Pharmacognostic characterization phytochemical profiling and biological activities of selected species of syzygium gaertner myrtaceae endemic to western ghats

Abstract

The genus Syzygium, known for its diverse medicinal applications, is represented by numerous endemic species in the Western Ghats. This study focused on the morpho- anatomical, pharmacognostic, and bioactive profiling of three such endemic species: S. laetum, S. occidentale, and S. palghatense. Detailed macroscopic examination revealed distinctive morphological features, including leaf shape, venation, and flower structure, that aid in species differentiation. Microscopically, variations in stomatal type, secretory structures, and crystal deposition were observed, reflecting their adaptation to the humid evergreen forest ecosystem. Histochemical studies demonstrated the presence of pharmacologically significant compounds such as tannins and oils, while powder microscopy and fluorescence analysis provided unique diagnostic markers for quality control. Physicochemical analyses showed significant nutritional and chemical differences across species, with S. laetum leaves rich in phenolics and vitamin C, S. occidentale bark high in fibre and minerals, and S. palghatense bark showing elevated extractive values and mineral content. A novel aspect of this study was the green synthesis of silver nanoparticles (AgNPs) using methanol extracts of S. palghatense bark. Comprehensive bioactivity assays revealed that these AgNPs exhibit potent antioxidant, antimicrobial, anti-inflammatory, anthelmintic, and anticancer activities. The antioxidant capacity of the AgNPs surpassed standard antioxidants in free radical scavenging assays, while antimicrobial tests demonstrated broad-spectrum efficacy, including disruption of biofilms by pathogenic bacteria. Anti-inflammatory assays showed multi-target enzyme inhibition comparable or superior to conventional drugs. The anthelmintic effect on Lumbricus terrestris was rapid and potent, and cytotoxicity assays on cancer cell lines indicated significant induction of apoptosis. The biological activity studies revealed that silver nanoparticles (AgNPs) synthesized from the methanol extract of S. palghatense bark exhibited significantly higher activity than both the isolated compound and the crude methanol extract alone. The enhanced efficacy of AgNPs is due to their nanoscale size, which improves bioavailability and interaction with biological targets. Among tested activities, AgNPs showed superior antioxidant, antimicrobial, anti-inflammatory, anthelmintic, andanticancer effects, followed by the isolated compound and lastly the crude extract. This demonstrates the promising potential of green-synthesized nanoparticles to amplify the therapeutic effects of natural plant compounds. Complementing experimental work, molecular docking and dynamic simulations provided mechanistic insights into the interaction of key phytochemicals and isolated compounds with protein targets, advancing the potential for drug discovery. The compound 2-Phenyl-4H-chromen-4-one, isolated from S. palghatense, consistently exhibited strong bioactivities across assays. This study not only clarifies taxonomic ambiguities through integrated morpho-anatomical and pharmacognostic data but also highlights the high medicinal potential and ecological importance of these Western Ghats endemics. Ultimately, the research supports their sustainable utilization in developing novel phytomedicines and nanomedicines, fostering conservation and validating traditional medicinal claims.