Yuanqiang Guo
State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy, Nankai University, Tianjin 300071, People’s Republic of China
Alzheimer’s disease (AD), a neurodegenerative disorder, is the most common form of dementia worldwide. Patients with AD usually have the characteristic symptoms of progressive memory loss and cognitive decline.1 For this disease, some remedies, such as donepezil, rivastigmine, tacrine, and galantamine, have been so far approved for the treatment of AD. However, all of these drugs provide only symptomatic treatment and the effectiveness has been questioned since they could not prevent or delay neurodegeneration.2,3 Therefore, there is a still urgent need to develop new agents to treat AD effectively.4,5 One strategy to develop new agents for AD is to search for biologically active substances or lead compounds from plant secondary metabolites, which has been proven to be effective and practicable for new drugs of medical field.6
Natural products play an important role in the research and development of new drugs and many natural bioactive substances have been found to be from plants.6,7 Substances from plants have provided many lead compounds for the new drugs. In our recent research, one goal is to search for bioactive natural products with promoting effects on neurite outgrowth from plants. Neurites have been proven to be important for the function maintenance of central nerve system and bioactive compounds with promoting effects of neurite growth may be expected to be potentially useful for the treatment of AD and other neurological disorders.8,9 With the guide of this goal, some plants were screened using the corresponding PC12 cells model, whose neurite outgrowth could be promoted by NGF, some plant extracts, and some compounds. Some plants, such as Casearia balansae, Saluia plebeian, Casearia graveolens, were screened, whose MeOH extracts showed promoting effects on neurite outgrowth of PC12 cells. The subsequent investigation for bioactive substances led to isolation of numerous bioactive compounds.10-12 The promoting effects on neurite outgrowth of PC12 cells of these compounds were evaluated and the EC50 values were described. These bioactive diterpenoids may be useful for the development of antineurodegenerative agents to combat Alzheimer's disease and other neurological disorders.
