Fall, the season of colors: Leaves turn red, yellow, and brown. The disappearance of the color green and the simultaneous appearance of these other colors are also signs of ripening fruit. A team led by Bernhard Kräutler at the University of Innsbruck (Austria) has now determined that the breakdown of chlorophyll in ripening apples and pears produces the same decomposition products as those in brightly colored leaves. As the researchers report in the journal Angewandte Chemie, these colorless decomposition products, called nonfluorescing chlorophyll catabolytes (NCC), are highly active antioxidants—making them potentially very healthy.
The beautifully colored leaves of fall are a sign of leaf senescence, the programmed cell death in plants. This process causes the disappearance of chlorophyll, which is what gives leaves their green color. For a long time, no one really knew just what happens to the chlorophyll in this process. In recent years, Kräutler and his team, working with the Zurich botanists Philippe Matile and Stefan Hörtensteiner, have been able to identify the first decomposition products: colorless, polar NCCs that contain four pyrrole rings—like chlorophyll and heme.
Now the Innsbruck researchers have examined the peels of apples and pears. Unripe fruits are green because of their chlorphyll. In ripe fruits, NCCs have replaced the chlorophyll, especially in the peel and the flesh immediately below it. These catabolytes are the same for apples and pears, and are also the same as those found in the leaves of the fruit trees. “There is clearly one biochemical pathway for chlorophyll decomposition in leaf senescence and fruit ripening,” concludes Kräutler.
When chlorophyll is released from its protein complexes in the decomposition process, it has a phototoxic effect: When irradiated with light, it absorbs energy and can transfer it to other substances. For example, it can transform oxygen into a highly reactive, destructive form. As the researchers were able to demonstrate, the NCCs have an opposite effect: They are powerful antioxidants and can thus play an important physiological role for the plant. It then became apparent that NCCs are components of the diets of humans and other higher animals, and that they could thus also play a role in their systems. Other previously identified important antioxidants in the peels of fruits include the flavonoids. Thus, the saying, “an apple a day keeps the doctor away” seems to be true, according to Kräutler.
Author: Bernhard Kräutler, Universität Innsbruck (Austria), http://pc43-c726.uibk.ac.at/oci/people/en_bernhard_kraeutler.html
Title: Colorless Tetrapyrrolic Chlorophyll Catabolites in Ripening Fruit Are Effective Antioxidants
Angewandte Chemie International Edition 2007, 46, No. 45, 8699–8702, doi: 10.1002/anie.200703587
Bernhard Kräutler | Angewandte Chemie
Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View
22.06.2018 | University of Sussex
New cellular pathway helps explain how inflammation leads to artery disease
22.06.2018 | Cedars-Sinai Medical Center
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
22.06.2018 | Materials Sciences
22.06.2018 | Earth Sciences
22.06.2018 | Life Sciences