Further transformation of fungal catalyzed transformed metabolite 11β-hydroxy-dianabol into new aromatase inhibitors

Secondary biotransformation of 11β-hydroxy-dianabol (11β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one) (1), catalyzed by using two fungi Gibberella fujikuroi and Cunninghamella blakesleeana at ambient conditions, was carried out to synthesize its analogues. Transformation of compound 1 with G. fujikuroi yielded a new metabolite, 11β, 17β-dihydroxy-17α-methyl-5β-androst-1-ene-3-one (2), while four new derivatives, 6β, 17β-dihydroxy-17α-methylandrost-1,4-diene-3,11-dione (3), 15α,17β-dihydroxy-17α-methylandrost-1,4-diene-3,11-dione (4), 6β,11β,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (5), and 7β,11β,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (6) were obtained by transformation with C. blakesleeana. Compounds 1-6 showed a significant aromatase inhibition with IC50 values in the range of 2.01-3.13 μM as compared to the standard drug, exemestane (IC50 = 0.21 ± 0.16 μM). Aromatase is a valid target for drug discovery against ER+ breast cancers. Compounds 1-6 were subjected to molecular docking studies to predict the key interactions, and the MMGBSA studies to analyze the binding affinity and thermal stability of the protein-ligand complexes. Further, the relationship between the metabolites 1-6 and breast tumor androgen receptors was evaluated by in silico approach to analyze the binding interactions between androgen receptors and metabolites. Moreover, compounds 1-6 were found as non-cytotoxic to BJ (Human fibroblast) normal cell line. Hence, these molecules can be further studied for optimization as potential aromatase inhibitors against breast cancer.

Describing the ligandin properties of Plasmodium falciparum and vivax glutathione transferase towards bromosulfophthalein from empirical and computational modelling viewpoints

Research has spotlighted glutathione transferase (GST) as a promising target for antimalarial drug development due to its pivotal role in cellular processes, including metabolizing toxins and managing oxidative stress. This interest arises from GST's potential to combat multidrug resistance in existing antimalarial drugs. Plasmodium falciparum GST (PfGST) and Plasmodium vivax GST (PvGST) are key targets; inhibiting them not only disrupt detoxification but also reduce their antioxidant capacity, a critical feature for potent antimalarials. Bromosulfophthalein (BSP), a clinical liver function dye, emerged as a potent cytosolic GST inhibitor. This study explored BSP's inhibitory properties on PfGST and PvGST, showcasing its binding capabilities through empirical and computational analyses. The study revealed BSP's ability to significantly inhibit GST activity, altering the proteins' structures and stability. Specifically, BSP binding induced spectral changes and impacted the proteins' thermal stability, reducing their melting temperatures. Computational simulations highlighted BSP's strong binding to PfGST and PvGST at their dimer interface, stabilized by various interactions, including hydrogen bonds and van der Waals forces. Notably, BSP's binding altered the proteins' compactness and conformational dynamics, suggesting a potential non-competitive, allosteric inhibition mechanism. This study provided novel insights into BSP's candidacy as an antimalarial drug by targeting PfGST and PvGST. Its ability to disrupt crucial functions of these enzymes' positions BSP as a promising candidate for further drug development in combating malariaCommunicated by Ramaswamy H. Sarma.

Structural transformation of methasterone with Cunninghamella blakesleeana and Macrophomina phaseolina

An anabolic-androgenic synthetic steroidal drug, methasterone (1) was transformed by two fungi, Cunninghamella blakesleeana and Macrophimina phaseclina. A total of six transformed products, 6β,7β,17β-trihydroxy-2α,17α-dimethyl-5α-androstane-3-one (2), 6β,7α,17β-trihydroxy-2α,17α-dimethyl-5α-androstane-3-one (3), 6α,17β-dihydroxy-2α,17α-dimethyl-5α-androstane-3,7-dione (4), 3β,6β,17β-trihydroxy-2α,17α-dimethyl-5α-androstane-7-one (5), 7α,17β-dihydroxy-2α,17α-dimethyl-5α-androstane-3-one (6), and 6β,9α,17β-trihydroxy-2α,17α-dimethyl-5α-androstane-3-one (7) were synthesized. Among those, compounds 2-5, and 7 were identified as new transformed products. MS, NMR, and other spectroscopic techniques were performed for the characterization of all compounds. Substrate 1 (IC50 = 23.9 ± 0.2 μg mL-1) showed a remarkable anti-inflammatory activity against nitric oxide (NO) production, in comparison to standard LNMMA (IC50 = 24.2 ± 0.8 μg mL-1). Whereas, its metabolites 2, and 7 showed moderate inhibition with IC50 values of 38.1 ± 0.5 μg mL-1, and 40.2 ± 3.3 μg mL-1, respectively. Moreover, substrate 1 was found to be cytotoxic for the human normal cell line (BJ) with an IC50 of 8.01 ± 0.52 μg mL-1, while metabolites 2-7 were identified as non-cytotoxic. Compounds 1-7 showed no cytotoxicity against MCF-7 (breast cancer), NCI-H460 (lung cancer), and HeLa (cervical cancer) cell lines.

Pharmacologically active metabolites, combination screening and target identification-driven drug repositioning in antituberculosis drug discovery

There has been renewed interest in alternative strategies to address bottlenecks in antibiotic development. These include the repurposing of approved drugs for use as novel anti-infective agents, or their exploitation as leads in drug repositioning. Such approaches are especially attractive for tuberculosis (TB), a disease which remains a leading cause of morbidity and mortality globally and, increasingly, is associated with the emergence of drug-resistance. In this review article, we introduce a refinement of traditional drug repositioning and repurposing strategies involving the development of drugs that are based on the active metabolite(s) of parental compounds with demonstrated efficacy. In addition, we describe an approach to repositioning the natural product antibiotic, fusidic acid, for use against Mycobacterium tuberculosis. Finally, we consider the potential to exploit the chemical matter arising from these activities in combination screens and permeation assays which are designed to confirm mechanism of action (MoA), elucidate potential synergies in polypharmacy, and to develop rules for drug permeability in an organism that poses a special challenge to new drug development.