PL221690B1 - Process for preparing optically pure (-)-(S)-6,4'-dihydroxyflavanone - Google Patents

Description

Description of the invention

The present invention relates to a process for the preparation of (-) - (S) -6,4'-dihydroxy flavanone of the formula 2 shown in the drawing.

The invention may find application in the food industry for the production of antioxidants, and in the pharmaceutical and cosmetic industries.

Flavonoids are used in the pharmaceutical, cosmetic and food industries due to the number of biological activities they exhibit.

Flavonoid compounds are the subject of many in vitro and in vivo studies, which show that they exhibit analgesic, anti-inflammatory, anti-cancer, anti-diabetic, anti-cramp, anti-ulcer, antibacterial, anti-viral and anti-fungal properties, as well as protective against the cardiovascular and skeletal systems ( prevent osteoporosis) and liver cells (G. di Carlo, et al. Flavonoids: Old and New Aspects of a Class of Natural Therapeutic Drugs, Life Sciences, 65 (4), 1999, 337-353; WA Verri Jr., et al. Chapter 9: Flavonoids as Anti-Inflammatory and Analgesic Drugs: Mechanisms of Action and Perspectives in the Development of Pharmaceutical Forms, Studies in Natural Products Chemistry, 36, 2012, 297-330 Bioactive Natural Products).

Flavonoid compounds are used in the cosmetic industry, inter alia, due to their antioxidant properties, soothing the skin, and preventing reddening of the skin by protecting the walls of blood vessels (J. Arct,

K. Pytkowska, Flavonoids as components of biologically active cosmeceuticals, Clinics in Dermatology, 26 (4), 2008 July-Aug., 347-357). Most of the flavonoid compounds taken orally prevent skin damage caused by ultraviolet radiation (Y. Kimuraa, M. Sumiyoshib, Effects of baicalein and wogonin isolated from Scutellaria baicalensis roots on skin damage in acute UVB-irradiated hairless mice, European Journal of Pharmacology, 661 (1- 3), 2011 July, 124-132).

Flavonoids have also been shown to prevent the oxidation of fatty acids, such as linoleic acid, which can be used in the food industry (BY Bekera et al., Antioxidant protective effect of flavonoids on linoleic acid peroxidation induced by copper (ll) / ascorbic acid system, Chemistry and Physics of Lipids, 2011 Nov., 164 (8), 732-739). On the other hand, flavonoids obtained from grapes show a protective effect, increasing the durability of fish oils, as well as frozen fish muscle tissue (M. Pazosa et.al., Activity of grape polyphenols as inhibitors of the oxidation of fish lipids and frozen fish muscle, Food Chemistry, 2005 Sept., 92 (3), 547-557.

It is important to search for new, optically pure natural substances with antioxidant properties that can be used in the pharmaceutical, cosmetics and food industries.

The human body is constantly subjected to oxidative stress caused by natural physiological processes or external factors. The resulting oxygen radicals are the cause of inflammatory processes, they are considered one of the causes of the aging of the organism, mutagenesis, carcinogenesis, as well as cardiovascular diseases. One of the most important biological properties of flavonoid compounds is their antioxidant activity (K. Heim et al., Flavonoid antioxidants: chemistry, metabolism and structure-activity relationships, Journal of Natural Biochemistry 2002 Oct; 13 (10): 572-584).

The essence of the invention is that the Aspergillus niger MB strain is introduced on the prepared medium. Once the fungus has reached its final log phase of growth, it is added

6-propionoxyflavanone, in an amount of 10 mg per 100 ml of medium, the microbial transformation process being carried out in an aqueous culture of the strain under continuous shaking. As a result of the enzyme system of the strain, the ester linkage is hydrolyzed at the 6-position followed by hydroxylation at the 4'-position of the 6-propionoxyflavanone substrate, followed by extraction with a water-immiscible organic solvent and chromatographic purification.

It is preferably carried out at a temperature of from 21 to 28 ° C.

It is also preferred that the organic solvent is ethyl acetate.

The obtained 6,4'-dihydroxy flavanone has a greater antioxidant potential than the precursor from which it was produced.

The main advantage of the invention is the preparation of (-) - (S) -6,4'-dihydroxy flavanone with an enantiomeric excess of 100% ee, at room temperature and at the natural pH of the strain. The invention is explained in more detail using an exemplary embodiment.

PL 221 690 B1

3

Example A 2000 cm Erlenmajer flask containing 500 cm of sterile medium containing 5 g of aminobac and 15 g of glucose is loaded with the A. niger MB strain. Late its growth is added 50 mg of 6-propionoksyflawanonu of formula 1, dissolved in 1 cm ₃ of tetrahydrofuran. The transformation is carried out at 25 degrees Celsius with continuous shaking for 9 days. The reaction mixture was then extracted three times with ethyl acetate, dried with anhydrous magnesium sulfate and the solvent was evaporated. The extract obtained is purified by chromatography using a 1: 1 mixture of ethyl acetate and methylene chloride as eluent.

In this way, 4.27 mg of (-) - (S) -6,4'-dihydroxy flavanone are obtained (yield 9.9%).

The obtained product is characterized by the following spectral data.

C15H12O4; top temp. 223-224 ° C; Rt 13.10 min (HPLC); 99% purity (HPLC); ([?] 1 ° ₉ = -19.49, c = 0.70, SD = 0.469, THF);

¹ H NMR (CD 3 CN) δ: 2.73 (1H, dd, J3eq, 3AX = 16.9 Hz, Jeq.2 = 2.9 Hz, H ^, 3.06 (1H, dd, J3ax, 3eq = 16.9 Hz, J3ax, 2 = 13.1 Hz, H-3ax), 5.37 (1H, dd, J _23ax = 13.1 Hz, J ₂ , 3eq = 2.8 Hz, H-2), 6.84 (2H, d, J = 8.5 Hz, H-3 ' , H-5 '), 6.89 (1H, d, J ₆ , ₇ = 8.9 Hz, H-8), 7.03 (1H, dd, J- = 8.9, J- = 3.0 Hz, H-7), 7.17 ( 1H, d, J57 = 2.9Hz, H-5), 7.32 (2H, d, J = 8.4Hz, H-2 ', H-6);

¹ H NMR (THF-d ₈₎ δ: 2.71 (1H, dd, J3eq, 3AX = 16.9 Hz, J ^ -. Y = 2.8 Hz, H-3 _e q), 3.02 (1H, dd, J3ax, 3eq = 16.9 Hz, J3ax, 2 = 13.5 Hz, H-3ax), 5.34 (1H, dd, J ₂ , 3ax = 13.5 Hz, J ₂ , 3eq = 2.8 Hz, H-2), 6.80 (2H, d, J = 8.4 Hz, H-3 ', H-5'), 6.88 (1H, d, J ₈ , ₇ = 8.9 Hz, H-8), 6.98 (1H, dd, J ₇ , ₈ = 8.9, J ₇ , 5 = 3.0 Hz, H-7), 7.21 (1H, d, J57 = 3.0 Hz, H-5), 7.33 (2H, d ', J = 8.4 Hz, H-2', H-6), 8.38 (1H, s, 4'-OH), 8.52 (1H, s, 6-OH).

Claims (3)

Patent claims A method for the production of optically pure (-) - (S) -6,4'-dihydroxy flavanone of the formula 2, characterized in that the Aspergillus niger MB strain is introduced on the prepared medium and when the fungus reaches the final log phase of growth, the 6-propionoxyflavanone of formula 1, in the amount of 10 mg per 100 ml of medium, the microbial transformation process is carried out with an aqueous culture of the strain under continuous shaking, as a result of which, with the participation of the enzyme system of the strain, the ester bond is hydrolyzed at position 6, and then 4 'hydroxylation of the 6-propionoxyflavanone substrate, then the product is extracted with a water-immiscible organic solvent and purified by chromatography. 2. The method according to p. The process of claim 1, wherein the process is carried out at a temperature of from 21 to 28 ° C. 3. The method according to p. The process of claim 1, wherein the organic solvent is ethyl acetate.