systems (KBS) and intelligent computing techniques (ICT) are widely used in the field of bioinformatics. A number of techniques have been applied for the interpretation and analysis of biological data. KBS consists of case based reasoning (CBR) whereas ICT consists of artificial neural network (ANN), fuzzy logic (FL), data mining techniques (DMT), swarm intelligence (SI) and evolutionary algorithm (EA). The aim of this review is to introduce briefly the various KBS and ICT and their integration such as ANN-DMT, CBR-DMT, EA-ANN, EA-DMT, EA-ANN-DMT, ANN-SI, ANN-FL, ANN-SI-EA-FL, EA-FL, EA-SI etc. which are applied in the field of bioinformatics. This study is exhibited in the form of a table which includes application area, intelligent technique used, machine learning task and the database/databank used. This study will help the novice researchers to choose appropriate KBS and ICT to deal with the challenges encountered during representation, integration, analysis, interpretation and management of biological data.

HPTLC detection of altitudinal variation of the potential antivenin stigmasterol in different populations of the tropical ethnic antidote Rauvolfia serpentina

OBJECTIVE To determine the altitudinal variation of stigmasterol, a potential antivenin, in roots from seven populations of Rauvolfia serpentina (L). Benth. ex Kurz. (Apocynaceae) (R. serpentina), an important herb found in Indian subcontinent which has long been used in the treatment of snakebite, blood pressure and schizophrenia. METHODS Altitudinal variation of stigmasterol content in R. serpentina roots was analyzed by high performance thin layer chromatography. Chromatography was performed on silica gel 60 F254 thin layer chromatography plates with benzene-acetone 86:14 (v/v) as mobile phase. Densitometric analysis was done at λ=366 nm after derivatization with vanillin-10% (v/v) sulphuric acid alcohol reagent. The method was validated for precision and recovery. RESULTS The present experiment demonstrates a simple, rapid, precise and sensitive high performance thin layer chromatography protocol for qualitative and quantitative determination of stigmasterol from different populations of R. serpentina. Results demonstrated that in root samples stigmasterol was present at Rf value of 0.44. CONCLUSIONS This investigation demonstrates that stigmasterol content in R. serpentina roots varies in different altitudes. Popular ethnomedicinal use of this herb against snakebite may be contributed by the occurrence of stigmasterol in its roots.

Arbuscular Mycorrhizal Fungi: Effects on Secondary Metabolite Production in Medicinal Plants

Medicinal plants are used by 80% of the world population for their primary health care. The medicinal value of plants is primarily attributed to the secondary metabolite content such as terpenoids, alkaloids, and phenolics. These compounds play a crucial role in plant defense, are merchandised valued for their therapeutic applications and ecological role, and are also used as flavoring agents. Arbuscular mycorrhizal fungi (AMF) or Glomeromycota is known to form a symbiotic relationship with many terrestrial plants. AM fungi–plant consortium enhanced the production of plant terpenoids, alkaloids, and phenolics, which are valuable to human health. The potential role of arbuscular mycorrhiza (AM) symbiosis in amplification of the secondary metabolite content has attained enormous recognition for sustainable cultivation of medicinally important crops. AMF–plant symbiosis not only improves the growth and nutrients but also exerts a synergistic effect on accumulation of bioactive compounds with medicinal importance. Current studies have also recognized AM-mediated modulation of morphology, biochemistry, and gene expression in medicinal as well as in the industrial important plants. This chapter provides an appraisal on contemporary finding in the area of AMF investigation with a marked emphasis on the yield of pharmaceutically important plant-derived secondary metabolites.