Neuroprotective potential of ocimum sanctum (Linn) leaf extract in preventing and attenuating stress induced substantia nigral neuronal damage in rats

Vincent Rodrigues; Muddanna S Rao; Gurumadhva S Rao; Mohandas Rao K G

doi:10.1016/j.jaim.2022.100651

Neuroprotective potential of ocimum sanctum (Linn) leaf extract in preventing and attenuating stress induced substantia nigral neuronal damage in rats

J Ayurveda Integr Med. 2022 Oct-Dec;13(4):100651. doi: 10.1016/j.jaim.2022.100651. Epub 2022 Nov 9.

Authors

Vincent Rodrigues¹, Muddanna S Rao², Gurumadhva S Rao³, Mohandas Rao K G⁴

Affiliations

¹ Department of Preclinical Sciences, Faculty of Medical Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago.
² Department of Anatomy, Faculty of Medicine, Kuwait University, Safat, Kuwait.
³ Department of Pharmacology, RAK Medical and Health Sciences University, Ras Al Khaimah, United Arab Emirates.
⁴ Department of Anatomy, Melaka Manipal Medical College, Manipal Academy of Higher Education, Manipal, India. Electronic address: mohandas.rao@manipal.edu.

Abstract

Background: In Ayurveda; an Indian system of traditional medicine, Ocimum sanctum is said to have remedial effect on hriddaurbalya (problems affecting the mind), aakshepayukta vikara (nervous disorders) and shiroroga (diseases of head). Hence, in Ayurvedic practice, it is profoundly used as an antistress medicine. Stress is known to affect neurons of functionally significant brain regions like substantia nigra. However, experimental evidence showing its effect on morphology of substantia nigral neurons is lacking. In addition, whether the O. sanctum treatment attenuates stress induced substantia nigral neuronal structural changes is not known.

Objectives: To know the effect of stress on morphology of substantia nigral neurons and the effect of O. sanctum fresh leaf extract (OSE) on substantia nigral neurons of stressed rats.

Material and methods: Present study included three experiments. Experiment I: To study the effect of 3 and 6 weeks of foot shock stress in rats; Experiment II- To study the effect of 3 weeks of OSE treatment on 3 week-stress undergoing rats and on 3 week-stressed rats; Experiment III- To study the effect of 6 weeks of OSE treatment in 6 week-stress undergoing rats and in 6 week-stressed rats.

Results: In experiment I, stress had significant deleterious effect on dendritic arborization of substantia nigral neurons. Experiments II and III showed prevention and attenuation of the stress induced dendritic atrophy of substantia nigral neurons in both 2 ml and 4 ml OSE treatment groups. Protective effect of OSE was more pronounced in rats which are treated for a longer duration.

Conclusions: Foot shock stress induces neuronal damage in the substantia nigra of rats. Treatment with fresh leaf extract of O. sanctum could prevent and attenuate the foot shock stress induced behavioral deficit and substantia nigral neuronal damage.

Keywords: Dendritic branching; Dendritic intersections; Foot shock stress; Herbal extract; Open field test; Stress behavior.