By Mathew Godswill
Scientific evidence suggests that the daily consumption of hibiscus tea, which is commonly known as zobo, in an amount readily incorporated into the diet, can help to lower blood pressure in mild to moderate hypertensive adults.
Now, in a study, experts say taking zobo along with the prescription drug lisinopril, a blood pressure medication, ensures its better effectiveness in blood pressure control.
Experts at the Usmanu Danfodiyo University, Sokoto, and Ahmadu Bello University, Zaria, had studied the effect of zobo, the Hibiscus Sabdariffa (Calyxes) water extract, on the availability of Lisinopril in animals.
The availability of lisinopril alone and in presence of Hibiscus tea was determined at the stomach, intestine and blood pH.
Zobo is commonly taken as a food drink alongside lisinopril, especially in people with hypertension, probably due to its reported antihypertensive effect.
Its tea and the drink has been shown to work as a natural diuretic, pulling salt out of the body which is a mechanism by which blood pressure is reduced.
Angiotensin converting enzyme (ACE) inhibitors such as lisinopril dilate the blood vessels to lower hypertension or treat heart failure.
The 2019 study, which involved I. Nasir, M. Aminu, A.M. Ismail, A Salisu and G Magaji, was published in the Tropical Journal of Pharmaceutical Research.
The researchers found that taking lisinopril with zobo drink or hibiscus tea could enhance its availability consequent to the increased dissolution of lisinopril in simulated gastric, intestinal and blood pH.
The significant increase in the availability of lisinopril when it interacted with Hibiscus sabdariffa, the study said, could enhance the dissolution of lisinopril when interacted or administered with zobo drink or hibiscus tea, especially in the stomach and in the blood.
Dr I. Nasir declared: “It is a common practice to see individuals taking a prescription drug for antihypertensive medications outside the hospital also taking zobo drink and moringa. They believe that when they take it together, they get better. And when you check their blood pressure, it would have dropped miraculously.”
He declared, “the result of the study has proven that zobo drink helps in checking their high blood pressure.”
According to him, “its pharmacological effect will definitely be seen. In fact, there is a banker; all that she takes in the morning for her hypertension is the sour zobo drink which contains no additive like sugar.
“Many studies have shown that zobo drink has some antihypertensive effect. In fact, some prescribers recommend that instead of using water to swallow the drug, they could use a zobo drink. But they advise not to take zobo drink that contains sugar.”
The researchers, however, said further studies on the effect of varying concentrations of zobo on the bioavailability of lisinopril would still need to be evaluated.
The antihypertensive efficacy of Hibiscus sabdariffa extract has been documented in both preclinical studies and randomized control trials. A multicentric pilot clinical study in Jordan reported in the Journal of Alternative and Complementary Medicine that zobo is generally well-tolerated and seems to be helpful in treating uncontrolled hypertension, with or without medication.
This 2019 study had assessed the use of Hibiscus sabdariffa in cases of uncontrolled hypertension, either with or without medication, as validated by several clinical trials.
This trial involve 38 participants with blood pressure above 140/90 mmHg consumed H. sabdariffa tea. The blood pressure and other parameters such as satisfaction, possible side effects, and interactions with other medications, were considered.
Of the 38 participants, 29 finished the programme, 72 per cent of whom were taking antihypertensive medication due to uncontrolled hypertension and 28 per cent of whom were not, zobo was generally well tolerated.
In addition, 38 per cent of participants reached the target blood pressure at the end of the study and 65 per cent saw their systolic blood pressure decrease by at least 10mmHg.
What is more, a double-blind randomised controlled trial that compared the antihypertensive effectiveness of hibiscus tea with black tea infusion in diabetic patients showed consuming hibiscus tea had positive effects on blood pressure in type 2 diabetes patients with mild hypertension.
Results in the Journal of Human Hypertension (2008) showed a statistically significant systolic blood pressure decrease in the sour tea group (134.4 to 112.7 mm Hg). In the black tea group, blood pressure increased from 118.6 to 127.6 mm Hg.
However, people taking blood pressure medications like the Angiotensin converting enzyme (ACE) inhibitors such as lisinopril should avoid eating large amounts of zobo as well as foods high in potassium including avocados, oranges and orange juice, potatoes, spinach, tomatoes and tomato sauce.