Variation in the phytochemical composition of Chromolaena odorata (L.) King and Robinson (Asteraceae) across climatic zones in Benin (West Africa)

Chromolaena odorata (L.) King and Robinson (Asteraceae) is a tropical shrub with interesting chemical potential widely used in agriculture and medical science and which can be affected by several geographic and climatic conditions. Therefore, we investigated the phytochemical composition of this plant across climatic zones in Benin. The plant material collected from different locations was phytochemically screened by staining and precipitation tests. The total phenolic, flavonoid and tannin contents were determined using, the colorimetric method of Folin-Ciocalteu, the method of aluminum chloride and the method of vanillin, respectively, then the obtained data were subjected to analysis of variance. The phytochemical analysis revealed the presence of the main chemical groups such as alkaloids, free anthracene, coumarins, flavonoids, mucilage, tannins, reducing compounds, saponins, quinone derivatives, steroids. There was a significant difference (P < 0.05) in the phytochemical contents across geographical sites. In comparing the levels of phytochemicals among geographical locations, the raw material collected from the north climatic zone contained the highest phenolic and flavonoid contents, 147.59 ± 3.04 mg/g and 17.17 ±0.31 mg/g, respectively, compared to others. Overall, the study highlighted the potential of C. odorata as source of natural products. There was no difference in the phytochemical markers whereas the phytochemical contents vary across climatic zones. These results can be of use in the development of biopesticides from the raw material of C. odorata

Synthesis, caracterization, trypanosomal activities on Trypanosoma bruceibrucei and toxicity against Artemiasalina leach of N(4)-aryl semicarbazones and thiosemicarbazones

N(4)-phenyl substituted semicarbazones and thiosemicarbazones (1-4) of propiophenone and 4'- methylacetophenone have been synthesized and characterized by spectrometrical methods analyses (IR, RMN 1H & 13C, SM). All compounds were evaluated for their in vitro trypanosomal activity against the bloodstream form of the strain 427 of Trypanosomabruceibrucei and have been tested on larvaeofbrine shrimp, Artemiasalina LEACH, for their toxic activity. The selectivity index (SI) of each molecule was too designed. In the group, propiophenone 4- phenyl-3-thiosemicarbazone 4 has exhibited greater trypanocidal activity with a half-inhibitory concentration (IC 50) value equal to 7.63 micromolar (μM). 4'-methylacetophenone 4-phenylsemicarbazone 1 showed moderate antitrypanosomal activity (IC 50 = 62.54 μM). Other, 2 and 3, presented little or no activity against the parasite (IC 50> 100 μM). Except propiophenone 4-phenylsemicarbazone 2 which offered a toxic activity on larvae given the halflethal concentration LC 50 = 107.49 μM and SI = 0.518 281 μM and SI > 1, compounds 1, 3 and 4). They turn out quite selective on the parasite. Synthesized compounds could constitute a new class of anti-trypanosomal drug candidates

Synthesis, characterization and anti-trypanosomal activity of R-(-)carvone and arylketones-thiosemi carbazones and toxicity against Artemia salina Leach

This work is focused on the synthesis and characterization of a series of N(4)- substituted thiosemicarbazones and the evaluation of their in-vitro anti-trypanosomal activity and toxicity. A series of thiosemicarbazones (1-4) and N(4)-phenyl-3-thiosemicarbazones (5-8) have been synthesized on R-(-)carvone, acetophenone, 4’-methylacetophenone and benzophenone by condensation reaction with good yields. All compounds were characterized by spectrometrical analysis methods infrared IR, nuclear magnetic resonance NMR (1H &13C) and mass spectrometry MS, confirming their structures respectively, and were evaluated for their invitro parasitic activity against the bloodstream form of the strain 427 of Trypanosoma brucei brucei using the “LILIT, Alamar Blue” method (Baltzet al., 1985; Hirumi et al., 1994; Räz et al.,1997). Their toxicity against brine shrimp larvae (Artemia salina Leach) was studied, according to the method of Michael et al. (1956) resumed byVanhaecke et al. (1981) and bySleet and Brendel (1983). Some of them have exhibited a strong trypanocidal activity, especially compounds 8, 3, 1 and 4 with their half-inhibitory concentrations (IC50) values equal to 8.48, 8.73, 39.71 and 67.17 micro-molar (µM) respectively. Except compounds 1 and 4whose half-lethal concentration (LC50) values were20.58 and 33.72 µM respectively and then toxics, all synthesized compounds showed negligible toxicity against Artemia salinaL. (LC50> 280 µM) and good selectivity (S) (SI “index” =1)

Trypanocidal and cytotoxic evaluation of synthesized thiosemicarbazones as potential drug leads against sleeping sickness

Thiosemicarbazones have become one of the promising compounds as new clinical candidates due to their wide spectrum of pharmaceutical activities. The wide range of their biological activities depends generally on their related aldehyde or ketone groups. Here, we report the pharmacological activities of some thiosemicarbazones synthesized in this work. Benzophenone and derivatives were used with N(4)-phenyl-3-thiosemicarbazide to synthesize corresponding five thiosemicarbazones (1-5). Their structures were characterized by spectrometrical methods analysis IR, NMR (1)H & (13)C and MS. The compounds were then screened in vitro for their antiparasitic activity and toxicity on Trypanosoma brucei brucei and Artemia salina Leach respectively. The selectivity index of each compound was also determined. Four thiosemicarbazones such as 4, 2, 3 and 1 reveal interesting trypanocidal activities with their half inhibitory concentration (IC50) equal to 2.76, 2.83, 3.86 and 8.48 μM respectively, while compound 5 (IC50 = 12.16 μM) showed a moderate anti-trypanosomal activity on parasite. In toxicity test, except compound 1, which showed a half lethal concentration LC50 >281 μM, the others exerted toxic effect on larvae with LC50 of 5.56, 13.62, 14.55 and 42.50 μM respectively for thiosemicarbazones 4, 5, 3 and 2. In agreement to their selectivity index, which is greater than 1 (SI >1), these compounds clearly displayed significant selective pharmaceutical activities on the parasite tested. The thiosemicarbazones 2-5 that displayed significant anti-trypanosomal and cytoxicity activities are suggested to have anti-neoplastic and anti-cancer activities