Medicinal plants are an integral part of African culture, one of the oldest and most diverse in the world. In South Africa, 21st century drug therapy is used side-by-side with traditional African medicines to heal the sick. While plants have been used in African medicine to treat fever, asthma, constipation, esophageal cancer and hypertension, scientific analyses of the purported benefits of many plants is still scant. A team of researchers has now examined the effectiveness of 16 plants growing in the country's Kwa-Zulu Natal region and concluded that eight plant extracts may hold value for treating high blood pressure (hypertension).
The study, entitled ACE Inhibitor Activity of Nutritive Plants in Kwa-Zulu Natal, was conducted by Irene Mackraj and S. Ramesar, both of the Department of Physiology and Physiological Chemistry; and H. Baijnath, Department of Biological and Conservation Sciences; University of Kwa-Zulu Natal, Durban, South Africa. Dr. Mackraj is presenting the team's findings at the 120th annual meeting of the American Physiological Society (APS; www.The-APS.org), being held as part of the Experimental Biology (EB '07) conference. More than 12,000 scientific researchers will attend the gathering being held April 28-May 2, 2007 at the Washington, DC Convention Center.
Background and Methodology
Hypertension is treated with medication, including drugs such as angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB). These drugs not only lower blood pressure but offer additional protection to the brain and heart. ACEI, in particular, provide beneficial properties to patients with type 1 diabetes.
In an effort to identify indigenous plants consumed by the local population in Kwa-Zulu Natal that hold potential antihypertensive properties, the researchers examined 16 plants to identify ACE inhibitor activity. The plants were:
Amaranthus dubius, a flowering plant also known as spleen amaranth
Amaranthus hybridus, commonly known as smooth pigweed or slim amaranth
Amaranthus spinosus, also known as spiny amaranth
Asystasia gangetica, an ornamental, ground cover known as Chinese violet. Also used in Nigerian folk medicine for the management of asthma.
Centella asiatica, a small herbaceous annual plant commonly referred to as Asiatic pennywort
Ceratotheca triloba, a tall annual plant that flowers in summer sometimes referred to as poppy sue
Chenopodium album, also called lamb's quarters, this is a weedy annual plant
Emex australis, commonly known as southern three corner jack
Galinsoga parviflora, commonly referred to as gallant soldier
Justicia flava, also known as yellow justicia and taken for coughs and treatment of fevers
Momordica balsamina, an African herbal traditional medicine also known as the balsam apple
Oxygonum sinuatum, an invasive weed with no common name
Physalis viscosa, known as starhair ground cherry
Senna occidentalis, a very leafy tropical shrub whose seeds have been used in coffee; called septic weed
Solanum nodiflorum, also known as white nightshade
Tulbaghia violacea, a bulbous plant with hairless leaves often referred to as society or wild garlic
Dried leaves from the plants were ground and used to prepare organic and acqueous extracts. Ten grams of ground plant material was suspended in either a methanol or distilled water solution for 48 hours. Each solution was subsequently filtered and the filtrate was left to air dry resulting in the specific test compound. ACE activity was determined using a flourimetric method with Hip-His-Leu as a substrate. The fluorescence of the o-phthaldialdehyde was measured to determine the effect of the plant on ACE activity.Plasma ACE activity was determined using rat plasma. The IC50 of the conventional ACEI, captopril was determined to test the sensitivity of the assay. At least three separate determinations were conducted for each test compound. A tannin test was only conducted on those plant extracts that exhibited over 50 percent ACE inhibition in the initial analysis. The data was subjected to GraphPad Instat (GraphPad Software Inc, San Diego, CA, USA). All values were expressed as mean ± SEM. A probability where p
Results: Eight of Sixteen Plants Showed ACEI
Eight of the 16 plants demonstrated ACE inhibition activity. The plants were then subjected to a gelatin salt block test for tannins to eliminate any false positive results. None of the plants tested positive for tannins, hence eliminating any false positive results.
Ultimately, the eight plants that showed significant ACEI activity in both extract forms were: Amaranthus dubius, Amaranthus hybridus, Asystasia gangetica, Galinsoga parviflora, Justicia flava, Oxygonum sinuatum, Physalis viscosa, and Tulbaghia violacea.
The Stand Out "Wild Garlic" (Tulbaghia violacea) Plant
Only one plant -- Tulbaghia violacea -- showed more than 50 percent inhibition in both extract preparations. These findings are in keeping with those of another group (1999). Further testing has revealed that the plant has promising hypotensive affects. The plant is commonly associated with onions and garlic and highly concentrated in Southern Africa. It is best known as "wild garlic."
Researchers have recorded (1962) that the plant was pounded into formulations and used by native South Africans to relieve stomach ailments, rheumatism and high fevers. Other researchers found (1966) that native South Africans rubbed the leaves of the plant on the head for sinus headaches and used plant infusions for colic and restlessness in young children. The most direct discovery is the 1993 finding that large doses of popular garlic preparations significantly decreased the diastolic blood pressure in human patients 5-14 hours after the dose with no significant side effects. In addition, wild and cultivated garlic preparations were shown to decrease systolic blood pressure in rats.
In this study Tulbaghia violacea has shown properties related to lowering blood pressure. Since the number of hypertensive individuals around the world is on the rise, it is worthwhile to pursue further studies involving this extract. Yesterday's folk remedies may one day be just what the 21st century doctor orders.
Donna Krupa | EurekAlert!
The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences
Transforming plant cells from generalists to specialists
07.12.2016 | Duke University
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine