The consumption of hibiscus tea or zobo is growing in popularity owing to accumulating evidence that it has benefits against excess weight, constipation, upset stomach, diabetes and can safely reduce blood pressure and cholesterol, two major risk factors for cardiovascular disease.
Among the best-described health benefits of Hibiscus sabdariffa, also commonly referred to as roselle, is blood pressure control for hypertension and many patients on conventional antihypertensives may also consume iced zobo drink to beat the increasing atmospheric temperature.
Studies have shown that a two-week period of zobo extract administration could produce the antihypertensive activity. However, in a new study, experts warn against long term consumption of zobo drink by individuals on captopril, a conventional hypertension medication.
According to them, regular intake of zobo drink with captopril, one of the angiotensin-converting enzyme inhibitor may be potentially dangerous. This could lead to a lowering of the blood pressure than initially planned.
Angiotensin converting enzyme (ACE) inhibitors such as captopril dilate the blood vessels to lower hypertension or treat heart failure.
Even though the intake of the antihypertensive with zobo drink does not influence the antihypertensive potency of captopril or cause any side effects, they said two weeks of regular intake of zobo drink with captopril can reduce the efficacy of the drug. This was contained in the 2020 edition of Evidence-based Complementary and Alternative Medicine.
Ingestion of zobo drink with conventional medicines such as paracetamol, chloroquine and antibiotics in many communities are very common, without regard to the possibility of herb-drug interactions. Being natural products, individuals wrongly believe they are always safe to be taken with drugs.
When herbal therapies and drugs (prescription or non-prescription medications) are used together, they can interact in the body, causing changes in the way the herbs and/or the drugs work. Such changes are called herb-drug interactions. They can be beneficial or harmful, depending on the type of interaction.
More than 300 species of hibiscus can be found around the world and most of its varieties are used as ornamentals. However, there are two main types of Hibiscus sabdariffa cultivated for its jute-like fibre and its edible calyces. Its infusion made from its bright red calyces, which is commonly called zobo, is consumed hot or cold. This tea is often sweetened with sugar.
For the study on the possible effect of prolonged administration of zobo extract on captopril in the body, male rats were divided into two groups of six. The first group received a single dose of captopril suspension while the second group received zobo daily for two weeks prior to the same captopril dose.
Multiple blood samples were collected at predetermined times after the antihypertensive was administration and its concentration in these blood samples were assessed using ultrahigh-pressure liquid chromatography-tandem mass spectrometry.
Previously, experts at the Usman Danfodiyo University, Sokoto, and Ahmadu Bello University, Zaria, said taking zobo along with the prescription drug lisinopril, a blood pressure medication, ensures its better effectiveness in blood pressure control.
The availability of lisinopril alone and in the presence of Hibiscus tea was determined at the stomach, intestine and blood pH.
The 2019 study, which involved I. Nasir, M. Aminu, A.M. Ismail, A Salisu and G Magaji, published in the Tropical Journal of Pharmaceutical Research, 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.
Dr I. Nasir declared: “It is a common practice to see individuals taking a prescription drug for antihypertensive medications outside the hospital while 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 added “the result of the study has proven that the 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.
However, people taking blood pressure medications like the Angiotensin converting enzyme (ACE) inhibitors such as lisinopril should avoid consuming large amounts of zobo as well as foods high in potassium including avocados, oranges and orange juice, potatoes, spinach, tomatoes and tomato source.
