Natural Products and Their Bioactive Compounds: Neuroprotective Potentials against Neurodegenerative Diseases

Table 4

Natural products and their bioactive compounds with neuroprotective activities in treating other neurodegenerative diseases and neurological disorders.

Plant extracts/phytochemicals (plant source)/natural products/substances	Study model	Neuroprotective activities	References
Ethanolic extract of Cocculus laurifolius leaves	Strychnine-induced convulsions in albino rats	(i) Exhibited anticonvulsant activity by delaying the onset convulsion	[274]
		(ii) Maintained the structure of neurons
		(ii) Decreased neuronal apoptosis
Coeloglossum viride var. bracteatum	A combination of D-galactose and aluminum chloride-induced aging mouse	(i) Improved learning and memory in aging mouse	[275]
		(ii) Upregulated mRNA expression of BDNF and fibroblast growth factor 2 (FGF2) in the hippocampus of aging mouse
		(iii) Inhibited mRNA expression of neuroinflammatory factors (TNF-α, IL-6, IL-1β, and NOS-2) in the hippocampus of aging mouse
		(iv) Activated PI3K/Akt signaling pathway
		(v) Inhibited the canonical caspase-3 apoptosis pathways
Methanolic extract of Cinnamomum camphora leaves	Maximal electroshock-induced seizures in albino Wistar rats	(i) Exhibited the anticonvulsant activity in maximal electroshock-induced seizures by reducing epileptic seizures	[276]
		(ii) Increased gamma-aminobutyric acid (GABA) release
		(iii) Decreased lipid peroxidation and acetylcholinesterase activity
		(iv) Increased GSH level
Phragmanthera austroarabica extract	Pentylenetetrazol-kindled mouse	(i) Reduced seizures and cortical malondialdehyde level	[277]
		(ii) Enhanced cortical GSH
		(iii) Reduced the percentage of pyknotic neurons in the hippocampus
		(iv) Increased the percentage of viable neurons
Parawixin 10, a compound isolated from Parawixia bistriata spider venom	A rat excitotoxicity model of brain injury by kainic acid, N-methyl-D-aspartate, and pentylenetetrazol	(i) Decreased glial proliferation in all hippocampal subfields studied, as well as the preservation of cell layers	[278, 279]
		(ii) Prevented the onset of seizures induced with kainic acid, N-methyl-D-aspartate, and pentylenetetrazol
		(iii) Increased the latency to the onset of kainic acid-, pentylenetetrazol-, and N-methyl-D-aspartate-induced seizures
White rose (Rosa hybrida) petal extract	Kainic acid-induced mouse and in HB1.F3 human neural stem cells	(i) Exhibited radical scavenging activities	[280]
		(ii) Inhibited lipid peroxidation
		(iii) Decreased scores of epileptiform seizures
		(iv) Decreased hippocampal pyramidal neuronal loss
		(v) Downregulated mRNA expressions of antioxidant enzymes
		(vi) Downregulated mRNA and protein expressions of inflammatory mediators
Rosemary extract	Kainic acid-induced rats	(i) Decreased neuronal loss in CA3 hippocampal region	[281]
		(ii) Decreased spatial memory and learning impairment
Walnut extract	Lipopolysaccharide-induced neurotoxicity in rat microglial cell line	(i) Downregulated iNOS and Iba-1 expressions	[273]
		(ii) Upregulated calmodulin expression

Taken together, these findings proposed that the natural products and their bioactive compounds may have a potential neuroprotective effect against neurodegenerative disease through various mechanisms, primarily through their antioxidant, anti-inflammatory, and antiapoptotic. This signifies the therapeutic evidence of the natural products and their bioactive compounds as neuroprotective agents.