Journal of Medicinal Plants Biotechnology

Abstract The excessive and improper use of antimicrobial agents has led to the emergence of drug-resistant strains. Therefore, It necessitates the discovery and implementation of new sources to combat microbial pathogens. This study aimed to evaluate the antibacterial effect of ethanolic extract of Ziziphus spina-christi leaves against four bacteria; Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Corynebacterium glutamicum. Initial screening of the antibacterial activity of the extract was performed using the disk diffusion method. Subsequently, the minimum inhibitory concentration (MIC) was determined using the microdilution method, and the minimum bactericidal concentration (MBC) was identified through microbial culture. According to the results, the highest antibacterial effect of the leaf extract was observed against Corynebacterium glutamicum. The microdilution test showed that the MIC for all bacteria, except Escherichia coli, was 75 mg/mL. The lowest survival rate was observed in Corynebacterium glutamicum and Staphylococcus epidermidis. The MBC for these two bacteria was determined to be 150 mg/mL, while for Escherichia coli, it was 300 mg/mL. The findings of this research demonstrated that Ziziphus leaf extract has notable antibacterial activity, especially against the studied Gram-positive bacteria, and could be considered a natural source for developing of new antibacterial drugs.

Abstract Medicinal plants are recognized as significant sources of natural antioxidants due to their bioactive compounds, particularly phenolics and flavonoids, which have shown potential in the prevention and treatment of various diseases. These compounds are widely studied for their notable antioxidant, anti-inflammatory, and anticancer properties. The efficiency and profile of extracted phytochemicals are highly influenced by extraction parameters, including solvent type, solvent concentration, and extraction time. This study aimed to evaluate the effects of different extraction methods, namely maceration and ultrasound, along with solvent type and concentration (ethanol and methanol at 50% and 70%), and extraction durations (5 and 10 minutes), on the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of extracts from Portulaca oleracea and the leaves and fruits of Ziziphus spina-christi. A factorial experiment was conducted based on a completely randomized design with two replications for statistical analysis. The results revealed that the highest phenolic content was obtained from P. oleracea extract using the maceration method with 70% methanol for 5 minutes. Similarly, the highest flavonoid content was observed in Z. spina-christi leaf extract under the same conditions. Regarding antioxidant activity, the most potent effect was recorded in the leaf extract of Z. spina-christi using 70% ethanol and an extraction time of 10 minutes. These findings highlight the importance of optimizing extraction conditions to enhance the recovery of beneficial bioactive compounds from medicinal plants, thereby improving the antioxidant potential of the resulting extracts.