Inhibitory Effectiveness of Alcoholic and Nano- Extracts of Calendula officinalis-flower against Some Ochratoxin A-Producing Fungi

Abstract

Abstract— The study investigated the antifungal activity of alcoholic and nano-extracts of Calendula officinalis (marigold) flowers against several ochratoxin A-producing fungi. 14 fungal food-based samples were isolated and identified, these samples represented nine types of Aspergillus, including A.flavus, A.niger, A.ochraceus, A.carbonarius, A.fumigatus, A.nidulans A.parasiticus, A. steynii, and A.wentii. There are five subspecies of Penicillium, which are P. chrysogenum, P. expansum, P. oxalicum, P. nordic, and P. verrucosum  . The results showed that all fungal isolates can produce ochratoxin A with a TLC-based technique . The antifungal efficacy of Calendula officinalis-flower -extracted alcohol (ethanol, chloroform) was tested against fungi pre-isolated from an ochratoxin-producing food at 100 mg/ml and 200 mg/ml concentrations. Concentration findings indicated that the two extracts efficiently inhibited fungal isolates. Inhibition was 100% for all the selected fungal isolates at 100 and 200 mg/mL concentrations in the chloroform extract ,   Likewise, the inhibition was 100% at a 200 mg/mL concentration of ethanol extract in the fungal samples under study. The inhibition was 100% at a 100 mg/ml concentration of the fungi A. flavus, A.ochraceus, A.fumigatus, A. steynii, P. nordicum, and P. oxalicum. As for the other fungal species, they were inhibited at different rates. However, the MIC results of the Calendula officinalis-flower -extracted ethanol showed different findings in the ochratoxin-producing fungi, as the 10 mg/ml concentration made a minimum inhibition in both P.nordicum, and A.steynii. Similarly, while the minimum inhibitory concentration was 25 mg/ml for A. fumigatus  and  P. oxalicum, it was 50 mg/ml for A. flavus and A. ochraceus, and a two-fold increase for the other fungi. The A.bisporus-extracted chloroform was found to be more efficient than the ethanolic extract in inhibiting ochratoxin-producing fungi. With a 10 mg/ml concentration as the minimum inhibition of A.fumigatus, A.steynii, P.nordicum, and P.oxalicum,  the 25 mg/ml concentration was the minimum inhibition found in the other fungi except for A.niger, as it inhibited as little as 50 mg/ml. Additionally, the Calendula officinalis-flower -extracted nanoparticles efficiently inhibited the fungi-producing ochratoxin A, with significantly different inhibitions compared with the Calendula officinalis-flower -extracted alcohol .The authors concluded that the C. officinalis flower extracts, particularly the nano-extract, hold promise as natural antifungal agents against ochratoxin A-producing fungi. This could have important implications for the food and feed industry, as the extracts may be used as a bio-preservative to prevent fungal contamination and mycotoxin production.The findings highlight the potential of C. officinalis, a widely used medicinal plant, as a source of potent natural antifungal compounds that could be leveraged to enhance food safety and quality.