Unravelling the wound healing ability and mode of action of pyridine carboxamide oxime using Caenorhabditis elegans as potential prescreen wound model.

AIM: In the current scenario of ethical issues related to animal usage in research, the present study was intended to explore the proficient utility of nematode, Caenorhabditis elegans as wound model in preliminary screening of wound healing therapeutics. MAIN METHODS: In this study, a new wounding protocol and quantitative assessment strategies for various healing parameters [survival, Reactive Oxygen Species (ROS), calcium signals, F-actin dynamics, new collagen synthesis and wound induced anti-microbial peptides] were developed and used for preliminary screening of wound healing actives from natural sources. Wound healing ability of positive lead Tridax procumbens (TP) and its major phytocompounds [Octa decenoic acid (ODA), Pyridine carboxamide oxime, known as Nicotinamide (NA) and Dimethyl Benz[c]acridine (DMB)] were assessed using C. elegans wound model and cell lines scratch wound healing assay. Mode of action of active lead was elucidated using metabolome analysis coupled with MALDI-MS followed by molecular docking. KEY FINDINGS: From the four tested methanolic extracts, TP was chosen as positive lead compared to control, Benzalkonium chloride (BKC) based on survival and new collagen synthesis analyses. Results indicated that the wound healing ability of TP was majorly contributed by NA. Further, it was found that NA acts in chloromethyl nicotinamide derivative form by interacting with the known wound healing biomarker, glycogen synthase kinase 3 (GSK-3) to exert wound healing ability. SIGNIFICANCE: The study evidenced that C. elegans, could be a reliable wound model for high-throughput screening of wound healing actives and to identify their possible mode of action.

Purification and characterization of a betanidin glucosyltransferase from Amaranthus tricolor L catalyzing non-specific biotransformation of flavonoids.

Betacyanins are the major pigments present in Amaranthus tricolor, a leafy vegetable consumed globally. The terminal glycosylation of the aglycone betanidin is an important step in the biosynthesis of this natural red antioxidant pigment. A betanidin 5-O-glucosyltransferase (BGT) was fully purified to 134 folds (specific activity, 265.2 nkat mg(-1)) from the red amaranth by ammonium sulfate precipitation followed by hydrophobic interaction, anion exchange and size exclusion chromatography. Homogeneity of the purified protein was confirmed by 2-dimensional polyacrylamide gel electrophoresis (2D PAGE). The molecular weight of the enzyme determined by liquid chromatography-mass spectrometry (LC-MS) was found to be 62.8 kDa. Furthermore, the enzyme glycosylated flavonoids (kaempferol and quercetin) but not anthocyanidins, presence of which is mutually exclusive to betacyanin accumulating plants. The apparent Km (344±2.34 µM) and Vmax (17.24 µM min(-1)) of the enzyme were determined by LC-MS/MS. Peptide mass fingerprinting of the purified protein showed 38.4% coverage of peptide masses with anthocyanidin 3-O-glucosyltransferase from Zea mays. Study on this purified enzyme, for the first time, revealed its role of glycosylation in biosynthesis of betacyanin in A. tricolor and indicates promiscuous substrate-specificity.