Local plants as antidote to snake venom
Until now, snakebite poisoning remains a public health hazard in tropical countries. Viper snakes are among the most common types of venomous snakes, which are responsible for many envenoming and deaths in most tropical areas.
Several studies have shown that the risk of snakebite to people in the rural region of tropical countries, where most people engage in agricultural, pastoral, and other outdoor livelihoods, is moderate to high.
In Nigeria, the Fulani herdsmen are more at risk because of their agro-pastoralist lifestyle. Their village settlement positions make it more difficult for them to assess antiserum, the only treatment available for snake bite.
But the usage of snake venom antisera has its own drawbacks. Due to its high cost and lack of availability of antisera makes it difficult for the rural patients to access. Further, due to its storage difficulty and short expiry, its use is restricted.
Snake venom antiserum or AVS has administration problem, the exact dosage is also a current problem. AVS administration is often associated with hypersensitivity reactions (early and late), which need further medical attention.
There are various medicinal plants, which have been used in folk and traditional medicines against snakebites especially among the Fulani herdsmen of Northern Nigeria. But till date no such drugs are available in the market, which possess anti snake venom activity.
However, scientists have recently validated some local plant as herbal medicines for snakebite management.
Top on the list are: English wild custard apple (Annona senegalensis), Velvet bean or Cowhage (Mucuna pruriens), Turmeric (Curcuma longa), Plantain (Musa paradiasica).
Commonly called English wild custard apple, Annona senegalensis belongs to the plant family Annonaceae.
In Nigeria, it is called umm boro in Arabic-Shuwa; ewura in Berom; boili in Fula-Fulfulde; ououd on Goemai; kmijirihi in Gwari; gwándàr daájiì and tàllàfà màraàyú in Hausa; uwu in Idoma; ukpokpo in Igala; uburu-ọcha in Ibo; ngónówù in Kanuri; oguoto in Yekhee; àbo and arere in Yoruba.
A recent study has scientifically validated the folklore use of Annona senegalensis in the treatment of snakebite by the farmers and herdsmen in Northern Nigeria.
The researchers from Department of Biochemistry, Faculty of Science, University of Maiduguri, Borno State, found that the root extract of Annona senegalensis possesses potent snake venom neutralising capacity and may provide protection against the toxicity posed by the Bitisarietans venom and could be used for therapeutic purposes in case of snakebite.
The study titled “Effects of aqueous root extract of Annona senegalensis on Bitisarietans venom protease and phospholipase A2 activities” was published in the Journal of Pharmacology and Biomedical Sciences.
Another study published in the Journal Ethnopharmacology has demonstrated the effect of Annona senegalensis root bark extracts on Naja nigricotlis nigricotlis venom in rats.
The researchers noted: “The potency of the methanol extract of the root bark of the plant was tested against cobra (Naja nigricotlis nigricotlis Wetch) venom in rats. The extract was also tested on brine shrimp (Artemia saline Leach). The activity of the extract against the venom induced mortality, occurrence of toxic signs, activity on liver enzymes as well as its ability to reverse experimentally induced increase in body temperature were evaluated.
“Results indicated that the extract caused reduction in the induced hyperthermia and directly detoxified the snake venom used by 16-33 per cent. It, however, failed to restore the biochemical functions (sGOT and sGPT) of the liver. The extract exhibited an LC(50) of 232.7 microg/ml in the brine shrimp test.”
According to The Useful Plants of West Tropical Africa, volume 1, “A bark infusion forms a mouth-wash to relieve toothache, and in the Zambesi region root-bark is used as an antidote to snakebite. Leafy twigs and bark are used by Fula of Senegal against sterility. They also consider the bark to be a galactogogue (induce breast milk production) for both humans and animals.
“The roots are sold in Hausa markets in Northern Nigeria and are used in the treatment of venereal diseases, the patient feeding for five or six days on a pap made by boiling the root with guinea-corn meal and native natron.”
Natron is a natural mixture of sodium carbonate decahydrate (a kind of soda ash) and about 17 per cent sodium bicarbonate (also called nahcolite or baking soda) along with small amounts of household salt (halite, sodium chloride) and sodium sulfate. Natron is white or without color when it is pure.
Botanically called Velvet bean or Cowhage, Mucuna pruriens belongs to the plant family Fabaceae. In Nigeria, it is called Agbala or Agbaloko in Ibo and Werepe in Yoruba.
Recent studies have found that Mucuna pruriens leaves are more effective than the standard drug, anti-venin, for curing snakebite.
The study published in the International Journal of Biochemistry Research & Review is titled “Anti-venom Activity of Mucuna pruriens Leaves Extract Against Cobra Snake (Naja hannah) Venom.”
The researchers from Bingham University Nassarawa and Federal Polytechnic, Nasarawa State, investigated the anti-venom activity of Mucuna pruriens leaves extract against cobra snake (Naja hannah) venom.
The mice were randomly grouped into six groups (A, B, C, D, E, and F) of five rats each. Group A served as the normal control (no induction), and the mice in the group were given normal saline (1ml/kg/body weight).