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 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 Onderstepoort Journal of Veterinary Research (OJVR), is the official publication of the Onderstepoort Veterinary Institute. It publishes scientific papers reporting original research on diseases and disease vectors of livestock and wildlife with a focus on Africa, but with results of more than local interest.

[This corrects the article DOI: 10.1155/2021/9081536.].

Crown rot, primarily caused by the fungus Colletotrichum musae and related pathogens, significantly impacts the postharvest quality and marketability of bananas. The increase in regulatory constraints and the emergence of fungicide-resistant strains highlight the urgent need for sustainable, residue-free alternatives. This research demonstrates that cell-free extracts (CFE) of Bacillus amyloliquefaciens effectively inhibit crown rot and activate host defence mechanisms in tissue-cultured banana plantlets. Treatment with CFE at 100 µg mL-1 reduced lesion formation by up to 78% and significantly decreased fungal biomass, providing protection comparable to that of a commercial fungicide. Molecular analyses revealed significant overexpression of defence-related genes, including PAL, PR5, CHI, and WRKY. Additionally, there was an increased accumulation of defence-associated proteins and phenolic compounds. Metabolomic and biochemical assessments showed enhanced structural and chemical barriers in the treated tissues. These findings provide mechanistic evidence that bacterial metabolites, even in the absence of living cells, can both inhibit pathogen colonization and activate systemic resistance pathways. The research supports the potential of B. amyloliquefaciens CFE as a sustainable and effective alternative to traditional fungicides for combating postharvest crown rot.