Objectives: 

Borago officinalis(Bo.)is a plant food also traditionally employed as antispasmodic,vasodilator and cardio-depressant.The aim of the study was to evaluate the effect of Bo.crude extracts on isolated intestine and aorta rat rings.

Materials: 

A solvent-free extract obtained from Bo.was tested on smooth muscle of different tissues.The extraction was carried out with a Soxhlet using ethanol as solvent.Pieces of male rats aorta,duodenum and colon were cut into segments,suspended in an organ bath.Each segment was connected to an isometric transducer and mechanical activities were analyzed using the MacLab Systems.Extracts were added to organ bath to study i)the effects on the contractions induced by norepinephrine in aorta, ii)on spontaneous contractions of duodenum and colon,and on the contractions induced by KCl.Antioxidant activity(Aa)was evaluated using the DPPH assay combined with thin layer chromatography and results were compared with ascorbic acid and ginseng extract.Mean differences were determined using a paired t-test,with a level of significance p<0.05.

Results: 

Bo.induced relaxant responses in all tissues.In aorta,the extract relaxed the contractions induced by norepinephrine approximately 22%.The extract reduced spontaneous contractions 18% and 13%, and the contractions induced by KCl 77% and 60% in longitudinal muscle of duodenum and circular muscle of colon respectively.The relaxant responses of Bo.were compared to papaverine or Ca2+ free Krebs.Bo.extract showed Aa(IC50=102mg/mL)although this effect was lower than ascorbic acid(IC50=8mg/mL)and much higher than ginseng extract.Phenolic compounds were detected by thin layer chromatography.

Conclusions: 

The results show a relaxant and antioxidant effect of Bo.and presence of phenolic compounds.Both effects can be mediated by polyphenols,which has been previously demonstrated as antioxidants and Ca2+ channels modulators.All these results might explain the traditional use of the plant in hyperactive gastrointestinal and cardiovascular disorders.