Evaluation of Abelmoschus moschatus extracts for antioxidant, free radical scavenging, antimicrobial and antiproliferative activities using in vitro assays

<p>Abstract</p> <p>Background</p> <p><it>Abelmoschus moschatus </it>Medik. leaves and seeds are considered as valuable traditional medicine. The aromatic seeds of this plant are aphrodisiac, ophthalmic, cardio tonic, antispasmodic and used in the treatment of intestinal complaints and check queasiness. To give a scientific basis for traditional usage of this medicinal plant, the seed and leaf extracts were evaluated for their antioxidant, free radical scavenging, antimicrobial and antiproliferative activities.</p> <p>Methods</p> <p>In this study, antioxidant, antimicrobial and antiproliferative activities of <it>A. moschatus </it>extracts were evaluated in a series of <it>in vitro </it>assay involving free radicals, reactive oxygen species and their IC₅₀values were also determined. The antioxidant activities of the seed and leaf extracts of <it>A. moschatus </it>were determined by total antioxidant, DPPH, and ferrous reducing antioxidant property (FRAP) methods. In addition, the antiproliferative activity was also evaluated using colorectal adenocarcinoma and retinoblastoma human cancer cell lines. Moreover, six bacterial reference strains, two gram-positive (<it>Bacillus subtilis </it>and <it>Staphylococcus aureus</it>), four gram-negative (<it>Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris </it>and <it>Salmonella enterica paratyphi</it>) and one fungal strain (<it>Candida albicans</it>) were used to evaluate its antimicrobial activity.</p> <p>Results</p> <p>The results from this study showed that the antioxidant activities of <it>A. moschatus </it>as determined by the total phenol, flavonoids, total antioxidant and FRAP methods were higher in leaf than that of the seed extracts. On the other hand, the aqueous overnight seed extract (AMS-I) has shown significant radical scavenging activity as in 1, 1- Diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide, hydroxyl radical, superoxide and lipid peroxidation as compared to other seed and leaf extracts. The AMS-I and AML-IV have shown activity against six and seven microorganisms respectively. Simulteneously, AMS-IV and AML-IV have demonstrated potential antiproliferative activity against two human cell lines - Colorectal adenocarcinoma (COLO-205) and retinoblastoma (Y79).</p> <p>Conclusion</p> <p>The seed and leaf extracts of <it>A. moschatus </it>possess significant antioxidant activity and could serve as free radical inhibitors or scavenger, or substitute, probably as primary antioxidants. The plant possesses moderate antibacterial activity against bacterial strains used in this study. Hydroalcoholic seed and leaf extracts also exhibited antiproliferative activity against two human cancer cell lines. <it>A. moschatus </it>may therefore, be a good candidate for functional foods as well as pharmaceutics.</p

Comparative analysis of the genomic regions flanking Xa21 locus in indica and japonica ssp. of rice (Oryza sativa L.)

Abstract Comparative analysis of a 100 kb region flanking of major bacterial blight resistance gene Xa21 (3.57 kb) was performed in the two subspecies of rice Oryza sativa L. ssp. japonica cv. Nipponbare and Oryza sativa L. ssp. indica cv. 93-11 to understand the evolution and divergence of Xa21 locus. A total of 12 genes in japonica and 14 genes in indica were predicted and annotated in this region. Functional annotation revealed the presence of 4 genes and 8 genes in japonica and indica, respectively, which could be putatively associated with disease resistance in the 100 kb region of Xa21 locus. The study also revealed that 50% of japonica genes and 42.8% of indica genes in the genomic region of interest were transposable elements protein coding genes. Analysis of each predicted gene in this region revealed more or less similar GC content in both the subspecies. A total of 109 SSRs have been identified in the region of interest in both indica and japonica. The numbers of repeated motifs were observed to decrease with the increased number of nucleotides. Interestingly, most of the leucine rich repeat (LRR) gene products were predicted to be localized in the plasma membrane and the transposable element related protein coding genes were localized in the nucleus. Phylogenetic tree analysis revealed that the majority of predicted genes with similar functions of both the subspecies were grouped together

Fine mapping and sequence analysis reveal a promising candidate gene encoding a novel NB-ARC domain derived from wild rice (Oryza officinalis) that confers bacterial blight resistance

Bacterial blight disease of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious constraints in rice production. The most sustainable strategy to combat the disease is the deployment of host plant resistance. Earlier, we identified an introgression line, IR 75084-15-3-B-B, derived from Oryza officinalis possessing broad-spectrum resistance against Xoo. In order to understand the inheritance of resistance in the O. officinalis accession and identify genomic region(s) associated with resistance, a recombinant inbred line (RIL) mapping population was developed from the cross Samba Mahsuri (susceptible to bacterial blight) × IR 75084-15-3-B-B (resistant to bacterial blight). The F2 population derived from the cross segregated in a phenotypic ratio of 3: 1 (resistant susceptible) implying that resistance in IR 75084-15-3-B-B is controlled by a single dominant gene/quantitative trait locus (QTL). In the F7 generation, a set of 47 homozygous resistant lines and 47 homozygous susceptible lines was used to study the association between phenotypic data obtained through screening with Xoo and genotypic data obtained through analysis of 7K rice single-nucleotide polymorphism (SNP) chip. Through composite interval mapping, a major locus was detected in the midst of two flanking SNP markers, viz., Chr11.27817978 and Chr11.27994133, on chromosome 11L with a logarithm of the odds (LOD) score of 10.21 and 35.93% of phenotypic variation, and the locus has been named Xa48t. In silico search in the genomic region between the two markers flanking Xa48t identified 10 putatively expressed genes located in the region of interest. The quantitative expression and DNA sequence analysis of these genes from contrasting parents identified the Os11g0687900 encoding an NB-ARC domain-containing protein as the most promising gene associated with resistance. Interestingly, a 16-bp insertion was noticed in the untranslated region (UTR) of the gene in the resistant parent, IR 75084-15-3-B-B, which was absent in Samba Mahsuri. The association of Os11g0687900 with resistance phenotype was further established by sequence-based DNA marker analysis in the RIL population. A co-segregating PCR-based INDEL marker, Marker_Xa48, has been developed for use in the marker-assisted breeding of Xa48t

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Antioxidant and antiproliferative activities of Abrus precatorius leaf extracts - an in vitro study

BACKGROUND: The use of traditional medicine at the primary health care level is widespread and plant-based treatments are being recommended for curing various diseases by traditional medical practitioners all over the world. The phytochemicals present in the fruits, vegetables and medicinal plants are getting attention day-by-day for their active role in the prevention of several human diseases. Abrus precatorius is a widely distributed tropical medicinal plant with several therapeutic properties. Therefore in the present study, A. precatorius leaf extracts were examined for their antioxidant and cytotoxic properties in vitro in order to discover resources for new lead structures or to improve the traditional medicine. METHODS: In this study, antioxidant and antiproliferative properties of the different leaf extracts (hexane, ethyl acetate, ethanol and water) from A. precatorius were investigated along with the quantification of the polyphenol and flavonoid contents. The ability of deactivating free radicals was extensively investigated with in vitro biochemical methods like DPPH(•), (•)OH, NO, SO(2-) scavenging assays and inhibition capability of Fe(II)-induced lipid peroxidation. Furthermore, antiproliferative activities using different human cancer cell lines and primary cell line was carried out by MTT method. RESULTS: Total phenolic content and total flavonoid content of the extracts were found in the range of 1.65 ± 0.22 to 25.48 ± 0.62 GAE mg/g dw and 6.20 ± 0.41 to 17.16 ± 1.04 QE mg/g dw respectively. The experimental results further revealed that A. precatorius extracts showed strong antiradical properties, capable to chelate Fe(2+) and possess good inhibition ability of lipid peroxidation. In addition, as a first step towards the identification of phytoconstituents endowed with potent chemopreventive activities, we evaluated the inhibitory effects of A. precatorius extracts on the proliferation of four different human tumour cell lines such as human colon adenocarcinoma cells (Colo-205), human retinoblastoma cancer cells (Y79), human hepatocellular carcinoma cells (HepG2) and Leukemia cells (SupT1). Ethanol extract (APA) and ethyl acetate extract (APE) of A. precatorius had apparent capabilities of inhibiting the survival of tested human cancer cell lines. Moreover, it was observed that the A. precatorius extracts did not inhibit the growth of mice peritoneal macrophages, thus confirming that plants extracts are selective against the cancer cell lines. CONCLUSION: This work provides a scientific support for the high antioxidant and antiproliferative activity of this plant and thus it may find potential applications in the treatment of the diseases caused by ROS. Further studies are needed to confirm in vivo anti-tumorgenicity and subsequent chemical characterization of the active molecule(s)

Nucleotide Diversity Analysis of Three Major Bacterial Blight Resistance Genes in Rice

<div><p>Nucleotide sequence polymorphisms among <i>R</i> gene alleles influence the process of co-evolutionary interaction between host and pathogen by shaping the response of host plants towards invading pathogens. Here, we present the DNA sequence polymorphisms and diversities present among natural alleles of three rice bacterial blight resistance genes, <i>Xa21</i>, <i>Xa26</i> and <i>xa5</i>. The diversity was examined across different wild relatives and cultivars of <i>Oryza</i> species. Functional significance of selected alleles was evaluated through semi-quantitative reverse transcription polymerase chain reaction and real time PCR. The greatest nucleotide diversity and singleton variable sites (SVS) were present in <i>Xa26</i> (π = 0.01958; SVS = 182) followed by <i>xa5</i> and <i>Xa21</i> alleles. The highest frequency of single nucleotide polymorphisms were observed in <i>Xa21</i> alleles and least in <i>xa5</i>. Transition bias was observed in all the genes and ‘G’ to ‘A’ transitions were more favored than other form of transitions. Neutrality tests failed to show the presence of selection at these loci, though negative Tajima’s D values indicate the presence of a rare form of polymorphisms. At the interspecies level, <i>O</i>. <i>nivara</i> exhibited more diversity than <i>O</i>. <i>sativa</i>. We have also identified two nearly identical resistant alleles of <i>xa5</i> and two sequentially identical alleles of <i>Xa21</i>. The alleles of <i>xa5</i> showed basal levels of expression while <i>Xa21</i> alleles were functionally not expressed.</p></div

Semi-quantitative PCR analysis of <i>Xa21</i> alleles in control and treated samples of IR24, IRBB21, OL1 and OLD.

<p>(a) Expression of <i>Xa21</i> gene in IRBB21 control and infected with <i>Xoo</i>. <i>Xa21</i> expression is absent in remaining samples. (b) Expression pattern of reference gene rice actin in the samples. (c) Phenotypic response of the genotypes after <i>Xoo</i> infection. Leaves with lesion length more than 5 cm are susceptible. IR24 and IRBB21 was used as susceptible and resistance controls, respectively. Control (C), Treated/Infected (T).</p

List of rice accessions used for isolation and nucleotide diversity analysis of alleles.

<p>R resistance, S susceptible, MR moderately resistance</p><p>List of rice accessions used for isolation and nucleotide diversity analysis of alleles.</p

Summary statistics of nucleotide diversity analysis of <i>Xa21</i>, <i>Xa26</i> and <i>xa5</i> genes.

<p>S = No. of polymorphic sites, K = Average nucleotide difference, π = Nucleotide diversity, Ө_w = No. of segregating sites</p><p>Summary statistics of nucleotide diversity analysis of <i>Xa21</i>, <i>Xa26</i> and <i>xa5</i> genes.</p