Marine Macrolides to Tackle Antimicrobial Resistance of Mycobacterium tuberculosis

Marine-Derived Cytosine Arabinoside (Ara-C) Inhibits Biofilm Formation by Inhibiting PEL Operon Proteins (Pel A and Pel B) of Pseudomonas aeruginosa: An In Silico Approach

Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative biofilm-forming opportunistic human pathogen whose vital mechanism is biofilm formation for better survival. PelA and PelB proteins of the PEL operon are essential for bacterial-synthesized pellicle polysaccharide (PEL), which is a vital structural component of the biofilm. It helps in adherence of biofilm on the surface and maintenance of cell-to-cell interactions and with other matrix components. Here, in-silico molecular docking and simulation studies were performed against PelA and PelB using ten natural bioactive compounds, individually [podocarpic acids, ferruginol, scopadulcic acid B, pisiferic acid, metachromin A, Cytarabine (cytosine arabinoside; Ara-C), ursolic acid, oleanolic acid, maslinic acid, and betulinic acid], those have already been established as anti-infectious compounds. The results obtained from AutoDock and Glide-Schordinger stated that a marine-derived cytosine arabinoside (Ara-C) among the ten compounds binds active sites of PelA and PelB, exhibiting strong binding affinity [Trp224 (hydrogen), Ser219 (polar), Val234 (hydrophobic) for PelA; Leu365 and Glu389 (hydrogen), Gln366 (polar) for PelB] with high negative binding energy - 5.518 kcal/mol and - 6.056 kcal/mol, respectively. The molecular dynamic and simulation studies for 100 ns showed the MMGBSA binding energy scores are - 16.4 kcal/mol (Ara-C with PelA), and - 22.25 kcal/mol (Ara-C with PelB). Further, ADME/T studies indicate the IC50 values of AraC are 6.10 mM for PelA and 18.78 mM for PelB, which is a comparatively very low dose. The zero violation of Lipinski's Rule of Five further established that Ara-C is a good candidate for drug development. Thus, Ara-C could be considered a potent anti-biofilm compound against PEL operon-dependent biofilm formation of P. aeruginosa.

Indole alkaloids from marine resources: Understandings from therapeutic point of view to treat cancers

Cancer is the leading cause of mortality all over the world. Scientific investigation has demonstrated that disruptions in the process of autophagy are frequently interrelated with the emergence of cancer. Hence, scientists are seeking permanent solutions to counter the deadly disease. Indole alkaloids have been extensively studied and are acknowledged to exhibit several bioactivities. The current state of disease necessitates novel pharmacophores development. In recent decades, indole alkaloids have become increasingly significant in cancer treatment and are also used as adjuvants. A substantial amount of pharmacologically active molecules come from indole alkaloids, which are widely distributed in nature. Indole alkaloids derived from marine organisms show immense potential for therapeutic applications and seem highly effective in cancer treatment. A couple of experiments have been conducted preclinically to investigate the possibility of indole alkaloids in cancer treatment. Marine-derived indole alkaloids possess the ability to exhibit anticancer properties through diverse antiproliferative mechanisms. Certain indole alkaloids, including vincristine and vinblastine, were verified in clinical trials or are presently undergoing clinical assessments for preventing and treating cancer. Indole alkaloids from marine resources hold a significant functionality in identifying new antitumor agents. The current literature highlights recent advancements in indole alkaloids that appear to be anticancer agents and the underlying mechanisms.