Phytochemical and Biological Evaluation of Selected Plants and their Use in Silver Nanoparticles Synthesis and Characterization

Abstract

This PhD dissertation study is about Bistorta affinis and Malcolmia cabulica belonging to Family Polygonaceae and Brassicacea, comprises physicochemical, phytochemical, silver nanoparticles synthesis and biological investigation of these two plants species to provideasuitable scientific ground linked to their traditional uses. B. affinis has a widespread ethnobotanical uses; muscle contraction, fever, flu, back pain, body pain, abdominal pain, expels worms, lung disorders, cough, cold, tonsillitis, anti-inflammatory, anti-pyretic and the rhizome of this plant is useful to prepare tea while M. cabulicais traditionally used for weight loss, carminative and galactogogue in animals. Results of qualitative phytochemical evaluations of B. affinis and M. cabulica are given. The crudeMeOHextract of both plant species gavepositive resultsfor sterols, alkaloids, terpenoids, carbohydrates, flavonoids, tannins, glycosides, saponin, phenols, proteins, free amino acids, free reducing sugar, steroids, fixed oils, fats and volatile oil. Elemental analysis revealed that carbon (C) and oxygen (O) in both plants were found in good quantity. Proximate analysis revealed that the content of fats, proteins, fibers, carbohydrate and moisture present in high amounts in both plants. In phytochemical investigation, the fraction of ethyl acetateof B. affinis was ledto various chromatographic techniques to explore pure chemical compounds isolation. With the help of advance techniques of spectroscopy includes 1H-NMR, 13C-NMR, IR, UV and EI-MS, the obtained pure compounds structureswereidentified. Isolation of six main and well identified compounds were done from B. affinis but identified in this plant first time in the history namely Kojic acid (1), Gallic acid (2), Kaempferol (3), Polygodial (4), β-sitosterol(5) and Myricetin(6). Page | XVII Seventeencomponentswereidentified inthe fixed oil of B. affinis obtained from n-hexane column chromatography and all were methyl esters. GC-MC analysis disclosed a total of 20 different constituents detectedin both plants essential oil and theirpercent concentration is given in which Carvacrol and Thymol found major constituents in both. The fabrication of silver nanoparticles by utilizing the aqueous form of B. affinis and M. cabulica was done via biological approach. Silver was of a particular interest for this process due to its unique properties, cost effective, environmental friendly, easy and efficient metal for nanoparticles production. The various types of phytochemicals present in plants act as reducing agent and help in formation of nanoparticles. The nanoparticles were characterized by utilizing various spectroscopic techniques. Ultraviolet-visible (UV-vis) spectroscopy is utilized in order to analyze the obtained nanoparticles stability. The UV–vis spectra of plant derived silver nanopartcles of B. affinis and M. cabulica showed maximum absorbance at 420 nm and 430 nm respectively. X-Ray Diffraction (XRD) study is utilized to confirm the crystallinity as well as the size of purified biologically prepared AgNPs. The average cyrstal size of B. affinis and M. cabulica nanoparticles were 4.05 Å and 4.07Å respectively and were calculated through Debye– Scherrer’s equation. Silver was found as major ingredient element and comprises of 17.87% (by weight) in B. affinis and 14.23% in M. cabulica was confirmed by Energy- Dispersive X- Ray (EDX) Spectroscopy. Simultaneous Thermo Gravimetric and Differential Thermal Analysis (TG/DTA) demonstrated that synthesized nanoparticles of both plants are thermally stable. The size as well as structure of plant derived nanoparticles was confirmed by means of Scanning Electron Microscopy (SEM) along with Transmission Electron Microscopy (TEM). The Page | XVIII nanoparticles of both plants were mostly spherical shaped and the estimated sizes of B. affinis and M. cabulica were 26.1 nm and 28.8 nm respectively. The folkloric use of these plants was scientifically justified by screening the test samples for different biological / pharmacological assays (in-vitro and in-vivo). The test samples exhibited significant antibacterial and cytotoxic activities. Good antioxidant, antitermite and phytotoxic activities were observed. The plants possess low to moderate antifungal, insecticidal and nematicidal potential while no haemagglutination and leishmanicidal activity were shown by test samples. The crude extract of both plants was also evaluated for tyrosinase inhibition assay. Results of both plants showed significant inhibitory action at treatment of 1000 mg/mL. Toxicological studies disclosed the consumption of both plants is safe for human health. It was found that the antihyperlipidemic activity of B. affinis was dependent on concentration of dose administered. The crude extract of B. affinis at 400 and 600 mg/kg remarkably lowered the levels of TC, TG, VLDL as well as LDL cholesterol (P<0.05) and remarkably higher the level of HDL cholesterol (P<0.05) in mice in comparison to the groups of control like triton as well as simvastatin. The current investigation has disclosed the immense and diverse medicinal properties of B. affinis and M. cabulica, both can be used for therapeutic purposes and may be helpful in preparations of many herbal products on commercial scale.