Macrolides From Stachytarpheta Cayennensisverbenaceae And Tetrapleura Tetraptera Fabaceae: Isolation, Characterisation, Pesticidal And Antifungal Evaluation :- Okoronkwo, Nnenna E

ABSTRACT

 Two plants: Stachytarpheta cayennensis and Tetrapluera tetraptera which have hitherto been employed locally in pests control were selected for study, with particular emphasis on the leaves and stem of Stachytarpheta cayennensis and leaves, bark, and root of Tetrapluera tetraptera respectively. The study evaluated the phytochemicals, antifungal and anticholinestrase activities of different fractions ofthe plants and also subjected the isolated pure samples to spectroscopic analysis. The results showed that the phytochemicals - alkaloids, tannins, saponins, flavonoids and phenols were all present in the parts ofthe plants studied with the highest percentage of alkaloid of 42.93 ±0.27% recorded for the bark of Tetrapluera tetraptera. The result of antifungal activities revealed that the ethanol extracts of leaves and stem of Starchytarpheta cayennensis and the bark and root of Tetrapleura tetraptera plants had promising activity against Aspergillus fumigatus and Rhizopus species fungi. The inhibitions of ethanol extracts of the leaves (13.0mm) and stem (9.0mm) of Starchytarpheta cayennensis and bark (11.0mm) and root (13.0mm) of Tetrapleura tetraptera showed activity against Rhizopus species There was no activity shown by the ethanol and water extracts of ' , the parts ofthe plants against Fugarium oxysporum, Penicillium chrysogemun and 'Mucor species fungi. All the different extracts of the parts of plants assessed for their inhibitory activities against acetyl cholinesterase (AChE) exhibited dose dependent inhibitory effects against the enzyme. The chloroform extracts of the bark of Tetrapluera tetraptera showed the highest inhibitory effect of 84.34% at a concentration of 1.0mg/l. Three chemical compounds were isolated from the two plants, nnenoside A from the root of Tetrapleura tetraptera while nnenoside B and a Benzofuran furanoside were from the leaves and stem of Starchytarpheta cayennensis, respectively. Their structures were established by spectroscopic evidences. The results obtained in this work justified some of the local (traditional) uses of the plants studied for insects and snakes repellents as well as management of fungi diseases of plants. The present investigation is an important step in developing plant based pesticides which are ecofriendly for the management and control of agricultural pests and also lead compound for the development of commercial formulation of botanicals.