RNA-dependent RNA polymerase (RdRp) natural antiviral inhibitors: a review.

Viral diseases are the cause of many global epidemics, leading to deaths, affecting the quality of life of populations, and impairing public health. The limitations in the treatment of viral diseases and the constant resistance to conventional antiviral treatments encourage researchers to discover new compounds. In this perspective, this literature review presents isolated molecules and extracts of natural products capable of inhibiting the activity of the nonstructural protein that acts as the RNA-dependent RNA polymerase. The literature review presented natural compounds with the potential to be tested as alternative medicines or used in the development of synthetic drugs to prevent the replication of RNA viruses, such as COVID-19, hepatitis C, and dengue viruses, among others. Natural products are known to exhibit remarkable activities in mitigation of different viral diseases, in addition, they help to decrease the aggravation of infections. Consequently, reducing hospitalization time and deaths.

In vitro Bioaccessibility of Proteins, Phenolics, Flavonoids and Antioxidant Activity of Amaranthus viridis.

The aim of this study was to investigate the chemical composition, mineral content and report the effect of gastrointestinal digestion on the proteins, phenolics, flavonoids and antioxidant activity of morphological parts of Amaranthus viridis (AV). The macronutrients found in the greatest quantity were proteins (leave, inflorescence and seeds) and fiber (roots and stem). The main minerals were calcium, potassium, iron and zinc. All the plant parts showed total phenolic (TPC) and total flavonoid (TFC) compounds that were correlated with antioxidant capacity (DPPH, ABTS and FRAP); the leaves and inflorescence presented the greatest potential. The antioxidant compounds from the leaves, inflorescence and roots decreased after static in vitro digestion, while the TPC and TFC of the digested seeds increased by more than 55%. Approximately 90% of the protein content was bioaccessible. To the best of our knowledge, for the first time, the bioaccessibility of proteins, phenolics, flavonoids and antioxidant activity of the leave, inflorescence, seeds, roots and stem from AV were reported. Taking into consideration the excellent nutritional properties, the morphological parts of the plant can be potentially explored as a source of protein, fiber, minerals and antioxidant compounds.

Chemical Composition and Biological Activities of Essential Oils in the Family Lauraceae: A Systematic Review of the Literature.

The Lauraceae family is predominantly found in Asia and in the rainforests of the Americas, and consists mostly of aromatic trees. Being an essential oil producer, this family is used in the food, pharmaceutical, and cosmetic industries. This work presents a systematic review of the chemical composition and bioactivity of the essential oils from the Lauraceae family. Medline, Scielo, Web of Science, Lilacs, and Scopus were employed to identify articles published between 2000 and 2018, using "Lauraceae", "essential oil", and "biological activity" as key words. From 177 studies identified, 53 met the inclusion criteria. These studies indicated a predominance of the compounds ß-caryophyllene and 1,8-cineole in Lauraceae species, and highlighted the antioxidant, antifungal, antibacterial, and anti-inflammatory activities. Essential oils extracted from this family thus have high potential for pharmacological applications.

Antinociceptive and Anti-Inflammatory Effects of Bixin, a Carotenoid Extracted from the Seeds of Bixa orellana.

Bixin is the main natural apocarotenoid extracted from the seeds of Bixa orellana, widely used as a cosmetic and textile colorant. Despite the description of several pharmacological properties of B. orellana extracts, little has been studied regarding the pharmacological properties of bixin. Then we aimed to investigate the potential anti-inflammatory and antinociceptive effect of bixin in preclinical models of inflammation and acute pain. The anti-inflammatory activity of bixin (15 or 30 mg/kg, orally) was determined using carrageenan-induced paw edema and the myeloperoxidase (MPO) activity in male Wistar rats. The antinociceptive effect of bixin was assessed in the formalin and hot plate tests in rats (at same doses) and in the acetic acid-induced writhing test in Swiss albino male mice (at doses of 27 or 53 mg/kg). General locomotor activity was evaluated in the open field test. Only the higher dose of bixin significantly decreased the carrageenan-induced paw edema and the MPO activity and increased the latency time in the hot plate. Both doses of bixin significantly reduced the number of flinches in both phases of the formalin test and the number of acetic acid-induced writhings without changing the locomotor performance in the open field test. This study validates the use of bixin as an anti-inflammatory trough mechanism related to the reduction of neutrophil migration. Furthermore, this is the first report showing the antinociceptive property of bixin, which does not appear to be related to the sedative effect. Further studies are necessary to characterize the mechanisms involved in these effects.

Traditional Uses, Phytochemistry, and Antimicrobial Activities of Eugenia Species - A Review.

Antimicrobial resistance is a critical health problem, and pathogens responsible for common infections have developed resistance to antimicrobials, posing a threat to global health and placing a huge burden on health services. During the past two decades, the search for new bioactive agents in nature has become extremely important for promoting health and in the development of more efficient antimicrobials. The genus Eugenia is one of the largest in the Myrtaceae family, comprising approximately 1000 species from Mexico to Argentina, with a few species distributed in Australia and Africa. Eugenia species are used in folk medicine, with antidiabetic, antirheumatic, antipyretic, anti-inflammatory, antidiarrheal, antifungal, and antibacterial properties. This study systematically reviews the Eugenia species to compile the phytochemical composition and antimicrobial effects. In addition, we provide information regarding the traditional uses and cytotoxic activity of Eugenia species. We conducted a systematic literature search of specialized databases (Web of Science, Scielo, Lilacs, Pubmed, Science Direct, Scopus) and selected articles published between 1973 and 2015 using Eugenia and antimicrobial activity, Eugenia and toxicity, and Eugenia and chemical composition as key words. Ninety-three studies were included, and the phytochemical analyses from these studies show that Eugenia species are a rich source of flavonoids, tannins, triterpenes, and sesquiterpenes. Chemical constituents play an apparent role in the antimicrobial effects and reinforce the known antimicrobial potential of the Eugenia genus. It is worth mentioning that some Eugenia species cause significant cytotoxicity.

Analgesic, Anti-Inflammatory, and Antioxidant Activities of Byrsonima duckeana W. R. Anderson (Malpighiaceae).

Background. Byrsonima is a promising neotropical genus, rich in flavonoids and triterpenes, with several proven pharmacological properties. Nevertheless, Byrsonima duckeana W. R. Anderson is an Amazonian species almost not studied. Objective. To assess the antioxidant, anti-inflammatory, and analgesic activities of Byrsonima duckeana leaves. Materials and Methods. We analyzed an ethanol extract and its fractions for polyphenol content and UHPLC-MS/MS, phosphomolybdenum, DPPH, TBARS antioxidant tests, formalin-induced pain, carrageenan-induced peritonitis, acetic acid-induced abdominal writhings, and hot plate assays. Results. All the samples showed high polyphenol content and antioxidant capacity in the phosphomolybdenum, DPPH, and TBARS tests. We identified ethyl gallate, quinic acid, gallic acid, catechin, epicatechin, quercetrin, and quercetin in the samples. B. duckeana was able to reduce leukocyte migration in the carrageenan-induced peritonitis by 43% and the licking time in the formalin test by 57%. In the acetic acid-induced writhing test, the chloroform (FCL) and ethyl acetate (FEA) fractions were the most active samples. FEA was selected for the hot plate test, where all the dosages tested (5, 50, and 200 mg·kg-1) showed significant analgesic activity. Conclusion. B. duckeana has interesting analgesic and antioxidant activities, due to its high phenolic content, especially phenolic acids.

Guettarda uruguensis (Rubiaceae): antioxidant and anti-inflammatory plant with quercetin and esters of p-coumaric acid.

Guettarda (Rubiaceae) is a genus known for its diverse range of bioactive compounds, with demonstrated anti-inflammatory and antioxidant properties. Guettarda uruguensis Cham. & Schltdl., commonly known as 'jasmim uruguaio' or 'veludinho,' is a native species of the Atlantic Forest that get interested in its potential therapeutic applications. In this study, we evaluated the phenolic content and antioxidant activity of the crude ethanol extract obtained from G. uruguensis leaves (EBGF) and fractions, as well as the antinociceptive, anti-inflammatory, and toxicity activity of the EBGF. Our findings revealed that the EBGF and its fractions contain polyphenolic compounds, including long-chain esters of p-coumaric acid and quercetin, which contribute to their potent antioxidant activity. The EBGF exhibited significant anti-inflammatory and antinociceptive effects, highlighting its potential as a natural product for treating pain and inflammation. Our study supports G. uruguensis as a promising source of bioactive compounds with pharmacological potential.

Morphoanatomical study of the species Zanthoxylum kleinii (R.S. Cowan) P.G. Waterman (Rutaceae).

The order Sapindales is comprised of nine families and in Brazil it is represented by six, including Rutaceae Juss., which constitutes the largest group of this order. A variety of species of Zanthoxylum L. are distributed throughout the country, and among them is the species Zanthoxylum kleinii (R.S. Cowan) P.G. Waterman, which is found in the states of Brazil. This study aimed to characterize the morphoanatomy of the leaf, petiole, rachis, and stem of the species Z. kleinii. Histochemical tests were performed, and the sections were visualized under optical and scanning electron microscopy. The analysis showed that the morphoanatomical characteristics of the species are: hypoestomatic leaflets; stomata classified as anomocytic, tetracytic, and anisocytic; dorsiventral mesophyll; cavities that produce a secretion of lipid nature, present in the leaflet, rachis, and petiole; colleters distributed in the leaf; presence of simple non-glandular trichomes in all structures; and prismatic crystals in the petiole. Histochemical tests indicated the presence of phenolic and lipophilic compounds, mucilage, and lignin. With the result of this research, it was possible to identify the nature of the compounds secreted by the secretory structures of the leaves; in addition, the morphoanatomical characterization of Z. kleinii can provide relevant data for future studies for other organs of the species not yet described. Furthermore, contributing concomitantly with data for the genus, in this way, supporting to differentiate them. RESEARCH HIGHLIGHTS: Ultrastructural features observed by microscopic techniques. Calcium oxalate crystals present in the rachis. Microchemical tests confirmed the presence of colleters in the leaflet.

Cytotoxic and Phytotoxic Activities of Native Brazilian Forest Gabiroba (Campomanesia xanthocarpa Berg.), Fruits, and Flour against Shrimp (Artemia salina L.) and Lettuce (Lactuca sativa L.).

Gabiroba, a native fruit in Brazil's Atlantic Forest region, has significant nutritional and therapeutic properties. However, due to its seasonality, consumption by the population is limited. Thus, the development of gabiroba byproducts would add significant value to the food and therapeutic industries. Therefore, it is essential to study and support the lack of toxicity of gabiroba fruit extracts. In the present study, physicochemical analyses of fresh fruits (GF) and dehydrated whole gabiroba flour (WGF) and preliminary toxicity analyses of WGF were performed. The toxicity results showed a microcrustacean LC50 of >1000 mg/mL when exposed to WGF extracts at various concentrations (10-1000 µg/mL; p = 0.062) using the Artemia salina method, with no evidence observed of proliferative activity or toxic metabolic compounds in the WGF extract. The phytotoxicity of WGF using Lactuca sativa L. allowed germination and root growth at various concentrations of WGF extract, with the lowest (100 µg/mL) and highest (1000 µg/mL) concentrations exhibiting 98.3% and 100% seed germination, respectively. In conclusion, these results indicate that the WGF preparation preserved the nutritional and antioxidant potential of gabiroba fruits and that WGF is safe for use as a raw material in the food industry and for therapeutic purposes.

Antinociceptive effects of a chloroform extract and the alkaloid dicentrine isolated from fruits of Ocotea puberula.

The present work describes the chemical characterization of a chloroform fraction (CF) obtained from an extract of Ocotea puberula (Lauraceae) fruits, and preliminary antinociceptive analysis of CF and the alkaloid dicentrine, isolated from this fraction. CF (30-300 mg/kg, p. o.) caused dose-related inhibition of abdominal constrictions caused by acetic acid and also inhibited both phases of formalin-induced nociception. However, hexane or ethyl acetate fractions did not produce any effect. Antinociception caused by CF (100 mg/kg, p. o.) in the acetic acid test was not affected either by caffeine, an adenosine receptor antagonist, or by naloxone, an opioid receptor antagonist, and neither was associated with nonspecific effects such as muscle relaxation or sedation. Furthermore, dicentrine (30-300 mg/kg, p. o.) produced dose-related inhibition of acetic acid-induced pain without causing changes in the motor performance of mice. The results show, for the first time, that CF from Ocotea puberula fruits produced marked antinociception in different models of chemical pain, and this effect appears to be, at least in part, due to the presence of dicentrine. The mechanism by which CF and the alkaloid produced antinociception still remains unclear, but the adenosinergic or opioid system seems unlikely to be involved in this action.

Microscopic investigations of Ocotea paranaensis-A Brazilian endemic and endangered species.

This article describes the morpho-anatomies of the leaves and stems of Ocotea paranaensis Brotto, Baitello, Cervi & Santos (Lauraceae) using light and scanning electron microscopy. The main anatomical features characterizing the species are the presence of simple non-glandular trichomes in the leaves and stems, large secretory cells in the leaves, flat-convex petioles with two small lateral ribs, brachysclereids in the stem cortex and pith, and the presence of starch grains and various types of calcium oxalate crystals in the pith. Histochemical tests indicated the presence of lignin in stone cells, fibers, and xylem. Lipophilic contents were found in the secretory cells. Phenolic compounds were detected in the epidermis, hypodermis, phloem, and xylem. The present study's findings can contribute to the taxonomy and authentication of O. paranaensis. RESEARCH HIGHLIGHTS: This article is the first morpho-anatomical study of Ocotea paranaensis. Anatomy and histochemistry of the leaves and stems were studied by light microscopy, FESEM and EDS. The findings of this study would aid in the species identification and taxonomy.

Ocotea nutans (Nees) Mez: structural elucidation of C-hetorosides flavonoids and evaluation of their antioxidant and antibacterial properties from ethyl acetate extract.

The Ocotea genus exhibits a variety of pharmacological, antibacterial and antioxidant effects. The aim of the present study was to evaluate the antioxidant potential and antibacterial properties of the ethyl acetate fraction of Ocotea nutans leaves. Isolation and identification of the phenolic compounds from the fraction was also carried out. The isolated compounds were characterised by one- and two-dimensional nuclear magnetic resonance analysis and identified as vitexin (1) and isovitexin (2). The ethyl acetate fraction of Ocotea nutans leaves demonstrated considerable antioxidant potential. The observed minimum inhibitory concentration of 250 µg.mL-1 was classified as a moderate antibacterial activity against Enterococcus faecalis. Findings from this study demonstrate the utility of this plant as a potential source of antioxidant and antibacterial agents.

Characterization and identification of chemical constituents of Ocotea paranaensis Brotto, Baitello, Cervi, & E.P. Santos and their biological properties.

The growing interest in the discovery of new compounds from medicinal plants justifies the study of phytochemical components of these plants and their biological activities. The genus Ocotea exhibits a variety of pharmacological, antimicrobial and antioxidant effects. The aim of the present study was to evaluate the antioxidant potential and antimicrobial properties of the ethyl acetate fraction of Ocotea paranaensis leaves. Isolation and identification of the phenolic compounds from the fraction was also carried out. The isolated compounds were characterized by one and two-dimensional nuclear magnetic resonance analysis and identified as (-) epicatechin (1), quercetin (2), kaempferol (3) and hyperin (4). The ethyl acetate fraction of Ocotea paranaensis leaves demonstrated considerable antioxidant potential. The observed minimum inhibitory concentration of 500 µg/mL was classified as a moderate antibacterial activity against Staphylococcus aureus. Findings from this study demonstrate the utility of this plant as a potential source of antioxidant and antimicrobial agents.

Preliminary evaluation of the larvicidal activity of extracts and fractions from Ocotea nutans (Nees) Mez against Aedes aegypti.

INTRODUCTION: Aedes aegypti is the main vector of dengue and yellow fever. Recently, the use of plant-sourced larvicides has gained momentum. METHODS: The hydroethanolic extracts and fractions ofOcotea nutansleaves and stems were bioassayed to determine the larvicidal efficacy of these samples. RESULTS: S-HEX (hexane fraction from the crude stem extract) demonstrated high potential for controlling third-stage larvae, with an LC50 of 14.14 µg.mL-1 (concentration required to inhibit 50% of the treated larvae). CONCLUSIONS: Extracts from O. nutans were effective against third-stage larvae ofA. aegyptiafter 24 h of exposure.

Myrcia hatschbachii: antifungal activity and structural elucidation of ellagic and 3-O-methyl ellagic acids.

Natural products, especially plants, have been investigated as sources of new substances with antimicrobial properties. In this context, the Myrcia genus is extensively researched for presenting such activities. This work aims to evaluate the antifungal, antibacterial, and antioxidant properties of extracts and fractions of stems of Myrcia hatschbachii, also to characterize two phenolic compounds. The antibacterial and antifungal activities were assessed by using the broth microdilution method. The ethyl acetate fraction (FGA) inhibited the growth of Candida albicans at a Minimum Inhibitory Concentration (MIC) of 15.6 µg/mL, presented 40% of phenolic compounds in its composition, obtained the most significant results in antioxidant methods (DPPH, FRAP, ABTS), besides the identification of ellagic and 3-O-methyl ellagic acids by NMR. Considering the relevant antifungal activity revealed by the fraction, new studies can be carried out to encourage the continuous search for antifungal alternatives.

Chemical composition of the volatile oil of Croton glandulosus Linnaeus and its allelopathic activity.

Several essential oils have allelochemicals with phytotoxic effects. Croton species are producers of secondary metabolites with biological potential. In the present study, chemical composition of the essential oil extracted from aerial parts of Croton glandulosus Linnaeus was evaluated by gas chromatography and the phytotoxicity of the oil on Lactuca sativa seeds was evaluated for the first time. The yield of the essential oil was 0.12% (v/w). Chromatographic analysis allowed the identification of 97.49% of the total compounds present in the oil. Sesquiterpenes were found to be the predominant constituents of the volatile oil, with ß-caryophyllene (53.24%) being the major compound. Treatment with 0.1%-1% (v/v) of the essential oil inhibited the development of the hypocotyl and radicle of L. sativa to a greater extent compared to the inhibition of seed germination, demonstrating the phytotoxic effect of the oil.

Optimisation of Bjerkandera adusta culture conditions for the production of α-α-trehalose.

Several factors affect the vegetative growth of fungi, such as temperature, pH, and culture medium. In addition to mycelial growth, these factors affect metabolite production. There are limited studies that have identified the metabolites produced by the fungus Bjerkandera adusta, which have potential biotechnological applications. Here, we evaluated the effects of temperature, culture medium, and incubation time on the production of mycelial mass and metabolites of B. adusta isolated from Pinus taeda. The highest mycelial mass was obtained at 24 °C, in the potato dextrose and malt extract media, upon incubation for 28 and 35 days. The disaccharide α-α-trehalose was for the first time isolated and identified by X-ray diffraction in this fungal genus.

Anti-Helicobacter pylori activity of plant extracts traditionally used for the treatment of gastrointestinal disorders.

The antibacterial activity of plant extracts obtained from Bixa orellana L., Chamomilla recutita L., Ilex paraguariensis A. St.-Hil., Malva sylvestris L., Plantago major L. and Rheum rhaponticum L. has been evaluated against two reference strains and eleven clinical isolates of Helicobacter pylori. All the plant species chosen are used in popular Brazilian cuisine and folk medicine in the treatment of gastrointestinal disorders. Initial screening was made by the disk diffusion test and then minimum inhibitory concentration was determined by the agar dilution method. The results presented in this work demonstrated that among the plant preparations analyzed, B. orellana L., C. recutita L., I. paraguariensis A. St.-Hil. and M. sylvestris L. were capable of inhibiting the in vitro growth of H. pylori.

Development of W1/O/W2 emulsion with gallic acid in the internal aqueous phase.

The aim of this work is to develop a W1/O/W2 multiple emulsion with gallic acid in the internal aqueous phase (W1). A quantification method for gallic acid using HPLC-UV was developed and validated. In the first step, a simple W1/O emulsion was prepared with distilled water, polyglycerol polyricinoleate, sodium chloride, gallic acid and pH 5.0 sodium acetate buffer system. The second step consisted of adding the simple emulsion to the external aqueous phase (W2) composed of distilled water, polysorbate 80 and xanthan gum. The multiple emulsion showed pseudoplastic behavior. After 28 days of analysis the multiple emulsion presented a stability index of 75% without pH variation, 89.61% of gallic acid concentration, 59.62% of antioxidant activity in the phosphomolybdenum complex assay and 80.58% of DPPH scavenging activity. It is concluded that the W1/O/W2 emulsion developed was stable for 28 days and maintained more than 50% of gallic acid antioxidant capacity.

Genotoxicity of Achillea millefolium essential oil in diploid cells of Aspergillus nidulans.

The essential oil of Achillea millefolium is commonly used in folk medicine for the treatment of several diseases and has been demonstrated previously to exert an in vitro antimicrobial activity against human pathogens. Current study investigates the genotoxic activity of A. millefolium oil. The oil's major constituents are: chamazulene (42.15%), sabinene (19.72%), terpin-4-ol (5.22%), beta-caryophyllene (4.44%) and eucalyptol (3.10%), comprising 74.63% of the total. The oil's genotoxic evaluation was performed at concentrations of 0.13 microL/mL, 0.19 microL/mL and 0.25 microL/mL with a heterozygous diploid strain of Aspergillus nidulans, named A757//UT448, with green conidia. A statistically significant increasing number of yellow and white mitotic recombinants, per colony, of the diploid strain was reported after oil treatment with 0.19 microL/mL and 0.25 microL/mL concentrations. The genotoxicity of the oil was associated with the induction of mitotic non-disjunction or crossing-over by oil.