Pharmacognosy
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Browsing Pharmacognosy by Author "Asres,Kaleab(PhD)"
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Item Aminoalkyl and Oxazine of 2-Naphthol Derivatives: Synthesis, In vitro Antimicrobial and In Silico Studies(Addis Ababa University, 2024-02) Motbaynor,Gizachew; Bisrat,Daniel(PhD); Asres,Kaleab(PhD)Despite remarkable advancements in the past decade, infectious diseases continue to pose a significant threat, affecting millions and burdening global public health systems and economies. Currently, there is growing interest in 2-naphthol derivatives, particularly 1-aminoalkyl-2- naphthol derivatives, owing to their biological activities and their potential application in synthesizing other significant bioactive molecules. Therefore, in this study, two compounds were synthesized from a 2-naphthol framework. The synthesized compounds were purified through column chromatography, and their chemical structures were identified using 1H and 13C, DEPT- 90, and DEPT-135 NMR spectral data, as 1-(phenyl(ortho-tolylamino)methyl)naphthalene-2-ol (37) and 2-benzyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazine (39). The potential antimicrobial activity of the synthesized compounds was evaluated by the disk diffusion and broth dilution method. At the same time, molecular docking and ADMET studies were conducted to investigate their possible mechanism of action and drug-like properties. From our findings, both synthesized compounds exhibited promising antibacterial activity against most tested bacterial strains at 200 μg/ml, showing zones of inhibitions (ZOIs) ranging from 6.0 mm to 15.5 mm. The positive standard ciprofloxacin demonstrated ZOIs between 11.5 mm and 20.5 mm. Compound 37 exhibited greater susceptibility against E. coli with a MIC value of 25 μg/ml followed by V. cholera (MIC) at 50 μg/ml. v In contrast, Gram-positive bacteria such as Bacillus pumilus and B. subtilis demonstrated the lowest sensitivity to compounds (37) and (39), displaying a ZOI value of 6.0 mm at 200 μg/ml. Both compounds 37 and 39 also displayed antifungal activity against most tested fungal species. In molecular docking analysis, compounds (37) and (39) demonstrated significant binding energy within the binding pocket of E. coli DNA gyrase B, yielding docking scores of -8.092 and -7.754 kcal/mol, respectively. Similarly, with C. albicans lanosterol 4α-demethylase, they displayed docking scores of -7.792 and -8.995 kcal/mol, respectively. Following the ADMET prediction analysis, both synthesized compounds exhibit favorable pharmacokinetics and drug-like characteristics, making them suitable for oral administration. In addition to the in vitro bioassay activity test, molecular docking results and ADMET predictions collectively convey the promising antimicrobial properties of both synthesized compounds. These findings imply that conducting further synthesis and evaluation of 2-naphthol derivatives could be beneficial in the ongoing efforts to develop antimicrobial drugs for combating infectious diseases and microbial resistance.Item Isolation and Characterization of a Pregnane Steroid from the Antiproliferative Active Extract of Caralluma speciosa (N.E.Br.) N.E.Br. Stem Latex(Addis Ababa University, 2024-05) Derese,Kalkidan; Asres,Kaleab(PhD); Bisrat,Daniel(PhD)Cancer is a broad term for a large diverse group of diseases that can affect any body part, standing as one of the leading global causes of death. In response to the challenges posed by cancers, researchers are actively investigating natural alternatives, specifically plant-derived compounds, seeking safer and more effective chemotherapeutic options to address the limitations of current treatments. In the traditional medical practices of Ethiopia, the stem latex of Caralluma speciosa (N.E.Br.) N.E.Br. stands for its traditional use in treating cancer. Thus, this study aimed at evaluating the antiproliferative activity of the latex and isolating its constituents. In vitro crystal violet cell proliferation assay was used to determine the antiproliferative/cytotoxic activity of the 80% methanolic extract of C. speciosa against four cancer cell lines. The latex extract exhibited cytotoxic effects against breast cancer cell line (MCF-7) and normal cervical cancer cell line (SiSoN) with Treated versus Control corrected percentage [(T/C)corr. (%)] values of -1.07 and - 0.95, respectively. Additionally, the latex demonstrated antiproliferative effects on lung cancer cell line (A427) and cervical cancer cells resistant to cisplatin (SiSoR) with (T/C)corr. (%) values of 0.43 and 1.07, respectively. Subsequently, a pregnane glycoside was isolated from the 80% methanol extract of the latex using chromatographic techniques including HPLC. The structure was tentatively identified as 20-O-benzoyl-12-O-acetyl-14-hydroxy-20-pregn-5-ene-3-O- -D- cymaropyranosyl-(1→4)- -D-canaropyranosyl-(1→4)- -D-glucopyranoside through 1D and 2D NMR spectral data. Although the antiproliferative activity of the isolated compound was not determined, considering the reported anticancer activity of pregnane glycosides, it was evident that the isolated compound could have contributed to the antiproliferative/cytotoxic activity of latex of C. speciosa. The present findings also support the traditional use of the plant for the treatment of cancer.