VOLATILE OIL OF THE LEAVES OF P.nigrum L. ALLEVIATES BETA AMYLOID PATHOLOGY IN Drosophila melanogaster

*B. Sugithra, Dr. K. Raadhika M.D., Dr. K. Periyanayagam, N. Subbulekshmi, S. Indumathi, T. Uma Poorani and R. Balasubramaniyan

ABSTRACT

Objective: To prescreen the in vivo neuro protective activity of the VO of the leaves of P.nigrum family Piperaceae commonly called as pepper, using the model organism Aβ42-amyloid neuro toxicity induced Drosophila melanogaster. Method: Isolation of leaf VO and its analysis by GC-MS were carried out. Acute toxicity assessment were also performed. The neuro protective effect of the VO of the leaves of P.nigrum (VOPNL) in vivo was evaluated on the transgenic Aβ42 model of Drosophila melanogaster, a novel model system for screening drugs for Alzheimer disease by Longivity Assay, Climbing Assay, Pseudopupil assay and nail polish imprint technique and SEM. Results: GC-MS Profile of the VO showed the presence of nerolidol, β- caryophyllene, cubein, globulol, α -pinene, α -terpinene, elemol, α–bisbolol, β- bisabolene, β-elemene. Toxicity assessment using brine shrimp lethality bioassay (BSLA) of the VOPNL showed nontoxic upto LC50 500ppm. The VOPNL possesses potential in vivo neuro protective activity on Drosophila melanogaster against beta amyloid induced neuronal toxicity. Conclusion: We investigated the in vivo neuroprotection of the VOPNL on the representative of Alzheimer disease model of transgenic Drosophila by overexpression of beta amyloid protein, Aβ42. In the present study we have presented the first evidence that the VO of the leaves could significantly ameliorate the adverse morphological changes from Aβ42 protein in Drosophila, as indicated by prolonging the lifespan, by improving locomotor abilities and rescuing neurodegeneration in ommatidia of Aβ expressing Drosophila which is comparable with donepezil. So it demonstrated the novel use of VOPNL against Aβ induced neurodegeneration which may be mediated through the multiple components of the VO. Based on this findings we suggest developing VO of the leaves of P.nigrum as a potential therapeutic intervention for neurodegenerative diseases like Alzheimer‟s disease. VOPNL effectively protect, rescue and most importantly restore the impaired movement activity (i.e climbing capability) in Drosophila melanogaster, a valid model of AD. It provides a framework for future studies to assess the suppression of oxidative stress and to restore and or maintain locomotor activity in AD patients. Elucidation of their mechanism of action will provide new insight for new targets.

Keywords: Piper nigrum, Piperacae, Neurooprotective, Drosophila melanogaster, Voaltile oil, Alzheimer disease.