Phytochemistry, Antimicrobial, Antigiardial and Antiamoebic Activities of Selected Plants from Albaha Area, Saudi Arabia

The study aimed at evaluating phytochemical components, antibacterial, antifungal, antigiardial and antiamoebic activities of methanol extract from Bidens biternata, Silybum marianum, Osteospermum vaillantii, Achyranthes aspera and Asphodelus tenuifolius plants. Phytochemical analysis revealed that B. biternata was rich in total phytocomponent (24.3 ± 1.2%), polyphenol (16.3 ± 1.6 mg g-1) and flavonoid (9.6 ± 0.66 mg g-1) contents. The highest level of alkaloid content was detected in A. aspera (9.2 ± 0.08 mg/g DW) and S. marianum (7.6 ± 0.24 mg/g DW) extracts. B. biternata extract strongly inhibited the growth of Staphylococcus aureus with an inhibition zone equal to 29 ± 1.3 mm and showed moderate antifungal activity towards Aspergillus niger (16 ± 0.3 mm) and Candida albicans (15 ± 0.2 mm). Extract from A. aspera had potent antigiardial activity against Giardia lamlia in vitro with an IC50 = 52.91 µg/ml while the treatment of Entamoeba histolytica with S. marianum extract resulted in a marked decrease of the parasite viability with an IC50 = 80.37 µg/ml. The antimicrobial and antiprotozoal activities of the extracted components give support and can strengthen the traditional uses of these plants.