UV visualisation of Mesembryanthemum alkaloids? UV has been used as a detection for mesembrine type alkaloids at a wavelength of 228 nm for HPLC analysis [1] and a Sceletium typical chromatogram presents as below [2] where the peak at 298 nm correlates to ∆ 7-mesembrenone. UV quenching of F254 TLC plates has also been used to visualise mesembrine-type alkaloids with some success [2]. Common UV LED lighting is generally assumed to emit at a typical emission in the 365 - 405 nm region. Also readily and cheaply available, shortwave UV emitted by means such as a UV water sterilisation lamp is generally considered to be closer to 254 nm The purpose of this paper was to explore if common UV sources allow for visualisation of mesembrine-type, or sceletenone-type alkaloids and explore fluorescent constituents in Mesembryanthemums. It is assumed that the more conjugated eg. enone forms of such alkaloids will be more likely to display fluorescence, eg mesembrenone. There is a high likelihood that other phytochemical constuents may also show fluorescence. Despite a wavelength outside the typical spectrum for mesembrine-type alkaloids, UV LED lighting has displayed a range of fluorescent constituents on TLC chromatographs. These constituents have been noted in Sceletium spp., Aptenia (Mesembryanthemum) spp. Delosperma spp., Trichodiadema spp. and traces have been noted in a diverse range of unrelated Mesembryanthemums including Lampranthus spp. Some of these constituents have been quite strikingly fluorescent, eg TLC of Aptenia has shown that UV LED visualisation may be feasible for some of these constituents. Delosperma floribundum and to a lesser extent D. bosseranum and others showed some fluorescent constituents and Trichodiadema stellatum quite notable fluorescence. 1 While sometimes hard to see via photo capture: Aptenia TLC under UV While the Sceletiums tend to show diverse chemotypic variation, some TLC chromatograms have showed notably visible constituents on visualisation with LED UV sources. A TLC of a superior quality (as bioassayed by an experienced sampler) Sceletium product showed the predominate constituents showed mild fluorescence under UV LED light. Various Sceletiums under UV [1] Patnala, Srinivas & Kanfer, Isadore. (2010). HPLC Analysis of Mesembrine-Type Alkaloids in Sceletium Plant Material Used as An African Traditional Medicine. Journal of pharmacy & pharmaceutical sciences : a publication of the Canadian Society for Pharmaceutical Sciences, Société canadienne des sciences pharmaceutiques. 13. 558-70. [2] Patnala, S., & Kanfer, I. (2017). Sceletium Plant Species: Alkaloidal Components, 2 Chemistry and Ethnopharmacology. InTech. https://www.intechopen.com/chapters/53426 3