Development of L-Dopa-containing diketopiperazines as blood-brain barrier shuttle

• In our overall goal to develop anti-Parkinson drugs, we designed novel diketopiperazines (DKP1-6) aiming to both reach the blood-brain barrier and counteract the oxidative stress related to Parkinson's Disease (PD). The anti-Parkinson properties of DKP 1–6 were evaluated using neurotoxin-treated PC12 cells, as in vitro model of PD, while their cytotoxicity and genotoxicity potentials were investigated in newborn rat cerebral cortex (RCC) and primary human whole blood (PHWB) cell cultures. The response against free radicals was evaluated by the total antioxidant capacity (TAC) assay. Comet assay was used to detect DNA damage while the content of 8-hydroxyl-2′-deoxyguanosine (8-OH-dG) was determined as a marker of oxidative DNA damage. PAMPA-BBB and Caco-2 assays were employed to evaluate the capability of DKP1-6 to cross the membranes. Stability studies were conducted in simulated gastric and intestinal fluids and human plasma. Results showed that DKP5-6 attenuate the MPP + -induced cell death on a nanomolar scale, but a remarkable effect was observed for DKP6 on Nrf2 activation that leads to the expression of genes involved in oxidative stress response thus increasing glutathione biosynthesis and ROS buffering. DKP5-6 resulted in no toxicity for RCC neurons and PHWB cells exposed to 10–500 nM concentrations during 24 h as determined by MTT and LDH assays and TAC levels were not altered in both cultured cell types. No significant difference in the induction of DNA damage was observed for DKP5-6. Both DKPs resulted stable in simulated gastric fluids (t1/2 > 22h). In simulated intestinal fluids, DKP5 underwent immediate hydrolysis while DKP6 showed a half-life higher than 3 h. In human plasma, DKP6 resulted quite stable. DKP6 displayed both high BBB and Caco-2 permeability confirming that the DKP scaffold represents a useful tool to improve the crossing of drugs through the biological membranes. 

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Farmaceutiska vetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Pharmaceutical Sciences (hsv//eng)

Nyckelord

Antioxidant

Blood brain shuttle

Brain delivery system

Diketopiperazine

Levodopa

Parkinson's disease

Animals

Antioxidants

Blood-Brain Barrier

Caco-2 Cells

Carcinoma

Renal Cell

Diketopiperazines

Humans

Kidney Neoplasms

Oxidative Stress

Parkinson Disease

Rats

8 hydroxydeoxyguanosine

free radical

glutathione

neurotoxin

piperazinedione

reactive oxygen metabolite

transcription factor Nrf2

animal cell

animal experiment

animal model

animal tissue

Article

biomembrane

biosynthesis

blood brain barrier

brain cortex

cancer model

cell culture

cell death

comet assay

controlled study

cytotoxicity

DNA damage

genetic marker

genotoxicity

half life time

human

hydrolysis

in vitro study

intestine fluid

male

newborn

nonhuman

rat

simulation

stomach juice

total antioxidant capacity

animal

Caco-2 cell line

kidney tumor

metabolism

renal cell carcinoma

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