Chartreusin is an antibiotic originally isolated from the bacteria ''

Streptomyces Chartreusis ''Streptomyces chartreusis'' is a bacterium species from the genus of ''Streptomyces'' which has been isolated from soil in Africa.Deutsche Sammlung von Mikroorganismen und Zellkulturenbr>/ref> ''Streptomyces chartreusis'' produces N-deacyltuni ...

.'' The crystalline compound itself has a yellow-green colour, as per its name, and is stable at room temperature for several hours. Chartreusin is chemically related to elsamitrucin, as the two share an aglycone chartarin structure, though they differ in their sugar moieties. Both chartreusin and elsamitrucin were found to have anticancer activity.

Biological activity

Chartreusin was shown to be effective as an antibiotic against some gram-positive species, as well as

mycobacteria ''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis ('' M. tuberculosis'') and ...

. This compound has also displayed anti-cancer activity, particularly against certain

melanoma Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...

s and leukemia in mice. However, this effect could only be observed in-vivo when the antibiotic was administered via intraperitoneal injection. Chartreusin administered by

intravenous therapy Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutri ...

was ineffective, as the compound would be excreted through the

bile Bile (from Latin ''bilis''), or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile ...

. This compound is believed to function by binding directly to DNA, preventing its replication. It binds cooperatively and has a high affinity for alternating AT or GC sequences. Upon binding, Chartreusin may inhibit the relaxation of negatively

supercoiled DNA supercoiling refers to the amount of twist in a particular DNA strand, which determines the amount of strain on it. A given strand may be "positively supercoiled" or "negatively supercoiled" (more or less tightly wound). The amount of a st ...

DNA, or induce strand

scission Scission may refer to: * Scission (chemistry), bond cleavage, the splitting of chemical bonds ** Chain scission, the degradation of a polymer main chain ** Beta scission, reaction in thermal cracking of hydrocarbons * ''Scission and Other Storie ...

. Consequently, this compound has been shown to interfere with mammalian cells' progression through the cell cycle. In the presence of chartreusin, cells in the G1 stage move more slowly into S, while cells in the G2 stage are entirely prevented from moving on to mitosis. Those cells already in the S phase are likely to experience lethal effects, though Chartreusin's lethality is also a function of both dosage and duration of exposure.

Pharmaceutical potential

Chartreusin is not currently considered to have significant potential as an anti-cancer drug. The concentration required for the drug to inhibit cell growth is typically also cytotoxic. Among surviving cells, prolonged exposure to Chartreusin leads to irreversible inhibition of growth and damage to DNA. Fortunately, the chemically similar elsamitrucin, or elsamicin A, has a better outlook.

References

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External links

Chartreusin, elsamicin A and related anti-cancer antibiotics
Antibiotics