Dietary flavonoids-rich Citrus reticulata peel extract interacts with CREB signaling to suppress seizures and linked neurobehavioral impairments in a kindling mouse model

ABSTRACT

Objectives: The citrus fruits peel contains a variety of bioactive metabolites that have shown multiple therapeutic effects. However, despite having substantial ethnomedicinal value, citrus peels remained underexplored and regarded as bio-waste. This present study was planned to investigate the effect of a characterized peel extract of Citrus reticulata c.v. (CRE) in pentylenetetrazole (PTZ)-induced kindling and associated cognitive and behavioral impairments in a mouse model.

Methods: The kindled animals were treated daily with CRE (100 and 200 mg/kg) and challenged with a sub-effective dose of PTZ every 5th day to record the severity of seizures. In the end, different tests were performed to record behavioral and cognitive performance.

Results: CRE-treated kindled animals showed a significant suppression in seizure severity following 20 days of the treatment. In the T-maze test, the extract treatment resulted in a marked increase in the spontaneous alternations, whereas it showed no change in anxiety behavior of kindled animals in the elevated plus-maze test. In both forced swim and tail suspension tests, CRE treatment demonstrated a considerable reduction in immobility time. However, no change in overall locomotion was observed in the open field test among all the groups. An increase in the hippocampal Creb and Bdnf expression and decreased glutamate-to-GABA ratio were observed in the CRE-treated kindled animals.

Discussion: The results showed that CRE treatment suppresses epileptic seizures and associated cognitive deficits and depression-like behavior in kindled mice. The gene expression findings supported that the observed protective effects of CRE be due to its interaction with CREB signaling.

KEYWORDS:

• Brain-derived neurotrophic factor
• cAMP response element-binding protein
• cognitive deficits
• epilepsy
• glutamate
• hippocampus
• hesperidin
• pentylenetetrazole

Acknowledgements

The authors are thankful to the Director, CSIR-IHBT, Palampur (HP), India, for providing the essential facilities. Ms. Pallavi Sharma and Ms. Poonam Dhiman are grateful to the ICMR, New Delhi, India and the CSIR, New Delhi, India for granting Senior Research Fellowship (File No.: 5/3/8/38/ITR-F/2018-ITR) and Junior Research Fellowship [File No.: 31/054(0158)/2020-EMR-I], respectively. The authors are grateful to Dr. Mahesh Gupta (Principal Scientist, CSIR-IHBT), a food technologist for identification and quality assessment of the procured peel. The institute manuscript communication number is 4958.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Council of Scientific and Industrial Research, India [grant number MLP-0204].

Notes on contributors

Pallavi Sharma

Pallavi Sharma earned her Masters of Pharmacy in Pharmacology from Kurukshetra University, Kurukshetra, India. She is pursuing her Ph.D. from AcSIR at CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India. She is a recipient of Senior Research Fellowship from the Indian Council of Medical Research, India. Her work is focused on the development of novel nutraceutical formulations for the comprehensive management of epilepsy and its associated comorbid conditions such as anxiety, depression, learning and memory deficit. She targeted CREB-BDNF pathway using bioactive molecules to suppress epileptic discharge in animal models.

Poonam Dhiman

Poonam Dhiman is working as a Junior Research Fellow (JRF) in the Pharmacology and Toxicology Laboratory at CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India. She completed her integrated M.Sc. degree in Zoology from Shoolini University of Biotechnology and Management Sciences, Solan, India. She was awarded with INSPIRE scholarship for higher education (SHE) by the Department of Science and Technology, Govt. of India. Currently, she is registered for her Ph.D. with AcSIR. Her work is focused on metabolic diseases-induced neurobehavioral impairments and to uncover the molecular mechanisms behind it preclinical models.

Damanpreet Singh

Damanpreet Singh did his M. Pharmacy from Guru Nanak Dev University, India. Thereafter, he obtained his Ph.D. in the area of Pharmacology from Punjabi University, India. He then joined the Department of Pharmaceutical Sciences and Drug Research, Punjabi University, India as an Assistant Professor and worked in the area of neuropharmacology to find out potential targets and ligands of natural origin for comprehensive management of epilepsy. Thereafter he joined the CSIR-Institute of Himalayan Bioresource Technology, India as a Scientist and continued to explore the molecular basis of natural products in management of neurological disorders. Presently, he is working as a Senior Scientist in the Pharmacology and Toxicology Laboratory of the same institute. His research group is focused on identification of novel phytopharmaceuticals to combat chronic neurological conditions.