In this paper, a rapid and sensitive fluorescent aptasensor for the detection of aflatoxin M₁ (AFM₁) in milk powder was developed. Graphene oxide (GO) was employed to quench the fluorescence of a carboxyfluorescein-labelled aptamer and protect the aptamer from nuclease cleavage. Upon the addition of AFM₁, the formation of an AFM₁/aptamer complex resulted in the aptamer detaching from the surface of GO, followed by the aptamer cleavage by DNase I and the release of the target AFM₁ for a new cycle, which led to great signal amplification and high sensitivity. Under optimized conditions, the GO-based detection of the aptasensor exhibited a linear response to AFM₁ levels in a dynamic range from 0.2 to 10 μg/kg, with a limit of detection (LOD) of 0.05 μg/kg. Moreover, the developed aptasensor showed a high specificity towards AFM₁ without interference from other mycotoxins. In addition, the technique was successfully applied for the detection of AFM₁ in infant milk powder samples. The aptasensor proposed here offers a promising technology for food safety monitoring and can be extended to various targets.

Zanthoxylum mezoneurispinosum Ake Assi and Zanthoxylum psammophilum Ake Assi are species endemic to Côte d’Ivoire. In this study, we determined, for the first time, the composition and biological activities of essential oils obtained from each of these plants. Essential oils were obtained by hydrodistillation from different organs of each plant with a Clevenger-type apparatus and analyzed by gas chromatography–mass spectrometry (GC-MS). Thirty-four components, accounting for more than 99.9% of the overall composition, were identified in the oils. The Z. psammophilum leaf and trunk bark oils exhibited two unusual methylketones, undecan-2-one and tridecan-2-one, whereas the root oil was rich in thymol and sesquiterpenoids. The Z. mezoneurispinosum leaf and trunk bark oils were rich in monoterpenoids, whereas sesquiterpenoids were predominant in the root oil. These samples produced, for the first time, some new chemical profiles of essential oils. The oils’ antioxidant activities were determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and ferric reducing antioxidant power (FRAP) assays. The results showed that the essential oil isolated from roots of Z. mezoneurispinosum had the highest antioxidant activity, which is in accordance with the high thymol content of that oil. We also determined the lipoxygenase inhibitory activities of the essential oils. The results showed that all of the tested oils displayed high and close lipoxygenase inhibitory activities.

Introduction. In the Comoros archipelago, as in many places in Africa, traditional medicine is the first reflex people have when it comes to finding a cure. This work illustrates the diversity of remedies found in this group of islands. The plant species potentially effective from a pharmaceutical point of view can be targeted through the comparison of different databases. The present study also illustrates the importance of preventing the loss of traditional knowledge based on hundreds of years of observations. Literature. The information in this paper originates from databases built by ethnobotanists as well as peer reviewed scientific articles. In addition, some information also come from work done by locals working with recognized organisms. Conclusions. The scientific literature cites 207 different species that are used for traditional practices in the Comoros archipelago, among which 9 are endemic. These species were compared to the pharmacopoeias of other islands and surroundings from the Indian Ocean in terms of similarities and differences between targeted ailments. Only 3% of the cited species present similarities in use among the islands of the Indian Ocean and surroundings.