Antioxidant, anti-inflammatory and antiulcerogenic activities of Anabasis articulata (Forssk.) Moq. extracts

Abstract

Using a variety of in-vitro, in-silico and in vivo models, the aim of the present study was to investigate the antioxidant, anti-inflammatory, analgesic and anti-ulcerogenic activities of several extracts of Anabasis articulata, a plant from the Algerian flora of arid and semi-arid regions belonging to the Chenopodiaceae family selected on the basis of an ethnobotanical survey (n=182 respondents) conducted at the El-Mergueb nature reserve. Identification of biomolecules, quantification of secondary metabolites and performance of eight tests to study the antioxidant activity of the extracts: Total antioxidant capacity (TAC), DPPH - 2,2-diphenyl-1picrylhydrazyl; ABTS - 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid, hydroxyl radical scavenging, metal-chelating hydrogen peroxide scavenging, reducing power test and β-carotene bleaching assay. In vitro anti-inflammatory activity was attested using the ovalbumin denaturation and BSA assay for DEAA, EEAA and their fractions. Molecular docking was performed using Autodock vina. Single oral doses of 2000 and 5000 mg/kg body weight were administered to albino mice to assess acute toxicity. The anti-inflammatory effect was assessed using the carrageenan-induced paw edema model in rats, the croton oil-induced ear edema model and the xylene-induced ear edema model in mice. Analgesic activity was achieved by intraperitoneal injection of acetic acid. Gastroprotective activity was assessed using ethanol-induced gastric ulceration in rats at doses of 50, 100 and 200 mg/kg p.o. for DEAA and 200, 400 and 600 mg/kg p.o. for EEAA. The mechanistic study involved pretreatment with appropriate antagonists/inhibitors such as glibenclamide, indomethacin and L-NAME. 46 plant species belonging to 23 botanical families were identified for the treatment of various ailments. Seven metabolites present in the n-butanol, ethyl acetate and chloroform fractions were qualitatively identified by LC-MS-MS: anthrone, beta-carotene, butylhydroxyanisole, butylhydroxytoluene, gallic acid, myricetin and rutin. The results showed that ChFA represents the largest quantity of total polyphenols and flavonoids. The n-butanol fraction showed the highest amount of total tannins. Quantitative evaluation of DPPH scavenging capacity showed that the ethanolic extract was the most active with IC50 values of 0.074±0.003 mg/mL, the chloroform fraction (ChFA) had the strongest effect in TAC, hydroxyl radical scavenging and hydrogen peroxide scavenging activity with EC50= 0.151±0.0017, IC50= 0.361±0.0087 and IC50= 1.777±0.0402 mg/mL), however, the nbutanol fraction had the highest activity in the ABTS radical scavenging test with an IC50 of 0.021±0.0007 mg/mL. All extracts showed good inhibition of linoleic acid oxidation. Good in vitro anti-inflammatory activity was attested using the ovalbumin denaturation and BSA assays for DEAA, EEAA and their fractions. Molecular docking of the identified biomolecules and the reference drug (indomethacin) revealed good interaction with the inflammatory protein COX2 (3LN0). Acute toxicity testing showed that DEAA and EEAA did not cause mortality or adverse effects. Oral administration of 100 or 200 mg/kg of DEAA and EEAA to rats and mice inhibited edema in three tests, with good percentages for both doses of both extracts. The analgesic activity result showed a good effect compared with the standard analgesic (aspirin) for the same doses and extracts. Oral administration of DEAA at doses of 100 mg/kg or 200 mg/kg protected the gastric mucosa against absolute ethanol. Pretreatment with L-NAME, an inhibitor of nitric oxide synthesis, indomethacin, an inhibitor of prostaglandin production, or glibenclamide, a KATP channel blocker, reversed the gastroprotective activity of (DEAA200 mg/kg, p.o.). DEAA effectively reduced basal gastric juice production without any effect on total acidity. The gastroprotective action of DEAA involved an increase in antioxidant enzymes and mucus secretion. This study provides for the first time the scientific basis for the traditional use of this plant for gastro-preventive effect and supports the traditional use of this plant to treat certain disorders linked to inflammation and oxidative stress. These results can be exploited in the pharmaceutical, food and cosmetics industries.