neolignans

Neolignans are a class of natural products closely related to lignans. Like lignans, they arise from the dimerization of phenylpropanoid units derived from cinnamyl alcohol derivatives, but neolignans differ in the interunit linkage and resultant skeletal patterns, extending beyond the conventional beta-beta' lignan framework. They are typically formed by oxidative coupling of two monolignol units, a process often catalyzed by plant oxidases such as peroxidases or laccases, which can generate a variety of interunit bonds and lead to diverse three‑dimensional structures.

The structural diversity of neolignans is high. In addition to biphenyl-type dimers, many neolignans feature cyclic cores, including ether‑ and lactone‑containing frameworks and occasionally furofuran arrangements. This skeletal variety gives rise to multiple subclasses that are distinguished by their specific interunit connections and ring formations. The term encompasses a broad range of compounds, not a single uniform skeleton.

Natural occurrence has been reported for neolignans in a variety of higher plants, with isolations from seeds, bark, heartwood, and other tissues. As with many secondary metabolites, the precise distribution depends on species and developmental stage, and isolation is often guided by bioactivity or chemotaxonomic interest. Analysts typically rely on spectroscopic methods, such as NMR and mass spectrometry, to determine their structures.

Biological activity data are heterogeneous; some neolignans exhibit antioxidant, anti-inflammatory, antimicrobial, or cytotoxic effects in vitro, but activities are highly structure-dependent and not yet broadly developed as therapeutics. Research continues to clarify biosynthesis, structure–activity relationships, and potential applications.