Neuroprotective Potential of Seed Extracts: Review of In Vitro and In Vivo Studies

Abstract

Introduction: Neurodegenerative diseases are characterized by neuronal dysfunction and death. Studies suggest that some seed extracts have a neuroprotective effect. Considering the increased incidence of these diseases and the need for new effective therapies with fewer side effects, this review aimed to assess the evidence of the efficacy and safety of seed extracts in experimental models of neurodegeneration.

Material and method: The search was carried out through studies published between 2000 and 2021 in Science Direct, PubMed, Scientific Electronic Library Online (SciELO), and Latin American Literature in Health Sciences (LILACS) databases, in which the effects of seed extracts in in vitro and in vivo experimental models of neurodegeneration were investigated. Based on the eligibility criteria, 47 studies were selected for this review.

Results: In the in vitro models, the neuroprotection of the seed extracts was a result of their antioxidant, anti-inflammatory, and anti-apoptotic properties. In the in vivo models, neuroprotection resulted from the antioxidant and anti-inflammatory properties, a decrease in motor deficits, an improvement in learning and memory, as well as the increased release of neurotransmitters. The results show promise for the future of clinical research on new therapies for neurodegenerative diseases. However, the studies are still limited, which does not allow us to extrapolate the results to human beings with ND.

Conclusions: Therefore, clinical trials are needed in order to prove the results of the in vitro and in vivo studies, as well as to assess the ideal, safe, and effective dose of these seed extracts in patients with neurodegenerative diseases.

Keywords: experimental models; neurodegenerative diseases; neuroprotection; seeds.

Figure 1

Seed extracts of plants that have shown neuroprotective potential in neurodegeneration models (in vitro and in vivo). (Illustration by Dr. Francisco Irochima).

Figure 2

Factors related to neurodegenerative diseases. Genetic aspects and others related to lifestyle and aging may result in oxidative stress, neuroinflammation, decreased levels of neurotransmitters, neuronal death, and motor deficit, as well as decreased memory, cognition, and learning. These deleterious events can cause abnormal accumulations of beta amyloid and TAU proteins, such as those that occur in Alzheimer’s disease, as well as in alpha-synuclein protein, such as those that occur in Parkinson’s disease. (Illustration by Dr. Francisco Irochima).

Figure 3

Seeds with anti-inflammatory, antioxidant, and anti-apoptotic properties, as demonstrated by in vitro studies with nerve cell culture. (Illustration by Dr. Francisco Irochima).

Figure 4

Seeds with protective effects on ischemic brain damage and with improvement in cognitive, learning, memory, and sensorimotor deficits as demonstrated by in vivo animal studies. (Illustration by Dr. Francisco Irochima).