Alkaloid phthalide subtype

In this review, the natural phthalides of plant origin are classified into four types based on chemical structure (Fig. (2-6)) 1) 3-substituted phthalides 2) non-3-substituted phthalides 3) phthalide dimers and 4) phthalide isoquinolines. The 3-substituted phthalide derivatives are further classified into two subtypes, namely non-alkaloid phthalides (Fig. (2 and alkaloid phthalides (Fig. (3 . Phthalide alkaloids without the isoquinoline structure are always 3-substituted and are accordingly subclassified as the... 

The details of the classifications and chemical structures of four types of natural phthalides are illustrated in Figs. (2-6). Most of the isolated natural phthalides belong to the 3-substituted phthalide type, which accounts for about 61% of the total known naturally occurring phthalides, and of these, non-alkaloid phthalides constitute the most important subtype due not only to their abundance in nature (75 compounds identified) but also their extensively reported pharmacological activities. The pharmacological activities of individual phthalides are discussed in the following Biological Activity Section. 

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