Flavonol Derivatives Research Articles

Density functional theoretical study on attachment sites of Mg2+ and Ca2+ and metal ion affinity to Crenulatin molecule

Crenulatin (C25H20O10) is a flavonol derivative and has been isolated from the roots of Rhodiola crenulata (Hook. F. et Thoms.), a widely used medicinal herb. Magnesium and calcium cations play an important physiological role in biological systems. In this work, interactions of magnesium and calcium divalent cations with Crenulatin molecule were studied. Density functional theory (DFT) was used to determine coordination geometries and absolute metal ion affinities (MIA) for all possible stable complexes. The results show that calcium and magnesium cations are able to interact with the Crenulatin molecule through mono-, bi-, and tricoordination. B3LYP/6-31G(d) bond energies for all complexes reveal that magnesium cation has a greater affinity to Crenulatin molecule than calcium cation. The calculated value of Mg2+ cation affinity, including the zero-point vibrational energy (ZPE) and basis set superposition error (BSSE), is 231.8 kcal mol−1 for the most stable complex. Entropy (ΔS) and free energy (ΔG) variations for the metalation processes considered here have also been reported.

Flavanol and Flavonol Contents of Cocoa Powder Products: Influence of the Manufacturing Process

Major brands of cocoa powder products present in the Spanish market were analyzed for monomeric flavanols [(+)-catechin and (-)-epicatechin] and flavonols [quercetin-3-glucuronide, quercetin-3-glucoside (isoquercitrin), quercetin-3-arabinoside, and quercetin]. In addition, the influence of the manufacturing process of cocoa powder products, in particular, the alkalinization treatment ( Dutching), on the original content of these flavonoids has been studied. (-)-Epicatechin was in the range of 116.02-730.26 microg/g, whereas (+)-catechin was in the range of 81.40-447.62 microg/g in the commercial cocoa products studied. Among flavonols, quercetin-3-arabinoside and isoquercitrin were the major flavonols in the cocoa powder products studied, ranging from 2.10 to 40.33 microg/g and from 3.97 to 42.74 microg/g, respectively, followed by quercetin-3-glucuronide (0.13-9.88 microg/g) and quercetin aglycone (0.28-3.25 microg/g). To our knowledge, these results are the first quantitative data in relation to the content of individualized flavonol derivatives in commercial cocoa powder products. The alkalinization treatment resulted in 60% loss of the mean total flavonoid content. Among flavanols, (-)-epicatechin presented a larger decline (67%, as a mean percentage difference) than (+)-catechin (38%), probably because of its epimerization into (-)-catechin, a less bioavailable form of catechin. A decline was also confirmed for di-, tri-, and tetrameric procyanidins. In the case of flavonols, quercetin presented the highest loss (86%), whereas quercetin-3-glucuronide, quercetin-3-arabinoside, and isoquercitrin showed a similar decrease (58, 62, and 61%, respectively). It is concluded that the large decrease found in the flavonoid content of natural cocoa powder, together with the observed change in the monomeric flavanol profile that results from the alkalinization treatment, could affect the antioxidant properties and the polyphenol biovailability of cocoa powder products.

Identification and quantification of polyphenolic compounds from okra seeds and skins

The aims of the present work were to identify and quantify the polyphenolic profile of okra (Abelmoschus esculentus), a vegetable almost worldwide consumed. Since the knowledge about the okra polyphenolic compounds is limited, the seeds and the skins of okra were separately analyzed. The seeds, which represent the 17% of the vegetable and are richer in phenolic compounds, were mainly composed by oligomeric catechins (2.5mg/g of seeds) and flavonol derivatives (3.4mg/g of seeds). The skins polyphenolic profile was composed principally by hydroxycinnamic and quercetin derivatives (0.2 and 0.3mg/g of skins). These findings in associations with the high content of okra in carbohydrates and proteins enhance the importance of this foodstuff in the human diet.

The opposing effects of the flavonoids isoquercitrin and Sissotrin, isolated from Pterospartum tridentatum, on oral glucose tolerance in rats

The effect of an aqueous extract of Pterospartum tridentatum on the blood glucose levels of normal Wistar rats was investigated in a situation of oral glucose challenge. The extract at 300 mg/kg showed an antihyperglycaemic effect in the first 30 min after glucose challenge but then the blood glucose levels rose above those of the control group, indicating the presence of compounds with different effects on glucose tolerance. Nine compounds of isoflavone and flavonol skeletons were identified in the extract by HPLC-ESI-MS(n), four of them being identified for the first time in this species. The isoflavone sissotrin and the flavonol derivative, isoquercitrin, were selected for the oral glucose tolerance test. Isoquercitrin (100 mg/kg) showed time-dependent antihyperglycaemic activity by delaying the post-oral glucose load glycaemic peak at 30 min, as did the sodium-dependent glucose transporter inhibitor phloridzin (100 mg/kg). In contrast, sissotrin (100 mg/kg) showed an opposite effect, impairing glucose tolerance. In conclusion, these preliminary results indicate that the effect of the extract on blood glucose may be either antihyperglycaemic or hyperglycaemic. Additionally, as far as is known, these are the first in vivo results on the acute antihyperglycaemic potential of isoquercitrin.

Effects of Hydroxy and Methoxy Substituents on NMR Data in Flavonols

Kaempferide, kaempferol, and galangin belong to flavonol, one of flavonoid classes. Even they have the same moiety as flavonol, their binding affinities for a hexahistidine-tagged C-terminal nucleotide-binding domain are different with each other. The dissociation constants of flavonol, kaempferide, kaempferol, and galangin are 10.1, 4.5, 6.7, and 5.3 mM, respectively. Galangin contains two more hydroxyl groups than flavonol, and kaempferol has three more hydroxyl groups. Kaempferide differs with kaempferol in only one substituent: 4'-hydroxyl group of kaempferol is switched to 4'-methoxyl group in kaempferide. Likewise, galangin and kaempferide show different enzymatic kinetic parameters, Vmax/Km, for cytochrome P450 isomers CYP2C9 and CYP1A1 which take an important role in oxidative metabolism of galangin and kaempferide. The values of Vmax/Km of galangin for CYP2C9 and CYP1A1 were 59.0 and 10.2 μL/min/mg, respectively, and those of kaempferide were 5.1 and 1.9, respectively. While kaempferide has 4'methoxyl group, galangin does not have it. As a result, it can be considered that the substitution of hydroxyl or/and methoxyl groups on flavonols results in significant changes of the biological activities. Flavonol derivatives are being found still from natural sources. One of the best methods to identify them is NMR spectroscopy. Since the substitution of hydroxyl or/and methoxyl groups causes the chemical shift changes in the H and C NMR spectra, the elucidation of the effects of substituents on the chemical shifts in flavonol derivatives may help us predict the structures of the unknown compounds based on the simple one dimensional NMR experiments. In order to elucidate the substituent effects of chemical shifts on flavonol derivatives, the NMR experiments of flavonol (1) and nine flavonol derivatives (2-10) were carried out in this study. Of them, the C NMR data of three derivatives were already published. Because only the partial NMR data of others have been known, however, the complete assignments of their H and C NMR data are reported here. One of the C NMR data published previously showed the incorrect C NMR data, thus their corrected values were determined in this study. The structures and nomenclatures of flavonol derivatives 1-10 are shown in Figure 1. As mentioned above, the NMR data of three derivatives 2, 8, and 9 have been previously reported. We found that the NMR data of derivative 8 were partially incorrect. The C chemical shifts of the derivatives 8, 5,7,4'-trihydroxy-3'-methoxyflavonol, were reported by Kumari et al. Whereas C-3' and C-4' of 8 were assigned to the signals at 149.4 and 147.9 ppm in Kumari’s data, respectively, we found them to be at 147.4 and 148.9 ppm, respectively. That is, the order of the C chemical shifts of C-3' and C-4' was opposite in the Kumari’s data. In order to decide whether our assignments are correct or not, the interpretation of the NMR data was carried further out. The H peak at 3.84 ppm suggested the presence of 3'-methoxy proton. In the HMBC spectrum, 3'-methoxy proton was long-range coupled to the C peak at 147.4 ppm. Therefore, 147.4 ppm should be assigned to C-3'. The C chemical shifts of C-4' can be known through the HMBC spectrum of H-2' and H-6'. The H-2' and H-6' signals showed a longrange coupling with two C peaks at 146.7 and 148.9 ppm. Those peaks should be assigned to C-2 and/or C-4', respectively. Because 3-hydroxy proton peak at 9.41 ppm was long-range coupled to the C peak at 146.7 ppm in

Nutrient depletion as a key factor for manipulating gene expression and product formation in different branches of the flavonoid pathway

The content of flavonoids increases in response to nitrogen and phosphorus depletion in plants. Manipulation of these macronutrients may therefore be used to control the levels of desirable compounds and improve plant quality. Key enzymes in the shikimate pathway, which feeds precursors into the flavonoid pathway, are regulated post-translationally by feedback from aromatic amino acids, and possibly by redox control through photosynthesis. Use of microarrays for global transcript analysis in Arabidopsis has revealed that transcript levels are less influenced by mineral nutrients in the shikimate pathway compared with the flavonoid pathway. The responses in the shikimate pathway appear complex, whereas in the flavonoid pathway, a single gene often responds similarly to mineral depletion, high light intensity and sucrose. MYB [production of anthocyanin pigment 1 (PAP1)/production of anthocyanin pigment 2 (PAP2)] and bHLH [GLABRA3 (GL3)] transcription factors are important for the nutrient depletion response. PAP1/2 stimulate gross activation of the flavonoid pathway, and different investigations support merging signal transduction chains for various abiotic treatments on PAP1/2. Flavonol synthase is not part of the PAP1/2 regulon, and expression is mainly enhanced by high light intensity and sucrose, not mineral depletion. Nevertheless, both cyanidin and flavonol derivatives increase in response to nitrogen depletion. Kaempferols are the dominating flavonols in Arabidopsis leaves under normal cultivation conditions, but quercetin accumulation can be triggered by nitrogen depletion in combination with other abiotic factors.

Theoretical study on the structure and properties of crenulatin molecule in herb Rhodiola crenulata

Crenulatin (C 25H 20O 10) is a flavonol derivative, which can be isolated from the roots of Rhodiola crenulata (Hook. F. et Thoms.), a widely used medicinal herb due to its nice curative effect. In this study, theoretical analysis on the geometries and electronic properties of its molecular structure (crenulatin-a or crenulatin-b diastereoisomers) in gas phase is reported. As judged by total energy, the frontier orbital energy gap, the maximum hardness principle and 13C chemical shifts, we predict that crenulatin-a structure is the preferable structure of crenulatin molecule. Both diastereoisomers are soluble in water which enhances its biological activity of antioxidant. In order to evaluate the antioxidant activity of the molecule, the best indicators of the antioxidative, the O–H bond dissociation enthalpy (BDE) and adiabatic ionization potential (IP) were computed by density functional theory (DFT). We obtained that the most active site is the 3-OH group and crenulatin is active as an electron donor. All these results suggest that crenulatin is a potential antioxidant similar to kaempferol.

Bioassay-guided isolation of kaempferol-3- O-β- d-galactoside with anti-inflammatory and antinociceptive activity from the aerial part of Calluna vulgaris L.

Calluna vulgaris L. (Ericaceae) is used for the treatment of various inflammatory ailments in traditional medicines. In order to evaluate this ethnobotanical information, its anti-inflammatory and antinociceptive activities were studied using in vivo experimental models in mice. The ethanolic extract of the plant was first fractionated into five extracts; namely, n-hexane, chloroform, ethyl acetate (EtOAc), n-butanol, and water fractions. Among them, the EtOAc Fr. was found to be the most effective and was further subjected to bioassay-guided fractionation and isolation procedures. After successive column chromatography applications, on Sephadex LH-20 and silica gel, a component, which is responsible for the above-mentioned activities of this species of Turkish origin, was isolated and its structure was elucidated as kaempferol-3- O-β- d-galactoside, a common flavonol derivative by means of spectral techniques.

Solid-phase extraction versus matrix solid-phase dispersion: Application to white grapes

The use of matrix solid-phase dispersion (MSPD) was tested to, separately, extract phenolic compounds and organic acids from white grapes. This method was compared with a more conventional analytical method previously developed that combines solid liquid extraction (SL) to simultaneously extract phenolic compounds and organic acids followed by a solid-phase extraction (SPE) to separate the two types of compounds. Although the results were qualitatively similar for both techniques, the levels of extracted compounds were in general quite lower on using MSPD, especially for organic acids. Therefore, SL-SPE method was preferred to analyse white “ Vinho Verde” grapes. Twenty samples of 10 different varieties (Alvarinho, Avesso, Asal-Branco, Batoca, Douradinha, Esganoso de Castelo Paiva, Loureiro, Pedernã, Rabigato and Trajadura) from four different locations in Minho (Portugal) were analysed in order to study the effects of variety and origin on the profile of the above mentioned compounds. Principal component analysis (PCA) was applied separately to establish the main sources of variability present in the data sets for phenolic compounds, organic acids and for the global data. PCA of phenolic compounds accounted for the highest variability (77.9%) with two PCs, enabling characterization of the varieties of samples according to their higher content in flavonol derivatives or epicatechin. Additionally, a strong effect of sample origin was observed. Stepwise linear discriminant analysis (SLDA) was used for differentiation of grapes according to the origin and variety, resulting in a correct classification of 100 and 70%, respectively.

Antifeedant activity of some Tanacetum species and bioassay guided isolation of the secondary metabolites of Tanacetum cadmeum ssp. cadmeum (Compositae)

Antifeedant activities of Tanacetum cadmeum ssp. cadmeum, Tanacetum parthenium, Tanacetum corymbosum ssp. cinereum, Tanacetum chiliophyllum var. chiliophyllum, Tanacetum kotschyi and Tanacetum cadmeum ssp. orientale were assessed on Spodoptera littoralis Boisd. (Lep: Noctuidae) third instar larvae. The highest antifeedant activities were found as 62 and 55.05% in the extracts of MeOH with T. cadmeum ssp. cadmeum aerial parts, MeOH with T. corymbosum ssp. cinereum flowers, respectively. Bioassay guided investigations on Tanacetum cadmeum ssp. cadmeum afforded three eudesmanolides; artesin (1), taurin (2), and artemin (3), three germacranolides; tavulin (4), tanachin (5), and tamirin (6), the coumarin; scopoletin (7), and two flavonol derivatives; tanetin (6-hydroxykaempferol 3,7,4′-trimethylether) (8) and 6-hydroxykaempferol 3,6-dimethylether (9). The structures of the compounds were elucidated by spectral methods, such as IR, UV, 1H NMR and 13C NMR (COSY, APT, DEPT, HMQC, HMBC, NOE, X-ray, EIMS, CIMS and HRMS). In this paper, the antifeedant activities of some Tanacetum species and the compounds isolated from T. cadmeum ssp. cadmeum are reported.

Flavones with free radical scavenging activity fromGoniothalamus tenuifolius

From the leaves of Goniothalamus tenuifolius, a new natural product namely 3'-hydroxy-3,5,7,4'-tetramethoxyflavone (1) was isolated, along with seven other known compounds (2-8). Each of these isolates was evaluated for free radical scavenging activity on the DPPH decoloration test. The data obtained in this study suggested that the ortho 3',4'-diphenolic structure was essential for the activity of these flavonol derivatives.

Complete NMR signal assignments of flavonol derivatives

Common substitution positions of flavonols are at C-5 and C-7; 6-substituted flavonol derivatives are rarely found in natural sources. Here, we report complete assignments of 1H and 13C chemical shifts of eight flavonol derivatives including four 6-substituted flavonols.

Cytotoxic Chalcones and Flavonoids from the Leaves ofMuntingia calabura

Two new dihydrochalcones, 2',4'-dihydroxy-3'-methoxydihydrochalcone, (-)-3'-methoxy-2',4',beta-trihydroxydihydrochalcone, a new flavanone, (2 S)-(-)-5'-hydroxy-7,3',4'-trimethoxyflavanone, and a new flavonol derivative, muntingone, along with sixteen known compounds, were isolated from the leaves of Muntingia calabura. The structures of these new compounds were determined using spectral analyses including extensive 2D NMR data. Among the isolates, (2 S)-5'-hydroxy-7,3',4'-trimethoxyflavanone, 4'-hydroxy-7-methoxyflavanone, 2',4'-dihydroxychalcone, and 2',4'-dihydroxy-3'-methoxychalcone exhibited cytotoxicity (IC (50) values < 4 microg/mL) against P-388 and/or HT-29 cell lines in vitro.

Complete assignment of1H and13C NMR data of some flavonol derivatives

Nine flavonol derivatives were studied. Previously reported NMR data of three of these derivatives were corrected. We report complete assignments of the NMR data for six flavonol derivatives not previously studied.

Inhibition of Hydrogen Peroxide-Induced Endothelial Apoptosis by 2′,4′,7-Trihydroxyflavanone, a Flavonoid Form

Oxidative stress contributes to cellular injury following clinical and experimental ischemia/reperfusion episodes. Oxidative injury can induce cellular and subcellular damage that results in apoptotic cell death. We tested whether 2',4',7-trihydroxyflavanone, a synthetic flavonoid derivative, inhibits hydrogen peroxide (H(2)O(2))-induced toxicity in human umbilical endothelial cells (HUVECs). Cultured HUVECs were incubated for 30 minutes with 0.2 mM H(2)O(2) in the absence and presence of 2',4',7-trihydroxyflavanone at a non-toxic concentration of 50 microM. The effect of 2',4',7-trihydroxyflavanone on apoptosis parameters was compared with that of naringenin and two flavonol derivatives, 2',4',7-trihydroxyflavonol and 2',4',6-trihydroxyflavonol. H(2)O(2) induced cell death within 24 hours over the range of 0.05-1.0 mM, and decreased cell viability by approximately 30% at 0.2 mM. This cytotoxicity was associated with nuclear condensation and DNA fragmentation, indicating induction of apoptosis. 2',4',7-Trihydroxyflavanone, as well as naringenin, was effective as an inhibitor of oxidative stress, protecting cell viability with >/=85% viable cells compared with the control, and no apparent nuclear condensation or DNA fragmentation. In contrast, the flavonol derivatives had no such effect. In addition, immunocytochemical data and Western blot analysis revealed that, unlike flavonol derivatives, the expression of Bcl-2 was markedly up-regulated, and that the expression of Bax and activation of caspase-3 were strongly inhibited by this flavanone derivative, thereby implicating antioxidant activity-related anti-apoptotic mechanisms of 2',4',7-trihydroxyflavanone. These results indicate that the synthetic flavonoid derivative 2',4',7-trihydroxyflavanone is an effective antioxidant, preventing endothelial apoptosis induced by H(2)O(2).

CLONING AND HETEROLOGOUS EXPRESSION OF FLAVONOID GENES OF OSTEOSPERMUM HYBRIDS

Petals of Osteospermum exhibit white, yellow and rose to lilac colours. Chemical and biochemical investigations elucidated the basis of flower colour in Osteospermum. Besides carotenoids, which were shown to be responsible for the yellow colour, flavonoids were identified to be the main colour-giving compounds. Different amounts of derivatives of the anthocyanidin delphinidin cause the rose to lilac colour range. In addition to delphinidin, derivatives of flavonols were found to be present in the petals. Enzyme assays elucidated the biosynthetic path leading to the formation of the 3’-, 4’-, and 5’-hydroxylated delphinidin. Because of distinct substrate specifities of the early enzymes of the flavonoid pathway, chalcone synthase, chalcone isomerase, and flavanone 3-hydroxylase, dihydrokaempferol is supposed to be the main branch point. This compound was shown to be hydroxylated in 3’- and 5’position by flavonoid 3’, 5’-hydroxylase to dihydromyricetin which is subsequently reduced by dihydroflavonol 4-reductase to leucodelphinidin, the precursor of delphinidin. Molecular biological investigations of two key steps allowed a confirmation of the enzymological findings. The protein of a heterologously expressed full length chalcone synthase cDNA-clone was shown to preferentially use 4-coumaroyl-CoA as a substrate leading to the formation of naringenin after isomerisation by chalcone isomerase. In contrast to this, caffeoyl-CoA as a substrate resulted in the formation of only low amounts of eriodictyol. 3’, 5’-hydroxylation, which is indispensable for the formation of delphinidin, was demonstrated with the protein of a heterologously expressed F3’5’H full-length cDNA-clone. Fragments of the other main structural flavonoid genes of Osteospermum are now available and further molecular biological investigation will be performed.

Structural investigations of flavonol glycosides from sea buckthorn (Hippophaë rhamnoides) pomace by NMR spectroscopy and HPLC-ESI-MS(n).

Four flavonol glycosides were isolated from an extract of sea buckthorn pomace (Hippophaë rhamnoides) by Sephadex LH-20 gel chromatography and semipreparative HPLC. Their structures were elucidated by hydrolysis studies, ESI-MS(n), UV, and (1)H and (13)C NMR spectroscopy. The occurrence of the major flavonol glycoside kaempferol 3-O-beta-sophoroside-7-O-alpha-rhamnoside in sea buckthorn is described here for the first time. A further 21 flavonol glycosides of Sephadex LH-20 fractions of sea buckthorn pomace were characterized by HPLC-DAD-ESI-MS. The characteristic MS-MS and MS(3) fragmentation pattern of flavonol glycosides previously identified in sea buckthorn juice and of flavonol glycosides identified by NMR spectroscopy gave valuable indications for their identification. The results demonstrate that loss of the sugar moiety from C-7 of the aglycon is more favored than fission of the glycosidic linkage at the C-3 position. Thus, most of the compounds identified were 7-rhamnosides of isorhamnetin, kaempferol, and quercetin, which exhibit different substitution patterns at the C-3 position, mainly glucosides, rutinosides, and sophorosides. In addition, numerous flavonol glycosides were detected lacking a sugar moiety at C-7. Finally, eight flavonol derivatives were identified that are acylated by hydroxybenzoic or hydoxycinnamic acids.

Characterization and quantification of anthocyanins and polyphenolics in bluehHoneysuckle (Lonicera caerulea L.).

Anthocyanins and phenolics of 10 blue honeysuckle (Lonicera caerulea L.) genotypes were characterized and quantified by HPLC-DAD. Peak assignments were confirmed by low-resolution electrospray mass spectrometry. Six anthocyanins were detected with the major peak identified as cyanidin 3-glucoside. Five additional anthocyanins were characterized as cyanidin 3,5-diglucoside, cyanidin 3-rutinoside, pelargonidin 3-glucoside, peonidin 3-glucoside, and peonidin 3-rutinoside. Four polyphenolics were identified as chlorogenic acid, neochlorogenic acid, quercetin 3-rutinoside, and quercetin 3-glucoside. Two additional unidentified phenolics were characterized as flavonol and hydroxycinnamic derivatives based on UV-vis spectra. Hydroxycinnamate levels ranged from 30.4 to 156.2 mg/100 g, whereas the flavonol content ranged from 12.6 to 32.8 mg/100 g. The L. caerulea subspecies boczkarnikovae contained the highest amounts of hydroxycinnamic derivatives and flavonols.

Stimulatory effect of naturally occurring flavonols quercetin and kaempferol on alkaline phosphatase activity in MG-63 human osteoblasts through ERK and estrogen receptor pathway

Many plant-derived substances have estrogenic activities. Due to their ability to bind the estrogen receptor (ER), these compounds have the potential to counteract the deleterious effects of estrogen deficiency on bone. In this study, we investigated the in vitro effect of two widespread flavonols, quercetin and kaempferol, on alkaline phosphatase (ALP) activity in MG-63 cultured human osteoblasts. We found that both flavonols significantly increased ALP activity. This effect was markedly reduced by PD 98059, an inhibitor of the extracellular regulated kinase (ERK) pathway, and by ICI 182780, an antagonist of ERs. Western blot studies confirmed that ERK is rapidly activated in cells treated by both flavonols. Finally, ICI 182780 markedly inhibits the flavonol-induced ERK activation. The data presented in this study support the conclusion that, in MG-63 osteoblasts (i) the increase in ALP activity by flavonols involves a rapid stimulation of ERK activation but also involves the ER, and that (ii) the activation of ERK by flavonols occurs most likely downstream of the ERs activation. Taken together, these results suggest that flavonols derivatives as quercetin and kaempferol can stimulate osteoblastic activity. Such compounds may represent new pharmacological tools for the treatment of osteoporosis.

Glucosylation of Phenolic Compounds byPharbitis nilHairy Roots: I. Glucosylation of Coumarin and Flavone Derivatives

Hairy roots of medicinal morning glory (Pharbitis nil) showed potent glucosylation activity against umbelliferone and aesculetin, so the glucosylation activity against several phenolic compounds was tested. Some coumarin derivatives and flavone derivatives having phenolic hydroxyl groups were incubated with the hairy roots. The coumarin derivatives and flavone derivatives almost disappeared from the culture medium in half a day. In the case of the coumarin derivatives, a 7-hydroxyl group was easily glucosylated. A methyl group at C-8 somewhat decreased the glucosylation to a hydroxyl group at C-7 of the coumarin skeleton. The 4-hydroxy coumarin derivatives were changed to acetophenone-type glucosides by incubation with the hairy roots through decarboxylation. Several flavonol derivatives were tested for glucosylation by the hairy roots. 3-Hydroxy flavone, 3.6-dihydroxyflavone and 3,7-dihydroxyflavone were glucosylated to give 3-glucosylated derivatives. Of these, 3,6-dihydroxyflavone was highly glucosylated, but not 3-hydroxyflavone or 3,7-dihydroxyflavone to the same degree. In the case of the flavones, a 3-hydroxy group could be predominantly glucosylated, and hydroxyl groups on the A and B ring of the flavones affected glucosylation by the hairy roots.