Synthesis of metallic nanoparticles using biometabolites: mechanisms and applications.

Bio-metabolites have played a crucial role in the recent green synthesis of nanoparticles, resulting in more versatile, safer, and effective nanoparticles. Various primary and secondary metabolites, such as proteins, carbohydrates, lipids, nucleic acids, enzymes, vitamins, organic acids, alkaloids, flavonoids, and terpenes, have demonstrated strong metal reduction and stabilization properties that can be utilized to synthesize nanomaterials and influence their characters. While physical and chemical methods were previously used to synthesize these nanomaterials, their drawbacks, including high energy consumption, elevated cost, lower yield, and the use of toxic chemicals, have led to a shift towards eco-friendly, rapid, and efficient alternatives. Biomolecules act as reducing agents through deprotonation, nucleophilic reactions, transesterification reactions, ligand binding, and chelation mechanisms, which help sequester metal ions into stable metal nanoparticles (NPs). Engineered NPs have potential applications in various fields due to their optical, electronic, and magnetic properties, offering improved performance compared to bulkier counterparts. NPs can be used in medicine, food and agriculture, chemical catalysts, energy harvesting, electronics, etc. This review provides an overview of the role of primary and secondary metabolites in creating effective nanostructures and their potential applications.

Strengthening global health resilience: Marburg virus-like particle vaccines and the One Health approach.

The Marburg virus (MARV), belonging to the Filoviridae family, poses a significant global health threat, emphasizing the urgency to develop Marburg virus-like particle (VLP) vaccines for outbreak mitigation. The virus's menacing traits accentuate the need for such vaccines, which can be addressed by VLPs that mimic its structure safely, potentially overcoming past limitations. Early Marburg vaccine endeavors and their challenges are examined in the historical perspectives section, followed by an exploration of VLPs as transformative tools, capable of eliciting immune responses without conventional risks. Noteworthy milestones and achievements in Marburg VLP vaccine development, seen through preclinical and clinical trials, indicate potential cross-protection. Ongoing challenges, encompassing durability, strain diversity, and equitable distribution, are addressed, with proposed innovations like novel adjuvant, mRNA technology, and structure-based design poised to enhance Marburg VLP vaccines. This review highlights the transformative potential of Marburg VLPs in countering the virus, showcasing global collaboration, regulatory roles, and health equity for a safer future through the harmonious interplay of science, regulation, and global efforts.

Spatial distribution of polycyclic aromatic hydrocarbons in water and sediment in the Ganga River: source diagnostics and health risk assessment on dietary exposure through a common carp fish Labeo rohita.

We evaluated spatial distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in water and sediments at four selected sites of the Ganga River. Also, we measured PAHs in muscle tissues of Rohu (Labeo rohita), the most common edible carp fish of the Ganga River and potential human health risk was addressed. Total concentration of PAHs (∑PAHs) in water was highest at Manika Site (1470.5 ng/L) followed by Knuj (630.0 ng/L) and lowest at Adpr (219.0 ng/L). A similar trend was observed for sediments with highest concentration of ∑PAHs at Manika (461.8 ng/g) and lowest at Adpr Site (94.59 ng/g). Among PAHs, phenanthrene (Phe) showed highest concentration in both water and sediment. Of the eight major carcinogenic contributors (∑PAH8C), Indeno (1,2,3-C,D) pyrene (InP) did appear the most dominant component accounting for 42% to this group at Manika Site. Isomer ratios indicated vehicular emission and biomass combustion as major sources of PAHs. The ∑PAHs concentrations in fish tissue ranged from 117.8 to 758.0 ng/g (fresh weight basis) where low molecular weight PAHs assumed predominance (above 80%). The risk level in fish tissues appeared highest at Manika Site and site-wise differences were statistically significant (p < 0.05). The ILCR (> 10-4) indicated carcinogenic risk in adults and children associated with BaP and DBahA at Manika Site and with BaP at Knuj Site. Overall, the concentrations exceeding permissible limit, carcinogenic potential and BaP equivalent all indicated carcinogenic risks associated with some individual PAHs. This merits attention because the Ganga River is a reservoir of fisheries.

Exploring the potentials of Ziziphus mauritiana Lam. seed kernel oil as pharmaceutical oil base: Physicochemical characterization and ketoconazole soap formulation.

Ziziphus mauritiana Lam. (Rhamnaceae) is a large spiny shrub or small tree, native to the Indian subcontinent that can reach a maximum height of 9-15 m. This plant stands as a renowned tropical fruit variety, commonly recognized as the Indian plum, Desert apple, or Indian Jujube. The objective of this study was to examine the standard physicochemical parameters of Z. mauritiana seed kernel oil and to formulate the ketoconazole soap (2 % w/w), using the obtained oil, as a base. The oil was obtained through hexane extraction from the seed kernels. To formulate pharmaceutical ketoconazole soap, Z. mauritiana seed kernel oil was subjected to a basic saponification reaction using potassium hydroxide. All the examined physicochemical parameters, namely acid value (4.71 mg KOH/g), saponification value (229.18 mg KOH/g), peroxide value (4.15 milliequivalents KOH/g), ester value (224.47 mg KOH/g), iodine value (11.19 mg KOH/g), refractive index (1.448), pH (5.93), viscosity (89 cP), and specific gravity (0.912 g/mL) were within the acceptable range for industrial purposes. The examination of quality control parameters, namely drug content (99.49 %), total fatty matter (71.13 %), foam retention time (17.21 min), foam height (18.56 cm), moisture content (9.14 %), and pH (7.16) indicated that the newly formulated ketoconazole soap complied with the acceptable limits. In summary, our research demonstrated the excellent physicochemical stability of Z. mauritiana seed kernel oil and its suitability as a soap base, supporting its promising prospects for cost-effective production of cosmetics, soaps, and shampoos in the pharmaceutical and cosmeceutical industries, reducing reliance on synthetic bases.

Adsorptive removal of oxytetracycline using MnO2-engineered pine-cone biochar: thermodynamic and kinetic investigation and process optimization.

Indiscriminate use of oxytetracycline is linked to the development of antibiotic-resistant genes, posing a serious threat to human health and ecosystem balance. This article reports the adsorptive elimination of oxytetracycline (OTC) from aqueous solution using a newly developed MnO2-modified pine-cone biochar (MnO2/PCBC). The MnO2/PCBC was characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, CHNS analyzer, inductively coupled plasma-optical emission spectroscopy, and Brunauer-Emmett-Teller N2 adsorption analyzer. Batch adsorption experiments, designed using the central composite design framework of response surface methodology, were conducted to investigate the influence of process variables on the adsorption of OTC onto MnO2/PCBC. The optimized conditions for achieving maximum removal (88.1%) were found to be at pH 8, MnO2/PCBC dose 0.44 g/L, initial OTC concentration 200 mg/L, and temperature 303 K. The adsorption process follows Langmuir (R2=0.95) and Freundlich (R2=0.95) isotherms and pseudo-second-order (R2=0.99) adsorption kinetics. The adsorption process was found to be endothermic (ΔH0 = 33.04 kJ/mol) and spontaneous in nature (ΔG0 from -1.33 kJ/mol at 283 K to -5.65 kJ/mol at 313 K). The synthesized MnO2/PCBC could be recycled and reused for OTC removal with a percentage removal of around 80% after fifth cycle. The results indicate an effective removal of oxytetracycline with only 0.44 g/L MnO2/PCBC with maximum adsorption capacity of 357.14 mg/g which demonstrates improved performance in comparison to many adsorbents reported in literature. This implies that MnO2/PCBC offers potential to be developed into a cost-effective technique for antibiotic removal from water.

Preliminary Study on the Antibacterial Activities and Antibacterial Guided Fractionation of Some Common Medicinal Plants Practices in Itum Bahal, Kathmandu Valley of Nepal.

The aim of this study was to evaluate the antibacterial activities of selected medicinal plant practices by a traditional healer of the Newar community in Itum Bahal, Kathmandu, Nepal. The antibacterial activities of the methanolic extract (1 mg/disc) of fifteen medicinal plants were screened against two Gram-positive bacteria (Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633) and two Gram-negative bacteria (Escherichia coli ATCC 25922 and Salmonella typhi CCM 5445) using the disc diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were calculated for the different fractions (hexane, chloroform, ethyl acetate, acetonitrile, and acetone) of the plants having a significant antimicrobial effect. Only Quercus infectoria G. Olivier (galls) and Mallotus repandus (Willd.) Müll.Arg. (seeds) exhibited prominent antibacterial effects. The acetone fraction from Q. infectoria had the strongest antibacterial effect, with a 41.00 mm inhibition zone against S. aureus. In contrast, the ethyl acetate fraction in M. repandus exhibited the highest efficacy, producing a 29.00 mm inhibition zone against S. typhi. In a similar manner, in the case of Q. infectoria, the acetoe fraction depicted the lowest MIC (0.19 mg/mL) and MBC (0.98 mg/mL) values against S. aureus, whereas the ethyl acetate fraction of M. repandus was most significant, showing the lowest MIC and MBC of 0.25 and 0.53 mg/mL, respectively, against S. typhi. This study suggested that the acetone extract of Q. infectoria galls can be used as a potential source against Gram-positive bacteria, whereas the ethyl acetate extract of M. repandus seeds could serve as a useful source to inhibit Gram-negative bacteria. Furthermore, extensive scientific investigation is mandatory to ensure the proper use of folk medicines.

High Concentration of Sulphate Coupled with Climate Warming Generates Ecosystem Feedback Under Sub-Oxic Conditions at Sediment-Water Interface in the Ganga River.

Here, we quantified sediment phosphorus (P) release in relation to concentrations of dissolved oxygen (DO) and sulphate, and increase in temperature in a major river of India subjected to long-term human perturbations. We found a substantial increase in sediment P release, an ecosystem feedback, at higher concentrations of sulphate, more towards the lower end of DO concentrations. A 2°C warming increased sediment P release upto 25.21% and caused a drop in DO level by 16%. Our findings reconcile the observed sulphate-driven changes in sediment P release across systems, and provide first experimental evidence of warming-induced increases. Our results imply that aquatic ecosystems will undergo self-fertilizing effect as the planet warming interacts with other human perturbations. This has implications for eutrophication linkages and ecosystem functioning.

Perception of Nepalese nursing students toward E-learning in Nepal.

BACKGROUND: E-learning is the delivery of learning and training through digital resources. Although e-learning is based on formalized learning, it is provided through computers, tablets, and even cellular phones those are connected to the Internet. This makes it easy for users to learn anytime, anywhere, with few, if any restrictions. MATERIAL AND METHODS: A cross-sectional study was done, and data was obtained through an online survey method from September 14, 2020 to October 08, 2020. Questions were created in "Google Forms." The targeted population was all nursing students from all over Nepal. There were a total of 365 respondents. A pilot study was done on 10 students. After the pilot study, the same question was distributed to all the respondents. RESULTS: Almost half (40.8%) got disturbed in their online class because of electricity; around half of the respondents (41.9%) are disturbed in their online class because of Internet problems. Moreover, around half of the respondents (44.4%) use the data pack daily, and 38.6% use the data sometimes. CONCLUSION: The study concludes that most students suffered from Internet disturbance and electricity problems during online classes. Because of electricity and Internet problems, most students feel anxious during class, and most of the students are not able to attend classes. Most students are compelled to use data packs for online classes. However, the course may not be completed if the problems arising during online classes are not solved.

Knowledge regarding Basic Life Support among Health Care Workers of the Hospital of Nepal.

Basic life support refers to a sequence of care provided to patients who are experiencing respiratory arrest, cardiac arrest, or airway obstruction. It is a specific level of prehospital medical care provided by the trained responders, including emergency medical technicians, in the absence of advanced medical care to maintain the patient's life. BLS course trains participants to promptly recognize several life-threatening emergencies, give high-quality chest compressions, deliver appropriate ventilations, and provide early use of an AED. According to American Heart Association (AHA) guidelines, every missed minute in applying defibrillation in a cardiac arrest decreases the survival rate by 70%-10%. According to European Resuscitation Council (ERC), early resuscitation and prompt defibrillation (within 1-2 minutes) can result in >60% survival. A quantitative, descriptive study design is used in this study. A purposive sampling technique was used, and the sample size was 95. A self-structuredclose-ended questionnaire was used to assess the level of knowledge of the participants. The finding revealed that among 95 participants, only 12% had adequate, 55% had moderate, and 32% had inadequate knowledge about Basic Life Support. The study showed that knowledge among healthcare workers about basic life support is insufficient for the majority of participants. There is a significant association between dependent and independent variables.

Impact of COVID-19 pandemic on learning status of student in Nepal.

BACKGROUND: This study was designed to evaluate the impact of the COVID-19 pandemic on the learning status of students from different educational boards and universities of Nepal. An online survey was conducted from tenth to twentieth of September 2020 to record the data. MATERIAL AND METHODS: A self-designed questionnaire link, using "Google form" was sent to the students via social networks. A total of 589 participants shared their complete information. The simple percentage distribution was employed to evaluate the learning status of the students. RESULTS: During the lockdown period, >70% of the students were engaged in online classes, most commonly by using the Zoom app. The majority of the students were using WIFI as an internet source to attend online classes. Students have been suffering from various problems related to anxiety, stress, economic crises, poor internet connectivity, deprivation of study materials, required e-learning accessories, and an unsuitable study environment. Mainly, students from remote areas and middle income families suffered enormously. Among those participants, who were able to attend the online classes, the majority of students (70%) were dissatisfied with the ongoing online classes. Only 23.3% of the participants suggested the feasibility of online classes in the near future. CONCLUSION: Our study recommended that training teachers and students about online classes might create effectiveness toward e-learning. The government needs to provide free internet services to the remote areas and the poor students since in the current scenario, huge numbers of the population are struggling with the economic burden.

COVID-19 lockdown-driven changes in the Ganga River ecosystem in response to human perturbations.

We examined 10 subsurface water, 5 benthic water and 19 sediment (02 cm) samples along a 518 km of the middle segment of the Ganga River to assess the possible improvements that resulted from the industrial shutdown during the COVID-19 pandemic. The sites included the main stem river, tributary confluences, and two point sources, one of which releases metal-rich effluents and the other flushes municipal sewage. We found significant declines in the carbon, nutrient and metal concentrations in both the water and sediment. Even the most polluted zones did not show hypoxia (dissolve oxygen; DO < 2.0 mg L-1) that had been observed in the previous year. Despite a significant decline in carbon and nitrogen as substrates, the activities of extracellular enzymes (EEs), such as ß-D-glucosidase, FDAase and protease in sediment (0-2 cm depth), increased significantly (p < 0.05) in response to the declining metal concentrations resulting from the industrial shutdown. We found strong negative correlations between EE activity and the concentrations of metal pollutants measured in 2019, but the correlations between these variables appeared poor in 2020 (lockdown period). Also, we found large variances (low stability coefficients) during the period of strong anthropogenic effects (2019). The study indicates that industrial sources are important contributors of metal pollution in the Ganga River and has relevance exploring river ecosystem recovery windows for management decisions.

Antibacterial and Antioxidant Activities of Prinsepia utilis Royle Leaf and Seed Extracts.

Our study was designed to screen the antibacterial potency of Princepia utilis leaf and seed extract and to measure their antioxidant effects, total phenol content, total flavonoid content, and total carbohydrate content. Collected samples were extracted by cold maceration. Hexane, ethyl acetate, methanol, and distilled water were used as extraction solvents. In the disc diffusion method, P. utilis ethyl acetate leaf extract was most prominent against Staphylococcus epidermis with a zone of inhibition (ZOI) of 13.83 mm. Similarly, methanolic leaf extract was most prominent against Staphylococcus aureus (ZOI-12.33 mm). Furthermore, the methanolic seed extract was most sensitive against Klebsiella pneumoniaee (ZOI-11.66 mm) Escherichia coli (ZOI-9.0 mm). The lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.5 mg/mL and 0.6 mg/mL, respectively, were shown by ethyl acetate leaf extract against S. epidermis. Similarly, the highest values of MIC and MBC, i.e., 20.8 mg/mL and 33.3 mg/mL, respectively, were shown by hexane leaf extract against S. epidermidis. On the other hand, evaluation of antioxidant capacity revealed that ethyl acetate leaf extract showed the maximum antioxidant effect (IC50: 66.69 µg/mL). The total flavonoid contents of different extracts were measured in the range of 37 ± 0.74 µg QE/mg dry extract weight (methanolic seed extract) to 321.84 ± 4.82 µg QE/mg dry extract weight (hexane seed extract). Likewise, the total polyphenol content ranged from the hexane leaf extract (17.33 ± 0.642 µg GAE/mg dry extract weight) to ethyl acetate leaf extract (62.56 ± 1.284 µg GAE/mg dry extract weight). We found a variation in total carbohydrate content in the range of 23.55 ± 1.125 µg glucose/mg dry extract weight (hexane leaf extract) to 96.63 ± 2.253 µg glucose/mg dry extract weight (aqueous leaf extract). Overall, this study revealed that leaf and seed extract of P. utilis exhibited noteworthy antibacterial effects against diverse pathogenic microorganisms.

Prolonged Use of Insecticide Dimethoate Inhibits Growth and Photosynthetic Activity of Wheat Seedlings: A Study by Laser-Induced Chlorophyll Fluorescence Spectroscopy.

This paper is an extension of the work published in Journal of Fluorescence (2011) 21: 785-791. In the previous work, we studied the effect of dimethoate (50, 100 and 200 ppm) on growth and photosynthetic activity of wheat seedlings after 10 days of dimethoate treatment. In the present study, new measurement conditions (dimethoate concentration: 25 ppm, treatment period: 20 days and 30 days) were used in addition to those used in the past work. Various plant growth parameters, photosynthetic pigment content, laser-induced chlorophyll fluorescence (LICF) spectra and fluorescence induction kinetics (FIK) curves were recorded after 10, 20 and 30 days of dimethoate treatments. LICF spectra were recorded in the region of 650-780 nm using violet diode laser (405 nm). FIK curves were recorded at 685 nm using red diode laser (635 nm). Fluorescence intensity ratio (FIR) of two fluorescence peaks around 685 and 730 nm, and variable chlorophyll fluorescence decrease ratio (Rfd) were determined from LICF spectra and FIK curves respectively. Curve-fitted parameters of LICF spectra were used for determination of FIR (F685/F730). The effect of treatment of the insecticide dimethoate on growth and photosynthetic activity of wheat seedlings was examined by using these parameters as well as the past work. In 10-days treatment, 25 and 50 ppm dimethoate showed stimulatory effect with better stimulation being observed at 25 ppm. All studied concentrations higher than 50 ppm exhibited inhibitory effect on wheat seedlings. In case of dimethoate treatment studied for longer durations (more than 10 days), all concentrations showed inhibitory effect. Lower doses which showed some positive response for short time duration become toxic with the extension of treatment periods. Thus, this study clearly confirms the toxic effect of dimethoate on wheat plants.

Caregivers' Knowledge, Attitude, and Practice towards Pressure Injuries in Spinal Cord Injury at Rehabilitation Center in Bangladesh.

The purpose of this study was to determine caregivers' knowledge, attitude, and practice (KAP) on the prevention and care of pressure injuries (PIs) in individuals with spinal cord injury. A quantitative cross-sectional study with descriptive correlation design was used to implement a modified semistructured questionnaire using a convenient sampling method. McDonald's standard of learning outcome measurement criteria was used to categorize caregivers' KAP. A Pearson product-moment correlation coefficient (r) was utilized to assess the relationships between caregivers' KAP, with a p value of 0.05 or less considered statistically significant. The study findings indicate that caregivers had a moderate level of knowledge (M = 73.68%, SD = 6.43), a neutral attitude (M = 70.32%, SD = 6.89), and a moderate level of practice (M = 74.77%, SD = 9.08). A positive correlation existed between caregivers' knowledge and attitude (r = 0.30, p < 0.01), as well as between knowledge and practice (r = 0.37, p < 0.01). Nevertheless, there was no correlation between attitude and practice (r = 0.12, p > 0.05). The study findings suggest that caregivers need to develop a positive attitude and expand their knowledge in order to improve their practice. The KAP factors that require higher priority were positioning and turning the patient, preventing skin breakdown, assessing weight changes over time, interest in patient care, additional care for PIs, frequently changing the individual's position, priority to PI care, interest in other types of care other than PIs, using special cushions, consulting doctors on a regular basis, being aware of clothing and fabrics, proper transfer technique, pressure relief, and skin inspection, among others.

Formulation of Ebastine Fast-Disintegrating Tablet Using Coprocessed Superdisintegrants and Evaluation of Quality Control Parameters.

Ebastine is a long-acting, nonsedating, second-generation antihistaminic drug that prevents histamine action, mainly in immediate hypersensitivity. This project was aimed to formulate and characterize orodispersible tablets of ebastine, utilizing different proportions of three disintegrants, namely crospovidone, sodium starch glycolate, and coprocessed superdisintegrant. Initially, fifteen trial batches of ebastine orodispersible tablets were outlined using the central composite design of Minitab software. The tablets were formulated by the direct compression method. The compressed tablets were then evaluated for precompression and postcompression physicochemical parameters, such as angle of repose, Carr's index, Hausner's ratio, hardness, thickness, weight variation, drug content, friability, wetting time, disintegration time, dispersion time, and water absorption ratio. The in vitro dissolution test was conducted according to Indian Pharmacopeia 2018, with the help of the rotating paddle method using 0.5% w/v sodium lauryl sulfate buffer in 0.1 N HCl. For the optimized batch (8th batch), all the physicochemical parameters like angle of repose (33.77°), Carr's index (19.34%), Hausner's ratio (1.24), weight variation (202.5 mg), hardness (4.3 kg/cm2), friability (0.44%), thickness (3.16 mm), dissolution (95.78%), and drug content (101.67%) were within the acceptable limit as per Indian Pharmacopeia 2018. The wetting time, disintegration time, dispersion time, and water absorption ratio were reported to be 25.1 seconds, 16.0 seconds, 38.6 seconds, and 91.92%, respectively. Hence, the results suggested that orodispersible tablets of ebastine can be formulated. Furthermore, the mixing of crospovidone, sodium starch glycolate, and coprocessed super disintegrants can result in excellent desirable properties in the orodispersible tablet.

Study of Antibacterial Activity of Root Bark, Leaves, and Pericarp Extracts of Diploknema butyracea and Evaluation of Prospective Antioxidant Activity.

This study was aimed to determine the antibacterial activity of root bark, leaves, and pericarp extract of Diploknema butyracea and to evaluate the prospective antioxidant activity, total flavonoid, polyphenol, and carbohydrate content. The plant parts were collected and extracted by cold maceration, using hexane, ethyl acetate, methanol, and distilled water. Phytochemical screening of different samples of D. butyracea in different solvents revealed the presence of varied extent of alkaloid, saponin, terpenoid, anthraquinones, tannin, cardiac glycoside, flavonoid, carbohydrate, polyphenol, protein and amino acid, resin, and phytosterol. Our study showed that methanolic root bark extract exhibited the potent antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Klebsiella pneumonia with an average zone of inhibition of 17.33 mm, 14.33 mm, and 13.0 mm, respectively. Surprisingly, all of the extracts were insensitive to Escherichia coli. The lowest minimum bactericidal concentration (MBC), 4.6 mg/ml, was observed with the aqueous pericarp extract against S. epidermidis and the highest was of 50 mg/ml shown by ethyl acetate pericarp against K. pneumonia. Our results showed that both the polar and nonpolar components present in the different parts of D. butyracea exhibit prominent antibacterial activities against different bacterial strains. The in vitro 2,2'-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity showed that the methanol extract of root barks displayed the most potent antioxidant activity (IC50 : 6.1 µg/ml). The total polyphenol content of the plant part extracts was observed between 19.48 ± 0.23 and 123.48 ± 1.84 µg gallic acid equivalent/mg of dry extract weight. Likewise, flavonoid content ranged from 40.63 ± 1.28 µg to 889.72 ± 3.40 µg quercetin equivalent/mg of dry extract weight and total carbohydrate content ranged from 11.92 ± 0.60 µg to 174.72 ± 0.60 µg glucose equivalent per/mg dry extract weight. Overall, our study showed that the root bark, pericarp, and leaves extract of D. butyracea evinced prominent antibacterial properties against various pathogenic bacterial strains.

Effects of COVID-19 lockdown on water quality, microbial extracellular enzyme activity, and sediment-P release in the Ganga River, India.

This study investigates possible improvement in water quality and ecosystem functions in the Ganga River as influenced by COVID-19 lockdown in India. A total of 132 samples were collected during summer-2020 low flow (coinciding COVID-19 lockdown) for water (sub-surface and sediment-water interface) and 132 samples separately for sediment (river bottom and land-water interface) considering 518-km main river stem including three-point sources (one releases urban sewage and the other two add metal-rich industrial effluents) and a pollution-impacted tributary. Parameters such as dissolved oxygen deficit and the concentrations of carbon, nutrients (N and P), and heavy metals were measured in water. Sediment P-release was measured in bottom sediment whereas extracellular enzymes (EE; alkaline phosphatase, FDAase, protease, and ß-D-glucosidase) and CO2 emission were measured at land-water interface to evaluate changes in water quality and ecosystem functions. The data comparisons were made with preceding year (2019) measurements. Sediment-P release and the concentrations of carbon, nutrients, and heavy metals declined significantly (p<0.05) in 2020 compared to those recorded in 2019. Unlike the preceding year, we did not observe benthic hypoxia (DO <2.0 mg L-1) in 2020 even at the most polluted site. The EE activities, which declined sharply in the year 2019, showed improvement during the 2020. The stability coefficient and correlative evidences also showed a large improvement in the water quality and functional variables. Positive changes in functional attributes indicated a transient recovery when human perturbations withdrawn. The study suggests that timing the ecosystem recovery windows, as observed here, may help taking management decision to design mitigation actions for rivers to recover from anthropogenic perturbations.

Pimarane Diterpenoids from Aerial Parts of Lycopus lucidus and Their Antimicrobial Activity.

The ethyl acetate fraction obtained from aerial parts of L. lucidus was subjected for isolation of new bioactive compounds, which enabled isolation of five new pimarane-type diterpenoids, namely, 3ß, 8ß, 12ß, 18-tetrahydroxy pimar-15-ene (10), 7α, 8ß, 12ß, 18-tetrahydroxy pimar-15-ene (11), 3ß, 8ß, 11ß, 12α, 18-pentahydroxy pimar-15-ene (12), 12ß acetoxy, 8ß, 3ß, 18-trihydroxy pimar-15-ene (13), and 3ß acetoxy, 8ß, 12ß, 18-trihydroxy pimar-15-ene (14), along with nine known compounds. The structures were elucidated by spectroscopic analysis and comparison with literature data. The isolated new pimarane diterpenoids were examined for antimicrobial activity against Gram-negative and Gram-positive bacteria strains. Among them, the compound 3ß, 8ß, 12ß, 18-tetrahydroxy pimar-15-ene (10) was most effective, exhibiting minimum inhibitory concentration (MIC) values of 15.62 µg/mL against Staphylococcus epidermidis, 31.25 µg/mL against Staphylococcus aureus, 62.5 µg/mL against Pseudomonas aeruginosa, and 125 µg/mL against Escherichia coli.

Collateral implications of carbon and metal pollution on carbon dioxide emission at land-water interface of the Ganga River.

Atmospheric CO2 source and sink is among the most debated issues that have puzzled climate change geochemist for decades. Here, we tested whether heavy metal pollutants in river sediments favor preservation of organic matter through shielding microbial degradation. We measured CO2 emission and extracellular enzyme activities at land-water interface (LWI) of 7 sites along a 285 km main stem of the Ganga River and 60 locations up- and downstream of two contrasting point sources discharging urban (Assi drain; Asdr) and industrial (Ramnagar drain; Rmdr) wastewaters to the river. We found the lowest CO2 flux at Rmdr mouth characterized by the highest concentrations of Cu, Cr, Zn, Pb, Ni, and Cd. The fluxes were relatively higher at locations up- and downstream Rmdr. Substrate induced respiration (SIR), protease, FDAase, and ß-D-glucosidase all showed a similar trend, but phenol oxidase and alkaline phosphatase showed opposite trend at the main river stem and Asdr. Sites rich in terrestrially derived organic matter have high phenol oxidase activity with low CO2 emission. The CO2 emission in the main river stem showed curvilinear relationships with total heavy metals (∑THM; R2 = 0.68; p < 0.001) and TOC (R2 = 0.65; p < 0.001). The dynamic fit model of main stem data showed that the ∑THM above 337.4 µg g-1 were able to significantly decrease the activities of protease, FDAase, and ß-D-glucosidase. The study has implications for understanding C-cycling in human-impacted river sediments where metal pollution shields microbial degradation consequently carbon and nutrient release and merits attention towards river management decisions.

Bioactive Chemical Constituents and Pharmacological Activities of Ponciri Fructus.

Ponciri Fructus is a crude drug obtained from the dried immature fruits of Poncirus trifoliata (L). Raf. (Syn. Citrus trifoliata L.). This study aims to compile and analyze the ethnomedicinal uses, bioactive constituents, and pharmacological activities of Ponciri Fructus. Various online bibliographic databases namely, SciFinder, PubMed, Google Scholar, and Web of Science were used for collecting information on traditional uses, biological activities, and bioactive constituents. Concerning ethnomedicinal uses, Ponciri Fructus is extensively used in traditional Korean, Chinese, and Kampo medicines to mitigate allergic reactions, inflammation, edema, digestive complications, respiratory problems, spleen-related problems, liver complications, neuronal pain, hyperlipidemia, rheumatoid arthritis, cardiovascular problems, hernia, sinusitis, and insomnia. Several studies have shown that Ponciri Fructus is a major source of diverse classes of bioactive compounds namely flavonoids, terpenoids, coumarins, phytosterols, and alkaloids. Several in vivo and in vitro pharmacological activity evaluations such as antidiabetic, anti-obesity, anti-inflammatory, antiallergic, antimelanogenic, gastroprotective, anticancer, and neuroprotective effects have been conducted from Ponciri Fructus. However, scientific investigations focusing on bioassay-guided isolation and identification of specific bioactive constituents are limited. Therefore, an in-depth scientific investigation of Ponciri Fructus focusing on bioassay-guided isolation, mechanism based pharmacological studies, pharmacokinetic studies, and evaluation of possible toxicities is necessary in the future.