Pramod Singh

Naturally Occurring Xanthones: Chemistry and Biology

Xanthones are one of the biggest classes of compounds in natural product chemistry. A number of xanthones have been isolated from natural sources of higher plants, fungi, ferns, and lichens. They have gradually risen to great importance because of their medicinal properties. This review focuses on the types, isolation, characterization, biological applications, and biosynthesis of naturally occurring xanthones isolated so far. Different physicochemical and instrumental methods such as liquid-solid and liquid-liquid extraction, TLC, flash chromatography, column chromatography, IR, 1H NMR and 13C NMR spectroscopy, GLC, HPLC, GC, and LCMS have been widely used for isolation and structural elucidation of xanthones. Hepatoprotective, anticarcinogenic, antileprosy, antimalarial, antioxidant, anticholinergic, mutagenicity, radioprotective, immunomodulatory, antibone resorption, antiparasitic, neuraminidase inhibitory, anticomplement, antibacterial, antifungal, algicidal, anti-HIV, cardioprotective, antitumoral, antidiabetes, antihyperlipidemic, antiatherogenic, anti-inflammatory, antiulcer, antidiabetic, hypolipidemic, analgesic, antiasthmatic, antihistaminic, antiamoebic, diuretic, antidiarrheal, larvicidal, and ovicidal activities have been reported for natural occurring xanthones. To a certain extent, this review provides necessary foundation for further research and development of new medicines.

Chemical constituents of Asparagus.

Asparagus species (family Liliaceae) are medicinal plants of temperate Himalayas. They possess a variety of biological properties, such as being antioxidants, immunostimulants, anti-inflammatory, antihepatotoxic, antibacterial, antioxytocic, and reproductive agents. The article briefly reviews the isolated chemical constituents and the biological activities of the plant species. The structural formula of isolated compounds and their distribution in the species studied are also given.

Synthesis, characterization and fluorescence studies of 3,5-diaryl substituted 2-pyrazolines.

A series of 2-pyrazolines have been synthesized from α, β unsaturated ketones and hydrazine hydrate with acetic/formic acid in ethanol/DMSO. The structures of 2-pyrazolines have been established by spectroscopic techniques i.e. UV, IR, (1)H NMR, (13)C NMR and micro element analysis. Fluorescence spectra were recorded in the solution at fixed concentration and same excitation wavelength at 290 nm. The absorption band positions of all the compounds broadly lie between 280 and 336 nm and fluorescence band positions in the range between 300 and 370 nm, the near ultraviolet region.

Paris polyphylla: chemical and biological prospectives.

Paris polyphylla J.E. Smith is extensively used in traditional systems of Indian and Chinese medicines mainly for its anticancerous property. The national and international demand for P. polyphylla is constantly increasing and most of the supplies come from wild. Illegal and unscientific exploitation coupled with habitat destruction decreases the natural population of the herb, as a consequence this species comes under vulnerable category. Restoration and conservation of the natural population of this potential herb is prerequisites. This article aims to provide an overview on chemical and biological prospective of P. polyphylla. Secondary metabolites such as daucosterol, polyphyllin D, β -ecdysterone, Paris saponins I, II, V, VI, VII, H, dioscin, oligosaccharides, heptasaccharide, octasaccharide, trigofoenoside A, protogracillin, Paris yunnanosides G-J, padelaoside B, pinnatasterone, formosanin C and 20-hydroxyecdyson saponins have been isolated from P. polyphylla. Several biological activities such as anticancerous, antitumor, cytotoxic, anthelmintic, antimicrobial, antiangiogenic, immunostimulating, contractile and hemostatic have also been reported. Consequently, this review will be helpful to the researcher and scientist for further research.

Synthesis and Characterization of a Novel 2-Pyrazoline

Abstract: Reaction of dibenzalacetone with hydrazine hydrate and formic acid yielded a novel 2-pyrazoline 1 , characterized by ESI-MS, FT-IR, UV, 1 HNMR and 13 CNMR data and microanalysis. Keywords: dibenzalacetone; hydrazine hydrate; pyrazoline; 5-phenyl-3-[( E )-2-phenyl-vinyl]-4,5-dihydro-1 H -pyrazole-1-carbaldehyde; fluorescence Introduction Substituted pyrazolines are useful in pharmaceutical and agrochemical research. Pyrazoline derivatives with a phenyl group at the 5-position possess good film-forming properties, exhibit excellent characteristics of blue photoluminescence and electroluminescence [1]. Pyrazolines are also used as optical brighteners and whiteners. Pyrazolines display various biological activities such as antimicrobial [2], antifungal [3], antidepressant [4], immunosuppressive [5], anticonvulsant [6], anti-tumor [7], antiamoebic [8], antibacterial [9] and antiinflammatory [10] activities. Syntheses of pyrazolines by reaction of α,β-unsaturated carbonyl compounds with diazoalkanes [11] or with hydrazine hydrate [12,13] were reported in literature. N-Substituted thiocarbamoyl-3,5-diphenyl-2-pyrazoline derivatives having NS donor, their palladium II complexes [14] and hydroxyl phenyl pyrazolines have also been synthesized [15]. The reaction of

High-performance liquid chromatography analysis of plant saponins: An update 2005-2010

Saponins are widely distributed in plant kingdom. In view of their wide range of biological activities and occurrence as complex mixtures, saponins have been purified and separated by high-performance liquid chromatography using reverse-phase columns at lower wavelength. Mostly, saponins are not detected by ultraviolet detector due to lack of chromophores. Electrospray ionization mass spectrometry, diode array detector , evaporative light scattering detection, and charged aerosols have been used for overcoming the detection problem of saponins.

Quantification of Mineral Elements of Rheum emodi Wallr. (Polygonaceae)

Present investigation was carried out to estimate mineral elements in Rheum emodi Wallr. by atomic absorption spectroscopy. The samples of R. emodi Wallr., both wild and cultivate populations, were collected from different localities at different altitudes of Uttarakhand, India. The concentration of micro- and macroelements was different in roots and leaves. The concentration of mineral elements was found in both the leaves and roots in the order of K > Ca > Fe > Mn > Na > Zn > Co > Li > Cu.

Synthesis, antiamoebic activity and thermal study of copper complexes of 1-formyl-2-pyrazolines

Copper complexes of 1-formyl-2-pyrazolines were prepared by the reaction of 1-formyl-2-pyrazolines with copper chloride and nitrate with methanol. The structures of copper complexes 1a–3a have been established by elemental analysis, FT-IR, UV and thermogravimetric analysis. These compounds were tested against HM1:IMSS strain of Entamoeba histolytica by the microdilution method. Complexes 2a and 3a are more active than other complexes.

Solvatochromic and single crystal studies of 3-(4-bromophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde.

The structure of 3-(4-bromophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde was determined by using X-ray diffraction analysis. Photophysical studies of the title compound were investigated in the solvents with different polarities. The emission spectrum of the compound was recorded in polar solvent DMSO (356 nm). In different solvents the extinction coefficients and quantum yield of the compound vary from 1.88×10(4) to 3.53×10(4) and 0.01 to 0.25, respectively. The ratio of the dipole moment of excited state to the dipole moment of ground state was calculated by using solvatochromic shift methods.

Determination of trace elements in Rheum moorcroftianum by AAS

Micro and macro elements such as Zn, Cu, Mn, Fe, Co, Na, K, Ca and Li were detected from Rheum moorcroftianum Royle, a plant used in folk medicines. Altitudinal and seasonal variation of these trace elements in cultivated and wild roots and leaves of R. moorcroftianum were quantified by atomic absorption spectroscopy. The highest concentrations of Zn, Cu, Mn, Fe, Co, Na, K, Ca and Li were found to be 376.0 ± 0.9, 83.0 ± 4.6, 322.0 ± 6.0, 920.0 ± 1.9, 72.0 ± 1.5, 402.0 ± 7.8, 10,235.0 ± 7.0, 12,336.0 ± 2.6 and 59.9 ± 0.3  mg kg−1, respectively, in all the samples analysed.