Antiviral and antibacterial properties of phloroglucinols: a review on naturally occurring and (semi)synthetic derivatives with potential therapeutic interest.

Phloroglucinol and derived compounds comprise a huge class of secondary metabolites widely distributed in plants and brown algae. A vast array of biological activities, including antioxidant, anti-inflammatory, antimicrobial, and anticancer has been associated to this class of compounds. In this review, the available data on the antiviral and antibacterial capacity of phloroglucinols have been analyzed. Some of these compounds and derivatives show important antimicrobial properties in vitro. Phloroglucinols have been shown to be effective against viruses, such as human immunodeficiency virus (HIV), herpes or enterovirus, and preliminary data through docking analysis suggest that they can be effective against SARS-CoV-19. Also, some phloroglucinols derivatives have shown antibacterial effects against diverse bacteria strains, including Bacillus subtilis and Staphylococcus aureus, and (semi)synthetic development of novel compounds have led to phloroglucinols with a significantly increased biological activity. However, therapeutic use of these compounds is hindered by the absence of in vivo studies and scarcity of information on their mechanisms of action, and hence further research efforts are required. On the basis of this consideration, our work aims to gather data regarding the efficacy of natural-occurring and synthetic phloroglucinol derivatives as antiviral and antibacterial agents against human pathogens, which have been published during the last three decades. The recollection of results reported in this review represents a valuable source of updated information that will potentially help researchers in the development of novel antimicrobial agents.

Reinwardtia indica: phytochemical screening and evaluation of wound healing activity of the extracts in experimental model rats.

Reinwardtia indica is traditionally used for wound healing. The main aim of this study was to evaluate the wound healing activity of leaves extracts of R. indica using the excision wound model in rats. The leaves of R. indica were collected from Gondrang, Chitwan, Nepal.  Leaves were shade dried, extracted by double maceration and subjected to phytochemical screening. Then, the fusion method was used for the formulation of ointment and evaluated. Rats (n=24) were divided into four groups with 6 in each. Excision wound model was used, 2 cm diameter (314 mm2), 2 mm depth wound was created. The treatment was given daily topically to all groups and the % mean wound contraction rate was calculated on days 4, 8, 12 and 16.  The result was analyzed statistically using Graph pad prism version 5. Phytochemical test revealed the presence of alkaloid, flavonoid, tannin, phenol, terpenoid, carbohydrate, etc.  All the evaluation parameters showed satisfactory results. The extract of R. indica ointment (2% w/w and 5% w/w) increased the wound contraction rate day by day. The % means wound contraction rate, on day 12, (80% and 88%), and on day 16, (97% and 100%) and statistically significant difference was at p<0.0001. The R. indica extract ointment showed an increased wound contraction rate. So, in further R. indica could be used for commercial production of wound healing ointment.

A Comparative Study on Ascorbic Acid Concentration, Total Phenol, and Flavonoid Content in Citrus Species Grown in a Different Region of Western Nepal.

Different genetic and environmental factors like altitude, temperature, light radiation, etc. affect the production of phytoconstituents like ascorbic acid, phenol, flavonoid, tannin, etc. So, it is necessary to evaluate phytoconstituents quantitatively and qualitatively because of their different medicinal values. This study is aimed at evaluating and comparing ascorbic acid concentration, total phenol, and flavonoid content in citrus species grown in different places in Western Nepal. For this, fruit collected from Lamjung and Nawalparasi was peeled, and collected juice was extracted with ethanol. Ascorbic acid was estimated using titration with dichlorophenolindophenol dye, and total phenol was estimated using Folin reagent; whereas, flavonoid content was determined by aluminum chloride colorimetric assay. The result showed the maximum ascorbic acid concentration in the fruit juice of Citrus maxima collected from Lamjung, i.e., 2.98 ± 0.161 mg/100 ml, and the least concentration was recorded on extract of Citrus limon collected from Nawalparasi, i.e., 1.005 ± 0.205 mg/100 ml. The total phenol content was comparatively higher in Citrus maxima and Citrus aurantifolia collected from Lamjung, i.e., 12.48 ± 0.40 mg GAE/gm, respectively. Flavonoid content was comparatively higher in Citrus maxima collected from Nawalparasi, i.e., 484.466 ± 3.055 mg QE/gm. This study showed a variation in the concentration of chemical constituents between different places in Western Nepal. This might be due to differences in climatic conditions, environmental factors, altitude, temperature, etc. This study helps to reflect the best-suited altitude for commercial cultivation of the citrus species as these phytochemicals have different medicinal values. Also, this study can help the food industry to use an alternative source of synthetic antioxidant such as ascorbic acid, phenol, and flavonoid. And local people will economically benefit by the commercial cultivation of citrus fruits.

Raised D-dimer among Admitted COVID-19 Patients in a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Introduction: Patients with COVID-19 are characterised by abnormal levels of inflammatory biomarkers. Elevated D-dimer in COVID-19 patients is associated with increased mortality. This study aimed to find out the prevalence of raised D-dimer among COVID-19 patients in a tertiary care centre. Methods: This descriptive cross-sectional study was conducted in COVID-19 unit of a tertiary care centre from 23 January 2021 to 19 June 2021. The ethical approval was taken from the Institutional Review Committee (Reference number: 077/078/159). D-dimer values and demographic data of the hospital-admitted COVID-19 patients were recorded. Convenience sampling technique was used. Point estimate and 95% Confidence Interval were calculated. Results: Out of 180 patients with COVID-19 admitted in the hospital, the D-dimer levels were raised in 85 (47.22%) (39.93-54.51, 95% Confidence Interval) patients. Conclusions: The prevalence of raised D-dimer among admitted COVID-19 patients was found to be lower when compared to other studies conducted in similar settings. Keywords: COVID-19; D-dimer; Nepal; prevalence.

Evaluation of the Antibacterial and Antioxidant Activity of Mimosa rubicaulis and Reinwardtia indica.

Many plants have the property of wound healing, but most of the people are using costly allopathic medicine for the wound. This might be due to lack of awareness about the traditional uses and lack of scientific study of ethnomedicinal plants. So, this study aimed to carry out the antibacterial and antioxidant activity of two medicinal plants which are used traditionally for wound healing activity, i.e.,Mimosa rubicaulis and Reinwardtia indica. Different parts of Mimosa rubicaulis (root, stem, and leaves) and Reinwardtia indica (flower and leaves) were used for the study. Extractions were done by maceration using ethanol as solvent. Antibacterial activity was carried out by the well diffusion method, and antioxidant activities were screened by DPPH radical scavenging and NO scavenging assays. Extract of M. rubicaulis has shown a weak zone of inhibition towards S. aureus and P. vulgaris whereas R. indica has shown no zone of inhibition towards selected bacterial strains. Leaf, root, and stem extracts of M. rubicaulis have shown potent antioxidant activity, i.e., IC50 value of 9.8 µg/ml, 10.19 µg/ml, and, 13.64 µg/ml, respectively. Similarly, leaf extract of R. indica exhibited antioxidant activity with an IC50 value of 19.73 µg/ml. The percentage inhibition of NO radicals of root and stem of M. rubicaulis and leaves of R. indica was 31%, 21%, and 22%, respectively. Out of these two plant species, M. rubicaulis had shown antibacterial activity towards selected microorganism, but antioxidant activity was shown by both plant species. These properties on above mentioned two plant species might help for the development of a marketed formulation for antibacterial and wound-healing agent since wound healing is promoted by antibacterial and antioxidant activities.

Total Phenolic Content, Flavonoid Content and Antioxidant Potential of Wild Vegetables from Western Nepal.

Eight selected wild vegetables from Nepal (Alternanthera sessilis, Basella alba, Cassia tora, Digera muricata, Ipomoea aquatica, Leucas cephalotes, Portulaca oleracea and Solanum nigrum) were investigated for their antioxidative potential using 2,2-dyphenyl-1-picrylhydrazyl (DPPH) scavenging, hydrogen peroxide (H2O2), ferric reducing antioxidant power (FRAP), and ferric thiocyanate (FTC) methods. Among the selected plant extracts C. tora displayed the highest DPPH radical scavenging activity with an IC50 value 9.898 µg/mL, whereas A. sessilis had the maximum H2O2 scavenging activity with an IC50 value 16.25 µg/mL-very close to that of ascorbic acid (16.26 µg/mL). C. tora showed the highest absorbance in the FRAP assay and the lowest lipid peroxidation in the FTC assay. A methanol extract of A. sessilis resulted in the greatest phenolic content (292.65 ± 0.42 mg gallic acid equivalent (GAE)/g) measured by the Folin-Ciocalteu reagent method, while the smallest content was recorded for B. alba (72.66 ± 0.46 GAE/g). The greatest flavonoid content was observed with extracts of P. oleracea (39.38 ± 0.57 mg quercetin equivalents (QE)/g) as measured by an aluminium chloride colorimetric method, while the least was recorded for I. aquatica (6.61 ± 0.42 QE/g). There was a strong correlation between antioxidant activity with total phenolic (DPPH, R² = 0.75; H2O2, R² = 0.71) and total flavonoid content (DPPH, R² = 0.84; H2O2, R² = 0.66). This study demonstrates that these wild edible leafy plants could be a potential source of natural antioxidants.