Comparative phytochemical screening of Rhazya stricta Decne (Apocynaceae) from Takht Bhai Hills, Mardan, Pakistan: Effect of solvent polarity

Background: Rhazya stricta Decne (Apocynaceae) is a perennial medicinal shrub distributed across South Asia, the Arabian Peninsula, and adjoining arid regions, where it is widely used in traditional medicine for gastrointestinal, dermatological, antipyretic, antidiabetic, and rheumatic conditions. Although more than one hundred alkaloids have been reported from this species, comparative solvent-based qualitative data on its major phytochemical classes particularly from populations growing in the sub-Himalayan foothills of Pakistan remain limited.
Methods: Aerial parts (leaves and stems) of R. stricta were collected from Takht Bhai hills, district Mardan, Khyber Pakhtunkhwa, Pakistan, shade-dried, and powdered. Crude extracts were prepared by cold maceration (15 days) in four solvents of increasing polarity ethanol, methanol, acetone, and distilled water and screened qualitatively for alkaloids (Mayer's and Wagner's tests), flavonoids (sodium hydroxide test), saponins (foam test), tannins (ferric chloride test), and phenolic compounds (ferric chloride test).
Results: Phenolic compounds were detected in all four extracts. Alkaloids and saponins were present in the methanolic, acetone, and aqueous extracts but absent from the ethanolic extract. Flavonoids were detected in the ethanolic, methanolic, and aqueous extracts but not in the acetone extract. Tannins were detected only in the ethanolic and acetone extracts, being absent from the methanolic and aqueous extracts.
Conclusion: The crude extracts of R. stricta collected from Mardan contain a broad spectrum of pharmacologically relevant secondary metabolites alkaloids, flavonoids, saponins, tannins, and phenolics whose relative distribution is strongly solvent-dependent. These findings support the traditional therapeutic use of this species and provide a rational basis for selecting extraction solvents in subsequent quantitative, chromatographic, and bioassay-based studies.
Keywords: Rhazya stricta; Apocynaceae; phytochemical screening; alkaloids; flavonoids; solvent polarity; traditional medicine.

Muhammad Salman is a plant biologist and Research Assistant at the Institute of Botany, Abdul Wali Khan University Mardan, Pakistan, where he completed his BS in Botany in October 2025. His research examines how heavy metal stress, including iron chloride and copper sulphate, affects germination, seedling growth, biomass, and photosynthetic pigments in wheat and maize. He has contributed to floristic studies and presented work on microplastic pollution in agroforestry ecosystems at conferences in Istanbul and Budapest. His interests include plant physiology, crop improvement, and sustainable agriculture. He is proficient in SPSS, R, EViews, and DSSAT.