No abstract

Chemical variability in the components of T. vogelii essential oils from eastern Uganda was identified using principal component analysis (PCA) and Agglomerative hierarchical clustering (AHC). Based on the profiles of the compounds of farnesene family three chemotypes were found: farnesol (chemotype 1), springene (β- Springene and α-Springene) and the β-Farnesene were distinctive in chemotype 2 and a mixed variety of farnesol and the Springene. In the three cases, alkybenzenes; o-xylene, m-xylene and ethylbenzene were significant components in the oil. 1,4-dihydroxy-p-menth-2-ene, 5,9-undecadien-2-one, 6,10-dimethyl, and 3-cyclohexen-1-carboxaldehyde,3,4-dimethyl were other prominent constituents. The yields of the essential oils did not vary significantly however the chemical composition varied with harvesting time during the rainy and dry seasons. In choice repellency tests, chemotype 1 and chemotype 2 were more active against Sitophilus zeamais than mixed chemotype. Farnesol was found to be effective only at a higher concentration as a repellent against S. zeamais. However, further study that aims to optimize and standardize the varieties and harvesting period needed for recommendation to smallhold farmers.

The aim of this research is to characterize the variation in the chemical composition of Tephrosia vogelii essential oils from different locations and to investigate the repellency of essential oils against Sitophilus zeamais. Chemical variability in the components of T. vogelii essential oils from eastern Uganda was identified using principal component analysis (PCA) and agglomerative hierarchical clustering (AHC). Based on the profiles of the compounds of the farnesene family, three chemotypes were found: farnesol (chemotype 1), springene (β-springene and α-springene) and β-farnesene were all distinctive in chemotype 2 and a mixed variety of farnesol and springene. In the three cases, alkyl benzenes (o-xylene, m-xylene and ethylbenzene) were significant components in the oil. The compounds 1,4-dihydroxy-p-menth-2-ene, 6,10-dimethyl-5,9-undecadien-2-one, and 3,4-dimethyl-3-cyclohexen-1-carboxaldehyde were other prominent constituents. The yields of the essential oils did not vary significantly, however the chemical composition varied with harvesting time during the rainy and dry seasons. In choice repellency tests, chemotype 1 and chemotype 2 were more active against Sitophilus zeamais than the mixed chemotype. Farnesol was found to be effective only at a higher concentration as a repellent against S. zeamais. We therefore hypothesize that farnesol is a key player in this and we demonstrated the weak repellency of this compound. However, further study that aims to optimize and standardize the varieties and harvesting period is needed for recommendation to smallhold farmers.

Purpose Bidens pilosa L. is traditionally used as a flavouring agent in foods, in the treatment of diseases, in agriculture as a biopesticide and herbicide, and in the phytoremediation of soils contaminated with heavy metals. The vast range of uses of B. pilosa for a variety of purposes is questionable, hence motivating the objectives of this study, which are to assess the cytotoxicity, health benefits, and/or risks of B. pilosa using chemical-based evidence. Methods A real-time cell analysis (xCELLigence system), ultra-high-performance liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer, high-performance liquid chromatography with a diode array detector, and chemical-based spectrophotometric methods were adopted in the study. Results High concentrations of the ethanol extracts exhibited cytotoxic activity on HepG2 (cancerous), and Vero (non-cancerous) cell lines, whereas the water extracts promoted cell proliferation at selected concentrations. The chemical profiling enabled the separation as well as characterisation of 137 phytochemicals. These were mainly phenolic acids, flavonoids, fatty acids, coumarins, and furanocoumarins. There was no toxic compound identified. Conclusion The ethanol extracts are generally more potent and exhibit stronger antioxidant activity and cytotoxicity, probably due to the presence of more flavonoids and phenolic acids, validating the uses of B. pilosa and its relevance as a source of functional phytochemicals.