When next you develop diarrhoea, scientists say several age long local remedies can prove useful in its treatment. In this report by Sade Oguntola, these include Calpurnea aurea, zobo and nutmeg.
Diarrhoea disease is a leading cause of ill health and death, especially among children in developing countries resulting in a major health care problem. Despite the availability of vast spectrum of approaches for diarrhoea management, vast majority of people in developing countries rely on herbal drugs for the management of diarrhoea.
Diarrhoea is a condition that involves the frequent passing of loose or watery stools - it is the opposite of constipation and can have many causes, which may be infectious or non-infectious.
Medicinal plants have been used for centuries as remedies for human diseases and World Health Organisation (WHO) has encouraged studies for treatment and prevention of diarrhoeal diseases depending on traditional medical practices that may reduce cases of death due to diarrhoea.
Extensive studies of the adverse effects of these herbal medicines and ensuring their effectiveness and quality are very important. However, there is a wide range of medicinal plants used by traditional healers to treat diarrhoeal. Some of these herbs, however, have not been confirmed effective by scientific studies.
Among these plants is Calpurnia aurea which is widely distributed throughout tropical Africa. Scientists in a new study had just established the scientific basis for its medicinal use and also a candidate for drug development in the future.
Also several studies have validated the use of antidiarrhoeal medicinal plants by investigating the biological activity of extracts of such plants, which have antispasmodic effects, delay intestinal transit, suppress gut motility, stimulate water adsorption, or reduce the intraluminal fluid accumulation.
Traditionally, the leaves of Calpurnia aurea (bomubomu in Yoruba) are used to treat stomach complaints, headache, eye diseases, amoebic dysentery, scabies (skin infection caused by ticks) and as an insecticide in Ethiopia.
In South Africa, Calpurnia leaves and powdered roots are used to kill lice and to relieve itches. Unspecified parts are used to kill maggots and the leaves are used to treat allergic rashes, particularly those caused by caterpillars. In East Africa, leaf sap is used to kill maggots in wounds. In Nigeria, the seeds are used to treat abscesses.
In testing its mode of action in diarrhoea caused by germs such as Shigella flexneri, Staphylococcus aureus, Escherichia coli and Salmonella typhi, the scientists made an extract of dried and powdered leaves of C. Aurea using methanol. This was tested in Swiss albino mice that were made to have diarrhoea under laboratory conditions.
The animals were observed over a period of four hours. The time of onset of diarrhoea, total number of faecal output (frequency of defecation) and weight of faeces excreted by the animals were recorded.
The 2013 study entitled "Antidiarrhoeal and antimicrobial activity of Calpurnia aurea leaf extract" was published in the BMC Complementary and Alternative Medicine.
They found that in these tested animals that had castor oil induced diarrhoea, the methanol leaf extract of C. aurea at different concentrations significantly reduced the time of onset of diarrhoea, the frequency of defecation (total number of faecal output) and weight of faeces.
Interestingly, the researchers also found that at the dose of 400 mg/kg body weight, the extract produced caused an 82.93 per cent reduction in diarrhoea compared with loperamide, the standard drug used in the treatment of diarrhoea. Its effectiveness was comparable with loperamide, which showed 87.80 per cent reduction in diarrhoea.
They wrote: "The extract of C. aurea showed highest activity against S.typhi and E. coli among the tested micro-organisms. The methanol extract of the leaves of C. aurea exhibited broad spectrum of antibacterial activity."
Aside the methanol extract of the leaves of C. aurea moderately inhibited the growth of all the tested bacterial strains; the researchers also confirmed that the extracts at the different doses had no toxic effects in any of the test animals.
Researchers at the Department of Veterinary Physiology and Pharmacology, University of Ibadan, Ibadan, have also confirmed the popular herbal drink, Zobo, prepared with roselle (fresh calyx of Hibiscus sabdariffa (Roselle, Soboroto or Ishapa) as main ingredient) scent leaf (Ocimum gratissimum), garlic and ginger could be effectively used to treat diarrhoea and pneumonia.
The researchers in the study published in African Journal of Biomedical Research wrote: "The extracts of both Ocimum gratissimum and Hibiscus sabdariffa could be useful at appropriate doses in the control of diarrhoea. Hibiscus sabdariffa would be more effective in this regard."
Although, they could not say specifically the mechanism by which Hibiscus sabdariffa caused this action in this study, they said that Hibiscus sabdariffa was more effective than Ocimun gratissimum in the treatment of diarrhoea.
What is more, nutmeg, the age long cooking spice is also used for the treatment of diarrhoea in many African communities. Researchers studying its efficacy in the treatment of diarrhoea have proposed that it is one herb that should be industrially processed.
The researchers, in validating the use of African nutmeg as anti-diarrhoeal remedy in traditional medicine, milled some dried African nutmeg seeds and then extracted its constituents with methanol. The test was verified in animals.
They found out that the methanol extract of African nutmeg significantly reduced the number of faecal droppings at the doses tested and reported that the African nutmeg reduced water and electrolytes secretion into the small intestine, which substantiates its use in the treatment of diarrhoea in traditional medicine.
Although the mechanisms by which the extract of African nutmeg reduced gastric contents and watery texture of diarrhoeal stools as well as gastrointestinal motility is still not clear, they suggested the possibility of formulating the powdered seed of this plant or its alcohol extract to a herbal anti-diarrhoea remedy.
They wrote, "From this study and the age long use as condiment, toxicity may not preclude use as a medicament."
From results of the toxicity test on the extract in mice, they suggested that the seeds may be generally regarded as safe, with a remote risk of acute intoxication. According to them, the high degree of safety is also consistent with its popular use as a local spice in food.
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