Antioxidant Potential of Gynura procumbens

Abstract

The leaves of Gynura procumbens (Merr.) Compositae, commonly called “sambung nyawa” in Malaysia, are often eaten raw with rice. The methanol extract was prepared from the dried leaves using a Soxhlet apparatus. The methanol extract was then fractionated into chloroform, ethyl acetate, n-butanol, and aqueous fractions using a separating funnel. In the current study, the antioxidant potency of G. procumbens extract and fractions were investigated, employing various established in vitro systems, such as trolox equivalent antioxidant capacity, β -carotene–linoleic acid model system, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, reducing power, and xanthine oxidase inhibitory activity. Based on the results obtained, the extract and fractions showed different antioxidant potential. Among the fractions, the ethyl acetate fraction displayed higher antioxidant properties. The contents of the potential antioxidant component of the extract and fractions were also determined using HPTLC densitometric and spectrophotometric (using Folin-Ciocalteu reagent) methods. HPTLC study revealed that the methanol extract and the ethyl acetate and n-butanol fractions contain 0.74% and 2.9%, 7.76% and 12.75%, and 4.52% and 0.33% of kaempferol-3-O-rutinoside and astragalin, respectively. The total phenolic content of the extract and fractions varied from 4.37% to 23.43% of dry weight, expressed as gallic acid equivalents (GAE). With further data analysis, it was found there was a significant correlation (p < 0.05) between the total phenolic content of the sample and its DPPH scavenging activity and reducing power with correlation coefficients (r) of 0.891 and 0.926, respectively. These results suggest that phenolics in these plants provide substantial antioxidant activity.     

Nanocomposite membranes of polybenzimidazole and amine-functionalized carbon nanofibers for high temperature proton exchange membrane fuel cells

Carbon nanofibers functionalized with aminobenzoyl groups (CNF–aminobenzoyl) were prepared via direct Friedel–Crafts acylation in polyphosphoric acid. The functionalization of CNFs was characterized using XPS, FTIR, TGA, and Raman analyses. Hexafluoroisopropylidene-containing polybenzimidazole (6FPBI) composite membranes containing pristine CNFs or CNF–aminobenzoyl were prepared using solvent-assisted dispersion and solvent-casting methods. In this work, the influence of the incorporation of functionalized CNFs on several physicochemical properties of the 6FPBI nanocomposite membranes, including their thermal stability, mechanical strength, and acid doping level, was studied. The results showed that CNF–aminobenzoyl provided better mechanical reinforcement for the nanocomposite membrane, compared to pristine CNF. The SEM observation confirmed the good compatibility between the CNF–aminobenzoyl fillers and the 6FPBI matrix. For the 0.3 wt% CNF–aminobenzoyl/6FPBI composite membrane, the tensile stress was increased by 12% to be 78.9 MPa (as compared to the 6FPBI membrane), the acid doping level was improved to 12.0, and the proton conductivity at 160 °C was measured above 0.2 S cm⁻¹. Furthermore, the fuel cell performance of the membrane electrolyte assembly (MEA) for each nanocomposite membrane was evaluated. The maximum power density at 160 °C was found up to 461 mW cm⁻² for the MEA based on the 0.3 wt% CNF–aminobenzoyl/6FPBI composite membrane.

Carbon nanofibers functionalized with aminobenzoyl groups (CNF–aminobenzoyl) were prepared via direct Friedel–Crafts acylation in polyphosphoric acid.     

Comparison of antimicrobial resistance in neonatal and adult intensive care units in a tertiary teaching hospital

Intrahospital variations in antimicrobial profiles may be related to many factors. This study compared causative agents of nosocomial bloodstream infections between a neonatal intensive care unit (NICU) that adopted a ward-tailored antibiotic policy and adult intensive care units (ICUs). Data on organisms from blood cultures obtained from the respective wards between 2005 and 2009 were analyzed. Compared with the adult ICUs, the NICU had a higher frequency of Enterobacteriacae and lower frequencies of typical hospital-acquired pathogens (eg, Klebsiella pneumoniae, 17.4% vs 10.0% [P < .001]; Acinetobacter baumannii, 3.9% vs 11.6% [P < .001]). Antibiotic resistance of gram-negative organisms was also significantly lower in the NICU, including resistance to imipenem (5.7% vs 32.1%; P < .001), amikacin (8.8% vs 30.3%), and ceftriaxone (36.1% vs 74.6%; P < .001). This could possibly be due to the ward-tailored antibiotic policy adopted by the NICU but not by the other ICUs.     

Cardiometabolic Morbidity and Other Prognostic Factors for Mortality in Adult Hospitalized COVID-19 Patients in North Jakarta,Indonesia

Background:Although there have been several studies investigating prognostic factors for mortality in COVID-19, there have been lack of studies in low- and middle-income countries, including Indonesia. To date, the country has the highest mortality rate among Asian countries.Objective:We sought to identify the prognostic factors of mortality in hospitalized patients with COVID-19 in Jakarta.Methods:In this retrospective cohort study, we included all adult inpatients (≥18 years old) with confirmed COVID-19 from Koja General Hospital (North Jakarta, Indonesia) who had been hospitalized between March 20^th and July 31^st, 2020. Demographic, clinical, laboratory, and radiology data were extracted from the medical records and compared between survivors and non-survivors. Univariate and multivariate logistic regression analysis were used to explore the prognostic factors associated with in-hospital death.Results:Two hundred forty-three patients were included in the study, of whom 32 died. Comorbid of hypertension (OR 3.59; 95% CI 1.12–11.48; p = 0.031), obesity (OR 6.34; 95% CI 1.68–23.98; p = 0.007), immediate need of HFNC and/or IMV (OR 64.93; 95% CI 11.08–380.61; p < 0.001), abnormal RDW (OR 3.68; 95% CI 1.09–12.34; p = 0.035), ALC < 1,000/µL (OR 3.51; 95% CI 1.08–11.44; p = 0.038), D-dimer > 500 ng/mL (OR 9.36; 95% CI 1.53–57.12; p = 0.015) on admission, as well as chloroquine treatment (OR 3.61; 95% CI 1.09–11.99; p = 0.036) were associated with greater risk of overall mortality in COVID-19 patients. The likelihood of mortality increased with increasing number of prognostic factors.Conclusion:The potential prognostic factors of hypertension, obesity, immediate need of HFNC and/or IMV, abnormal RDW, ALC < 1,000/µL, D-dimer > 500 ng/mL, and chloroquine treatment could help clinicians to identify COVID-19 patients with poor prognosis at an early stage.     

Toxicology evaluation of standardized methanol extract of Gynura procumbens

Aims of the study

Gynura procumbens (Merr.), which is known as “Sambung nyawa”, is widely used in South East Asian countries in the traditional treatment of many ailments. However, there is little toxicological information available regarding safety following repeated exposure.The present investigation describes the toxicity of a methanol extract of Gynura procumbens leaves in rats.

Materials and methods

For acute toxicity studies, a methanol extract of Gynura procumbens was orally administered to Sprague–Dawley rats (female and male) at a dose range of 1000–5000 mg/kg. For sub-chronic toxicity studies, the rats were orally administered the methanol extract of Gynura procumbens at the doses of 125, 250, and 500 mg/(kg day) for a period of 13 weeks. The animals were sacrificed, followed by examination of their organs and blood serum.

Results and conclusions

Administration of the methanol extract from Gynura procumbens leaves at 1000–5000 mg/kg did not produce mortality or significant changes in the general behaviour, body weight, or organ gross appearance of rats. There were no significant differences in the general condition, growth, organ weights, haematological parameters, clinical chemistry values, or gross and microscopic appearance of the organs from the treatment groups as compared to the control group. Therefore, the NOAEL for the Gynura procumbens methanol extract is 500 mg/(kg day) administered orally for 13 weeks.