Phenolic Profile and Antioxidant-Related Activities of Astrophytum ornatum (DC) Britton & Rose Flowers Cultivated in Egypt

Abstract

Objectives: The current study aimed at the phenolic profiling, antioxidant, anti-aging, anti-arthritic in vitro screening of the 80% aq. methanol extract of Astrophytum ornatum (DC) Britton & Rose flowers for the first time. Methods: Phytochemical screening was accomplished using the standard adopted techniques as per constituent. Total phenolic and flavonoid contents were quantified using Folin-ciocalteau and aluminum chloride colorimetric assays, respectively. HPLC, using available reference phenolics, was implemented for the tentative identification of the phenolic metabolites. The extract was subjected to fractionation and isolation of its major components using open column chromatography packed with relevant stationary phases, while the structure of the isolated metabolites was elucidated based on the physical, chromatographic properties and/ or spectroscopic data. Finally, the antioxidant, anti-aging, and anti-arthritic potential of the extract was determined in terms of the DPPH radical scavenging, anti-collagenase, and protein denaturation inhibitory effect, respectively. Results: panel of metabolites were revealed from the qualitative phytochemical screening for instance, carbohydrates and/glycosides, flavonoids, tannins, saponins, and essential oils. The quantified total phenolic and flavonoid contents were calculated as 222.51± 0.24 µg GAE/mg and 138.18± 0.10 µg QE/mg, respectively. The HPLC tentatively identified eleven phenolic acids (representing 5.4626 %) and eleven flavonoids (representing 19.5273 %) among which naringin represents the major identified flavonoid glycoside (5.7055 %) while, apigenin (4.1018%) is the major identified aglycon. In the same context, the chromatographic fractionation afforded four metabolites viz , mixture of isoquercetrin ( 1 ), hyperoside ( 2 ), quercetin ( 3 ), and kaempferol ( 4 ). From the pharmacological perspective, the tested extract displayed promising IC 50 =79.3 ± 3.8, 62.4 ± 2.1, and 54.6 ± 2.7 µg/ml in the DPPH radical scavenging, anti-collagenase, and protein denaturation assays, respectively. Conclusion: Astrophytum ornatum flowers are valuable source of bio-active flavonoids that may in part displayed a significant role in the management of free radical related disorders just as aging and arthritis.