Preliminary Phytochemical Screening, In-vitro Evaluation of Antioxidant and Antimicrobial Activities of the Aerial Parts for Astragalus pelecinus (L.) Barneby a member of Palestinian Flora

Supervisor: Dr. Nidal Jaradat

ABSTRACT

Background: Phytochemical agents have been traditionally used by indigenous healers and herbalists for treatment and prevention of infectious and non-infectious diseases. Astragalus pelecinus aerial parts have been used in the Palestinian folk medicine for the healing of the infected wounds for the soldiers from the ancient times.

Objectives: This study was designed to screen the phytochemical compounds (acetone, ethanolic, methanol and aqueous extracts) and to evaluate the antimicrobial and antioxidant activities of methanolic and aqueous extract of Astragaluspelecinus (L.) Barneby aerial parts.

Methods:The antioxidant property of extract was evaluated using DPPH free radical scavenging activity method. Detection of antimicrobial activity and determination of minimal inhibitory concentration (MIC) of aqueous and methanolic extracts ofAstragaluspelecinus(L.) Barne were performed using broth micro-dilution method. The antimicrobial activity was examined against Staphylococcus aureus(ATCC 25923),Escherichia coli(ATCC 25922),Pseudomonas aeruginosa(ATCC 27853),Staphylococcus aureus(positive MRSA) and a clinical isolate of Candida albicans.

Results: The results showed that Astragalus pelecinus (L.) Barneby methanolic, acetone, aqueous, ethanolic extracts contains a mixture of phytochemical classes as proteins, carbohydrates, phenolic tannins, flavonoids, glycosides, terpenoids , alkaloids and steroids and revealed that this plant has mild antioxidant activity (IC50=3.26 µg/ml,  SD=0.217429).

Aqueous extract of Astragalus pelecinus (L.) possessed antimicrobial activity against Staphylococcus aureus, MRSA, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, were the MIC values were 33, 33, 33, 66 and 33 mg/ml, respectively.  On the other hand, methanol extract exhibited antimicrobial effect against Staphylococcus aureus, MRSA and Escherichia coli , where the MIC value was  51.5 mg/ml in all cases.

Conclusions: The results of the present study indicated that the Astragalus pelecinus (L.) Barneby aerial parts have wide diversity range of the phytochemical compounds, therefore the plant has high antioxidant activity. In addition, aqueous extract, exhibited strong antibacterial activity against Staphylococcus aureus, MRSA, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, which indicate that the plant can strongly provide natural source of antimicrobial and antioxidant medications and can be useful in preventing various dangerous diseases including diabetes mellitus and cancer.