Synthesis of lactoferrin mesoporous silica nanoparticles for pemetrexed/ellagic acid synergistic breast cancer therapy.

Despite the clinical approval of few nanomedicines for cancer therapy, some drawbacks still impede their improved efficiency including low drug loading, off-target toxicity and development of multi-drug resistance. Herein, lactoferrin (Lf)-coupled mesoporous silica nanoparticles (MSNPs) were developed for combined delivery of the cytotoxic drug pemetrexed (PMT) and the phytomedicine ellagic acid (EA) for synergistic breast cancer therapy. While the hydrophobic EA was physically encapsulated within the pores of MSNPs via the adsorptive properties of MSNPs and the electrostatic interactions between the negatively charged EA and positively charged amino modified MSNs, the highly water soluble PMT was chemically anchored to the Lf shell through chemical conjugation to the surface of lactoferrin coated MSNPs by carbodiimide reaction to avoid pre-mature drug release and systemic toxicity. The dual drug-loaded Lf-MSNPs (284 nm) demonstrated a sequential faster release of EA followed by a sustained release of PMT. The dual drug-loaded Lf-MSNPs exhibited highest cytotoxicity against MCF-7 (Michigan Cancer Foundation-7) breast cancer cells as revealed by the lowest combination index (CI = 0.885) compared to free drugs. The combination index value (< 1) revealed synergy between both loaded drugs. Furthermore, high cellular uptake of the nanocarriers into MCF-7 breast cancer cells was observed via Lf-receptor mediated endocytosis. Altogether, the dual drug-loaded Lf-targeted MSNPs showed to be a promising carrier for breast cancer therapy through triggering different signaling pathways, and hence overcoming the multi-drug resistance and minimizing the systemic toxicity.

Novel pyrazine based anti-tubercular agents: Design, synthesis, biological evaluation and in silico studies.

TB continues to be a leading health threat despite the availability of powerful anti-TB drugs. We report herein the design and synthesis of various hybrid molecules comprising pyrazine scaffold and various formerly identified anti-mycobacterial moieties. Thirty-one compounds were screened in vitro for their activity against Mycobacterium tuberculosis H37Rv strain using MABA assay. The results revealed that six compounds (8a, 8b, 8c, 8d, 14b and 18) displayed significant activity against Mtb with MIC values ≤6.25 µg/ml versus 6.25 µg/ml for pyrazinamide. The most active compounds were then assessed for their in vitro cytotoxicity against PBMC normal cell line using MTT assay and showed SI > 200. Several in silico studies have been carried out for target fishing of the novel compounds such as shape-based similarity, pharmacophore mapping and inverse docking. Based on this multi-step target fishing study, we suggest that pantothenate synthetase could be the possible target responsible for the action of these compounds. The most active compounds were then successfully docked into the active site of pantothenate synthetase enzyme with favorable binding interactions. In addition, in silico prediction of physicochemical, ADMET and drug-like properties were also determined indicating that compounds 8b, 8c and 8d are promising candidates for the development of new anti-TB agents with enhanced activity and better safety profile.

Novel click modifiable thioquinazolinones as anti-inflammatory agents: Design, synthesis, biological evaluation and docking study.

Click chemistry was used to synthesize a new series of thioquinazolinone molecules equipped with propargyl moiety,1,2,3-triazolyl and isoxazolyl rings. Our design was based on merging pharmacophores previously reported to exhibit COX-2 inhibitory activities to a thioquinazolinone-privileged scaffold. The synthesized compounds were subjected to in vitro cyclooxygenase COX-1/COX-2 and 15-LOX inhibition assays. Compounds 2c, 3b, 3h, 3j, and 3k showed COX-2 inhibition with IC50 (µM) 0.18, 0.19, 0.11, 0.16 and 0.17 respectively. These values were compared to celecoxib (IC50 0.05 µM), diclofenac (IC50 0.8 µM) and indomethacin (IC50 0.49 µM) reference drugs. They also showed 15-LOX inhibition with IC50 (µM) 6.21, 4.33, 7.62, 5.21 and 3.98 respectively. These values were compared with Zileuton (IC50 2.41 µM) and Meclofenamate sodium (IC50 5.64 µM) as positive controls. These compounds were further challenged by PMA-induced THP-1 differentiation assay where compounds 2c and 3j inhibited monocyte to macrophage differentiation efficiently with IC50 values of 4.78 µM and 5.63 µM, respectively, compared to that of diclofenac sodium (4.86 µM). On the other hand, 3h demonstrated a significantly increased potency compared to diclofenac in this assay (IC50 = 0.13 µM). The same compounds exhibited significant in vivo anti-inflammatory effect as indicated by the formalin-induced rat-paw edema test. Docking experiments of compounds 2c, 3b, 3h, 3j, and 3k into COX-2 binding pocket have been conducted, where strong binding interactions have been identified and effective overall docking scores have been recorded. Their drug-likeness has been assessed using Molinspiration, Molsoft and Pre-ADMET software products.

Synthesis and biological evaluation of some thiazolyl and thiadiazolyl derivatives of 1H-pyrazole as anti-inflammatory antimicrobial agents.

Four series of pyrazolyl benzenesulfonamide derivatives have been synthesized. The first series was prepared by cyclization of the intermediate N,N-dimethylaminomethylene-4[3-phenyl-4-(substituted thiosemicarbamoyl hydrazonomethyl)-1H-pyrazol-1-yl]benzenesulfonamide 2a-c with ethyl bromoacetate to afford the corresponding thiazolidinyl derivatives 3a-c. The second series was prepared by cyclization of the key intermediates 2a-c with 4-bromophenacyl bromide giving rise to thiazolinyl derivatives 4a-c. Thiadiazolyl derivatives 5a-c were obtained by heating 2a-c with 2M FeCl(3) solution. Refluxing the intermediates 2a-c in acetic anhydride yielded the corresponding thiadiazolinyl derivatives 6a-c. All the target compounds showed anti-inflammatory activity and three of them 3b, 3c and 4c surpassed that of indomethacin both locally and systemically in the cotton pellet granuloma and rat paw edema bioassay. The active compounds showed selective inhibitory activity towards COX-2 enzyme as revealed by the in vitro enzymatic assay. All the tested compounds proved to have superior gastrointestinal (GI) safety profiles as compared to indomethacin, when tested for their ulcerogenic effects. The acute toxicity study of compounds having promising anti-inflammatory activity (3b, 3c and 4c) indicated that they are well tolerated both orally and parenterally. Antimicrobial activity tests expressed as minimal inhibitory concentrations (MIC), revealed that compounds 3b and 4a showed comparable antibacterial activity to that of ampicillin against Escherichia coli, while compounds 3a, 3c and 4a possessed about half the activity of ampicillin against Staphylococcus aureus. On the other hand, the results showed that all the tested compounds have weak or no antifungal activity against Candida albicans except for compounds 6b and 6c that showed half the activity of the control antifungal drug used (clotrimazole).