Abstract

Hyoscyamus muticus is an endangered desert plant spread in the Arabian Peninsula and the Middle East deserts. The methanol extract of the aerial parts of H. muticus grown in the arid zones in the Northern regions of Saudi Arabia were subjected to primary phytochemical analysis which revealed the presence of phenolic compounds, flavonoids, tannins and sterols, the gas chromatography-mass spectrometry (GC-MS) analysis of the methanolic extract exhibited different types of phenolic compounds, including ferulic acid, 4-hydroxy-cinamic acid-ester, methyl salicylate and methyl ferulate. The accumulation of phenolic compounds supports the antioxidative properties of the plant against oxidative stress. The antioxidant testing showed that the methanolic extract of H. muticus has a noticeable antioxidant activity with an IC₅₀ of 8.1±0.65 mg/ml and an EC₅₀ of 12.74±1.12 mg/ml. The antimicrobial investigation on 11 microbial strains revealed that the methanolic extract of H. muticus areal parts showed average or weak antibacterial activity against gram-positive bacteria, weak antibacterial activity against gram-negative bacteria and no antifungal activity. Moreover, the investigations exhibited the presence of an antifeedant potential on the methanol extract of H. muticus on the 4^th instar larvae of Spodoptera littoralis.

Key words: Hyoscyamus muticus, phytochemical analysis, antioxidant capacity, antimicrobial activity, antifeedant assay Spodoptera littoralis.