Evaluation of the in vitro and in vivo antioxidant potential of Punica granatum L. against toluene-induced liver injuries in rats.

Background and Aim: Humans are more frequently exposed to chemicals in daily life by inhalation of indoor and outdoor air. However, abusers and workers are the most exposed to those chemicals and their health risks particularly, liver diseases. The present study investigated the protective effects of pomegranate juice (PJ) (Punica granatum) and pomegranate peel aqueous extract (PAE) supplementation against toluene (Tol)-induced hepatotoxicity in Wistar rats. Materials and Methods: A phytochemical analysis and assessment of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity were performed for the PJ and the PAE. The in vivo study was carried out using 70 Wistar rats that were divided into seven groups, each consisting of 10 rats. All groups were treated orally for 6 weeks as follows: Control (C), positive controls (CO: 1.25 mL/kg body weight [BW]; PJ: 4 mL/kg BW; and PAE: 400 mg/kg BW), Tol (550 mg/kg BW), and a mixture each of PJ-Tol and PAE-Tol. At the end of the 45th day of study, the hepatic biochemical markers (transaminases, alkaline phosphatase, total bilirubin, albumin, and total proteins) were auto-analyzed, as well as histology and oxidative stress markers of the liver were evaluated. Results: The phytochemical analysis revealed that the DPPH scavenging activity and the total phenolic, flavonoid, and tannin contents were higher in the pomegranate peel extract versus the juice. The results also showed that Tol significantly increased liver enzyme activities and total bilirubin levels, whereas albumin and total proteins were significantly decreased. Similarly, Tol provoked a significant increase in hepatic malondialdehyde levels, with a decrease in glutathione content and glutathione peroxidase activity. The biochemical changes agreed with the hepatic histological alterations. A significant improvement in all parameters was observed in the PAE-Tol group compared with the PJ-Tol group. Conclusion: Exposure to Tol altered the hepatic antioxidant and biochemical parameters and histological profile of the rats, and PAE was more powerful than PJ in reducing Tol liver injuries through its antioxidant activity.

Phytochemical Screening, In vitro Antioxidant and Enzyme Inhibitory Properties, and Acute Toxicity of Extracts from the Aerial Parts of Ephedra nebrodensis, a Source of Bioactive Compounds.

BACKGROUND: Due to the strong association between the chemistry of medicinal plants and their biological properties, it is important to determine their phytochemical composition to justify experimental tests. OBJECTIVE: The aim of this study was to evaluate the in vitro antioxidant and the enzyme inhibitory properties and to identify the bioactive compounds present in the extracts of Ephedra nebrodensis growing in Algeria. METHODS: Total phenolic and flavonoids content in these extracts were quantified by Folin- Ciocalteu and aluminum chloride methods. The antioxidant capacity was assessed using DPPH, ABTS, ß-carotene/linoleic acid, CUPRAC and FRAP assays, and in vitro cholinesterase activity against acetylcholinesterase and butyrylcholinesterase were evaluated. The chemical constituents of the extracts were analyzed by high-performance liquid chromatography coupled with mass spectrometric detection and gas chromatography. For the acute toxicity study, extracts were administered to mice at single dose of 2 g/kg and 5 g/kg by gavage. RESULTS: Plant extracts were rich in phenolic compounds. Ethyl acetate extract presented the highest phenolic (238.44 ± 1.50 µg GAE /mg of extract) and flavonoid (21.12 ± 0.00 µg QE /mg of extract) contents. Likewise, ethyl acetate extract showed potent radical scavenging and reducing properties. Ethanol-acetone extract showed inhibitory activity against acetylcholinesterase, and was a potent inhibitor of butyrylcholinesterase. In all extracts, flavonoids were the most abundant compounds. The phytochemical investigation showed the presence of alkaloids (ephedrine and pseudo-ephedrine). In the acute toxicity, the LD50 was superior to 5 g/kg body weight. There were no alterations in the histology of the liver and kidneys. CONCLUSION: This study demonstrated a good antioxidant potential and anticholinesterase activity of aerial parts of E. nebrodensis.

Antioxidant, Anti-inflammatory, and Analgesic Activities of Alcoholic Extracts of Ephedra nebrodensis From Eastern Algeria

Objectives: Ephedra nebrodensis (Ephedraceae) presents a wide range of biological activities. It is used to treat respiratory problems and hepatic pathologies in traditional medicine. The aim of this study is to evaluate the antioxidant, in vitro and in vivo anti-inflammatory and analgesic properties of two hydro-alcoholic extracts of E. nebrodensis in mice. Materials and Methods: The antioxidant capacity of hydro-methanolic (HM) and hydro-ethanolic (HE) extracts of E. nebrodensis was evaluated via assays of their superoxide radical scavenging capacity and ferrous ion chelating activity. The in vitro anti-inflammatory activity of the extracts (5, 10, and 20 mg/kg) was also determined using the bovine serum albumin denaturation test. Croton oil-induced ear edema was then employed to evaluate the in vivo anti-inflammatory effect of the extracts (200 and 400 mg/kg). Finally, the analgesic activity of the extracts (200 and 400 mg/kg) was determined by the acetic acid-induced torsion test. Results: The hydro-alcoholic extracts of E. nebrodensis present significant antioxidant activity. The HE and HM could inhibit protein denaturation by 82.99%±20.21% and 56.25%±2.12%, respectively. The extracts (HM and HE) also show strong anti-inflammatory effects in vivo and could reduce ear edema by 70.37%±2.00% and 72.22%±1.94%, respectively. The HM extract (72.51%±2.43%) demonstrates greater pain inhibitory effects than HE (70.76%±2.58%). Conclusion: The hydro-alcoholic extracts of E. nebrodensis produce antioxidant, anti-inflammatory, and analgesic effects. These results confirm the traditional use of the herb in the treatment of various diseases.

In-vivo anti-inflammatory activity and safety assessment of the aqueous extract of Algerian Erica arborea L. (Ericaceae) aerial parts.

ETHNOPHARMACOLOGICAL RELEVANCE: Erica arborea known as Khlenj in Algeria is a small shrub belonging to Ericaceae family. E. arborea Aqueous extract (EAAE) is used in traditional medicine for anti-inflammatory, diuretic, antimicrobial, and antiulcer purposes. AIM OF THE STUDY: To our knowledge, no data reveal the combination between in-vivo anti-inflammatory and toxicological studies of EAAE. For this purpose, the aim of this study is to evaluate the biological activity cited above and assess its safety. MATERIAL AND METHODS: Anti-inflammatory activity was undergone using carrageenan-induced paw edema and croton oil-induced ear edema. The acute and sub-acute toxicity were conducted following the OECD guidelines 423 and 407, respectively. Phytochemical identification was carried out using HPLC-DAD-MS. Quantitative evaluation of polyphenols; flavonoids and antioxidant activity of EAAE were also determined. RESULTS: Oral administration of EAAE (250 and 500 mg/kg) significantly (p < 0.05) reduced the edema induced by carrageenan. Administration of EAAE dosed at 250 and 500 mg/kg exhibited efficacy in reducing edema induced by croton oil. The acute administration of EAAE at doses of 2000 and 5000 mg/kg did not cause any mortality or adverse effects indicating that the LD50 is above 5000 mg/kg. The prolonged administration of EAAE (500 and 1000 mg/kg) showed a significant reduction in triglycerides levels in male and female rats whereas no significant changes in other biochemical and hematological parameters were observed. Histopathological damages were recorded in both liver and kidney animal's tissues of both sexes treated with medium and maximum doses of EAAE. Phytochemical characterization of EAAE revealed a high amount of phenolic compounds, HPLC-DAD-MS analysis led to the identification of chlorogenic acid and five flavonol glycosides: myricetin pentoside, quercetin-3-O-glucoside, myricetin-3-O-rhamnoside, quercetin-3-O-pentoside, and quercetin-3-O-rhamnoside. CONCLUSION: In the light of the results obtained in this study, EAAE corroborates the popular use to treat the anti-inflammatory impairments. EAAE can be considered as non-toxic in acute administration and exhibited a moderate toxicity in sub-acute administration. High phenolic content and in-vitro antioxidant activity observed indicate that EAAE may reduce oxidative stress markers in-vivo.

Buffering deleterious polymorphisms in highly constrained parts of HIV-1 envelope by flexible regions.

BACKGROUND: Covariation is an essential process that leads to coevolution of parts of proteins and genomes. In organisms subject to strong selective pressure, coevolution is central to keep the balance between the opposite requirements of antigenic variation and retention of functionality. Being the viral component most exposed to the external environment, the HIV-1 glycoprotein gp120 constitutes the main target of the immune response. Accordingly its more external portions are characterised by extensive sequence heterogeneity fostering constant antigenic variation. RESULTS: We report that a single polymorphism, present at the level of the viral population in the conserved internal region C2, was sufficient to totally abolish Env functionality when introduced in an exogenous genetic context. The prominent defect of the non-functional protein is a block occurring after recognition of the co-receptor CCR5, likely due to an interference with the subsequent conformational changes that lead to membrane fusion. We also report that the presence of compensatory polymorphisms at the level of the external and hypervariable region V3 fully restored the functionality of the protein. The functional revertant presents different antigenic profiles and sensitivity to the entry inhibitor TAK 779. CONCLUSIONS: Our data suggest that variable regions, besides harbouring intrinsic extensive antigenic diversity, can also contribute to sequence diversification in more structurally constrained parts of the gp120 by buffering the deleterious effect of polymorphisms, further increasing the genetic flexibility of the protein and the antigenic repertoire of the viral population.

Genetic diversity of the highly variable V1 region interferes with Human Immunodeficiency Virus type 1 envelope functionality.

BACKGROUND: The HIV envelope (Env) promotes viral entry in the host cell. During this process, Env undergoes several conformational changes to ensure its function. At the same time, the gp120 component of Env is the protein of the virus presenting the largest genetic diversity. Understanding how the virus maintains the balance between the competing requirements for maintenance of functionality and antigenic variation of this protein is central for the comprehension of its strategies of evolution and can highlight vulnerable aspects of its replication cycle. We focused on the variable domains V1 and V2 of the HIV-1 gp120 that are involved in conformational changes and are critical for viral escape from antibody neutralization. RESULTS: Despite the extensive sequence diversity found in the epidemic for these regions and their location on the external face of the protein, we observed that replacing V1V2 of one primary isolate with that of another severely interferes with Env functionality in more than half of the cases studied. Similar results were obtained for intra- and intersubtype chimeras. These observations are indicative of an interference of genetic diversity in these regions with Env functionality. Therefore, despite the extensive sequence diversity that characterizes these regions in the epidemic, our results show that functional constraints seem to limit their genetic variation. Defects in the V1V2 chimeras were not relieved by the insertion of the V3 region from the same isolate, suggesting that the decrease in functionality is not due to perturbation of potential coevolution networks between V1V2 and V3. Within the V1V2 domain, the sequence of the hypervariable loop of the V1 domain seems to be crucial for the functionality of the protein. CONCLUSIONS: Besides the well-documented role of V1V2 in the interplay with the immune response, this work shows that V1 is also involved in the selection of functional envelopes. By documenting a compromise between the opposing forces of sequence diversification and retention of functionality, these observations improve our understanding of the evolutionary trajectories of the HIV-1 envelope gene.

Molecular mechanisms of recombination restriction in the envelope gene of the human immunodeficiency virus.

The ability of pathogens to escape the host's immune response is crucial for the establishment of persistent infections and can influence virulence. Recombination has been observed to contribute to this process by generating novel genetic variants. Although distinctive recombination patterns have been described in many viral pathogens, little is known about the influence of biases in the recombination process itself relative to selective forces acting on newly formed recombinants. Understanding these influences is important for determining how recombination contributes to pathogen genome and proteome evolution. Most previous research on recombination-driven protein evolution has focused on relatively simple proteins, usually in the context of directed evolution experiments. Here, we study recombination in the envelope gene of HIV-1 between primary isolates belonging to subtypes that recombine naturally in the HIV/AIDS pandemic. By characterizing the early steps in the generation of recombinants, we provide novel insights into the evolutionary forces that shape recombination patterns within viral populations. Specifically, we show that the combined effects of mechanistic processes that determine the locations of recombination breakpoints across the HIV-1 envelope gene, and purifying selection acting against dysfunctional recombinants, can explain almost the entire distribution of breakpoints found within this gene in nature. These constraints account for the surprising paucity of recombination breakpoints found in infected individuals within this highly variable gene. Thus, the apparent randomness of HIV evolution via recombination may in fact be relatively more predictable than anticipated. In addition, the dominance of purifying selection in localized areas of the HIV genome defines regions where functional constraints on recombinants appear particularly strong, pointing to vulnerable aspects of HIV biology.