Naphthoquinone is a class of natural phenol

Natural phenol

Natural phenols, bioavailable phenols, plant phenolics, low molecular weight phenols or phenoloids are a class of natural products. They are small molecules containing one or more phenolic group. These molecules are smaller in size than polyphenols, containing less than 12 phenolic groups...

s based on the C6-C4 skeleton.

1,4-Naphthoquinone can be viewed as derivatives of naphthalene

Naphthalene

Naphthalene is an organic compound with formula . It is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings...

 through the replacement of two hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 atoms by two 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...

 groups.

The name is also used generically for two other isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

s:

• 1,2-Naphthoquinone
  1,2-Naphthoquinone
  1,2-Naphthoquinone or ortho-naphthoquinone is a polycyclic aromatic organic compound with formula .This double ketone is a reactive metabolite of naphthalene and is found in diesel exhaust particles...
  
  
• 1,4-Naphthoquinone
• 2,6-Naphthoquinone (amphi-naphthoquinone)

Naturally occurring naphtoquinones

• Juglone
  Juglone
  Juglone, also called 5-hydroxy-1,4-naphthalenedione or 5-hydroxynaphthoquinone, is an organic compound with the molecular formula C10H6O3. In the food industry, juglone is also known as C.I. Natural Brown 7 and C.I. 75500...
  
  
• Plumbagin
  Plumbagin
  Plumbagin or 5-hydroxy-2-methyl-1,4-naphthoquinone is an organic compound with the chemical formula . It is regarded as a toxin.Plumbagin is a yellow dye, formally derived from naphthoquinone....
  
  
• Droserone
  Droseraceae
  Droseraceae is the botanical name for a family of flowering plants. The family is also known under its common name, the sundew family.It consists of carnivorous plants: besides the sundews, the genus Drosera, it also contains the even more-famous Venus fly trap Dionaea muscipula...
  
  

Properties

1,4-Naphthoquinone forms yellow triclinic crystals and has an odor similar to benzoquinone

1,4-Benzoquinone

1,4-Benzoquinone, commonly known as para-quinone, is a chemical compound with the formula C6H4O2. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor, resembling that of chlorine, bleach, and hot plastic. Impure samples are often dark-colored due to the presence...

. It is sparingly soluble in cold water, slightly soluble in petroleum ether

Petroleum ether

Petroleum ether, also known as benzine, VM&P Naphtha, Petroleum Naphtha, Naphtha ASTM, Petroleum Spirits, X4 or Ligroin, is a group of various volatile, highly flammable, liquid hydrocarbon mixtures used chiefly as nonpolar solvents...

, and freely soluble in most polar organic solvents. In alkaline solutions it produces a reddish-brown color. Because of their aromatic stability, 1,4-naphthoquinone derivatives are known to possess anti-bacterial and anti-tumor properties.

Naphthoquinone forms the central chemical structure of many natural compounds, most notably the K vitamins

Vitamin K

Vitamin K is a group of structurally similar, fat soluble vitamins that are needed for the posttranslational modification of certain proteins required for blood coagulation and in metabolic pathways in bone and other tissue. They are 2-methyl-1,4-naphthoquinone derivatives...

.

Medicinal uses

Naphthoquinone derivatives have significant pharmacological properties. They are cytotoxic, they have significant antibacterial, antifungal, antiviral

Antiviral drug

Antiviral drugs are a class of medication used specifically for treating viral infections. Like antibiotics for bacteria, specific antivirals are used for specific viruses...

, insecticidal

Insecticidal

Insecticidal is a 2005 [Horror Thriller featuring giant, killer insects. A college student is modifying insects until a housemate tries to kill them...

, anti-inflammatory

Anti-inflammatory

Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. Anti-inflammatory drugs make up about half of analgesics, remedying pain by reducing inflammation as opposed to opioids, which affect the central nervous system....

, and antipyretic

Antipyretic

Antipyretics ; an-tee-pahy-ret-iks; from the Greek anti, against, and pyreticus, are drugs or herbs that reduce fever. Normally, they will not lower body temperature if one does not have a fever. Antipyretics cause the hypothalamus to override an interleukin-induced increase in temperature...

properties. Plants with naphthoquinone content are widely used in China and the countries of South America, where they are used to treat malignant and parasitic diseases.