Occurrence in Woody Plants

In nature, terpenoids are found to occur both in free and combined states. Most of the terpenoids that are not highly functionalized occur free. Carboxylic acids invariably occur in a free state, though occasional occurrence of methyl and other esters is known. Alcohols often occur both in the free state and as esters, in which the acid moiety is usually a simple aliphatic acid (e.g., acetic, tiglic, angelic, etc.) or less often an aromatic acid (e.g., benzoic, cinnamic), though esters 

In common with many other naturally occurring organic compounds, the percentage and nature of terpenoids in a given plant may vary widely with the time of harvesting of plant material (87, 118, 171). Different parts of the same plant may contain different terpenoids (87, 154, 204). 

---

A listing of some major acids and their occurrences in woody plants is found in Table 6.1.2. 

---