In this study, we investigated the phytochemical composition and biological activities of aerial parts, roots, and stems of Pallenis hierochuntica collected during the fructification period in the Betita region, Tebessa Province, Algeria. Chemical screening was carried out to highlight the presence of the main secondary metabolites groups. Total phenolic (TPC) and total flavonoid contents (TFC) were quantified. Antioxidant activity was evaluated using DPPH, ABTS, and CUPRAC assays; the antidiabetic potential was performed via the alphaamylase test, while the sun protection factor (SPF) was determined to assess photoprotective properties. The phytochemical screening revealed the presence of many chemical groups. The highest TPC was recorded in roots extract; however the highest TFC was noted in aerial parts extract. Antioxidant activity assays indicated the roots had the highest antioxidant capacity. The alphaamylase inhibitory activity was notably potent (IC50=136.77±0.19 μg/mL) in roots compared to aerial parts and stems extracts. All extracts demonstrated better alpha-amylase inhibition than the standard antidiabetic drugs. Furthermore, SPF values for all extracts were around 31.50 indicating strong UV protection. The preliminary results obtained through this study are encouraging and will contribute to further research on P. hierochuntica extracts and highlight its potential in developing natural therapeutic and cosmetic products.