Pharmacological and clinical evaluation anthelmintic activity of albizia anthelmintica maerua edulis de wolf and maerua subcordata plant extracts in sheep and mice
The use of medicinal plants for the control of helminthoses has been in practice for centuries and there are many plants claimed to have anthelmintic activity. However, it is only a few of these plants that have their anthelmintic activity scientifically evaluated. These studies were done to evaluate the anthelmintic activity of Albizia anthelmintica Brogn, Maerua edulis De Wolf and Maerua subcordata De Wolf in sheep and mice and to determine the bioactivity of these plants using brine shrimp lethality test. An attempt was also made to separate the pharmacological active ingredient in Albizia anthelmintica water extract. A questionnaire was used to obtain medicinal plants used by farmers and herbalists in Kibwezi Division of Makueni district and Tunyo division of Marakwet district as anthelmintic. Out of 51 useful plants identified in Kibwezi, Albizia anthelmintica (Kyoa in Kikamba) and Maerua edulis (Munatha in Kikamba) were singled out by herbalists as very potent anthelmintics. In Tunyo division Albizia anthelmintica (Kitwongwo in Marakwet) and Maerua subcordata (Liswa in Marakwet) were identified as potent anthelmintics. For this reason, they were collected and botanically identified for further testing and analysis. The anthelmintic activity of the three plants was evaluated in the present study. Crude extraction of the plant samples was done as described by the herbalists. An aqueous extract from both unground and ground material of each plant material was prepared using boiling water. Twenty one clinically healthy sheep of mixed breeds and sexes were randomly allocated to four treatment groups of four animals each. The control group had three sheep. Faecal egg counts were done for all the sheep on day O. A single oral dose of 1.2 ml/kg body weight (Albizia anthelmintica ) and 0.8 ml/kg body weight (Maerua edulis) was administered to the sheep in the 4 treatment groups. The control was left untreated. Albizia anthelmintica extract was the only one which reduced faecal egg count. At double the dose, the percentage faecal egg count reduction was 55, 49, 38, 16 and 14 for powdered Albizia anthelmintica, powdered Maerua edulis, fresh Maerua subcordata, fresh Maerua edulis and fresh Albizia anthelmintica respectively. Therefore, the crude product could control helminthoses to a reasonable extent and maintain the animal at clinically healthy state. Brine shrimp assay was used to detect bioactivity (LC50) in the vanous extracts of Albizia anthelminitica, Maerua subcordata and Maerua edulis. The various extracts were made using water, methanol and chloroform and immediately freeze dried. Brine shrimp eggs obtained from pet shops were hatched using marine salt solution as media and yielded a large number of larvae. Serial dilution of the plant extracts were put into tubes with 10 brine shrimps each. The number of live larvae was determined after 24 hours. Probit method of the Finney computer programme was used to determine the lethal concentration fifty (LC50) and 95% confidence intervals. It was evident that the chloroform extract of the three plant extracts was the most toxic to the brine shrimps compared to water and methanol extracts. Albizia anthelmintica extracts of all the solvents was the most potent compared with the two Maerua species. The anthelmintic efficacy of the three plants was studied in mice experimentally infected with Heligmosomoides polygyrus. The results indicated a percentage faecal xv Heligmosomoides polygyrus egg count reduction of 72%, 69%, 50%, 42% using water extracts of Albizia anthelmintica at 10gm/kg bodyweight, Maerua edulis at 20gm/kg bodyweight, Albizia anthelmintica at 20gm/kg bodyweight and Albizia anthelmintica at 5gmlkg bodyweight respectively. Seven days after treatment there was a reduction in worm counts at postmortem of 68%, 36%, 20%, 19%,16% and 14% for water extracts of Albizia anthelmintica at 5gmlkg bodyweight, Maerua edulis at 10gmlkg bodyweight, Albizia anthelmintica at 10gmlkg bodyweight, Albizia anthelmintica at 20gm/kg bodyweight, Maerua edulis at 20gm/kg bodyweight and Maerua edulis at 5gm/kg bodyweight respectively. Mice treated with Albizia anthelmintica at 5gm/kg bodyweight had a significantly lower mean worm counts than the rest of the treatment groups and the control (p<0.05).There was insignificant reduction in worm counts for other treatment groups compared with the control (p<0.05). The column and thin layer chromatography done on the aqueous extract of Albizia anthelmintica yielded only one fraction which was active and had a relative fraction (Rf) of 0.75. The results therefore indicate that the plant have some anthelmintic activity though low with Albizia anthelmintica being most efficacious. The bioactive fraction in Albizia anthelmintica obtained through chromatographic techniques indicate that there is a rationale in the use of this plant as an anthelmintic by the pastoralists. There is therefore a need to identify the active ingredient in Albizia anthelmintica for future commercial use.