Comparative Evaluation of the Cytotoxic Activity of Ethanolic Leaf Extracts of Pink and White Catharanthus roseus Using the Brine Shrimp Lethality Assay

ABSTRACTCatharanthus roseus (L.) G. Don (Apocynaceae), commonly known as Madagascar periwinkle, is a wellknown medicinal plant rich in bioactive phytochemicals, particularly indole alkaloids, flavonoids andphenolic compounds, which possess diverse pharmacological activities including cytotoxic effects. Thepresent in vitro study was undertaken to comparatively evaluate the cytotoxic activity of ethanolic leafextracts of the pink- and white-flowered varieties of C. roseus using the Brine Shrimp Lethality Assay(BSLA). Fresh leaves of both varieties were collected from Namakkal, Tamil Nadu, authenticated, shadedried, powdered and extracted with 95% ethanol by maceration (1:10, 72 h). The ethanolic extracts weresubjected to preliminary phytochemical screening and evaluated for cytotoxic activity by exposing Artemiasalina nauplii to extract concentrations of 50, 100, 250, 500 and 1000 μg/mL, with mortality recorded after24 h; percentage mortality and LC₅₀ values were determined and compared between the two varieties. Thepercentage yield of the ethanolic extract was 16.8% for the pink variety and 14.9% for the white variety.Both extracts tested positive for alkaloids, flavonoids, phenolics, tannins, glycosides, terpenoids, steroidsand saponins. Both extracts produced concentration-dependent mortality of A. salina nauplii; the pinkvariety produced 90% maximum mortality with an LC₅₀ of 248 μg/mL, while the white variety produced80% maximum mortality with an LC₅₀ of 372 μg/mL, indicating higher cytotoxic potency for the pinkvariety. Both pink and white C. roseus ethanolic leaf extracts exhibit concentration-dependent cytotoxicactivity, with the pink variety showing greater potency, likely reflecting a higher content of terpenoid indolealkaloids and related phytoconstituents. These findings support the traditional medicinal use of C. roseusand provide a scientific basis for further phytochemical isolation and anticancer research.