Comparative Qualitative Phytochemical Profiling of Common Medicinal Plant Leaves Found in Kerala

Abstract

The present study provides a comparative qualitative phytochemical screening of aqueous leaf extracts of four medicinal plants commonly available in Kerala, India: guava (Psidium guajava), karinochi (Vitex negundo), bottlebrush (Callistemon sp.), and vathakodi (Justicia gendarussa). Leaf extracts were prepared under two extraction conditions using 5 g of leaf material in 50 mL of deionised water: reflux extraction at 100 °C for 1 h and mild heating at 80 °C for 30 min. The resulting extracts were subjected to qualitative colour and precipitation tests to detect alkaloids, flavonoids, glycosides, saponins, steroids, tannins, phenols, terpenoids, carbohydrates, proteins, coumarins, quinones, anthraquinones, phlobatannins, and unsaturated compounds. All four plant extracts exhibited a diverse phytochemical profile, with flavonoids, glycosides, saponins, steroids, and unsaturated compounds consistently detected under both extraction conditions. Anthraquinones were not detected in any of the investigated extracts. Differences were observed in the phytochemical profiles depending on plant species and extraction conditions. Alkaloids were detected following extraction at 80 °C but were not detected after prolonged reflux at 100 °C, suggesting possible thermal degradation or alteration of alkaloid constituents. Karinochi exhibited a distinctive profile, showing positive reactions for quinones and phlobatannins under both extraction conditions. Vathakodi consistently showed negative results for terpenoids, carbohydrates, proteins, and coumarins. Overall, the findings demonstrate that both plant source and extraction temperature and duration can influence the qualitative phytochemical composition of aqueous leaf extracts. The study provides a comparative baseline for selecting appropriate extraction conditions for subsequent phytochemical characterization and bioactivity-guided investigations of these medicinal.