In vivo antiplasmodial properties of fractions and flavonoids of Pseudarthria hooheri Wight & Arn. (Fabaceae)

Malaria is regarded as one of the most lethal diseases. Resistance to artemisinin and its derivatives jeopardises effective malaria treatment. Finding novel antimalarial chemicals is critical given the existing treatment situation. This work aimed to examine the antiplasmodial capabilities of <i>Pseudarthria hookeri</i> fractions and flavonoids in vivo. The fractions and compounds antiplasmodial activity were evaluated on male Swiss albino mice infected with <i>Plasmodium berghei</i>, and on healthy female Swiss albino mice, the crude extract's acute toxicity was assessed. The EtOAc fraction had significant antiplasmodial activity (32.53 percent suppression at 500 mg/kg BW) and considerably prolonged the survival period of infected mice (9.8 days) compared to control mice (7.8 days). Parasitaemia was dramatically reduced (85.01, 59.41, and 70.39 percent), and the mean survival time extended (11.33, 10.00, and 9.33 days) with 15, 20 and 35 mg/kg of quercetin (<b>1</b>), 7-O-benzyl-6-prenylpinocembrin (<b>6</b>) and 6,8-diprenyleriodictyol (<b>11</b>) (isolates of the EtOAc fraction), respectively. BW loss and PCV reduction were also averted. Moreover, at 2500 mg/kg, the crude extract of <i>P. hookeri</i> showed no acute toxicity in mice. LC-MS analysis of the EtOAc fraction enabled the identification of nine flavonoids, with <b>8</b> and <b>11</b> being the main components. The present investigation confirmed <i>P. hookeri</i>'s antiplasmodial action, substantiating its ethnomedicinal application for malaria treatment.

Argentine stingless bee honey: bioactive compounds and health-promoting properties

Despite all the advantages of consuming meliponid honey, meliponiculture has not been sufficiently promoted in Argentina yet, and published studies on these species of bees are very scarce. <i>Tetragonisca fiebrigi</i> honey (<b>TfH</b>) or Yateí honey has recently been incorporated into the Argentine food code. This study assesses antioxidant, anti-inflammatory and analgesic properties and acute toxicity by oral administration of <b>TfH</b> in rats. In addition, we present the melissopalynological analysis and physicochemical characterization. High-performance liquid chromatography identifies and quantifies sugars and phenolic compounds. The <i>T. fiebrigi</i> honey analyzed exhibited ABTS^•+ and DPPH radical scavenging effect (IC₅₀= 98.28 mg/ml and IC₅₀=337.83 mg/ml, respectively). A significant reduction in hind paw edema (44.44%) was observed in rats pretreated with <b>TfH</b> honey (1000 mg/kg b.w.) 3.0 h after dosing and significantly reduced transudative and granuloma weights at all doses tested (27.34%, 35.53% and 47.53% granuloma inhibition). The <b>TfH</b> honey oral administration produced analgesic responses in the three models used (acetic acid, formalin, tail immersion). Ferulic, ellagic, coumaric, gallic, cinnamic acids and the flavonoids quercetin and hesperetin were identified and quantified. Fructose (40.9%), glucose (29.02%) and sucrose (1.06%) were the main sugars. <b>TfH</b> honey administration did not produce lethal effects or clinical signs of disease in the acute toxicity study. The results showed that <i>T. fiebrigi</i> honey could be a good source of bioactive natural compounds with therapeutic and nutritional value.

Spinosyns Delivered in Sugar Meals to Aedes aegypti and Aedes albopictus (Diptera: Culicidae): Acute Toxicity and Subacute Effects on Survival, Fecundity, and Fertility

Sugar is an essential source of nutrition for adult mosquitoes to acquire energy. Toxic sugar bait (TSB) provides a promising method for mosquito control by incorporating toxins into artificial sources of sugar (i.e., toxic baits) presented to wild populations. Spinosyns comprise a family of bacterial secondary metabolites with a unique mode of action against the insect nervous system, an appealing environmental safety profile, and potential for incorporation into sugar baits. This research evaluated acute and subacute effects of spinosad (spinosyns A and D) and spinetoram (spinosyns J and L) in sugar meals on survival, fecundity, and fertility of Aedes aegypti and Aedes albopictus. Acute toxicity of spinosyns doubled from 24 to 48 h of assessment, revealing a relatively slow and cumulative action of the formulated spinosyns. Median lethal concentrations at 48 h were lower for spinetoram than for spinosad, lower for Ae. albopictus than Ae. aegypti, and lower for males than females. When exposed to subacute LC50 concentrations of spinosad and spinetoram for 24 h, survival of males and females of both species was diminished compared with controls, fecundity of females was increased, but fertility as measured by hatch rate of eggs was decreased. The formulations may have increased the nutritive value of the sugar meals thereby boosting fecundity, while toxifying embryos, reducing fertility. The inclusion of subacute effects of spinosyns allows assessment of the broader consequences of TSB for adult mosquito control.

Environmental hazard of polypropylene microplastics from disposable medical masks: acute toxicity towards Daphnia magna and current knowledge on other polypropylene microplastics

The COVID-19 pandemic has increased the use of disposable plastics, including medical masks, which have become a necessity in our daily lives. As these are often improperly disposed of, they represent an important potential source of microplastics in the environment. We prepared microplastics from polypropylene medical masks and characterised their size, shape, organic chemical leaching, and acute toxicity to the planktonic crustacean Daphnia magna. The three layers of the masks were separately milled and characterised. Each of the inner frontal, middle filtering, and outer layers yielded different types of microplastics: fibres were obtained from the inner and outer layer, but irregular fragments from the middle layer. The shape of the obtained microplastics differed from the initial fibrous structure of the intact medical mask layers, which indicates that the material is deformed during cryo-milling. The chemical compositions of plastics-associated chemicals also varied between the different layers. Typically, the inner layer contained more chemicals related to antimicrobial function and flavouring. The other two layers also contained antioxidants and their degradation products, plasticisers, cross-linking agents, antistatic agents, lubricants, and non-ionic surfactants. An acute study with D. magna showed that these microplastics do not cause immobility but do physically interact with the daphnids. Further long-term studies with these microplastics are needed using a suite of test organisms. Indeed, studies with other polypropylene microplastics have shown numerous adverse effects on other organisms at concentrations that have already been reported in the environment. Further efforts should be made to investigate the environmental hazards of polypropylene microplastics from medical masks and how to handle this new source of environmental burden.

Improved up-and-down procedure for acute toxicity measurement with reliable LD50 verified by typical toxic alkaloids and modified Karber method

Background Up-and-down procedure (UDP) was recommended to replace traditional acute toxicity methods. However, it was limited due to the long experimental period (20–42 days). To improve UDP, an improved UDP method (iUDP) was developed by shortening observation time between sequence dosages. The aim of this study was to test the reliability of iUDP to provide a reliable method for the acute toxicity measurement of valuable or minor amount compounds. Methods Oral median lethal dose (LD50) of nicotine, sinomenine hydrochloride and berberine hydrochloride were measured both by iUDP and modified Karber method (mKM). Results LD50 of the three alkaloids measured by iUDP with 23 mice were 32.71 ± 7.46, 453.54 ± 104.59, 2954.93 ± 794.88 mg/kg, respectively. LD50 of the three alkaloids measured by mKM with 240 mice were 22.99 ± 3.01, 456.56 ± 53.38, 2825.53 ± 1212.92 mg/kg, respectively. The average time consumed by the two methods were 22 days and 14 days respectively. Total grams of the alkaloids used by the two methods were 0.0082 and 0.0673 (nicotine), 0.114 and 1.24 (sinomenine hydrochloride), 1.9 and 12.7 (berberine hydrochloride). Conclusion iUDP could replace mKM to detect acute toxicity of substances with comparable and reliable result. And it is suitable for valuable or minor amount substances.