A Phytochemical and Ethnopharmacological Review of the Genus Erythrina

In 1978, the World Health Organization (WHO) recognized folk medicine and its beneficial effects to health, during the Alma Ata conference, which published in 1985 that approximatly 80% of the global population, resorted to traditional medicine as their primary health treatment (Herbarium, 2008). Medicinal plants have been used as a means of curing or preventing diseases, now called phytotherapy, in all regions of the world, with regional variations due to the influence of cultural characteristics of the population, as well as its flora, soil and climate (Lewinsohn, 2003).

Studies have demonstrated the presence of analgesic and anti-inflammatory effects in extracts obtained from E. senegalensis, E. velutina and E. mulungu (Vasconcelos et al., 2003).In folk medicine, various species are utilized as a tranquilizer, against insomnia and to treat inflammation (Garcia-Mateos et al., 2001).

Bibliographic review
We conducted a literature review using the database SciFinder Scholar ® , and from the results obtained, we prepared two tables of data showing the correlation between popular use and the plant part utilized, as well as the form of utilization (Table 1), and the biological activities of the extracts obtained from Erythrina species (Table 2).Due to the large amount of data for phytochemicals isolated from the Erythrina species, we organized them in a simplified table (Table 3

Ethnopharmacological data
Plants of the Eryhtrina genus are utilized for a wide array of human diseases (Table 1).With regards the parts of the plants that are utilized, the most used is the bark, being 40.8% of the total of citations, as shown in Graphic 1.
Graphic 1. Parts of the plants utilized in folk medicine.

Biological activity data
Analysis of the biological activity data (Table 2) shows the wide variety of biological activity of plants from the Erythrina genus, and shows too that most of this corroborates with popular knowledge and uses.
It is noteworthy to point out that most of these activities, mainly the antibacterial and analgesic properties, confirm the different popular applications of extracts obtained from plants of this genus.We would like also to draw attention to the fact that in the Brazilian market there is the availability of a phytotherapeutic product from Erythrina mulungu widely used for anxiolytic purposes and as a sedative, activities confirmed by popular knowledge, but that, to our knowledge, have not yet been confirmed in pharmacological tests, showing that, despite the wide array of available data related to plants of this genus, there is still a need for more research about some of them.
It is important to note that some of the activities shown in the biological tests were not cited in the ethnopharmacological studies, which indicates yet another importance for plants of the Erythrina genus, which have the potential to provide new compounds for the development of drugs for the treatment of diseases such as cancer, diabetes and hypertension.

Phytochemical data
The phytochemical data (Table 3) analysis allowed for the verificationof a predominance of alkaloids and flavonoids in the Erythrina genus.It is important to note that alkaloids are recognized as markers for plants of this genus in addition to showing a wide array of biological activities, and being important candidates in the development of new drugs.

Conclusion
This review showed that Erythrina species are commonly utilized for numerous diseases and that many ethnopharmacological studies have been performed in order to confirm the activities attributed to these species.Moreover, several classes of substances have been isolated from the Erythrina genus, mainly alkaloids (41.57%) and flavonoids (29.76%).
Despite the large amount of available data, some of the plants of this genus remain to be studied.An example is Erythrina mulungu, largely used in Brazil, yet a significant number of studies regarding its pharmacological properties and chemical composition were unable to www.intechopen.comPhytochemicals -A Global Perspective of Their Role in Nutrition and Health 342 be found.A recent contribution to the knowledge about this plant is given by our group, regarding the anti-inflammatory and antinociceptive activities of a hydroalcoholic extract obtained from E. mulungu (Oliveira et al., in press).

Uses Part Utilized Kind of Extract/ Way of Use and Administration Species Locality Reference
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Table 1 .
Popular uses of Erythrina species www.intechopen.com

Table 2 .
Biological activity of Erythrina extracts.

Table 3 .
Occurrence of the different classes of compounds in the Erythrina genus Some important alkaloids that are distributed within plants from the Erythrina genus are erytharbine, erythartine, erysotramidine and erysotrine, shown in figure1.It is noteworthy that a characteristic feature of these alkaloids is the spiro structure in the rings bearing the nitrogen atom.