Dosage and shelf life of medicinal plants, herbs
With more claims and researches validating the nutritional and health benefits of medicinal plants and herbs, there has been an increase in the use of these substances to spice, enrich foods and drinks globally. Especially in this part of the world, more people are embracing the idea of fortifying their health and immune system with medicinal plants and herbs. The efficacy of these substances is so widely acclaimed that many people use them as treatment for various ailments. So, it is quite common to see these food items displayed practically everywhere in markets and even by the roadsides.
Coming in fresh and dried forms, medicinal herbs and plants that are easily available around here include turmeric, garlic, yeast, ginger, black seed, scent leaf, bitter kola and bitter leaf, among others.
According to World Health Organisation (WHO), 80 per cent of people globally rely on herbal medicines for some aspect of their primary healthcare needs. WHO further estimated that 21, 000 plants species have the potential for being used as medicinal plants.
In developed countries such as the United States, plant drugs constitute as much as 25 per cent of the total drug, while in developing countries such as China and India, they contribute as much as 80 percent.
While some scientists condemn their usage, some findings have approved their usage to complement orthodox medicine in the management and treatment of various diseases.
Studies have shown that turmeric could be beneficial for pain caused by inflammatory diseases, such as arthritis, preventing cancer, stopping DNA mutations and several skin diseases, among other health benefits.
Similarly, ginger is said to reduce cold and flu, treats inflammation, muscle pain and severe indigestion, protects liver, prevents cancer, reduces menstrual cramps, kills bad bacteria, as well as improves brain functionality, among other benefits.
Also, garlic regulates blood pressure, lowers cholesterol, reduces risk of heart disease, improves memory, sex drive, has antiviral properties against viral infections, enhances skin and athletic performance, among others.
Black seed is used for treating digestive tract conditions, diarrhoea, dysentery, constipation and hemorrhoids, and for such respiratory conditions as asthma, allergies, cough, bronchitis, emphysema, flu, swine flu, and congestion.
All this notwithstanding, experts have pointed out that just as herbal medicines have health benefits, so also they can have some side effects, if not properly used. Like all other things, there is need for moderation and caution regarding use and storage.
And because they have become so common and are widely used, there are pertinent issues of shelf life and appropriate use. Dr. Joy Odimegwu of the Department of Pharmacognosy, Faculty of Pharmacy, University of Lagos, explained that medicinal plants and herbs are appreciated for their natural compounds, which have medicinal values and biological activities in human system.
She said: “Turmeric has bioactive compound that is inflammatory, as it helps calm distressed cells in the body and reduces inflammation. All these plants have bioactive compounds that are medicinal, which is why they are referred to as medicinal plants. When mixed, these plants and herbs could sometimes be helpful, when there is synergistic interaction, although they can also be a problem.
“For instance, garlic and ginger have antimicrobial principles. So, when you mix them, they become more powerful and we have a depth of information on the mechanism of action.
“People have been mixing these medicinal plants over the years. When they have flu, cold and other illnesses, they use them to treat themselves and because these medicinal plants are food, they are not toxic or poisonous.
“However, we know that even too much food can lead to illness. There is nothing you take too much of that will not cause a problem, but the medicinal plants are safe because they are food.”
On the dosage, Odimegwu said herbal medicine just like orthodox medicine has dosage, which should be strictly adhered to.
“Herbs are food, but when a person takes too much of it, there would be problem,” she said.On the issue of shelf life of medicinal plants, Odimegwu said this depends on when the plants get spoilt.
She explained that researches have shown that the fresh and aged medicinal plants are beneficial. However, aged plants contain compounds that have become more potent for treatment of diseases.
“There is actually no shelf life for medicinal plants, until when they get spoilt. And even if they are dry, they are still all right, but if rotten or spoilt, you don’t use them. Presently, there is no duration the medicines can stay before being discarded. Just like pepper and onion that don’t have shelf life until they get spoilt and are thrown away, medicinal plants and herbs can stay for long,” she said.
, Dr. Ishola Ismail, a Senior lecturer at the Department of Pharmacology, Therapeutics and Toxicology, College of Medicine, University of Lagos, said studies are still going on regarding the efficacy of medicinal plants and other herbal products for the management of diseases, especially as some researchers had previously carried out studies on the antiviral, immunostimulatory and immunomodulatory activities of the plants.
He said: “Herbal remedies are not medicinal treatment for COVID-19. Equally, we cannot categorically state that garlic, black seed or turmeric are rightly medicinal products you can prescribe or recommend to someone, due to the fact that some things need to be done before you can actually say that. I am not ruling out the fact that they are medicinal products, as several constituents present in them could be beneficial. But we need to be careful with what we say or use with respect to disease management.
“Meanwhile, some studies have shown that medicinal plants are used for different ailments such as hypertension and diabetes, among others. Some scientists have also made claims about this, but until scientific studies are done to validate those claims and research, including clinical trial to show the medicinal plants are for treatment of ailments, they are otherwise viewed as medical claims.”
Speaking on the mixture of herbal medicines, Ismail said while some of the mixed products could give a synergistic interaction that are beneficial or additive for human consumption, care needs to be taken, due to other toxic effects of mixing herbal products.
He said: “In pharmacology, we look at the beneficial and toxic effects of any drug. If the beneficial effects outweigh the toxic effects, then we say the medicinal plants are safe to use. But if it is otherwise, people should not consume it.
“There could be a slow degeneration of certain organs in the body that are not seen immediately. In such situation, caution needs to be taken because we have a lot of chronic diseases caused by adverse effect of drugs, either orthodox or herbal.”
On the dosage of herbal medicines, Ismail said they should be handled just like orthodox medicines, which usually have dosage that should be strictly followed.
He is angry that people who take herbal medicines do not adhere strictly to the dosage, which has adverse effect on body organs, thereby leading to such chronic illnesses as kidney and liver diseases, among others.
“There are measurements and dosage, which are based on the body mass index. You can weigh the amount of active constituents that are present and with that, you can do the formulation. But because of the issue of standardisation, people think that herbs can be taken anyhow. Individuals need to know what quantity of constituents should be added and how much should be extracted, but because herbs are natural, people feel they can abuse the dosage.
“Yes, herbal medicines are natural, but everything is poisonous, if the dosages were not followed correctly,” he said. On the shelf life of medicinal plants, Ismail said during the process of standardisation, the shelf life could be determined.
He explained that during preparation of the products, there could be an adulteration, due to addition of substance that could cause fermentation or poor manufacturing process that could affect the shelf life of the herbal medicines. He said if these processes are not taken into consideration, there could be microbial growth inside the substance.
“Although there are microbes that are beneficial, those that are as a result of unhygienic preparation of the substances could be dangerous to the body, thereby destroying organs,” he said.
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