Anticancer activity of quinones isolated from different organism.
Cancer is a group of related diseases in which there is uncontrolled cell growth that spreads to the surrounding tissues and damages them. Cancer remains the disease with the leading cause of death worldwide, and incidence and mortality are increasing rapidly. The main cancer treatment is chemotherapy; however, the compounds used in this treatment have serious side effects for this reason, is necessary to develop new therapeutic strategies. Natural products are an excellent pharmacological alternative for the treatment of cancer and infections. In search of new compounds with cytotoxic and antimicrobial activity, we have found quinones that have a high pharmacological potency in the treatment of these health problems. Quinones are an aromatic system of one or diketone and are mainly isolated from plants, fungi, bacteria, and other organisms. These compounds are secondary metabolites derived from the oxidation of hydroquinones; they include benzoquinones, naphthoquinones, anthraquinones, and polyquinones. This review summarizes the activity of 152 anticancer and 30 antimicrobial quinones.
- natural product
Cancer is a group of a collection of related diseases where there is uncontrolled cell growth and spread into surrounding tissues, producing damage to them. In many cases, these cells form tumors and some cancer cells travel through the lymphatic system or blood to other places of the body and form new tumors.
Cancer remains the disease with major cause of death globally. In 2018, there were reported about 18 million new cases of cancer  and approximately 9.6 million deaths from this disease ; in addition, all over the world, the incidence and mortality of cancer are increasing. The risk of incidence of cancer is associated with age, infections, and human habits like poor diet, consumption of alcohol, tobacco, and others ; also, there are genetic predisposition and immune conditions .
Diseases due to the infections of bacteria and fungi are a very important health problem throughout the world. In 2019, the incidence of infection transmitted by food and water increased. The treatment of infection by bacteria is the administration of antibiotics; however, these drugs have been losing effectiveness because there is increased bacterial drug resistance . The main causes of bacterial resistance are unnecessary prescriptions  and the unregulated antibiotics sale in many countries, leading to inadequate and unnecessary consumption . Then, infections treatments become more expensive and have less effective.
From ancient times, natural products have been used in the treatment of different diseases, for example, in Egypt around 1550 BC, the “Ebers Papyrus” reported the use of 700 drugs . Nowadays, natural products are an important source of compounds with great potential for the treatment of infections and different forms of cancer .
Quinones are an important family of natural products. They have a variety of biological effects, such as anticancer and antimicrobial activities [10, 11]. The 1,4-naphthoquinones, since ancient times, have been used as cosmetics for coloring skin, as well as the treatment of some diseases. These compounds have several activities like anti-inflammatory, antiviral, anticancer, and antibacterial, among others.
For example, juglone and plumbagin show an antimicrobial effect on bacteria and fungi, and they are defensive compounds in the plant. Cytosporaquine A-D and physcion exhibited cytotoxic activity against several human cell cancer lines.
The cytotoxic and antimicrobial activities of 1,4 naphthoquinones are due mainly to two carbonyl groups present in these compounds, which can accept one or two electrons to form a semiquinone radical or di-anion species and for their acid–base properties .
2. Anticancer and antimicrobial activity of quinones obtained from plants, animals, and microorganisms
The incidence of cancer has increased; in 2018, around 9.6 million deaths in the world were due to this disease. The drugs used in chemotherapy have side effects and the cancer cells can have resistance to these drugs. Therefore, the study of new molecules with anticancer activity has become important.
Infectious diseases are an international health public problem, especially in undeveloped countries. For the treatment of these diseases are used antibiotics; however, several microorganisms present resistance to these drugs.
The search for new compounds with these activities has become important. Plants, marine organisms, fungi, and bacteria are natural sources to obtain substances with pharmacological effects.
Quinones are natural products with different pharmacological activities, such as anticancer and antimicrobial effects. These compounds can be obtained by synthesis or the structure modified to increase their activity.
This chapter shows the revision of the literature generated in the last 5 years of quinones isolated from 65 plant species, bacteria, fungi, algae, or sponges. The plants were the most different species studied, followed by fungi with 10 species, Streptomyces with 4 strain investigated, and bacteria with only one studied. Nowadays, the study of marine organisms has become more important, with 3 species of sponges studied and from which these compounds have been isolated, and there was 1 scorpion studied.
The cytotoxic properties of isolated quinones in the period 2015 to 2020 were mainly determined by in vitro and in vivo studies. This was due to some factors such as the sensitivity of these tests and the consumption of small amounts of compound to obtain the results. There are different methods to carry out these tests. In this review, the activities were determined by the use of MTT, SRB, NR, IDO, iodide propidium, violet crystal, cell counting kits, resazurin reduction, sulforhodamine B, AGS, Trypan blue, immunophenotyping, Alamar blue, FITC Annexin V Apoptosis, the CCK-8 colorimetric method, and Annexin V/7-AAD.
The determination of antimicrobial activity was carried out by MIC, micro-dilution, and broth microdilution volatilization.
Quinones have good activity against numerous cell cancer lines; they also exhibit good antimicrobial activity. This situation, along with the wide variety of structures that these compounds exhibit, make them a very interesting topic to continue to explore for other mechanisms of action and the chemical modification of their structures, among other topics.
Conflict of interest
The authors declare no conflict of interest.