Caffeic acid
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| General | ||||||||||||||||||||||
| Surname | Caffeic acid | |||||||||||||||||||||
| other names |
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| Molecular formula | C 9 H 8 O 4 | |||||||||||||||||||||
| Brief description |
yellow solid |
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| properties | ||||||||||||||||||||||
| Molar mass | 180.16 g mol −1 | |||||||||||||||||||||
| Physical state |
firmly |
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| Melting point |
234–237 ° C (decomposition) |
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| solubility |
bad in water |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||||||||
Caffeic acid (Engl. Caffeic acid ) is the common name for 3,4-dihydroxycinnamic . It belongs to the group of hydroxycinnamic acids and thus to the phenolic acids .
Occurrence
Caffeic acid in addition to the ferulic acid - a methyl ether of caffeic acid and a hydroxycinnamic - the most abundant phytochemical in food plant-based. Coffee contains high amounts of caffeic acid. A cup of coffee contains around 25–75 mg of caffeic acid.
properties
In animal experiments, caffeic acid was found to have an inhibitory effect on the development of induced gastric cancer , whereby it also plays an essential role as an inhibitor in endogenous nitrosamine formation in humans.
However, studies on the carcinogenicity of caffeic acid have produced ambivalent results. Some studies have shown anti-cancer effects, while others show cancer-promoting effects. Oral administration of high doses of caffeic acid to rats resulted in papillomas in the abdomen. However, the same study also showed that large doses of combined antioxidants , including caffeic acid, at the same rats to a significant decline in growth of the intestine - tumors resulted. No other significant effects could be demonstrated. Caffeic acid is listed as a potential carcinogen in some hazardous substance data sheets , for example on the IARC list as a group 2B carcinogen (“possibly carcinogenic in humans”). More recent data show that bacteria in the rat intestine influence the formation of metabolites of caffeic acid, but no such disease-promoting effects are known in humans.
Applications
In addition to medical applications, caffeic acid acts as a developing substance in alternative black and white developers (see Caffenol ). Among other things, it is used in combination with vitamin C (ascorbic acid) to reduce exposed silver halides to metallic silver.
See also
- Chlorogenic acid ( ester of caffeic acid with quinic acid )
Web links
- Bernhard Watzl and Gerhard Rechkemmer, Karlsruhe: Phenolic acids . In: Ernähr-Umschau 48 (2001) issue 10 (PDF file; 58 kB)
Individual evidence
- ↑ Entry on CAFFEIC ACID in the CosIng database of the EU Commission, accessed on May 13, 2020.
- ↑ a b c Data sheet caffeic acid (PDF) from Merck , accessed on January 19, 2011.
- ↑ a b Entry on caffeic acid in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .
- ↑ a b M Hirose, Y Takesada, H Tanaka, S Tamano, T Kato and T Shirai: Carcinogenicity of antioxidants BHA, caffeic acid, sesamol, 4- methoxyphenol and catechol at low doses, either alone or in combination, and modulation of their effects in a rat medium-term multi-organ carcinogenesis model . In: Carcinogenesis . 19, No. 1, 1998, pp. 207-212. doi : 10.1093 / carcin / 19.1.207 . PMID 9472713 .
- ↑ Caffeic Acid . In: IARC Summary & Evaluation . 56, 1993. Retrieved September 24, 2013.
- ↑ Agents Classified by the IARC Monographs (PDF; 134 kB), International Agency for Research on Cancer
- ↑ MA Peppercorn and P Goldman: Caffeic acid metabolism by gnotobiotic rats and their intestinal bacteria . In: Proceedings of the National Academy of Sciences . 69, No. 6, 1972, pp. 1413-1415. doi : 10.1073 / pnas.69.6.1413 . PMID 4504351 . PMC 426714 (free full text).
- ↑ MP Gonthier, MA Verny, C Besson, C Rémésy and A Scalbert: Chlorogenic acid bioavailability largely depends on its metabolism by the gut microflora in rats . In: Journal of Nutrition . 133, No. 6, June 1, 2003, pp. 1853-1859. PMID 12771329 .