Today's primary challenges include identifying efficient, affordable, and environmentally sustainable substances to serve as raw materials in industrial, agricultural, and medicinal applications. This study aimed to evaluate the chemical composition and biological properties (namely antioxidant and allelopathic activities) of the methanolic extract derived from the above-ground portions of collected in Jazan, Saudi Arabia. GC-MS was used to evaluate the chemical composition of the methanolic extract derived from . GC-MS analysis revealed a total of 22 volatile compounds in the extract. The most prominent compounds identified were 2-ethylhexanoic acid, 5-hydroxy-6-(1-hydroxyethyl)-2,7-dimethoxynaphtho-quinone, and piperitone. The extract demonstrated strong antioxidant activity in both the DPPH and ABTS radical scavenging assays, comparable to the standard antioxidant ascorbic acid. The IC value for the extract was 31.82 mg/mL in the DPPH assay and 39.93 mg/mL in the ABTS testing. Additionally, the extract exhibited dose-dependent inhibition of seed germination, root growth, and shoot growth of the weed in allelopathic bioassays. The most significant suppression was observed in shoot growth with an IC value of 45.90 mg/mL, which was lower than the IC values for root development and seed germination of , recorded at 56.16 mg/mL and 88.80 mg/mL, respectively. Furthermore, the findings indicated that methanolic extracts had significant lethal toxic effects on the life cycle of . Future research will focus on extracting uncontaminated substances and evaluating the biological effects of each specific constituent.