Pharmacognostic, Toxicity, Antibacterial And Antihaemonchosis Evaluations Of Bidens Pilosa L. (Asteraceae)

Abstract

The vast uses of Bidens pilosa in traditional medicine for the treatment of various ailments such as cancer, inflammation, diabetes, infections, and haemonchosis in Nigeria, has prompted the research on this plant to evaluate its use in traditional medicine . This study was primarily designed to determine the pharmacognostic parameters, evaluate the safety of the plants in animals, determine its effects on bacteria and nematode parasite which cause haemonchosis in goats and sheep. Pharmacognostic studies as well as toxicity study carried out in two phases using 39 mice of opposite sex . Animals were administered methanol extract (ME) of the crude plant following intraperitoneal (i.p) at 10, 100, 1000, 1600, 2900 and 5000mg/kg body weight(b.w). Antibacterial study was conducted using ME of leaves on Bacillus subtilis NCTC8239, Salmonella typhi ATCC9184, Staphylococcus aureus NCTC6571, Escherichia coli NCTC10418, Klebsiella pneumonia ATCC10031, and Staphylococcus aureus ATCC13704. Effects leaf extracts were tested on Haemonchus contortus infective L3 larvae which cause haemonchosis in goats and sheep to determine % embryonation inhibition (%EI), % hatching inhibition (%HI) and % mortality rate of L3 larvae (%MR). Results showed that the plant possess covering trichome, diacytic stomata 22-23.3-25 mm2 and 31-34.1-38mm2 , Stomata index 12.5-13.24-14.2% and 22.4-23.80-26%, Vein islet and vein termination numbers 12-14-16 mm2 and 20-21-22 mm2 , Palisade ratios 8-9.4-12 mm2 and 4.2-7.5-10 mm2 upper and lower epidermis respectively. Phytochemical screening of leaf extract revealed the presence of many metabolites; with alkaloids, saponins, and tannins content more compared to other metabolites in the ME. Physico-chemical parameters showed that water extractive values of leaf were greater than that of stembarks and roots. The plant displayed great antibacterial activities on most of the microbes. Toxicity study showed that the animals survived the intoxication even at dosage of 5000 mg/kg b.w. Antihaemonchosis evaluations showed dose dependent activities of extracts. Methanol extract (ME) showed more potent on L3 larvae in terms of %EI, %HI and %MR from concentration 0.625 to 5.0 mg/mL after 48h. Our study showed that methanol extracts of Bidens pilosa were safe at the doses investigated and can serve as an ethnomedicinal prescription as well as treatment for haemonchosis in Nigeria. The data from pharmacognostic studies will serve as a tool for monograph in pharmacy.