Inhibition of Porcine Pancreatic Amylase Activity by Sulfamethoxazole: Structural and Functional Aspect

Mitochondrial Impairment by Cyanine-Based Small Molecules Induces Apoptosis in Cancer Cells

Mitochondrion, the powerhouse of the cells, has emerged as one of the unorthodox targets in anticancer therapy due to its involvement in several cellular functions. However, the development of small molecules for selective mitochondrial damage in cancer cells remained limited and less explored. To address this, in our work, we have synthesized a natural product inspired cyanine-based 3-methoxy pyrrole small molecule library by a concise strategy. This strategy involves Vilsmeier and Pd(0) catalyzed Suzuki cross-coupling reactions as key steps. The screening of the library members in HeLa cervical cancer cells revealed two new molecules that localized into subcellular mitochondria and damaged them. These small molecules perturbed antiapoptotic (Bcl-2/Bcl-xl) and pro-apoptotic (Bax) proteins to produce reactive oxygen species (ROS). Molecular docking studies showed that both molecules bind more tightly with the BH3 domain of Bcl-2 proteins compared to obatoclax (a pan-Bcl-2 inhibitor). These novel small molecules arrested the cell cycle in the G0/G1 phase, cleaved caspase-3/9, and finally prompted late apoptosis. This small molecule-mediated mitochondrial damage induced remarkably high cervical cancer cell death. These unique small molecules can be further explored as chemical biology tools and next-generation organelle-targeted anticancer therapy.

Correlation between antibiotic-induced feeding depression and body size reduction in zooplankton (rotifer, Brachionus calyciflorus): Neural response and digestive enzyme inhibition

The study analyzed the correlation between the antibiotic-induced feeding depression and body size reduction in rotifer, Brachionus calyciflorus, involving exposure, post-exposure and re-exposure periods. The filtration and ingestion rates of the rotifers were inhibited in these three exposure periods at any given concentration of the antibiotic sulfamethazine (SMZ). As food for rotifer, the cell size of the green algae was unchanged, which indicated that it could not drive feeding depression. Secondly, several corresponding physiological responses were considered. Reactive oxygen species (ROS) levels increased in the post-exposure and the re-exposure; acetylcholinesterase (AChE) activity was significantly decreased in the exposure and the re-exposure, whereas it was induced in the post-exposure. The activities of amylase and lipase were always inhibited in these three exposure periods. Additionally, significant decreases in lorica length, width and biovolume of rotifers occurred after the feeding depression. Statistical analysis indicated a positive correlation between the activity of the digestive enzyme and the body size. Our results demonstrated that SMZ could influence the neurotransmission, inhibit the activity of the digestive enzyme, and finally result in body size reduction. These results provided an integrated perspective on assessing the toxicity effects of antibiotic in non-lethal dosage on the feeding behavior of non-target aquatic organisms.

Inhibitory kinetics and mechanism of flavonoids from lotus (Nelumbo nucifera Gaertn.) leaf against pancreatic α-amylase

In this study, lotus leaf flavonoids (LLF) were found to show a notable inhibition activity on α-amylase in a mixed-type manner with IC₅₀ value of (5.58 ± 0.10) mg/mL. The intrinsic fluorescence of α-amylase was quenched by the interaction with LLF through a static quenching mechanism, and LLF-α-amylase complex was spontaneously formed mainly driven by the hydrophobic interaction and hydrogen bonding. Multispectroscopic analyses (synchronous fluorescence, three-dimensional fluorescence, circular dichroism (CD) and fourier transform infrared spectra (FT-IR)) comprehensively demonstrated that the binding of LLF to α-amylase would change the conformation and microenvironment of α-amylase, resulting in inhibiting the enzyme activity. The present study indicated that LLF had potential to be as an ingredient in functional food for the prevention of type-2 diabetes.

α-Glucosidase inhibitory activity and cytotoxic effects of some cyclic urea and carbamate derivatives

The inhibitory activities of selected cyclic urea and carbamate derivatives (1-13) toward α-glucosidase (α-Gls) in in vitro assay were examined in this study. All examined compounds showed higher inhibitory activity (IC₅₀) against α-Gls compared to standard antidiabetic drug acarbose. The most potent was benzyl (3,4,5-trimethoxyphenyl)carbamate (12) with IC₅₀ = 49.85 ± 0.10 µM. In vitro cytotoxicity of the investigated compounds was tested on three human cancer cell lines HeLa, A549 and MDA-MB-453 using MTT assay. The best antitumour activity was achieved with compound 2 (trans-5-phenethyl-1-phenylhexahydro-1H-imidazo[4,5-c]pyridin-2(3H)-one) against MDA-MB-453 human breast cancer cell line (IC₅₀ = 83.41 ± 1.60 µM). Cyclic ureas and carbamates showed promising anti-α-glucosidase activity and should be further tested as potential antidiabetic drugs. The PLS model of preliminary QSAR study indicated that, in planing the future synthesis of more potent compounds, the newly designed should have the substituents capable of polar interactions with receptor sites in various positions, while avoiding the increase of their lipophilicity.