Search

Pyrazole-bearing compounds are known for their diverse pharmacological effects including potent antileishmanial and antimalarial activities. Herein, some hydrazine-coupled pyrazole derivatives were successfully synthesized and their structures were verified by employing elemental microanalysis, FTIR, and 1H NMR techniques. The in vitro antileishmanial and in vivo antimalarial activities of the synthesized pyrazole derivatives (9–15) were assessed using the clinical isolate of the Leishmania aethiopica strain and mice infected with Plasmodium berghei ANKA strain, respectively. The result revealed that compound 13 displayed superior antipromastigote activity (IC50 = 0.018) that was 174- and 2.6-fold more potent than the standard drugs miltefosine (IC50 = 3.130) and amphotericin B deoxycholate (IC50 = 0.047). The molecular docking study conducted on Lm-PTR1 justified the better antileishmanial activity of compound 13. Furthermore, the target compounds 14 and 15 elicited better inhibition effects against Plasmodium berghei with 70.2% and 90.4% suppression, respectively. In conclusion, the hydrazine-coupled pyrazole derivatives may be considered potential pharmacophores for the synthesis of safe and effective antileishmanial and antimalarial agents.

Plants have been used to treat diverse types of diseases in different cultural groups around the globe. In this regard, the root of Plectocephalus varians (P. varians) is claimed to have a beneficiary effect in treating cancer and hemorrhoids in Ethiopia. Hence, this study aimed at the phytochemical investigation, antioxidant, and antibacterial activities of n-hexane, acetone, and methanolic extracts of P. varians root. The different crude extracts of P. varians were obtained through maceration technique. The total phenolic content (TPC) and total flavonoid contents (TFC) of the extracts were estimated using Folin-Ciocalteu Reagent (FCR) and aluminum chloride colorimetric assays, respectively. The antioxidant activities of the extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing antioxidant power (FRAP) assays. The antibacterial activities of the extracts were assessed by using disc diffusion method. The results echoed the presence of alkaloids, saponins, flavonoids, steroids, phenols, tannins, anthraquinones, terpenoids, polyphenols, and glycosides in the root of P. varians. The methanolic root extract (MRE) had the highest TPC (107.18 mg GAE/g) and TFC (120.194 mg QE/g) followed by acetone root extract (ARE) (TPC = 98.68 mg GAE/g; TFC = 64.038 mg QE/g) and n-hexane root extract (HRE) (TPC = 12.39 mg GAE/g; TFC = 9.917 mg QE/g). The DPPH radical scavenging and FRAP assays demonstrated the antioxidant effects of HRE (IC50 = 681.75 ppm; EC50 = 60.65 ppm), ARE (IC50 = 165.73 ppm; EC50 = 51.67 ppm) and MRE (IC50 = 132.06 ppm; EC50 = 30.97 ppm) of P. varians. Furthermore, the root fractions elicited pronounced dose-dependent growth inhibition against Staphylococcus aureus, Streptococci pyogenes, Escherichia coli, and Klebsiella pneumoniae with mean zone of inhibition (MZI) ranging from 11 ± 0.38 to 20 ± 0.04 mm at 800 ppm. Overall, the present study provides ethnopharmacological evidence suggesting the medicinal importance of P. varians. The results also call for further bioassay-guided phytochemical screening and in vitro and/or in vivo bioactivity testing.