Biological deterioration of wood is a big concern to the timber industry due to the economic losses resulting to wood in service or in storage. Fungi, insects, termites, marine borers, and bacteria are the principal wood biodegraders. Cellulose is the major structural component of wood and also the major food of insects and decay fungi. 

 

Polyphenols are the secondary metabolites of plants and are generally involved in defense against ultraviolet radiation or aggression by pathogens. 

Polyphenols are naturally occurring compounds found largely in fruits, vegetables, cereals, and beverages. In food, polyphenols may contribute to the bitterness, astringency, color, flavor, odor, and oxidative stability.

Furthermore, epidemiological studies and associated meta-analyses strongly suggest that long term consumption of diets rich in plant polyphenols offer protection against the development of cancers, cardiovascular diseases, diabetes, osteoporosis, and neurodegenerative diseases.

 

Flavonoids, a type of polyphenols, have an important effect on the durability of wood.

The general structure of flavonoids  includes a C15 (C6-C3-C6) skeleton joined to a chroman ring.

 

Some examples are:

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Flavonoids protect heartwood against fungal colonization by a dual function: fungicidal activity and being excellent free radical scavengers (antioxidants). The radical scavenging activity is particularly important because fungi use radicals to disrupt cell walls. Fungicidal activity, on the other hand, includes the repulsion of termites and insects.

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For more information: https://pdfs.semanticscholar.org/f654/d5678a49ebff62c73323f247b903e5ce2c26.pdf