Phthalides are a relatively small group of natural compounds confined to several plant families and some genera of fungi and liverworts. They are divided into two structural groups, the monomeric and dimeric phthalides, and known mainly as bioactive constituents of different plant species used traditionally for medicinal purposes in Asia, Europe, and North America.The first reports on the chemistry of phthalides appeared at the end of the nineteenth century, in which they were identified as the odor constituents of the essential oil of celery (Apium graveolens) by Ciamician and Silber (1897). In the first half of the last century, phthalides were isolated from Cnidium officinale and Ligusticum acutilobum, species widely used in Asian traditional medicine, and from Levisticum officinale, a species used as food and condiment. Throughout the second part of the twentieth century, phthalides have been characterized from several plant families, namely Asteraceae, Leguminosae, Orchidaceae and Rutaceae, among others, but mainly from the Umbelliferae (syn Apiaceae) family, and the major contributors have been the following species used in traditional medicine: Ligusticum chuanxiong (Chinese name: Chuanxiong), Angelica sinensis (Chinese name: Danggui), Cnidium officinale (Japanese name: Senkyu), Angelica acutiloba (Japanese name: Toki), and Ligusticum porteri (Hispanic name: Oshá). Phthalides are also constituents of several genera of fungi, such as Penicillium, Alternaria and Pestalotiopsis, and some liverworts.Different chromatographic, spectrometric, and two-dimensional nuclear magnetic resonance (NMR) techniques have been used for the isolation and structural characterization of phthalides in extracts, and for assessing the quality of plant material containing this type of compound. Isotopic labeling has established the biosynthesis of phthalides via linkage of acetate units forming polyketide intermediates.Chemical transformations of monomeric phthalides have included oxidation, reduction, addition, elimination, and cycloaddition reactions, and treatments with Lewis acids of (Z)-ligustilide have afforded linear dimers. Some intramolecular condensations and differentiated cyclizations of the dimeric phthalides have been carried out, providing evidences for the particular chemical reactivity of these compounds.Several structural modifications of phthalides have been carried out subjecting them to microbial transformations by different species of bacteria, fungi and algae, and these included resolutions of racemic mixtures and oxidations, among others.The [π4s + π2s] and [π2s + π2s] cycloadditions of (Z)-ligustilide for the synthesis of dimeric phthalides have been reported, and different approaches involving cyclizations, Alder-Rickert reactions, Sharpless asymmetric hydroxylations, or Grignard additions have been used for the synthesis of monomeric phthalides. The use of phthalides as building blocks for divergent oriented synthesis has been proven.Many of the naturally occurring phthalides display different biological...

Four natural analogues of podophyllotoxin obtained from the Mexican medicinal plant Bursera fagaroides, namely, acetyl podophyllotoxin (2), 5'-desmethoxy-β-peltatin A methyl ether (3), 7',8'-dehydro acetyl podophyllotoxin (4), and burseranin (5), have been characterized, and their interactions with tubulin have been investigated. Cytotoxic activity measurements, followed by immunofluorescence microscopy and flow cytometry studies, demonstrated that these compounds disrupt microtubule networks in cells and cause cell cycle arrest in the G2/M phase in the A549 cell line. A tubulin binding assay showed that compounds 1-4 were potent assembly inhibitors, displaying binding to the colchicine site with Kb values ranging from 11.75 to 185.0 × 10(5) M(-1). In contrast, burseranin (5) was not able to inhibit tubulin assembly. From the structural perspective, the ligand-binding epitopes of compounds 1-3 have been mapped using STD-NMR, showing that B and E rings are the major points for interaction with the protein. The obtained results indicate that the inhibition of tubulin assembly of this family of compounds is more effective when there are at least two methoxyl groups at the E ring, along with a trans configuration of the lactone ring in the aryltetralin lignan core.

Three new aryldihydronaphthalene-type lignans were isolated and characterized from the stem bark of Bursera fagaroides var. fagaroides. Their antimitotic action mechanism by disturbing microtubule cytoskeleton was demonstrated by using the developing zebrafish embryos model.

The chemical constituents of the organic extracts from the rhizomes of Ligusticum porteri were isolated, characterised and identified as Z-ligustilide, Z-butylidenephthalide, diligustilide, tokinolide B, riligustilide, senkyunolides F and I, ferulic acid, among other known compounds. The preparation of 4,5-dehydrotokinolide B from tokinolide B is reported, and its structure confirmed by X-ray analysis. The sedative and spasmolytic activities of some of these natural products and derivatives were evaluated by applying them to in vivo and in vitro models. Several of these dimeric phthalides displayed sedative and spasmolytic properties that may correlate with some popular uses of L. porteri.

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