Shikimic acid is a tri-hydroxy cyclohexene carboxylic acid implicated in biosynthesis of many compounds. The shikimate pathway is named after it. Shikimic acid can be used for the biosynthesis of the aromatic amino acids[1].

Shikimic acid can be isolated from the needles of a variety of plants and microorganisms, such as the Chinese star anise and the seeds of the sweetgum fruit. Shikimic acid can be used as a starting material for the synthesis of oseltamivir. Although shikimic acid is a biosynthetic intermediate existed in most autotrophic organisms general found in very low concentrations [1].

In vitro: In SH-SY5Y cells, 10nM, 10μM, and 10 mM shikimic acid showed antioxidant activity without exerting cytotoxic effects. In addition, shikimic acid protected the cells against H2O2-induced increases in ROS levels and DNA damage. Shikimic acidexhibited neuroprotective actions against oxidative stress-induced toxicity on SH-SY5Y cells [2].

References:
Liza B.  Enrich, Margaret L. Scheuermann, Ashley Mohadjer,et al. Liquidambar styraciua: a renewable source of shikimic acid., Tetrahedron Letters, 2008, 49: 2503–2505,
Rabelo T K, Zeidán-Chuliá F, Caregnato F F, et al.  In vitro neuroprotective effect of shikimic acid against hydrogen peroxide-induced oxidative stress[J]. Journal of Molecular Neuroscience, 2015, 56(4): 956-965.