Medicinal plants with antidiarrheal properties have been widely used by the traditional healers. However, the effectiveness of many of these plants has not been scientifically evaluated and proven. One of such plants is Parquetina nigrescens.
In a new study, experts confirm that a leaf decoction or infusion of Parquetina nigrescens treats diarrhoea and an alternative in improved management of diarrhoea, especially in children.
This research was carried out to formulate the extract of Parquetina nigrescens into a suspension, validate its antidiarrheal effect as a suspension for oral administration and characterise the suspension was done in wistar rats.
Also, a pharmacological analysis was carried out to validate the antidiarrheal properties of Parquetina nigrescens (Pn) suspension when administered orally.
Diarrhoea is one of the leading causes of morbidity and mortality in both children and adults. This is mainly due to poor hygiene and sanitation. Diarrhoea kills more children than malaria, measles and AIDS combined.
According to World Health Organisation (WHO), diarrhoea is defined as the passage of three or more loose or liquid stools per day or more frequent passage than is normal for the individual.
Aside interventions such as ensuring proper hygiene, improved sanitation and rehydration, several orthodox medicines have been used to treat diarrhoea.
From folklore, a leaf decoction or infusion of Parquetina nigrescens (kwankwanin in Hausa, mgbidim gbe in Igbo, ewidun or inuwu elepe in Yoruba) is drunk to treat diarrhoea and other diseases. A leaf decoction with honey added is also drunk to treat fatigue, jaundice, stomach ulcers and anaemia, as a tonic.
It is also taken to treat hypotension and to ease childbirth. The body is washed with a leaf decoction to treat general fatigue. The leaf is a common ingredient in medications used to treat insanity.
The extract of Parquetina nigrescens has a great potential to reduce the frequency of stooling at a dose comparable to loperamide, a conventional drug for the treatment of diarrhoea that was used as control. The extract was able to reduce the motility of the gut and thus reduce diarrhoea.
The result also showed that at 5 mg/kg body weight of extract and loperamide, the levels of inhibition produced by the extract were greater than that produced by loperamide.
All the suspensions inhibited diarrhoea in a dose-dependent pattern. As the concentration of extract increased, there was a remarkable decrease in the number of loose stools passed by the test animals.
In addition to preventing the passage of loose stools in test animals, suspensions of Pn were able to maintain the inhibition for up to an hour, thereby confirming a longer duration of pharmacological effect and thus reducing the need for repeated dosing.
The 2019 study in the Journal of Experimental Pharmacology involved Adeola Tawakalitu Kola-Mustapha; Yusuf Oluwagbenga Ghazali; Hameedat Taiye Ayotunde; Soliu Abiola Atunwa; and Sukurat Olasumbo Usman, all from the University of Ilorin.
According to the researchers, “It can, therefore, be said that only a small concentration of the extract is required for antidiarrhoeal effect and thus less amount of drug in the system.”
Having established the antidiarrheal effect of Parquetina nigrescens, they said it is pertinent to formulate the extract into dosage forms that can ease administration, mask the characteristic odour and colour of the plant and elicit a faster onset of action, hence, the choice of a suspension.
Also, further investigations the researchers said would be carried out to validate the dose of the plant extract that produced the best activity in the formulation and develop the drug moiety into dosage forms that can be subjected to clinical evaluation.
Experts showed that extract of the seeds and pods of Acacia nilotica (gum arabic or Booni) was the most active against diarrhoea causing organisms in a comparison of Uvaria afzelii (gbogbonishe in Yoruba, Umimi ofia in Igbo and Osu-umimi in Hausa), Acacia nilotica, Terminalia avicennioides (Baushe in Hausa, Idi in Yoruba and Edo in Igbo) and Fagara zanthoxyloides (orin ata in Yoruba).
In fact, the researchers in the 2015 edition of Green Chemistry said that extract of the seeds and pods of Acacia nilotica may be a potential source of a broad spectrum antibiotic for the treatment of diarrhoea.
Similarly, other researchers named guava leaves, Momordica balsamina, Sanseviera liberica root, Piliostigma reticulatum bark, Xylocarpus granatum bark, Stachytarpheta indica and Rauwolfia serpentina as medicinal plants that people use in treating diarrhoeal.
Sanseviera liberica is commonly called òòjá ikòòokò in Yoruba and guru in Hausa. Piliostigma reticulatum is commonly called in Yoruba: ‘abafin’; in Hausa: ‘kalgo’ and in Igbo: okpo atu’. Momordica balsamina is known as Balsam apple (English), Garahuni (Hausa), Akbon-ndewe (Igbo) and Ejirin (Yoruba).
Stachytarpheta indica is known locally as snakeweed (English), Tsarkiyar kusu (Hausa); or amure (Yoruba). Rauwolfia serpentine is called asofeyeje (Yoruba), akanta (Igbo) and wada (Hausa).