In the present study, the relationship between the phenolic counts, chemical composition, and biological activities of two Mentha species (Mentha rotundifolia (MR) and Mentha pulegium (MP)) was analyzed. The characterization of the action mode against pathogenic bacteria and the inhibition of spore germination of two fungal species using prepared methanolic extracts were studied here for the first time. The obtained data highlighted the presence of positive correlation between the secondary metabolites contents and the biological activities of the investigated extracts. In fact, HPLC analysis showed that the major components in both the extracts were eriocitrin and rosmarinic acid (25 and 20mg/ml and 12 and 8mg/ml in methanolic extracts of MR and MP, respectively). Moreover, the MR extract was rich in polyphenols and presents the highest antioxidant activity than MP ones. In addition, both extracts possess an antimicrobial activity against four Gram-positive and five Gram-negative bacteria and one yeast species (Candida albicans) and were able to inhibit the spore germination of two fungi species (Aspergillus niger and Aspergillus flavus). But, the significant activity was observed in the presence of MR methanolic extract. The effect of time on cell integrity of E. coli and L. monocytogenes determined by time-kill and bacteriolysis assays showed that the MR extract had a rapid bacteriolytic effect compared to the MP extract, and their capacities were significant against Gram-negative bacteria than positive ones. Based on the obtained data, it can be concluded that Saudi Mentha species have high pharmacological and industrial importance and they can be used in preparation of food or drugs.

The present study aims to evaluate the chemical composition, metabolites secondary and pharmacology activities of methanolic extract of Marrubium vulgare collected from King Saudi Arabia. Moreover, the primary mode of action of the tested extract was studied here for the first time against E. coli and L. monocytogenes. HPLC analysis shows that the major components in the tested extract are luteolin-7-O-d-glucoside, ferulic acid and premarrubiin. Obtained data demonstrated that the investigated extract was richer in phenol (26.8 ± 0.01 mg/GAE g) than in flavonoids (0.61 ± 0.05 mg EC/mL). In addition, the methanolic extract showed an important antioxidant capacity against the DPPH (IC₅₀ = 35 ± 0.01 µg/mL) and ABTS (IC₅₀ = 25 ± 0.2 µg/mL) radical scavenging and a strong inhibition of acetylcholinesterase enzyme with an IC₅₀ value corresponding to 0.4 mg/mL. The antibacterial activity demonstrated that the evaluated extract had significant activity against both Gram-positive and Gram-negative bacteria. The effect of time on cell integrity on E. coli and L. monocytogenes determined by time–kill and bacteriolysis tests showed that the M. vulgare extract reduced the viability of both strains after 8 and 10 h and had a bacteriolytic effect against two different categories of bacteria, Gram-positive and negative, which are not of the same potency. Based on obtained data, it can be concluded that Saudi M. vulgare has a high pharmacological importance and can be used in preparation of food or drugs.

The aim of the present study was to synthesize silver nanoparticles (AgNPs) using Saudi Mentha pulegium leaves, to characterize the physicochemical properties of the resulting AgNPs, and to evaluate the biological activities of the resulting AgNP‐containing extract. The formation of AgNPs in M. pulegium extract was indicated by a change in color following the addition of silver nitrate and was confirmed using UV‐visible spectroscopy with a maximum absorbance at 425 nm. Energy dispersive X‐ray spectroscopy (EDX) indicated that the anisotropic AgNPs were spherical, and Fourier transform infrared spectroscopy (FTIR) spectral analysis indicated that the aqueous M. pulegium extracts were responsible for reducing Ag⁺ to Ag⁰. The secondary metabolite contents of the methanolic M. pulegium extract corresponded to 17 mg GAE/g DW. DPPH and ABT radical‐scavenging assays indicated that the M. pulegium extracts possessed antioxidant activity (IC₅₀ = 6 and 3 μg/mL, respectively). Disc and broth dilution assays revealed that the extracts exerted significant antibacterial activity, with the inhibition zone diameters and minimal inhibition concentrations of 17–24 mm and 0.08–0.62 mg/mL, respectively. These findings clearly indicate that modified plant extracts have high biological importance and potential use as preservatives in the pharmaceutical and food industries.

The aim of this work was to evaluate phenolic profile, antioxidant capacity and allelopathic effects of six Ziziphyus spina-christi provenances in Saudi Arabia. Total phenols, flavonoids, tannins and antioxidant activity were evaluated. Total phenols, condensed tannins and total flavonoids were present at levels of 62.29 mg GAE/g DM, 16.69 mg CE/g DM and 15.45 µg mg QE/g DM, respectively. The high antioxidant activity (0.15 mg/ml) was noted in Mecca Road provenance. The highest germination, shoots and radicle lengths of tested species were observed in At-taif provenance. Z. spina-christi leaf extracts may be suggested in foods and pharmaceutical industries. Leaf extracts could also provide a natural herbicide with a positive impact on the environment. Provenance of Jizan, Northern Borders and Mecca Road were shown to be particularly effective in antioxidant capacity, while Provenance of Riyadh and Northern Borders shown to have the best allelopathic activity.