GC/MS Profiling and Evaluation of Leaf Essential Oil for Bactericidal Effect and Free Radical Scavenging Activity of Plectranthus amboinicus (Lour.) Spreng Collected from Odisha, India.

Plectranthus amboinicus (Lour.) Spreng, known as the Indian borage or Mexican mint, is one of the most documented species in the family Lamiaceae for its therapeutic and pharmaceutical values. It is found in the tropical and subtropical regions of the world. The leaf essential oil has immense medicinal benefits like treating illnesses of the skin and disorders like colds, asthma, constipation, headaches, coughs, and fevers. After analyzing earlier reports with regard to the quantity and quality of leaf oil yield, we discovered that the germplasm taken from Odisha is preferable to other germplasms. The objective of the present work is to evaluate the free radical scavenging activity and bactericidal effect of leaf essential oil (EO) of Plectranthus amboinicus (Lour.) Spreng collected from the state of Odisha, India. The hydro distillation technique has been used for essential oil extraction. Upon GC/MS analysis, approximately 57 compounds were identified with Carvacrol as the major compound (peak area=20.25 %), followed by p-thymol (peak area=20.17 %), o-cymene (peak area=19.41 %) and carene (peak area=15.89 %). On evaluation of free radical scavenging activity, it was recorded that the best value of inhibitory concentration, was for DPPH with IC50 =18.64 ppm and for H2 O2 with IC50 =9.35 ppm. The EO showed efficient bactericidal effect against both gram positive (Mycobacterium smegmatis, Staphylococcus aureus, Enterococcus faecium) and gram negative (Escherichia coli, Vibrio cholerae, Klebsiella pneumoniae) bacteria studied through well diffusion method. Fumigatory action of the essential oil was found against M. smegmatis, the model organism for tuberculosis study. Alamar Blue assay, gave a result with MIC value for M. smegmatis i. e., 0.12 µg/ml and the MBC value of 0.12 µg/ml. Hence, P. amboinicus found in Odisha can be suggested as an elite variety and should be further investigated for efficient administration in drug formulation.

Green synthesis and characterization of silver nanoparticles using Eugenia roxburghii DC. extract and activity against biofilm-producing bacteria.

The green synthesis of silver nanoparticles (AgNPs) and their applications have attracted many researchers as the AgNPs are used effectively in targeting specific tissues and pathogenic microorganisms. The purpose of this study is to synthesize and characterize silver nanoparticles from fully expanded leaves of Eugenia roxburghii DC., as well as to test their effectiveness in inhibiting biofilm production. In this study, at 0.1 mM concentration of silver nitrate (AgNO3), stable AgNPs were synthesized and authenticated by monitoring the color change of the solution from yellow to brown, which was confirmed with spectrophotometric detection of optical density. The crystalline nature of these AgNPs was detected through an X-Ray Diffraction (XRD) pattern. AgNPs were characterized through a high-resolution transmission electron microscope (HR-TEM) to study the morphology and size of the nanoparticles (NPs). A new biological approach was undertaken through the Congo Red Agar (CRA) plate assay by using the synthesized AgNPs against biofilm production. The AgNPs effectively inhibit biofilm formation and the biofilm-producing bacterial colonies. This could be a significant achievement in contending with many dynamic pathogens.

De novo transcriptome and tissue specific expression analysis of genes associated with biosynthesis of secondary metabolites in Operculina turpethum (L.).

This study reported the first-ever de novo transcriptome analysis of Operculina turpethum, a high valued endangered medicinal plant, using the Illumina HiSeq 2500 platform. The de novo assembly generated a total of 64,259 unigenes and 20,870 CDS (coding sequence) with a mean length of 449 bp and 571 bp respectively. Further, 20,218 and 16,458 unigenes showed significant similarity with identified proteins of NR (non-redundant) and UniProt database respectively. The homology search carried out against publicly available database found the best match with Ipomoea nil sequences (82.6%). The KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis identified 6538 unigenes functionally assigned to 378 modules with phenylpropanoid biosynthesis pathway as the most enriched among the secondary metabolite biosynthesis pathway followed by terpenoid biosynthesis. A total of 17,444 DEGs were identified among which majority of the DEGs (Differentially Expressed Gene) involved in secondary metabolite biosynthesis were found to be significantly upregulated in stem as compared to root tissues. The qRT-PCR validation of 9 unigenes involved in phenylpropanoid and terpenoid biosynthesis also showed a similar expression pattern. This finding suggests that stem tissues, rather than root tissues, could be used to prevent uprooting of O. turpethum in the wild, paving the way for the plant's effective conservation. Moreover, the study formed a valuable repository of genetic information which will provide a baseline for further molecular research.

Lrcasp9 shares similarity in structural motifs with human caspase-9 and is activated following bacterial infection and anti-viral vaccination.

Among various caspases, caspase-9 plays a crucial role in the initiation phase of apoptotic cascade. To investigate about it in a high-valued freshwater fish species rohu (Labeo rohita), we cloned and characterized full-length caspase-9 cDNA (Lrcasp9) and analyzed its expression following bacterial infections and anti-viral vaccinations. The Lrcasp9 consisted of 1619-bp nucleotides (nt) having an ORF of 1302 nt encoding a polypeptide of 433 amino acids (aa) with a molecular mass of ∼ 48.20 kDa. Structurally, Lrcasp9 comprised of one CARD domain (1-89 aa) and one CASc domain (161-430 aa). The CASc domain consisted of one large subunit (p20) spanning from 168 to 300 aa, and a small sub unit (p10) from 343 to 430 aa. The caspase family signature histidine active motif H233SAYDCCVVIILSHG247, cysteine active motif K287PKLFFIQACGG298 and pentapeptide "QACGG" active sites present in the p20 domain of Lrcasp9 was conserved across fish species, mouse and human caspase-9. Phylogenetically, it was closely related to common carp caspase-9 and exhibited significant similarity (90.1%) and identity (85.3%) in their amino acid sequence. In the uninfected fish, Lrcasp9 gene expression was highest (~ 5.3-fold) in blood and lowest in gill. In response to Aeromonas hydrophila and Edwardsiella tarda infection and rhabdoviral vaccination, Lrcasp9 gene expression was significantly (p > 0.05) enhanced in gill, liver, kidney and spleen, and also in vitro during cell death, suggesting activation of the intrinsic apoptotic pathway in bacterial infections and anti-viral vaccination in Labeo rohita.