The present study was carried out to investigate the phytochemical composition and antioxidant activity of two Terminalia species (T. muelleri and T. myriocarpa). Antioxidant activity of the two Terminalia extracts was evaluated in vitro using DPPH, FRAP, and total phenolic content using rutin, iron sulfate, and gallic acid as reference materials. Polyphenol compounds of the two Terminalia leaves were investigated using HPLC and HPLC-MS/MS. It was shown that the two species leaves exhibited high antioxidant activity. The polyphenols content of T. muelleri and T. myriocapa are 0.19 and 0.155 mg equivalent of gallic acid/mg crude extract respectively. HPLC analysis of the two extracts revealed that the phenolic acids in T. muelleri and T. myriocarpa are predominantly in the free form. The main compounds are cinnamic acid and gallic acid in all analytical fractions of both Terminalia species. LCMS/MS analysis of the ethyl acetate extracts of the two species identified the following flavonoid compounds such as rutin, quercetin, methyl gallate, and cafoylacetylhexoside in T. muelleri while rutin, quercetin, epigallocatechin gallate, and myricetin were identified in T. myriocarpa. The antioxidant activity observed by the examined extracts may be attributed to the high amount of polyphenols. These results support the medicinal and pharmaceutical importance of Terminalia species.

Objectives: Essential oils (EOs) are valuable natural products whose composition pattern, concentration of individual components and yield depend on many intrinsic and extrinsic factors. This study aimed to evaluate the impact of foliar spray of ethephon, water stress, organic and inorganic fertilizers on the EOs composition of Foeniculum vulgare, Miller, var. Dulce roots. Methods: Automated rapid headspace solid phase micro extraction (SPME) was applied for the extraction of volatile components combined with gas chromatography coupled to mass spectrometry GC/MS for identification of the volatile compounds. Results: forty two volatile components were identified in Foeniculum vulgare, Miller, var. Dulce roots which were dominated by hydrocarbons (55.36%-87.2%) with monoterpenes being the major class of components (53.15%-87.08%) in the six various applied conditions. Dehydro-p-cymene represented the major constituent (55.8%) in the oil of the non-treated control plant while limonene was the major component in both condition 4 and 6 upon applying drought stress, while alpha terpinolene is the major component in conditions 1, 2, 3 and 5 (30.59%, 39.93%, 50.37% and 35.41% respectively) using different organic and inorganic fertilizers. Conclusion: It is concluded that manipulation of agricultural conditions strongly affects biosynthesis and accumulation of essential oils obtained from Foeniculum vulgare Miller var. dulce roots.