Secondary metabolite contents and safety assessment study of the aqueous extract from the Algerian Echium trygorrhizum Pomel roots

Abstract

Ethnopharmacological relevance: Species of Echium trygorrhizum Pomel, belonging to the Boraginaceae family, grow wild in North Africa. This plant is used in traditional Algerian medicine for the treatment of Diabetes, Jaundice and Tonsillitis.

Aim of the study: To our knowledge, no work has been done on the phytochemistry and biological activities of this plant. Moreover, no study has yet corroborated that the use of this plant is safe. Therefore, the present study was carried out to gather information on the various medicinal uses of this plant and to evaluate the total phenolic content and assess its safety after acute and sub-acute toxicity tests with rodents (mice and rats).

Material and methods: An ethnopharmacological survey was carried out using a direct questionnaire. It included some questions relating to the plant. The content of polyphénols, flavonoids and tannins present in the aqueous extract was determined by colorimetric methods. In the acute toxicity tests, three groups each containing five males and five females Albino mice were formed. The control group received water, while the test groups received different doses of aqueous extract (2000 and 5000) mg/kg body weight. In the subacute toxicity study, different doses (250, 500 and 1000 mg/kg) of the aqueous extract were administered to male and female rats for 28 consecutive days. Hematological analysis, biochemical parameters estimation and histopathological examination have been determined at the end of the treatment.

Results: Data from the ethnopharmacological survey showed that 25, 31% of people used this plant in Algeria as a traditional medicine for the treatment of Jaundice (100%), Diabetes (28, 33%) and Tonsillitis (10%). Results also revealed that aqueous extract contains high amounts of polyphenols, flavonoids and tannins. The extract did not cause any toxicity during the 14-days observation period after a single dose of 5000 mg/kg was administered to mice, with LD50 values greater than 5000 mg/kg. In a further step, the administration of the aqueous extract at all dose levels (250, 500, and 1000 mg/kg) to male and female rats during the 28-days study did not result in any deaths or behavioral changes, and there were no changes in body weight, relative organ weights, or food consumption as a result of this experiment. However, male rats showed a significant difference in relative liver weight in the high dose group (1000 mg/kg) (p < 0.05) and the satellite group (p < 0.01). In female rats, liver weight significantly increased only in the satellite group compared with the control group (p < 0.01). The results showed an increase in red blood cells (RBC), hemoglobin (Hb), and hematocrit (Hct) in the female groups. However, a clear decrease was observed in plasma ALP enzyme activities in females treated with the doses of 250 and 1000 mg/kg (p < 0.05) after the treatment periods.

Conclusion: The study indicated that the single dose of 5 g/kg AQE can be considered relatively safe as it did not cause death or any signs of toxicity in mice. Repeated oral administration of AQE at doses below 250 g/kg/day for 28 consecutive days can be considered relatively safe.

Keywords: Acute toxicity; Condensed tannins; Echium trygorrhizum; Flavonoid; Phenolic; Sub-acute toxicity.