Antidiarrhoeal Activities of Some Medicinal Plants

It is against this background that the plants such as Uvaria afzelii Sc, Acacia nilotica Linn., Terminalia avicennioides Guill & Perr and Fagara zanthoxyloides Lam which were extensively used as herbal preparation in some parts of Nigeria were investigated. The plants were selected base on their medicinal importance among traditional medicine practitioners in Nigeria. The diarrhoea causing organism commonly found in the affected sites of the patients such as Staphylococcus aureus, Escherichia coli, Campylobacter species, Clostridium difficile, Vibrio species, Salmonella enteritidis, Salmonella typhi and Shigella dysentriae were used for this study. These plants were used for various ailments throughout Nigeria. For example, Uvaria afzelii is used in the treatments of liver problems, pulmonary troubles, naso-pharyngeal infections, food poisoning and venereal diseases [3]. Acacia nilotica Linn, is used in the treatments of intestinal pains, diarrhea, nerve stimulant, cold, congestion, coughs, dysentery, fever, hemorrhages, leucorrhea, ophthalmia and sclerosis [4]. And Terminalia avicennioides Guill & Perr is used in the treatment of diarrhoea, dysentery, dropsy, swellings, oedema, gout, leprosy, mucosae, vermifuges, skin irritations and as pain killers [5].


Introduction
Over 75-80% of the world's population in developed and developing countries depends on. Herbal medicines derived from medicinal plants for their health care [1]. Herbs have medicinal property due to presence of different active principles like alkaloids, volatile essential oils, glycosides, resins, oleoresins, steroids, tannins, terpenes and phenols found them [2].
It is against this background that the plants such as Uvaria afzelii Sc, Acacia nilotica Linn., Terminalia avicennioides Guill & Perr and Fagara zanthoxyloides Lam which were extensively used as herbal preparation in some parts of Nigeria were investigated. The plants were selected base on their medicinal importance among traditional medicine practitioners in Nigeria. The diarrhoea causing organism commonly found in the affected sites of the patients such as Staphylococcus aureus, Escherichia coli, Campylobacter species, Clostridium difficile, Vibrio species, Salmonella enteritidis, Salmonella typhi and Shigella dysentriae were used for this study. These plants were used for various ailments throughout Nigeria. For example, Uvaria afzelii is used in the treatments of liver problems, pulmonary troubles, naso-pharyngeal infections, food poisoning and venereal diseases [3]. Acacia nilotica Linn, is used in the treatments of intestinal pains, diarrhea, nerve stimulant, cold, congestion, coughs, dysentery, fever, hemorrhages, leucorrhea, ophthalmia and sclerosis [4]. And Terminalia avicennioides Guill & Perr is used in the treatment of diarrhoea, dysentery, dropsy, swellings, oedema, gout, leprosy, mucosae, vermifuges, skin irritations and as pain killers [5].

Sample collection
The plants parts were collected in Kaduna, Zaria and Nasarawa state. It was identified by Dr Ajibade, at the Herbarium of Biological Sciences, Faculty of Science, Nigeria Defence Academy, Kaduna. The seeds and pods of Acacia nilotica were collected in Nasarawa state and it has a voucher number of 403. The roots of Uvaria afzelii and Terminalia avicennoides were collected in Zaria and they have voucher numbers of 405 and 406 respectively. The plant materials were air-

Abstract
The phytochemical screening, extraction and antimicrobial analysis of the crude extracts from the seeds and pods of Acacia nilotica Linn, the roots of Uvaria afzelii Sc and Terminalia avicennioides Guill & Perr were carried out using standard methods. The results of the phytochemical screening showed that the plants contained saponins, flavonoids, phenols, tannins, terpenoids and triterpenoids. The results of the antibacterial screening showed that the ethyl acetate extract of Acacia nilotica Linn exhibited the highest activities against the test microbes with zones of inhibition diameter ranging from 27-32 mm. It was closely followed by the ethyl acetate extract of Terminalia aviccenoides with zones of inhibition diameter ranging from 25-30 mm and finally, the ethyl acetate extract of Uvaria afzelii with zones of inhibition ranging from 24-29 mm. The results of Minimum Inhibitory Concentration (MIC) showed that the extracts of the plants gave MIC values at a concentration of 800, 700, 600 µg/cm 3 against Escherichia coli, Vibro cholerea, Shigella dysentriae and Salmonella enteritidis respectively. The Minimum Bactericidal Concentration (MBC) values occur at the same concentration against the same microbes. The results of this study showed that the ethylacetate extract of the seeds and pods of Acacia nilotica was the most active against diarrhoea causing organisms and may be a potential source of a broad spectrum antibiotic for the treatment of diarrhoea.
dried, pulverized by the use of a wooden mortar and pestle and stored in bags.

Extraction
A portion (100 g) each of the ground plant parts was separately percolated in 300 cm 3 each of methanol, ethyl acetate, chloroform and petroleum ether for two weeks. The extracts were separately filtered and evaporated on rotary evaporator at 40°C. The marc was repercolated with the recovered solvents for an additional one week. The extracts were drained, filtered and combined with the previous residue and evaporated on rotary evaporator. Each extract was cooled, weighed and stored in the refrigerator until needed. the antimicrobial test while Tables 3 showed the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) respectively.

Discussion
The results of the phytochemical screening of the chloroform, ethylacetate, methanol and petroleum ether extracts of Uvaria afzelii Sc, Acacia nilotica Linn., Terminalia avicennioides Guill & Perr and Fagara zanthoxyloides Lam showed that they contain Saponins, flavonoids, phenols, tannins, terpenoids and triterpenoids.. These phytocompounds were synthesized by plants to safeguard themselves against antimicrobial infections [7]. They are known to be effective against diarrhoea caused by Tripanasome and Plasmodium and possess the ability to initiate human physiological activities such as the stimulation of phargocytic cells and mediation of tumor activities [8].
In addition, the extracts of Acacia nilotica also contain Alkaloids and Steroids. This therefore showed that the extracts of this plant could be effective against diarrhea because these phytocompounds have been reported to have antimicrobial properties due to their ability to form complex with nucleophilic amino acids of the microorganism. These therefore suggested that the extracts of the plants targeted may possess antimicrobial activities against diarrhoea causing microbes.
The results of the antimicrobial screening of the extracts (Table 2) showed that Acacia nilotica exhibited the highest activity and possess appreciable antibacterial properties by inhibiting the growth of the test organisms at concentrations of 7 × 10 2 -8 × 10 2 µg/cm 3   of Acacia nilotica. These differences in the activities of the crude extracts could be due to the fact that they contain different types of phytocompounds [9].

Conclusion
The result of the phytochemical screening carried out on Uvaria afzelii, Acacia nilotica, Terminalia avicennioides and Fagara zanthoxyloides revealed that the plants contained Saponins, flavonoids, phenols, tannins, terpenoids and triterpenoids. The crude extract from the four plants are found to be very active against Escherichia coli, Streptococcus feacalis, Salmonella enteritidis and Candida krusei. These therefore showed that the phytocompounds from these plants could be used as broad spectrum antibiotic against diseases caused by the test microbes.
These results also showed that the ethylacetate extract of Acacia nilotica Linn was the most active extract and it suggested that the extracts of this plant could be a good source of new antimicrobial compounds as shown by the preliminary results. It was therefore selected for further work, which include isolation and characterization of the phytocompounds responsible for the activity of the plant extract.  This article was originally published in a special issue, Green Chemistry handled by Editor(s). Dr. Michael Shapiro, University of Maryland Baltimore USA