# Metabolic Profiling of _Conyza sumatrensis_ ([PERSON].) [PERSON] from Lugazi, Uganda
## 3 Results and Discussion
### TLC-UV/Vis Analysis Suggests the Presence of Steroids and Other Trepenes in the Plant Extracts  
In order to obtain an initial overview of the chemical composition and a first comparison of the aqueous and ethanolic extracts of _C. sumatrensis_, we carried out a TLC UV/Visanalysis. TLC is known as a very convenient, cost-effective, and rapid method to separate non-volatile metabolites. The use of suitable detection reagents allows a preliminary identification of specific compound classes. With respect to the available literature [23; 24], we focused on the detection of terpenes using anisaldehyde/H\({}_{2}\)SO\({}_{4}\). Trepenes represent a highly diverse and extensive group of natural products [25]. Potential effects of terpenoid compounds in plants include functions in defense mechanisms, responses to environmental stresses [26], and the attraction of pollinators [27].  
Anisaldehyde/sulphuric acid produces distinct visible color changes with the separated analytes, including those which might not be detected in standard HPLC-UV analysis [24]. Indeed, after derivatization, the TLC chromatograms displayed various colored spots indicating the presence of different classes of terpenes. Examination of the plates under visible light and UV light revealed the presence of triterpenes and steroids in both the aqueous and ethanolic extracts of _C. sumatrensis_ but monoterenes only in ethanolic extracts (Table 1), as detailed below.  
In detail, the TLC chromatograms displayed a single blue spot with an R\({}_{\text{f}}\) of 0.75 in the chromatogram, suggesting a distinct monoterpene in the ethanolic extract. Smaller terpenes, such as monoterenes and sesquiterpenes, are typically volatile; therefore, their presence in the extracts was unexpected. However, the gentle shade-drying process might have helped to preserve some of these volatile compounds adsorbed to cell components or trapped inside intact cell wall compartments. In contrast, larger terpenoids, including diterpenes, sesquter terpenes, and triterpenes, are predominantly non-volatile [28]. Three blue to violet-colored spots with R\({}_{\text{f}}\) values of 0.50, 0.83, and 0.90 for ethanolic extracts (data shown in Figure S1 and Table S1) and two similarly colored spots for the aqueous extracts with R\({}_{\text{f}}\) values of 0.72 and 0.77 indicate the presence of such terpenes.  
In the TLC chromatograms, distinct gray spots were detected as tentative steroids [29] with R\({}_{\text{f}}\)-values of 0.36 and 0.20 in the ethanolic extracts and 0.87, 0.38, and 0.13 in the aqueous extracts. These findings suggest the presence of different steroids and other terpenes in aqueous and ethanolic extracts of _C. sumatrensis_. Steroids, a subclass of terpenes, are mainly present in plants as phytosterols. The antimicrobial, anti-inflammatory, antioxidant, and anti-cancer properties of terpenes in general and of phytosterols in particular have been extensively studied [30]. Moreover, phytosterols stabilize plant cell membranes and regulate membrane fluidity [31]. In TLC analysis, carbohydrates can be observed in different colors (gray, red, turquoise) depending on their structure [24]. Neither ethanolic nor aqueous extracts showed any definitive carbohydrate-related signals in our analyses. However, four specific pink-red colored signals with R\({}_{\text{f}}\)-values of 0.96, 0.93, 0.66, and 0.56 only occurred in the aqueous extract and could be interpreted either as triterpenes, glycosides, or carbohydrates. Overall, the TLC analysis of extracts of _C. sumatrensis_ indicated a rich terpenoid profile, which prompted us to a more detailed investigation.