QUALITATIVE SCREENING AND SPECTROSCOPIC EVALUATION OF THERAPEUTIC PHYTOCHEMICALS IN SELECTED MEDICINAL HERBS

Abstract

Plant derived compounds have been a topic of continued scientific scrutiny globally, especially in the era of increased antimicrobial resistance and the growing epidemic of chronic non communicable diseases. This dissertation discusses the phytochemical composition and medicinal significance of two widely used medicinal plants: Bougainvillea spectabilis Willd. (Nyctaginaceae), Thymus vulgaris L. (Lamiaceae), Rosmarinus officinalis L and Harsingar or Parijat Nyctanthes arbor-tristis — through a comprehensive review of current literature. Bougainvillea spectabilis is particularly rich in a large number of secondary metabolites including betalains (betacyanins and betaxanthins), flavonoids (such as quercetin and kaempferol), the insulin sensitizing agent pinitol, hydrolysable tannins and gallic acid. Experimental studies have shown that these constituents work synergistically to exhibit antioxidant, anti-inflammatory, antidiabetic and antimicrobial properties, with well-defined molecular mechanisms. Thymus vulgaris has a similarly interesting phytochemical profile, with the phenolic monoterpenes thymol and carvacrol, polyphenolic acid rosmarinic acid, and flavones luteolin and apigenin. These compounds have been extensively studied for their pharmacological activities that have substantiated the plant's efficacy as an antimicrobial, anti fungal, antioxidant and anti-inflammatory. Various parts of the plant such as leaves, flowers, seeds, bark and stems are employed for treating several health problems. Its therapeutic importance is mainly attributed to the presence of bioactive compounds like flavonoids, glycosides, alkaloids, tannins, phenolics and essential oil One of the key goals of this work is to establish a mechanistic correlation based on experimental data between the specific phytochemicals identified in these 2 plants and the molecular pathways where they are acting on disease processes. The review shows that both species have coherent and scientifically established pharmacological mechanisms for the traditional and contemporary applications, providing scientific backing for ongoing research and possible drug development.