Synthesis, pharmacological evaluation and Molecular modelling studies of pregnenolone derivatives as inhibitors of human dihydrofolate reductase

Novel Glu-based pyrazolo[3,4-d]pyrimidine analogues: design, synthesis and biological evaluation as DHFR and TS dual inhibitors

A novel series of multifunctional pyrazolo[3,4-d]pyrimidine-based glutamate analogs (6a-l and 7a,b) have been designed and synthesized as antifolate anticancer agents. Among the tested compounds, 6i exhibited the most potent anti-proliferative activity towards NSCLC, CNS, Ovarian, Prostate, Colon, Melanoma, Breast, and Renal cancers with good to weak cytostatic activity and non-lethal actions. 6i demonstrated higher selectivity for cancer than normal cells. 6i could significantly increase the accumulation of S-phase cells during the cell cycle distribution of cancer cells with high potency in the induction of apoptosis. The results unveiled that 6i probably acts through dual inhibition of DHFR and TS enzymes (IC₅₀ = 2.41 and 8.88 µM, correspondingly). Docking studies of 6i displayed that N1-p-bromophenyl and C3-Methyl groups participate in substantial hydrophobic interactions. The drug-likeness features inferred that 6i met the acceptance criteria of Pfizer. Taking together, 6i could be a promising prototype for further optimization as an effective anticancer drug.

Phytochemistry, anti-diabetic and antioxidant potentials of Allium consanguineum Kunth

Aim

The study was planned to investigate the phytochemicals, antidiabetic and antioxidant studies of A. consanguineum.

Methods

The preliminary studies were performed on crude extract and different solvent fractions. Based on the potency, the chloroform fraction was semi-purified to phyto-fractions CHF-1 – 5. Furthermore, CHF-3 was subjected to isolation of pure compounds using column chromatography. The α-glucosidase, α-amylase and antioxidant assays (DPPH, ABTS, H₂O₂) were performed on all samples. The in-vivo experiments on compounds 1 and 2 were also performed using oral glucose tolerance test. Docking studies were performed on α-glucosidase and α-amylase targets.

Results

Among all fractions, the chloroform fraction exhibited excellent activities profile giving IC₅₀ values of 824, 55, 117, 58 and 85 μg/ml against α-glucosidase, α-amylase, DPPH, ABTS and H₂O₂ targets respectively. Among the five semi-purified chloroform phyto-fractions (CHF-1-5), CHF-3 was the leading fraction in activities giving IC₅₀ values of 85.54, 61.19 and 26.58 μg/ml against α-glucosidase, α-amylase and DPPH respectively. Based on the overall potency and physical amount of CHF-3, it was subjected to purification to get compounds 1 and 2. The two compounds were also found potent in in-vitro activities. The observed IC₅₀ values for compound 1 were 7.93, 28.01 and 6.19 μg/ml against α-glucosidase, α-amylase and DPPH respectively. Similarly, the compound 2 exhibited IC₅₀ of 14.63, 24.82 and 7.654 μg/ml against α-glucosidase, α-amylase and DPPH respectively. Compounds 1 and 2 were potent in decreasing the blood glucose levels in experimental animals. Compounds 1 and 2 also showed interactions with the respective enzymes with molecular docking.

Conclusions

We can conclude that A. Consanguineum is a rich source of natural antidiabetic agents. Bioguided isolation of compound 1 and 2 showed potential inhibitions in all tested in-vitro antidiabetic targets. Further, both the compounds were also able to decrease the blood glucose levels in experimental animals.

Phytochemical Analysis, Total Phenolic, Flavonoid Contents, and Anticancer Evaluations of Solvent Extracts and Saponins of H. digitata

Cancer is one of the most challenging diseases in the modern era for the researchers and investigators. Extensive research worldwide is underway to find novel therapeutics for prevention and treatment of diseases. The extracted natural sources have shown to be one of the best and effective treatments for cell proliferation and angiogenesis. Different approaches including disc potato model, brine shrimp, and chorioallantoic membrane (CAM) assay were adopted to analyze the anticancer effects. Habenaria digitata was also evaluated for MTT activity against NIH/3T3 cell line. The dexamethasone, etoposide, and vincristine sulfate were used as a positive control in these assays. All of the extracts including crude extracts (Hd.Cr), saponin (Hd.Sp), n-hexane (Hd.Hx), chloroform (Hd.Chf), ethyl acetate (Hd.EA), and aqueous fraction (Hd.Aq) were shown excellent results by using various assays. For example, saponin and chloroform have displayed decent antitumor and angiogenic activity by using potato tumor assay. The saponin fraction and chloroform were shown to be the most efficient in potato tumor experiment, demonstrating 87.5 and 93.7% tumor suppression at concentration of 1000 μg/ml, respectively, with IC50 values of 25.5 and 18.3 μg/ml. Additionally, the two samples, chloroform and saponins, outperformed the rest of the test samples in terms of antiangiogenic activity, with IC50 28.63 μg/ml and 16.20 μg/ml, respectively. In characterizing all solvent fractions, the chloroform (Hd.Chf) and saponin (Hd.Sp) appeared to display good effectiveness against tumor and angiogenesis but very minimal activity against A. tumefaciens. The Hd.Chf and Hd.Sp have been prospective candidates in the isolation of natural products with antineoplastic properties.

Design, synthesis, antiproliferative activity, estrogen receptors binding affinity of C-3 pregnenolone-dihydropyrimidine derivatives for the treatment of breast cancer

Breast cancer (BCa) is very common malignancy and globally, has become the second leading cause of cancer death among women. For the treatment of BCa, estrogen receptors-alpha (ERα) has proven to be a therapeutic target. In continuation of our previous reported dihydropyrimidine-based pregnenolone derivatives, we modified at C-3 hydroxyl group. Structural architecture of estrogen receptors (ER) with excellent ER binding affinity was used for modification. MTT assay was used to evaluate the synthesized steroidal analogs for their antiproliferative activities against ER-positive MCF-7, ER-negative MDA-MB-231 (ER^-) breast cancer cells and non-cancerous HEK-293 cells. Structure activity relationship (SAR) studies revealed that diethanolamine containing pregnenolone derivatives showed significant cytotoxicity against ER + MCF-7 and also showed good binding affinity with ERα and are relatively safe against HEK-293 cell model. Docking studies demonstrated that high binding affinity of diethanolamine analogs is due to their binding interaction with key amino acid residues present in the binding site of Erα.

Cephalosporin as Potent Urease and Tyrosinase Inhibitor: Exploration through Enzyme Inhibition, Kinetic Mechanism, and Molecular Docking Studies

In present study, eleven cephalosporin drugs were selected to explore their new medically important enzyme targets with inherited safety advantage. To this end, selected drugs with active ingredient, cefpodoxime proxetil, ceftazidime, cefepime, ceftriaxone sodium, cefaclor, cefotaxime sodium, cefixime trihydrate, cephalexin, cefadroxil, cephradine, and cefuroxime, were evaluated and found to have significant activity against urease (IC50 = 0.06 ± 0.004 to 0.37 ± 0.046 mM) and tyrosinase (IC50 = 0.01 ± 0.0005 to 0.12 ± 0.017 mM) enzymes. Urease activity was lower than standard thiourea; however, tyrosinase activity of all drugs outperforms (ranging 6 to 18 times) the positive control: hydroquinone (IC50 = 0.18 ± 0.02 mM). Moreover, the kinetic analysis of the most active drugs, ceftriaxone sodium and cefotaxime sodium, revealed that they bind irreversibly with both the enzymes; however, their mode of action was competitive for urease and mixed-type, preferentially competitive for tyrosinase enzyme. Like in vitro activity, ceftriaxone sodium and cefotaxime sodium docking analysis showed their considerable binding affinity and significant interactions with both urease and tyrosinase enzymes sufficient for downstream signaling responsible for observed enzyme inhibition in vitro, purposing them as potent candidates to control enzyme-rooted obstructions in future.

3-(((1S,3S)-3-((R)-Hydroxy(4-(trifluoromethyl)phenyl)methyl)-4-oxocyclohexyl)methyl)pentane-2,4-dione: Design and Synthesis of New Stereopure Multi-Target Antidiabetic Agent

The chiral drug candidates have more effective binding affinities for their specific protein or receptor site for the onset of pharmacological action. Achieving all carbon stereopure compounds is not trivial in chemical synthesis. However, with the development of asymmetric organocatalysis, the synthesis of certain vital chiral drug candidates is now possible. In this research, we have synthesized 3-(((1S,3S)-3-((R)-hydroxy(4-(trifluoromethyl)phenyl)methyl)-4-oxocyclohexyl)methyl)pentane-2,4-dione (S,S,R-5) and have evaluated it potential as multi-target antidiabetic agent. The stereopure compound S,S,R-5 was synthesized with a 99:1 enantiomeric ratio. The synthesized compound gave encouraging results against all in vitro antidiabetic targets, exhibiting IC₅₀ values of 6.28, 4.58, 0.91, and 2.36 in α-glucosidase, α-amylase, PTP1B, and DPPH targets, respectively. The molecular docking shows the binding of the compound in homology models of the respective enzymes. In conclusion, we have synthesized a new chiral molecule (S,S,R-5). The compound proved to be a potential inhibitor of the tested antidiabetic targets. With the observed results and molecular docking, it is evident that S,S,R-5 is a potential multitarget antidiabetic agent. Our study laid the baseline for the animal-based studies of this compound in antidiabetic confirmation.

Crude extract and isolated bioactive compounds from Notholirion thomsonianum (Royale) Stapf as multitargets antidiabetic agents: in-vitro and molecular docking approaches

Background

Diabetes mellitus is a common disease effecting the lifestyles of majority world population. In this research work, we have embarked the potential role of crude extracts and isolated compounds of Notholirion thomsonianum for the management diabetes mellitus.

Methods

The crude extracts of N. thomsonianum were initially evaluated for α-glucosidase, α-amylase and antioxidant activities. The compounds were isolated from the activity based potent solvent fraction. The structures of isolated compounds were confirmed with NMR and MS analyses. The isolated compounds were tested for α-glucosidase, α-amylase, protein tyrosine phosphatase 1B (PTP1B) and DPPH activities. The molecular docking studies were carried out to find the binding interactions of isolated compounds for α-glucosidase, α-amylase and PTP1B.

Results

Initially, we screened out crude extracts and subfractions of N. thomsonianum against different in-vitro targets. Among all, Nt.EtAc was observed a potent fraction among all giving IC₅₀ values of 67, 70, < 0.1, 89 and 16 μg/mL against α-glucosidase, α-amylase, DPPH, ABTS and H₂O₂ respectively. Three compounds (Nt01, Nt02 and Nt03) were isolated from Nt.EtAc of N. thomsonianum. The isolated compounds Nt01, Nt02 and Nt03 exhibited IC₅₀ values of 58.93, 114.93 and 19.54 μM against α-glucosidase, while 56.25, 96.54 and 24.39 μM against α-amylase respectively. Comparatively, the standard acarbose observed IC₅₀ values were 10.60 and 12.71 μM against α-glucosidase, α-amylase respectively. In PTP1B assay, the compounds Nt01, Nt02 and Nt03 demonstrated IC₅₀ values of 12.96, 36.22 and 3.57 μM in comparison to the standard ursolic acid (IC₅₀ of 3.63 μM). The isolated compounds also gave overwhelming results in DPPH assay. Molecular docking based binding interactions for α-glucosidase, α-amylase and PTP1B were also encouraging.

Conclusions

In the light of current results, it is obvious that N. thomsonianum is potential medicinal plant for the treatment of hyperglycemia. Overall, Nt.EtAc was dominant fraction in all in-vitro activities. Three compounds Nt01, Nt02 and Nt03 were isolated from ethyl acetate fraction. The Nt03 specifically was most potent in all in-vitro assays. The molecular docking studies supported our in-vitro results. It is concluded that N. thomsonianum is a rich source of bioactive antidiabetic compounds which can be further extended to in-vivo based experiments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03443-7.