BIOTRANSFORMATION AND ODOUR CHARACTERISTIC OF THE LACTONIC BETA-IONONE DERIVATIVES
DOI:10.30825/5.EJPAU.179.2019.22.4

Małgorzata Grabarczyk, Katarzyna Wińska, Wanda Mączka
Department of Chemistry, Wrocław University of Environmental and Life Sciences, Poland

ABSTRACT

Three halolactones with the trimethylcyclohexene system obtained from beta-ionone by chemical synthesis were biotransformed by filamentous fungal cultures (Fusarium, Absidia, Aspergillus). Bromolactone, converted to hydroxylactone by hydrolytic dehalogenation, was the most susceptible to the action of microorganisms. However, chloro- and iodolactone were only slightly transformed. Both substrates and product were subjected to odour evaluation. The one of them, iodolactone had a very interesting coconut-cream fragrance. The fragrance of a biotransformation product, a hydroxylactone, was less interesting than the odour of its precursor. The significant differences between the odours of lactones obtained from beta-ionone with their corresponding earlier obtained alpha-ionone derivatives were presented.

Key words: beta-ionone, lactones, odour activity, hydrolytic dehalogenation.

INTRODUCTION

Beta-ionone is a cyclic unsaturated ketone belonging to the isoprenoids. It is widely occurring and distributed in plants, being a product of the secondary metabolic pathway, whose common precursor is mevalonic acid [47]. It occurs in the essential oils of various plants, such as rose oil [26], and tobacco leaves [6]. As it is a product of the degradation of beta-carotene, traces of it can be detected in food products [7]. It has also been found in cow’s milk, which is passively transferred from the pasteurization species alphalpha (lucerne) [27], and in various species of tea, in green [8, 18, 48], as well as in black and oolong [19]. It has also been identified in fruits such as raspberries [25], a variety of sweet cherry called Hongdeng [41], and apricots in which, apart from beta-ionone, its derivatives, ie 2,3-epoxy-beta-ionone, dihydro-beta-ionone and dihydro-beta-ionol have also been distinguished [22]. Dihydro-beta-ionone has also been uncovered in banana wine produced in Rwanda [28].

It is important to mention at this point that beta-ionone is a non-toxic compound for both humans and animals. Studies showed that beta-ionone used externally even undiluted does not irritate the skin or mucous membranes of the eyes. There was also no evidence of phototoxicity or photoallergy when 8% beta-ionone solution in humans and 40% in guinea pigs was used. Studies in mice and rats showed that this compound given orally at low doses is harmless. A toxic dose for rodents is a dose above 2 g/kg body weight. Experiments carried out on bacteria have showed that beta-ionone is not a mutagenic or genotoxic compound [2]. In addition, beta-ionone showed high cytotoxic activity against mouse B16 melanoma cells, ascites sarcoma BP8 cells in rats, MCF-7 human breast cancer cells, at concentrations of 26.9 mg/L, 192 mg/L and 96 mg/L respectively [39].

As a pure compound, beta-ionone has a fragrance reminiscent of cedar wood, but a 10% alcoholic solution has the odour of fibres (Viola odorata) [38]. However, beta-ionone has not only an attractive fragrance, but also anti-cancerous properties, which is the reason why many derivatives with interesting biological activity have been obtained from it [1, 4, 33–34]. Interestingly, these compounds were actually odorless. Nevertheless, the combination of a terpenoid with a lactone ring may result in an appealing fragrance. Lactones similar to compounds described here originating from alpha-ionone have also been established to possess an interesting fragrance [12].

The implications of these fragrances on both the consumer and the environment must be tested and pass safety regulations. When a compound is released into the environment, biodegradation plays a major role in their destruction. All living organisms have metabolic potential to participate in the degradation of xenobiotics, but bacteria and fungi perform a prominent part in the bioremediation process. They have developed an extraordinary ability to adapt to the changing environment, largely due to enzymatic defense systems that protect them from toxic compounds [5]. Fungi may have certain advantages over other microorganisms with respect to biodegradation due to their tolerance to pollutants and their penetration in soil via mycelia, what is usually the first step of biodegradation [21, 23, 29, 37].

Our previous research on biotransformation of the halolactones obtained from beta-ionone [14] showed that fungi of the genus Fusarium are capable of converting these compounds to hydroxylactone. As a continuation of the mentioned above research, further previously untested strains of the genus Fusarium, Absidia and Aspergillus were used for biotransformation. Fusarium are common soil fungi in countries with moderate temperate and warm climates that infest plants such as corn, barley, oats, wheat, sorghum, millet, and rice [32]. Their ability to transform halolactones was tested during our earlier studies [9–11, 13, 15, 42, 43]. The genus Aspergillus are found worldwide and consist of more than 180 officially recognized species. Their ability to hydroxylate a broad spectrum of compounds is well known [3, 30–31]. The Absidia genus includes ubiquitous soil fungi with a growth temperature ranging from 20–42ºC [20]. Some mesophilic species are used in the biotransformation of steroids [17, 36], triterpenes [16], fragrances [35, 40] and industrial dyes [24].

Our goal was to check whether these strains would allow to obtain any products, the most likely of which was hydroxylactone, already known from previous biotransformation. Our second goal was to determine the odour characteristics of the tested lactones and to compare them with the odours of analogous lactones previously obtained from alpha-ionone [12].

MATERIALS AND METHODS

Analysis
The purity of all products and the progress of biotransformation were checked by analytical TLC on silica gel-coated aluminium plates and by GC analysis carried out on an Agilent Technologies 6890N instrument using a DB-17 column (cross-linked methyl silicone gum, 30 m × 0.32 mm × 0.25 µm). The temperatures during the GC analysis were as follows: injector 150ºC, detector (FID) 280ºC, column temperature: 120ºC, 120–280ºC (rate 25ºC/min), 280ºC (hold 1 min). The products were purified using preparative column chromatography on silica gel with mixture of hexane-acetone 6:1 as eluent. The TLC plates were spraying the plates with 1% Ce(SO₄)₂ and 2% H₃[P(Mo₃O₁₀)₄] in 10% H₂SO₄.

Microorganisms
The fungal strains which were used in this study were obtained from a collection held by the Institute of Biology and Botany, Medical University, Wrocław: Fusarium culmorum AM7, AM9, AM196, Fusarium avenaceum AM12, Fusarium equiseti AM15, Fusarium oxysporum AM21, Fusarium scirpi AM199, Absidia glauca AM254, Absidia cylindrospora AM336, Aspergillus wenthi AM413, Aspergillus ochraceus AM456. All these strains were available in the collection of the Department of Chemistry, University of Environmental and Life Sciences. The strains were cultivated on Sabouraud’s agar containing 0.5% of aminobac, 0.5% of peptone, 4% of glucose and 1.5% of agar dissolved in distilled water at 28ºC and stored in a refrigerator at 4ºC.

Screening procedure
Fungal strains used for biotransformations were cultivated at 25ºC in 300 mL Erlenmayer flasks containing 100 mL of medium, composed of 3 g of glucose and 1 g of peptobac. The three-day old cultures were supplemented with 10 mg of substrate dissolved in 1mL of acetone per flask. The cultures were shaken and incubated with the substrate for seven days. After three, five and seven days of incubation one third of the content of each flask was removed and extracted with 15 mL of dichloromethane. After evaporation of the solvent, the residue was dissolved in 2 mL of acetone and analyzed by GC (DB-17 column).

Preparative transformations
This stage was performed using 10 flasks with three-day cultures of fungal strains prepared as described above. The flasks were supplemented with 100 mg of bromolactone 2 dissolved in 10 mL of acetone. After seven days the content of all flask was extracted with dichloromethane (3 x 40 mL). The combined organic solutions were dried over anhydrous magnesium sulphate and the solvent was evaporated in vacuo. The crude product was purified by column chromatography (silica gel, hexane:acetone at a ratio of 3:1).

Odour evaluation
Fragrance assessment was carried out for 10% ethanol solutions of the test compounds, which were applied to paper strips. The samples (above 98% purity) were evaluated by a team of five experienced researchers (3 females and 2 males) who assessed the odour characteristics of the new compounds according to previous literature [42, 44]. Fragrances of the obtained particles were compared with 10% alcohol solutions of ionones and other terpene compounds.

RESULTS

In a four-step synthesis of commercially available racemic beta-ionone, halolactones 1–3 with the preserved trimethylcyclohexene systems were obtained (Fig. 1). A full description of the synthesis and NMR spectra of all compounds are provided in our previous article [14].

Fig. 1. Structures of halolactones 1–3

The halolactones 1–3 were subjected to screening biotransformation with 11 strains of filamentous fungi. The following strains were selected for the analyses: for the genus Fusarium: F. culmorum AM7, F. culmorum AM9, F. culmorum AM196, F. avenaceum AM12, F. equiseti AM15, F. oxysporum AM21 and F. scirpi AM199; for the genus Absidia: A. glauca AM254 and A. cylindrospora AM336; and for the genus Aspergillus: A. wenthi AM413 and A. ochraceus AM456.

The aim of this phase was to examine whether halolactones 1–3 would undergo transformation into other products under the influence of the microorganisms. Screening biotransformation was carried out by adding 10 mg of substrate to the growing mycelium located in 100 mL of medium. Samples were taken after 3, 5 and 7 days and analyzed on GC, controlling the proportions of the amount of product relative to the amount of substrate. Parallel control tests showed that the substrates added to the medium alone (in the amount of 10 mg of halolactone per 100 mL of medium) did not undergo any transformation. The results of this step are presented in Table 1.

Table 1. Results of the screening biotransformation of halolactones 1–3 after 3,5 and 7 days (in % according to GC)

Entry	Strain	Time [days]	Chloro lactone 1	Hydroxy lactone 4	Bromo lactone 2	Hydroxy lactone 4	Iodo lactone 3	Hydroxy lactone 4
1	F. culmorum AM7	3	96.2	3.8	90.5	9.5	83.4	16.6
		5	82.0	12.0	78.8	21.2	75.3	24.7
		7	76.7	23.3	63.2	36.8	67.7	32.3
2	F. culmorum AM9	3	91.4	8.6	86.6	13.4	77.7	22.3
		5	78.9	21.1	72.0	28.0	69.5	30.5
		7	60.5	39.5	57.2	42.8	62.5	37.5
3	F. avenaceum AM12	3	100	0	80.2	19.8	100	0
		5	100	0	66.5	33.5	86.5	13.5
		7	100	0	49.0	51.0	58.2	41.8
4	F. equiseti AM15	3	100	0	85.5	14.5	87.7	12.3
		5	100	0	45.2	54.8	78.2	21.8
		7	100	0	29.1	70.9	66.7	33.3
5	F. oxysporum AM21	3	100	0	86.2	13.8	100	0
		5	94.5	5.5	72.4	27.6	100	0
		7	82.8	17.2	59.7	40.3	100	0
6	F. culmorum AM196	3	100	0	68.4	31.6	83.7	16.3
		5	100	0	51.8	48.2	73.3	26.7
		7	81.5	18.5	37.8	62.2	56.8	43.2
7	F. scirpi AM199	3	95.0	5.0	79.4	20.6	87.9	12.1
		5	88.2	11.8	53.2	46.8	77.4	22.6
		7	76.7	23.3	30.9	69.1	62.6	37.4
8	A. glauca AM254	3	93.0	7.0	78.8	21.2	100	0
		5	86.2	13.8	73.8	26.2	100	0
		7	75.5	24.5	69.9	30.1	100	0
9	A. cylindrospora AM336	3	100	0	94.3	5.7	88.3	11.7
		5	91.5	8.5	88.6	11.4	79.4	20.6
		7	81.6	18.4	81.8	18.2	74.5	25.5
10	A. wenthi AM413	3	100	0	100	0	100	0
		5	100	0	100	0	100	0
		7	100	0	100	0	100	0
11	A. ochraceus AM456	3	100	0	100	0	100	0
		5	100	0	88.5	11.5	89.8	10.2
		7	100	0	76.3	23.7	72.0	28.0

The data presented in Table 1 shows that the majority of microorganisms selected for screening tests were able to bioconvert halolactones 1–3 to the same product. Only A. wenthii AM413 (entry 10) was unable to carry out the biotransformation. The type of halogen present in the molecule of lactone had a decisive effect on the product formation process. Chlorolactone 1 was transformed to a small degree, not exceeding 40%. A similar tendency was observed for iodolactone 3. The highest transformation yield was determined for bromolactone 2. The four strains: F. avenaceum AM12 (entry 3), F. equiseti AM15 (entry 4), F. culmorum AM196 (entry 6) and F. scirpi AM199 (entry 7) transformed this substrate with a yield of 51–70.9%.

Analyzing the results obtained from screening biotransformations, it can be seen that regardless of the type of halogen, the same product was created. Thus, to determine its structure, biotransformation of bromolactone 2 was executed at a preparative scale using four strains of Fusarium fungi selected during screening. Each biotransformation was performed in 10 Erlenmayer flasks containing 100 mL of medium, to which 10 mg of substrate was added (in total, 100 mg of substrate was used). The biotransformation process lasted 7 days each time. The biotransformation product was obtained with significant yields of 52–78%. The results of this stage are shown in Figure 2.

Fig. 2. The results of preparative biotransformation of bromolactone 2 after 7 days (according to GC)

Analysis of the 1H NMR spectra showed that as a result of biotransformation hydroxylactone 4 was obtained. This proved to be the same compound as acquired from biotransformation of halolactones with the trimethylcyclohexene system during our previous studies [14] (Fig. 3).

Fig. 3. Structure of hydroxylactone 4

In order to confirm whether the biotransformation process was enantioselective, the optical rotation of the hydroxylactone 4 retrieved was measured. The results showed that in all cases hydroxylactone 4 was produced as a racemic mixture.

In the next step the halolactones 1–3 and obtained as a product of their biotransformation hydroxylactone 4 were subjected to sensory analysis to determine their odor characteristics. The received data was presented in Table 2.

Table 2. The odour characteristic of the lactones 1–4.

Entry	Strain	Isolated yield [g / %]	ee [%]
1	F. avenaceum AM12	0.012 / 15.4	2.0	-1.54 (c=0.43%, CHCl3)
2	F. equiseti AM15	0.039 / 48.9	1.6	-1.16 (c=0.64%, CHCl3)
3	F. culmorum AM196	0.017 / 21.1	0	–
4	F. scirpi AM199	0.022 / 28.0	0	–

The data presented in Table 2 showed that halolactones 1–3 have a fragrance profile unrelated to their precursor, beta-ionone. The odours of halolactones were very interesting. Therefore, it was verified how the change of the halogen atom to the hydroxy group in the molecule of lactone affected the change of smell. It turned out that odour of hydroxylactone 4 is not such interesting.

DISCUSSION

The halolactones 1–3 were obtained from commercially available racemic beta-ionone during four-step synthesis: reduction of ketone, Claisen’s rearragment of alcohol, basic hydrolysis of ester and halolactonization of acid. All these steps are described in our earlier article [14]. Due to the presence of three chiral centers in the molecules of halolactones 1–3 it was possible to obtain them as mixtures of 8 diastereomers. It was observed that halolactones were actually formed in the form of mixtures of two diastereoisomers (named A and B) with an advantage of one of them. The lactones 1 and 2 were formed mainly as an isomer A, while lactone 3 – as an isomer B. In isomer A, the lactone ring lies in a plane perpendicular to the cyclohexane ring, while in isomer B the lactone and cyclohexane rings are in the same plane. The CH3-12 group is in the same plane as the lactone ring for lactones 1 and 2, and across this plane for iodolactone 3, respectively.

Because the substrates used for biotransformation, lactones 1–3, occurred as a mixtures of the two diastereoisomers A and B, therefore, it would be expected that hydroxylactone 4 would also be such a mixture. It turned out, however, that product 4 was just one of several possible diastereoisomers. Analysis of the 1H NMR spectra proved that in this compound the cyclohexane ring, lactone ring and CH3-12 group lied in the same plane. It means that the use of microorganisms allow to obtain only one isomer, which is much harder when chemical synthesis is use. Hydroxylactone 4 was obtained as a result of biotransformation of halolactones 1-3. The type of halogen present in the molecule of lactone had a decisive effect on the product formation process. Differences in the reactivity of selected substrates can be explained by the substrate specificity of selected microorganisms. The main isomer (B) of iodolactone 3 has a different structure than the main isomers (A) of chloro- 1 and bromolactone 2. These differences resulted from a different mechanism of the formation of these compounds, namely ionic for iodolactone 3 and free radical for chloro- 1 and bromolactone 2. Our previous research of halolactones obtained from beta-ionone showed that conversion rates in excess of 50% have been achieved with chlorolactone (one strain) and bromolactone (six strains) [14]. A similar result was obtained during the research presented here. The strains tested here were able to convert only bromolactone 2 to hydroxylactone 4 with an extent greater than 50%, and for chlorolactone 1 and iodolactone 3 the conversion rate did not exceed 40%. Our previous experience indicates also that the hydrolytic dehalogenation reaction depends on the structure of the compound, i.e. the amount and location of the methyl groups in the cyclohexane ring or the position of the linkage in the cyclohexene ring. This reaction proceeds with a different percentage of conversion for various halolactones. Sometimes, hydroxylation of bromolactone [9, 10, 14, 42], and in other cases – chlorolactone [12] or iodolactone [13, 15] was preferred.

The same factors, i.e. the structure of the compound and the type of microorganisms used, also determine the enantioselectivity of the process. It can be concluded that the greater number of steric hindrances in the substrate results in greater selectivity of the product. Fusarium strains are characterized by very different enantioselectivity, they are able to produce products with both high and very low enantiomeric excess. This is well illustrated by the example of a bromolactone with a trimethylcyclohexane system which was converted to the same hydroxylactone with ee = 81% (F. avenaceum AM11) and ee = 0% (F. semitectum AM20) [10]. A similar situation occurred in biotransformation of chlorolactone obtained from alpha-ionone, where hydroxylactone had ee = 62% (F. culmorum AM10) or ee = 9% (F. semitectum AM20) [12]. In the case of compounds obtained earlier from beta-ionone [14], the enantiomeric excess of hydroxylactone received from bromolactone was in the range of 0-18%. As a result of the studies presented here, hydroxylactone 4 was obtained as a racemic mixture. This means that the strains presented here were not able to carry out the hydrolytic dehalogenation reaction in an enantioselective manner.

Attractive aromas do not usually characterize organochlorine compounds. Among the many compounds we have acquired so far, only halolactones with methylcyclohexane [10] and trimethylcyclohexene rings [12] should be considered. Significantly, two of the halolactones presented in our study were endowed with pleasant scents. There were bomolactone 2 possessing herbal, green odour and iodolactone 3 characterized with coconut smell. As it is known, small changes in the structure of molecules greatly affect the change of their fragrance profile [45]. Therefore, in addition to presenting the odour characteristics of halolactones discussed here, we decided to compare them with the corresponding halolactones previously obtained from alpha-ionone [12]. Both compounds, i.e. alpha- and beta-ionone, are structural analogues, differing only in the position of the double bond in the cyclohexene ring. In agreement with our assumptions, the odours of the halolactones obtained from alpha- and beta-ionone have been completely different. When the double bond was between C4-C5 carbons, the odours were more intense. In addition, a floral smell, typical of ionones, was observed for chloro- and iodolactones. Shifting the bond between C5-C6 caused the disappearance of the odour typical of Viola odorata. The scent of chlorolactone molecules differed the most. The lactone obtained from alpha-ionone had a pleasant green-wood odor, while its analog was completely odorless. The obtained iodolactones also differed in the intensity and character of the odour. The pleasant floral fragrance of the lactone with a bond between C4–C5 changed with the shift of the double bond to coco-cream. Moreover both bromolactones had intense aromas. Obtained from beta-ionone lactone had a herbal odour with a green note while the previously obtained lactone was characterized by a pleasant, vegetable scent with a hint of celery.

The hydroxylactone obtained from alpha-ionone was characterized by unpleasant aroma. Taking into consideration that the small change of molecule’s structure have a great impact on its smell we were hopefull that hydroxylactone 4 will have a more interesting smell. It turned out, however, that this compound was characterized by chemical smell with a hint of wood.

CONCLUSIONS

Subjecting the halolactones 1–3 to biotransformation should illustrate if they are susceptible to transformation by cultures of filamentous fungi. It emerged that the best biocatalysts were fungi from the Fusarium genus. Chlorolactone 1 and iodolactone 3 were converted to a minor degree, not exceeding 40%, to hydroxylactone 4. Bromolactone 2 was converted to hydroxylactone 4 to a greater extent; the degree of substrate conversion was 52–78%. All halolactones were transformed into hydroxylactone 4 by hydrolytic dehalogenation. It is worth noting that iodolactone 3 could have potential use as an essence in the perfume industry because it achieved an alluring and delightful scent of coconut cream. It has been shown that the smell of different lactones obtained from the alpha- and beta-ionone is closely dependent on the structure of the molecule.

REFERENCES

1. Ansari M., Emami S., 2016. Beta-ionone and its analogs as promising anticancer agents. Eur. J. Med. Chem., 123, 141–154.
2. Belsito D., Bickers D., Bruze M., Calow P., Greim H., Hanifin J.M., Rogers A.E., Saurat J.H., Sipes I.G., Tagami H., 2007. A toxicologic and dermatologic assessment of ionones when used as fragrance ingredients. Food Chem. Toxicol., 45, S130–S167.
3. Borges K.B., de Souza Borges W., Duran-Patron R., Tallarico Pupo M., Sueli Bonato P., Gonzalez Collado I., 2009. Stereoselective biotransformation using fungi as biocatalysts. Tetrahedron: Asymm., 20, 385–397.
4. Cho H.K., Suh W.S., Kim K.H., Kim S.Y., Lee K.R., 2014. Phytochemical constituents of Salsola komarovii and their effects on NGF induction. Nat. Prod. Sci., 20, 95–101.
5. Cresnar B., Petric S., 2011. Cytochrome P450 enzymes in the fungal kingdom. Biochim. Biophys. Acta, 1814, 29–35.
6. Fujimori T., Kasuga R., Matsushita H., Kaneko H., Noguchi M., 1976. Neutral aroma constituents in Burley Tobacco. Agric. Biol. Chem., 40, 303–315.
7. Gomes-Carneiro M.R., Dias D.M.M., Paumgartten F.J.R., 2006. Study on the mutagenicity and antimutagenicity of beta-ionone in the Salmonella/microsome assay. Food Chem. Toxicol., 44, 522–527.
8. Gong X., Han Y., Zhu J.C., Hong L., Zhu D., Liu J.H., Zhang X., Niu Y.W., Xiao Z.B., 2017. Identification of the aroma-active compounds in Longjing tea characterized by odor activity value, gas chromatography - olfactometry, and aroma recombination. Int. J. Food Prop., 20, 1107–1121.
9. Grabarczyk M., 2012. Fungal strains as catalysts for the biotransformation of halolactones by hydrolytic dehalogenation with the dimethylcyclohexane system. Molecules, 17, 9741–9753.
10. Grabarczyk M., Białońska A., 2010. Biotransformations of chloro-, bromo- and iodolactone with trimethylcyclohexane system using fungal strains. Biocatal. Biotransform., 28, 408–414.
11. Grabarczyk M., Mączka W., Wińska K., Żarowska B., Anioł M., 2013. Antimicrobial activity of hydroxylactone obtained by biotransformation of bromo- and iodolactone with gem-dimethylcyclohexane ring. J. Braz. Chem. Soc., 24, 1913–1919.
12. Grabarczyk M., Mączka W., Wińska K., Żarowska B., Anioł M., 2014. The new halolactones and hydroxylactone with trimethylcyclohexene ring obtained through combined chemical and microbial processes. J. Mol. Catal. B: Enzymatic, 102, 195–203.
13. Grabarczyk M., Wińska K., Mączka W., Żarowska B., Białońska A., Anioł M. Hydroxylactones with the gem-dimethylcyclohexane system – synthesis and antimicrobial activity. Arabian J. Chem., doi. 10.1016/j.arabjc.2015.02.018
14. Grabarczyk M., Wińska K., Mączka W., Żarowska B., Maciejewska G., Dancewicz K., Gabryś B., Anioł M., 2016. Synthesis, biotransformation and biological activity of halolactones obtained from beta-ionone. Tetrahedron, 72, 637–644.
15. Grabarczyk M., Wińska K., Mączka W., Żołnierczyk A.K., Żarowska B., Anioł M., 2015. Lactones with methylcyclohexane system obtained by chemical and microbiological methods and their antimicrobial activity. Molecules, 20, 3335–3353.
16. Guo N., Zhao Y., Fang W., 2010. Biotransformation of 3-oxo-oleanolic acid by Absidia glauca. Planta Medica, 76, 1904–1907.
17. Habibi Z., Yousefi M., Ghanian S., Mohammadi M., Ghasemi S., 2012. Biotransformation of progesterone by Absidia griseolla var. igachii and Rhizomucor pusillus. Steroids, 77, 1446–1449.
18. Han Z.X., Rana M.M., Liu G.F., Gao M.J., Li D.X., Wu F.G., Li X.B., Wan X.C., Wei S., 2017. Data on green tea flavor determinantes as affected by cultivars and manufacturing processes. Data in Brief, 10, 492–498.
19. Ho C.T., Zheng X., Li S., 2015. Tea aroma formation. Food Science and Human Wellness, 4, 9–27.
20. Hoffmann K., Discher S., Voigt K., 2007. Revision of the genus Absidia (Mucorales, Zygomycetes) based on physiological, phylogenetic, and morphological characters; thermotolerant Absidia spp. form a coherent group, Mycocladiaceae fam. nov. Mycol. Res., 111, 1169–1183.
21. Ijoma G.N., Tekere M., 2017. Potential microbial applications of co-cultures involving ligninolytic fungi in the bioremediation of recalcitrant xenobiotic compounds. Int. J. Environ. Sci. Technol., 14, 1787–1806.
22. Inserra L., Cabaroglu T., Sen K., Arena E., Ballistreri G., Fallico B., 2017. Effect of sulphuring on physicochemical characteristics and aroma of dried Alkaya apricot: a new Turkish variety. Turk. J. Agric. For., 41, 59–68.
23. Jaiswal D.K., Verma J.P., Yadav J, 2017. Microbe induced degradation of pesticides in agricultural soils [in:] Microbe-Induced Degradation of Pesticides. Environmental Science and Engineering, Singh S., Eds; Springer, Cham., 167–189.
24. Kristanti R.A., Fikri Ahmad Zubir M.M., Hadibarata T., 2016. Biotransformation studies of cresol red by Absidia spinosa M15. J. Environ. Manage., 172, 107–111.
25. Larsen M., Poll L., 1990. Odour thresholds of some important aroma compounds in raspberries.Z. Lebensm. Unters. Forsch., 191, 129–131.
26. Leffingwell J.C., 2000. Rose (Rosa damascena). Leffingwell Reports, 1, 1–3.
27. Liu Q., Dong H.W., Sun W.G., Liu M., Ibla J.C., Liu L.X., Parry J.W., Han X.H., Li M.S., Liu J.R., 2013. Apoptosis initiation of beta-ionone in SGC-7901 gastric carcinoma cancer cells via a PI3K-AKT pathway,Arch. Toxicol., 87, 481–490.
28. Lyumugabe F., Iyamarere I., Kayitare M., Museveni J.R., Songa E.B., 2018. Volatile aroma compounds and sensory characteristics of traditional banana wine “Urwagwa” of Rwanda. Rwanda Journal, 2.
29. Marco-Urrea E., García-Romera I., Aranda E., 2015. Potential of non-ligninolytic fungi in bioremediation of chlorinated and polycyclic aromatic hydrocarbons. N. Biotechnol., 32, 620–628.
30. Parshikov I.A., Sutherland J.B., 2015. Biotransformation of steroids and flavonoids by cultures of Aspergillus niger. Appl. Biochem. Biotechnol., 176, 903–923.
31. Parshikov I.A., Woodling K.A., Sutherland J.B., 2015. Biotransformations of organic compounds mediated by cultures of Aspergillus niger. Appl. Microbiol. Biotechnol., 99, 6971–6986.
32. Pfeiffer E., Hildebrand A.A., Becker C., Schnattinger C., Baumann S., Rapp A., Goesmann H., Syldatk C., Metzler M., 2010. Identification of an aliphatic epoxide and the corresponding dihydrodiol as novel congeners of zearalenone in cultures of Fusarium graminearum. J. Agric. Food Chem., 58, 12055–12062.
33. Potu B., Rao M.S., Nampurath G.K., Chamallamudi M.R., Prasad K., Nayak S.R., Dharmavarapu P.K., Kedage V., Bhat K.M., 2009. Evidence-based assessment of antiosteoporotic activity of petroleum-ether extract of Cissus quadrangularis Linn. on ovariectomy-induced osteoporosis. Ups. J. Med. Sci., 114, 140–148.
34. Rao A.S., Satyanarayana A., Reddy D.R., Khan I.A., 2013. Structure elucidation and absolute configuration of megastigmane derivatives from Cissus quadrangularis Linn. IJPBR, 4, 52–58.
35. Siddhardha B., Vijay K.M., Murty U.S., Ramanjaneyulu G.S., Prabhakar S., 2012. Biotransformation of alpha-pinene to terpineol by resting cell suspension of Absidia corulea. Indian J. Microbiol., 52, 292–294.
36. Song Y., Yan S.S., Lin H.J., Li J.L., Zhai X.G., Ren J., Chen G.T., 2017. (R)-panaxadiol by whole cells of filamentous fungus Absidia coerulea AS 3.3382. J. Asian Nat. Prod. Res., 1–8.
37. Spina F., Cecchi G., Landinez-Torres A., Pecoraro L., Russo F., Wu B., Cai L., Liu X.Z, Tosi S., Varese G.C., Zotti M., Persiani A.M., 2018. Fungi as a toolbox for sustainable bioremediation of pesticides in soil and water. Plant Biosyst., 152, 474–488.
38. Surburg H., Panten J., 2006. Individual Fragrance and Flavor Materials. In Common Fragrance and Flavor Materials, Wiley-VCH Verlag GmbH, 7–175.
39. Vespermann K.A.C., Paulino B.N., Barcelos M.C.S., Pessoa M.G., Pastore G.M., Molina G., 2017. Biotransformation of alpha- and beta-pinene into flavor compounds. Appl. Microbiol. Biotechnol., 101, 1805–1817.
40. Tisserand R., ‎Young R., 2013, Essential Oil Safety – E-Book: A Guide for Health Care Professionals. Elsevier Health Sciences, 572–573.
41. Wen Y.Q., He F., Zhu B.Q., Lan Y.B., Pan Q.H., Li C.Y., Reeves M.J., Wang J., 2014. Free and glycosidically bound aroma compounds in cherry (Prunus avium L.). Food Chem., 152, 29–36.
42. Wińska K., Grabarczyk M., Mączka W., Żarowska B., Maciejewska G., Dancewicz K., Gabryś B., Szumny A., Anioł M., 2016. Biotransformation of bicyclic halolactones with a methyl group in the cyclohexane ring into hydroxylactones and their biological activity. Molecules, 21, 1453.
43. Wińska K., Grabarczyk M., Mączka W., Żarowska B., Maciejewska G., Dancewicz K., Gabryś B., Anioł M., 2017. Biotransformation of lactones with methylcyclohexane ring and their biological activity. Appl. Sci., 7, 12.
44. Wińska K., Kula J., Wawrzeńczyk C., 2011. Synthesis and odor characteristics of racemic and optically active oxy-derivatives of gem-dimethylcyclohexene. Flavour Fragr.J., 26, 329–335.
45. Wińska K., Potaniec B., Mączka W., Grabarczyk M., Anioł M., Wawrzeńczyk C., 2014. Isomers and odor or nose as stereochemist. Chemik, 68, 83–90.
46. Wińska K., Wawrzeńczyk C., 2007. Synthesis of chiral odoriferous oxy-derivatives of 1,5,5-trimethylcyclohexane. Pol. J. Chem., 1, 1887–1897.
47. Winterhalter P., Rouseff R.L., 2001. Carotenoid-derived aroma compounds: an introduction. In Carotenoid-derived aroma compounds. Washington, DC: ACS Symposium Series, 802, 1–17.
48. Yamanishi T., Nose M., Nakatani Y., 1970. Studies on the flavor of green tea. Agric. Biol. Chem., 34, 599–608.

Received: 14.02.2019
Reviewed: 10.12.2019
Accepted: 15.12.2019

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Małgorzata Grabarczyk
Department of Chemistry, Wrocław University of Environmental and Life Sciences, Poland
ul. Norwida 25
50-375 Wrocław
Poland
email: malgorzata.grabarczyk@upwr.edu.pl

Katarzyna Wińska
Department of Chemistry, Wrocław University of Environmental and Life Sciences, Poland
ul. Norwida 25
50-375 Wrocław
Poland
email: katarzyna.winska@upwr.edu.pl

Wanda Mączka
Department of Chemistry, Wrocław University of Environmental and Life Sciences, Poland
ul. Norwida 25
50-375 Wrocław
Poland
email: wanda.maczka@upwr.edu.pl

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