Chilean Soapbark Tree (Quillaja saponaria)

The aqueous extract of the Chilean soapbark tree (Quillaja saponaria Molina) is made up of many bioactive triterpenoid saponins (Guo and Kenne, 2000). It has U.S. Food and Drug Administration clearance (21 CFR 172.510) as a natural flavouring substance and is used in food mainly as a foaming agent and in beverages as an emulsifier (Chino and Wako 1992; Murakami and Watanabe 1988a, 1988b; Naknukool et al., 2011).

In addition to Chile, this soapbark tree is native to China and many other South American countries including Bolivia and Peru. This quillaja extract is also authorised by the European Union for use in water-based nonalcoholic drinks under the code, E999 (CAS number: 68990-67-0) (Tam and Roner, 2011). Additionally, in Japan, it is used as an emulsifier and foaming agent and for application in cosmetics (FAO, 2004). In order to avoid deforestation, and to have a sustainable, relatively inexpensive source of the food-additive, the aqueous extracts are obtained from the bark of the tree or wood of the branches (Tam and Roner, 2011; FAO, 2004).

The aqueous extract of Quillaja (QE) is stable over a wide pH range, that is pH 2 to 11 (Roner et al., 2007). QE is known to have anti-viral activity against vaccinia virus, herpes simplex virus type 1 (HSV-1), varicella zoster virus (VZV), human immunodeficiency viruses 1 and 2 (HIV-1, HIV-2), reovirus and rhesus rotavirus (RRV) (both in vitro and in vivo) (Roner et al., 2007, 2010).

References

Chino, Y., Wako, M. (1992) Manufacture of transparent emulsions for foods and beverages. US Patent 04 51:83.

Guo, S., Kenne, L. (2000) Structural studies of triterpenoid saponins with new acyl components from Quillaja saponaria Molina. Phytochemistry 55 pp.419–28

Naknukool, S., Horinouchi, I., Hatta, H. (2011) Stimulating macrophage activity in mice and humans by oral administration of Quillaja saponin. Biosci. Biotechnol. Biochem. 75 pp. 1889–93

Murakami, F., Watanabe, T. (1988a) Manufacture of stabilized cream using Quillaja saponin. US Patent 63 (1988):735

Murakami, F., Watanabe, T. (1988b) Production of emulsified fat and oil-containing soy sauce. US Patent 63:23371.

Roner, M.R., Sprayberry, J., Spinks, M., Dhanji, S. (2007) Antiviral activity obtained from aqueous extracts of the Chilean soapbark tree (Quillaja saponaria Molina). J. Gen. Virol. 88 pp. 275–285

Roner, M.R., Tam, K.I., Kiesling-Barrager, M. (2010) Prevention of rotavirus infections in vitro with aqueous extracts of Quillaja saponaria Molina. Future Med Chem 2 pp. 1083–97.

Tam, K.I., Roner, M.R. (2011) Characterization of in vivo anti-rotavirus activities of saponin extracts from Quillaja saponaria Molina. Antiviral Res. 90 pp. 231–41.