Ethnomedicinal documentation and anti-inflammatory effects of n-butanol extract and of four compounds isolated from the stems of Pituranthos scoparius: An in vitro and in vivo investigation

Abstract

Ethnopharmacological relevancePituranthos scoparius is a medicinal plant belonging to the Apiaceae family. It thrives in North Africa, and is widely distributed in the high plateau of most parts of the Sahara in Algeria. This plant is widely used in the Algerian traditional medicine to treat numerous infectious diseases, dermatoses, nervous breakdowns, digestive disorders, and calm abdominal pain. Aim of the studyThe aim of the present work was to examine the ethnomedicinal uses of Pituranthos scoparius in Setif region, Algeria, isolate and identify the chemical constituents of the n-butanol stem extract of P. scoparius (BEPS), and to determine the toxicity and anti-inflammatory effects of these compounds in addition to the extract. Materials and methodsThe anti-inflammatory effects of BEPS and the four compounds isolated from the extract were evaluated using the in vitro protein denaturation assay, whereas the topical anti-inflammatory activity was assessed using the croton oil-induced ear edema in mice. Toxicity was determined based on assessment of in vitro cytotoxicity using hemolytic activity against human red blood cells (RBCs). ResultsFour compounds, identified as the rare isorhamnetin-3-O-β-apiofuranosyl (1 → 2)-β glucopyranoside (2), in addition to three known compounds, namely isorhamnetin-3-O-β-glucoside (1), D-mannitol (3), and isorhamnetin-3-O-β-glucopyranosyl-(1 → 6)-β-glucopyranoside (4) were isolated from BEPS. These compounds were characterized by means of NMR and high-resolution mass spectral (HRMS) data. These four compounds were isolated for the first time from this traditional Algerian medicinal plant. Screening of the extract indicated the presence of alkaloids, polyphenols, flavonoids, free quinones, coumarins and tannins. Topical anti-inflammatory effect showed that the four isolated compounds, as well as BEPS, exhibit a significant (p < 0.05) dose-dependent (0.5 and 1 mg/ear) anti-inflammatory effect. At a dose of 1 mg/ear, compounds 1, 2, and 4, exhibited remarkable anti-inflammatory effect with a percentage inhibition of 85.50 ± 2.78, 79.78 ± 4.68, and 75.78 ± 2.98%, respectively. Results from in vitro cytotoxicity showed that the % lysis of the extract, along with isolated compounds was found to be virtually nontoxic. ConclusionsThese results suggest that BEPS and isolated compounds are safe, nontoxic, and exert remarkable anti-inflammatory effects, and can be new sources of natural anti-inflammatory agents.