Perilla ketone is a natural terpenoid

Terpenoid

The terpenoids , sometimes called isoprenoids, are a large and diverse class of naturally occurring organic chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways. Most are multicyclic structures that differ from one another not only in...

 that consists of a furan

Furan

Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen. The class of compounds containing such rings are also referred to as furans....

 ring with a six-carbon side chain

Side chain

In organic chemistry and biochemistry, a side chain is a chemical group that is attached to a core part of the molecule called "main chain" or backbone. The placeholder R is often used as a generic placeholder for alkyl group side chains in chemical structure diagrams. To indicate other non-carbon...

 containing a ketone

Ketone

In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

 functional group. It is a colorless oil that is sensitive to oxygen, becoming colored upon standing.

Perilla ketone is present in the leaves and seeds of purple mint (Perilla

Perilla

Perilla is the common name of the herbs of the genus Perilla of the mint family, Lamiaceae. In mild climates, the plant reseeds itself. There are both green-leafed and purple-leafed varieties, which are generally recognized as separate species by botanists. The leaves resemble stinging nettle...

 frutescens), which is toxic to some animals. When cattle and horses consume purple mint when grazing in fields in which it grows, the perilla ketone causes pulmonary edema

Pulmonary edema

Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...

leading to a condition sometimes called perilla mint toxicosis.