A Review on Pharmacognostic Features, Phytochemistry, and Therapeutic Potential of Nerium oleander L

Review Article

Abstract

Nerium oleander L. (Apocynaceae) is an evergreen shrub characterized by ornamental foliage, therapeutic bioactive constituents, and profound cardiac toxicity. Native to the Mediterranean region and warm temperate zones of Asia, the species accumulates complex secondary metabolites across all anatomical organs. Cardenolides, primarily oleandrin, digitoxigenin, folinerin, adynerin, and odoroside variants, represent the central bioactive and toxic principles. These cardiac glycosides exert potent pharmacological effects through competitive inhibition of the plasma membrane Na⁺/K⁺-adenosine triphosphatase (Na⁺/K⁺-ATPase) pump, altering intracellular ion homeostasis and inducing positive inotropy alongside lethal arrhythmias at toxic concentrations. Apart from cardenolides, there are also pentacyclic triterpenes such as ursolic acid, oleanolic acid, betulinic acid, and betulin, alongside polyphenols, flavonoids including quercetin and kaempferol glycosides, and volatile monoterpenes. Pharmacognostic characterization reveals linear-lanceolate coriaceous leaves arranged in whorls of three, sunken stomatal crypts lined with protective trichomes, and laticiferous vessels containing latex. Agronomic evaluations document marked drought tolerance, adaptability to saline or nutrient-depleted soils, and optimal development under full sunlight with well-drained substrate. Pharmacological investigations establish cytotoxic activity against diverse neoplastic cell lines, antimicrobial broad-spectrum efficacy, antioxidant capacity, and anti-inflammatory action. Ethnomedicinal records indicate traditional topical applications for dermatological lesions, scabies, and localized inflammation, though systemic application remains restricted by severe toxicity. A rigorous appraisal of botanical traits, chemical constituents, toxicity pathways, and therapeutic properties elucidates the dual nature of Nerium oleander as both a botanical hazard and a valuable source for pharmaceutical development.