HPLC-UV-ESI-MS phyto-analysis and biological activities of Rhanterium adpressum extracts (Asteraceae) from southern Algeria

Abstract

Biological activities of dichloromethane, ethyl acetate and 1-butanolextracts from Rhanterium adpressum flowers was evaluated. The antioxidant activities were measured by three different methods, namely DPPH, phosphomolybdenum and ABTS assays. The results suggested that all extracts possessed an antioxidant activity and capacity. In addition, the dichloromethane extract of April showed the best antimicrobial activity against Pseudomonas aeruginosa (MIC = 6.5 mg/ml) and Staphylococcus aureus (MIC = 20mg/ml). However, anti-diabetic activity tested using an in vitro model by α-glucosidase and α-amylase inhibition testsshowed that the extracts was found to be more effective in inhibiting the activities of maltase with an IC 50 values ranging from 125 to 397 µg/ml when compared to that of α-amylase with IC 50 varying from 1040 to 2710 µg/ml. The phenolic analysis of the most active extract obtained from Rhanterium adpressum has been done by HPLC-UV-ESI/MS. Several flavonoids and phenolics were identified, such as syringic and vanillic acids which were known as important antioxidant phenols.The obtained results suggest that plant extracts could be used as an ingredient in treatment of infectious diseases or as antioxidant. • Antioxidant activity was assessed by three tests in vitro . All extracts exhibited a high antioxidant capacity compared with vitamin C. • Antibacterial activity indicated that DCM extract has been considered as the best extract (MIC = 6.5mg/ml). • Anti-diabetic activity tested using an in vitro model by α-glucosidase and α-amylase inhibition showed a higher inhibition i.e. lower IC 50 (201.09±0.08 µg/mL; 185±0.02 µg/ml & 171±0.01µg/ml for DCM, EtAc & BuOH respectively). • HPLC-UV-ESI/MS analysis of the most active extracts shows several important bioactive compounds (vanillic acid, synringic acid, quercetine).