Homoeriodictyol
DaMocles Sommersemester 2019 Prof. Dr. rer. nat. Wolf-Dieter Fessner Group: Luca Wenchel, Lennart Weber, Alina Weber
Table of contents
General information 2 Flavonoids 3 Applications 3 Synthesis 3 Yerba Santa 5
General information
Structure
UPAC (2S)-5,7-dihydroxy-2-(4-hydroxy-3- methoxyphenyl)-2,3-dihydrochromen-4-one
Molar mass 302,28g/mol
Melting point 223°C
Homoeriodictyol (3`-methoxy-4`,5,7-trihydroxyflavanone) is a bitter masking substance[1] that can be extracted from the airdried roots of Yerba Santa, a plant growing in America and Mexico. It can be categorized as a flavonoid, which is a secondary metabolite. They are antioxidants able to regulate the glucose intake and responsible for the colour of flower blossoms.[2] The general structure of flavonoids is shown in below:[3]
Flavan
Flavonoids
Flavonoids are secondary metabolites present in and synthesised by plants. They can be grouped into aglycones, glycosides and methylated flavonoids. Homoeriodictyol is an aglycone and has therefore one of the basic structures of the flavonoids. They occur in all plant parts but mostly within the cells responsible for photosynthesis. Not only can they influence the colour of flower blossoms but are also responsible for taste, prevention of fat oxidation and the protection of vitamins and enzymes. By forming scavenging free radical or by chelating with metal ions they can act as antioxidants in the human body. This has health promoting effects and finds many applications especially in pharmaceuticals. The flavonoids present in black tea, including homeriodictyol, are able to lower the level of cholesterol such as the blood pressure. Aglycones can be absorbed especially easily by the small intestine while glycosides have to be converted into aglycones first. When absorbed they are conjugated in the liver to smaller phenolic compounds.[4] Applications
Specifically spoken homoeriodictyol is a yellow flavanone. It´s ability to mask bitter flavours finds a lot of applications especially in medicines. Therefore, it is used in black tea, multiple antibiotics, paracetamol and in solutions of caffeine to reduce bitter tastes.[5] It also reduces the effect of caffeine by propably inhibiting TAS2R43. As bitter substances stimulate the stomach to produce a higher amount of gastric acid there is a possibility to use homoeriodictyl for the regulation of stomach flora.[6] Furthermore, it acts as an inhibitant to the growth of certain bacteria such as Stapylococcus aureus, Salmonella Typhi and Pseudomonas Aerugonosa.[7] It is also able to reduce the level of serotine within the blood plasma by approximately 39%.[8]
Synthesis
As mentioned before Homoeriodictyol can be gained from Yerba Santa via biolaogical synthesis. Therefore, the plants roots which contain the wanted liquid are to be airdried and cut into pieces. A white yellowish substance can then be extracted with methanol and later on filtered and recrystallised in methanol.[9]
On the contrary the chemical synthesis is still a working process. The starting molecule of the chemical syntheses shown below is Phloroglucin. In a Hoesch Reaction a carbonyl group is added to the ring. It is then followed by a benzoylation in ortho and para positions. After that there is an alkaline hydrolysis. To start off Phloroglucin is dissolved in NaOH and benzoylchloride is added drop by drop. After stirring for three hours a white precipitate has formed. It is filtered and recrystallised in methanol. 0,01mol of this substance is added to 0,02mol of vanillin and stirred in ethanolic NaOH at room temperature for four days. The mixture is acidified with HCl, extracted using CHCl3, filtered, washed with water and dried with [10] Na2SO4.
H 5 C 5 6 OCO 6H HO OH HO OH OCOC Hoesch Reaction Benzoylation O O
OCOC OH CH OH CH3 3
6
H
5 CH O 3
Alkaline OH Hydrolysis
O
H CH3 5C O 6 OCO 5 6H
OCOC OH OCOC
6 HCl
H EtOH 5 CH3 O OH
HO O
HO O
Yerba Santa
Yerba Santa is Spanish for holy herb.[11]
In Mexico Yerba Santa is especially known for its healing effects on the human body. It is able to reduce stress in the respiratory tracks and the Indians of North America used it for disfunctions of stomach and intestines. The holy plant was also believed to cure sadness and unacceptable behaviour. Natives used to think, that burning their precious herb would manifest negative energies, whereas its smell would be able to create a healing atmosphere. It is still used in modern medicines today to treat respiratory diseases such as asthma and bronchitis and to cure bladder infections.[11] The flavanone homoeriodictyol also can be extracted from Yerba Santa and is able to reduce bitter tastes. A mechanism of how exactly this is possible has yet to be established. However, it is known that the function of bitter receptors works via g-proteins. Those have to be somehow inhibited by homoeriodictyol.[12]
[1]https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0094451#pone.00944 51-Fletcher1 (15.06.2019)
[2]https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0094451#pone.00944 51-Fletcher1 (15.06.2019)
[3] https://www.spektrum.de/lexikon/biologie/flavonoide/24810 (15.06.2019)
[4] https://www.hindawi.com/journals/tswj/2013/162750/ (26.05.12019)
[5] https://patentimages.storage.googleapis.com/0a/df/60/a88712de9dff03/US8685436.pdf (15.06.2019)
[6] https://medienportal.univie.ac.at/presse/aktuelle- pressemeldungen/detailansicht/artikel/bitterrezeptoren-in-mund-und-magen-wirken- regulierend-auf-die-koffeinbedingte-magensaeureausschuettu/ (17.6.2019)
[7]http://nopr.niscair.res.in/bitstream/123456789/21554/1/IJCB%2042B%283%29%20648 -650.pdf (15.06.2019)
[8] https://onlinelibrary.wiley.com/doi/pdf/10.1002/mnfr.201700459 (15.06.2019)
[9] http://digital.bibliothek.uni-halle.de/ulbhalhs/urn/urn:nbn:de:gbv:3:4-18744 (24.5.19)
[10] http://nopr.niscair.res.in/bitstream/123456789/21554/1/IJCB%2042B%283%29%20648- 650.pdf (26.5.2019)
[11] https://www.hexenladen-hamburg.de/kraeuter-almanach/santakraut-yerba-santa- eriodictycon-glutinosum/ (14.6.2019)
[12] https://patents.google.com/patent/EP3235492A1/it (14.6.2019)