BACKGROUND AND OBJECTIVE: Ribes khorassanicum has beneficial cardiovascular effects in normotensive and hypertensive animals. For further investigation, the effect of three fractions of aqueous (polar), ethyl acetate (polar and non-polar) and n-hexane (non-polar) of the plant s hydroalcoholic extract on cardiovascular parameters in normotensive rats was compared with its total extract. METHODS: In this experimental study, 42 rats were divided into 7 groups (6 in each group): control, three

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... of total extract 4, 12 and 24 mg/kg and three fractions of aqueous, ethyl acetate and n-hexane (20 mg/kg). Femoral artery cannulation and heart rate (HR), mean arterial pressure (MAP) and systolic blood pressure (SBP) were recorded throughout the experiment and then the changes (Δ: difference before and after injection) were calculated and statistically analyzed. FINDINGS: 24 mg/kg of the extract significantly increased ΔHR (117.5±11.6 beats per minute) compared to control (5.3±2.7, p<0.001) and 12 mg/kg of the extract significantly decreased ΔMAP (-15.1±2.8 mm Hg) and ΔSBP (-18.4±3 mm Hg) compared to the control (p<0.05). The fractions increased ΔHR, which was not significant but was significant compared to 24 mg/kg of the extract (p<0.05). Furthermore, the increase of ΔMAP and ΔSBP in n-hexane fraction (19.45±3.1 mm Hg and 34.6±11.5 mm Hg, respectively) was significant compared to the control and 12 mg/kg of the extract (p<0.01 to p<0.05). CONCLUSION: The active ingredients in the cardiovascular effects of Ribes khorassanicum extract are spread in all fractions and the total extract has a better effect than each of the fractions alone due to its various non-polar and polar compounds as well as the synergistic effect.