Many Nigerian medicinal plants are used locally for the treatment of typhoid fever by traditional medicine practitioners and herb sellers. Now, in a laboratory evaluation of the efficacy of six medicinal plants used to treat typhoid fever, experts say that water extract of mango leaf was the most effective.

The researchers had tested leaves of Momordica charantia and Ficus exasperata, and stem barks of Lannea egregia, Lophira alata, mango and Morinda lucida. They found that they have varied effectiveness against Salmonella typhi, the germ that is transmitted through the ingestion of contaminated food or drinks, which causes typhoid fever.

For the study, different concentrations of the ethanol and water extracts of these medicinal plants were tested on Salmonella typhi in the laboratory. Their effect was compared with the standard antibiotics, ciprofloxacin and amoxicillin. It was in the University Of Lagos Journal Of Basic Medical Sciences.

All the plant extracts except the water extract of L. alata and ethanolic extract of M. charantia produced anti-salmonella activity. Among the six plants, the most effective in killing the typhoid fever germ was the water decoction of the bark of mango tree followed by that from Morinda lucida. The least was the water extract of M. charantia.

While other plant extracts were effective at concentrations of 12.5 to 50 mg/ml, both the ethanolic and aqueous extracts of L. egregia only inhibited the growth of Salmonella typhi at a concentration of 100 mg/ml and not effective at lower doses. This means that high doses of these plant extracts will be needed for the treatment of typhoid fever.

Although, the aqueous extract of mango at concentration of 100 mg/ml exhibited the highest antisalmonella activity by producing the highest zone of inhibition among the six studied plants, this activity was less than those of the conventional anti-typhoid drugs, amoxicillin and ciprofloxacin.

Despite the availability of effective conventional medicines, many Nigerians believe in and prefer the use of herbal medicines for the treatment of their ailments. In Lagos State alone, about 80 different medicinal plants are used for the treatment of typhoid fever by traditional medicine practitioners and herb sellers.

Ficus exasperate, commonly called Sand paper tree (English), ‘Ewe Ipin´ (Yoruba), and ‘Anwerenwa´ (Igbo), is used for the treatment of ulcer, cough, hypertension, intestinal pains and epilepsy. Lannea egregia is known locally as ‘Fula-pulaar´ (Guinea), and ‘Ekudan´ (Yoruba). It is used in traditional medicine for the treatment of scurvy, rickets, cancer, anaemia, menorrhagia and after-birth excessive blood loss.

Lophira alata is known as iron wood (English) or ‘Ekki´ and ‘Ponhan´ (Yoruba). Its bark decoctions in traditional medicine are used for the treatment of malaria, pain, menstrual problems, hernia, stomach problems, kidney pain and toothache. Its leaves are used for wound healing, leprosy, respiratory disease, dysentery, yellow fever and insomnia.

Aside, the local use of mango for the treatment of typhoid fever,  it is used as a remedy for exhaustion and heat stroke (unripe mango fruit juice), as food (fruit), for blood disorders, gastrointestinal disorders, scurvy, night blindness caused by Vitamin A deficiency (ripe fruit) diabetes (leaves), and diarrhoea (seed).

Momordica charantia, commonly called bitter melon, is known locally as ‘Ejinrin wewe´. The concoctions of root or leaf are used for boils and as a sedative, leaf as an analgesic, infusion of leaf and roots for induction of abortion and hastening of childbirth, fruit pulp as insect repellent and roots for diabetes.

Local names for Morinda lucida in Nigeria include ‘Oruwo´ or ‘Eze-Ogu´ or ‘Njisi´ (Igbo). Its local uses include the treatment of malaria, yellow fever, trypanosomiasis, diabetes, hypertension, dysentery, ulcers, leprosy and gonorrhoea, jaundice, ringworm and wound infections.

According to the study, the plant extracts possess anti-salmonella activities, justifying their traditional use in Nigeria for the treatment of typhoid fever and their chemical constituents probably serving as a lead for the production of new antityphoid drugs.

Meanwhile, an ethnobotanical survey of medicinal plants used for the treatment of typhoid fever in Kaduna metropolis, listed over 24 recipes based on self-structured questionnaires administered among herbalists and individuals representing the consumer population.

The recipes, according to the 2020 study in the International Journal of Current Research in Biosciences and Plant Biology, included boiling pineapple, lemon grass, Citrus medica, sweet orange, mango and Vitex doniana (Black plum,  ‘Dinya’ (Hausa), ‘Oriri’ (Yoruba) or ‘Uchakoro’ (Igbo)  in water or water extract from fermented maize (omi ogi). A full cup is taken three times daily.

Others are freshly extracted juices from the fruits of Citrus medica and pineapple that is be taken orally; a full tumbler of pawpaw and garlic that is cut into pieces and boiled in water for about an hour is taken twice daily; and half a tumbler of the concoction made by boiling Olax subscorpioidea (Ufon  (Yoruba); Gwaanon kurmii or Gwaanon raafii in (Hausa), Vitex doniana, ginger, garlic, and pineapple in water for two hours and is taken morning and night for seven days.

In addition, half a tumbler of bitter leaf squeezed in water and mixed with juices of the Citrus fruits is taken three times daily for seven days. Half a tumbler of pawpaw and mango that is boiled with water extract from fermented maize is taken twice daily.

The barks of Olax subscorpioidea and Albizia ferruginea (Ngu (Igbo) or Ayinre-ogo (Yoruba)), are soaked in water for two days and a half tumbler of the concoction taken once daily for 10 days. Albizia ferruginea, Daniellia oliveri (Iya (Yoruba), Ozabwa (Igbo) or Kadaura (Hausa)]  and pineapple is boiled using water or water extract from fermented maize for two hours and this is taken three times daily for seven days.

A cup of grind dried bark of mango tree is sieved and macerated with water is taken a cup twice a day. The leaves of pawpaw and guava are boiled together and taken twice a day. The patient also baths with it.