Comprehensive Phytochemical Characterization of Herbal Parts from Kidney Vetch (Anthyllis vulneraria L.) by LC/MSn and GC/MS.

Extracts of kidney vetch (Anthyllis vulneraria L.) are becoming increasingly interesting as ingredients for the health and cosmetics industry. However, comprehensive phytochemical investigations of this plant are scant in the literature. Thus, the aim of the present work was an in-depth characterization of semi-polar constituents from A. vulneraria. To capture a broad spectrum of compounds, the aerial parts of A. vulneraria were extracted with EtOH/water and the resulting crude extracts fractionated by partition between AcOEt and BuOH. Secondary plant metabolites were analyzed by HPLC-ESI-MSn and GC/MS. In a fraction obtained from the BuOH extract via Amberlite® XAD-7 purification glycosides of kaempferol, quercetin, isorhamnetin and rhamnocitrin were detected by LC/MSn , besides flavonoids acylated with meglutol (3-hydroxy-3-methylglutaric acid), acetic and ferulic acids. Moreover, aglycons were analyzed in extracts after 1 N HCl hydrolysis and derivatization with BSTFA. GC/MS analysis of the hydrolysates revealed the incidence of compounds like meglutol, OH/OMe-substituted benzoic acids, ferulic and fatty acids, flavonoids, sugars and the triterpenoid medicagenic acid. Furthermore, a hemolytic activity was detected in the AcOEt extract using a blood-agar assay, and this was ascribed to the occurrence of saponins. In a saponin fraction, obtained from the AcOEt extract by chromatographic purification, two main saponins were characterized by LC/MSn and HR-ESI-MSn . A pure sapogenin could be isolated via VLC and CC purification upon acid hydrolysis of the saponins and assigned to saikogenin D by NMR analysis.

Rapid Spectrophotometric Method for Assessing Hydroperoxide Formation from Terpenes in Essential Oils upon Oxidative Conditions.

Essential oils are widely used in the food and cosmetics industry as natural flavoring and fragrance substances. For this reason, a thorough quality control applying selected analytical methods is required. Oxidation along with hydroperoxide formation is an important drawback during production and storage of essential oils. Hydroperoxides constitute the main products formed upon photo-oxidation of essential oils. Due to hydroperoxide instability, gas chromatography (GC) and high-performance liquid chromatography (HPLC) analyses are required. According to the European Pharmacopoeia, titration is the official method for oxidation assessment. However, this analysis is time-consuming, and large sample quantities are required. Here, we present a simple and accurate spectrophotometric method for the detection of peroxide trace amounts in essential oils and terpenes. The principle is based on the formation of Wurster's red, which is enforced by the peroxide-driven oxidation of N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD). The method was validated using dibenzoyl peroxide (DBP) and cumene hydroperoxide (CHP). To demonstrate the suitability of the method for routine analysis, various oxidized terpenes and essential oils were chosen. Moreover, photo- and thermal oxidation experiments were compared and evaluated using gas chromatography/mass spectrometry (GC/MS) and a synthesized limonene-2-hydroperoxide (Lim-2-OOH) reference standard to gather detailed information on the structural changes of the respective terpenes.

Structure Elucidation of the Main Tetrahydroxyxanthones of Hypericum Seeds and Investigations into the Testa Structure.

Seeds from Hypericum species have recently been identified as an interesting source of xanthone derivatives. Extraction of seeds from H. perforatum with MeOH and subsequent concentration via polyamide adsorption yielded a fraction enriched in tetrahydroxyxanthones (THX), which were further semipurified by silica gel chromatography. Based on tentative structure assignment of the two main THX X1 and X2 by NMR a total synthesis was performed for both compounds (THX 1 and 2, respectively), starting with an Ullmann ether synthesis. The synthesized 1 and 2 were characterized via 1D- and 2D-NMR methods as well as by LC/HR-MS analysis and proven to be 1,4,6,7-THX (1) and 1,2,6,7-THX (2). Final structure assignment of the natural Hypericum THX constituents was accomplished by comparing chromatographic and spectroscopic data (LC/MSn and GC/MS) with those of 1 and 2 which were obtained by synthesis. Beyond, investigations into the seeds of H. perforatum and H. tetrapterum by scanning electron microscopy (SEM) provided insights of the structure of the testa (seed coat), which is established by two cell layers, with the lignified sclerenchyma presumably being the depository of the xanthones.

Comprehensive Characterisation of n-Alkylresorcinols and Other Lipid Constituents of Mercurialis tomentosa L. from Alicante, Spain.

Mercurialis tomentosa L. has been used in Spanish ethnomedicine. In the present study the first phytochemical characterisation of a lipid fraction from M. tomentosa was performed. The CHCl3 extraction of aerial parts from M. tomentosa and GC/MS investigations revealed the occurrence of cuticular lipid and wax constituents, like long chain n-alcohols and n-aldehydes (C22  - C30 ), besides several aromatic constituents, i.e., phenylpropanoids and n-alkylresorcinols. The latter were further purified by CC and analysed by LC/MSn . In contrast to other Mercurialis species, i.e., M. annua, M. perennis, which exclusively contain 5-n-alkylresorcinols (1a - j, Cn ), mainly 5-n-alkyl-2-methylresorcinols (2a - j, Cn *) with side chain lengths of C15  - C25 were found in M. tomentosa, in addition to 1a - j. Thus, the latter compounds may be utilised for analytical characterisation and authentication of M. tomentosa based on fingerprinting methods. For structure elucidation a novel facile total synthesis of one representative 5-n-alkyl-2-methylresorcinol homologue (2d, C19 *) was developed, starting with a Grignard reaction from a substituted benzoic acid chloride (19). The compound obtained by synthesis was identical to the natural product 2d in terms of its chromatographic and spectroscopic features. Futhermore, 2d exhibited satisfactory DPPH free radical scavenging activity (IC50  = 37.8 µm) when compared to trolox (IC50  = 21.0 µm), corroborating the antioxidant features of these amphipathic molecules.

1-Acetyl-3-[(3R)-hydroxyfatty acyl]glycerols: Lipid Compounds from Euphrasia rostkoviana Hayne and E. tetraquetra (Bréb.) Arrond.

Five homologous acetylated acylglycerols of 3-hydroxyfatty acids (chain lengths C(14) - C(18)), named euphrasianins A - E, were characterized for the first time in Euphrasia rostkoviana Hayne (Orobanchaceae) by gas chromatography/mass spectrometry (GC/MS) and high-performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MS(n) ). In addition to mass spectrometric data, structures of euphrasianins were verified via a three-step total synthesis of one representative homologue (euphrasianin A). The structure of the latter was confirmed by 1D- and 2D-NMR experiments as well as high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS). The absolute configuration of the 3-hydroxyfatty acid moiety at C(3) was found to be R in the natural euphrasianins, which was determined by alkaline hydrolysis and methylation of a purified fraction, followed by chiral GC analysis. Furthermore, in extracts of Euphrasia tetraquetra (Bréb.) Arrond. euphrasianins C and E were detected exclusively, indicating that this subclass of lipid constituents is possibly valuable for fingerprinting methods.

Quillajasides A and B: New Phenylpropanoid Sucrose Esters from the Inner Bark of Quillaja saponaria Molina.

The phenolic composition of freshly prepared aqueous extracts of the inner bark of Quillaja saponaria Molina was compared to that of commercially available Quillaja extracts, which are currently used as emulsifiers in foods and cosmetics. Major phenolics in both extracts were (+)-piscidic acid and several p-coumaroyl sucrose esters. Among the latter, two new compounds were isolated and characterized: α-l-rhap-(1→4)-α-l-rhap-(1→3)-(4-O-(E)-p-coumaroyl)-α-d-glup-(1→2)-(3-O-(E)-p-coumaroyl)-ß-d-fruf (quillajaside A) and ß-d-apif-(1→4)-α-l-rhap-(1→4)-α-l-rhap-(1→3)-(4-O-(E)-p-coumaroyl)-α-d-glup-(1→2)-(3-O-(E)-p-coumaroyl)-ß-d-fruf (quillajaside B). In addition, a putative biosynthetic pathway of at least 20 structurally related p-coumaroyl sucrose esters was tentatively identified. Besides their antioxidant activity and their potential function as substrate for enzymatic browning reactions, the new compounds are highly characteristic for both the inner bark of Q. saponaria and commercial extracts derived therefrom. Consequently, they might serve as authenticity markers for the detection of Quillaja extracts in food and cosmetic formulations.

Sesquiterpene Lactone Composition of Wild and Cultivated Sunflowers and Biological Activity against an Insect Pest.

Sesquiterpene lactones in sunflowers, Helianthus spp., are important to interactions with pathogens, weeds, and insects. Across a broad range of Helianthus annuus, differences in composition of sesquiterpene lactones extracted from disc florets were found between wild and cultivated sunflowers and also between distinct groups of inbreds used to produce sunflower hybrids. Discriminant function analysis showed the presence and relative abundance of argophyllone B, niveusin B, and 15-hydroxy-3-dehydrodesoxyfruticin were usually (75%) effective at classifying wild sunflowers, cultivated inbreds, and hybrids. Argophyllone B reduced the larval mass of the sunflower moth, Homeosoma electellum, by >30%, but only at a dose greater than that found in florets. Low doses of mixed extracts from cultivated florets produced a similar (≈40%) reduction in larval mass, suggesting combinations of sesquiterpene lactones act additively. Although the results support a role for sesquiterpene lactones in herbivore defense of cultivated sunflowers, additional information is needed to use these compounds purposefully in breeding.

Phenolic constituents in commercial aqueous Quillaja (Quillaja saponaria Molina) wood extracts.

Phenolic compounds in aqueous, saponin-rich soapbark tree (Quillaja saponaria Molina) extracts were qualitatively and quantitatively characterized by HPLC-PDA-MS(n) and NMR spectroscopy. (+)-Piscidic acid represented the major constituent (75-87% (w/w) of total phenolics) in all examined extracts (n = 4), ranging from 22.1 ± 0.1 to 34.0 ± 0.2 mg/g of dry matter (DM). Derivatives of p-coumaric acid were present at concentrations from 2.2 to 9.3 mg/g of DM (8.1-20.4% of total phenolics), whereas other phenolic constituents such as glucosyringic acid and vanillic acid derivatives accounted for less than 7% of total phenolics. Generally, all Quillaja extracts showed a highly similar but unique pattern, potentially being useful to authenticate Quillaja extracts in foods, cosmetics, and pharmaceutical formulations. Furthermore, the desired antioxidant activity as well as undesired browning reactions in the final product might also be explained by these phenolic compounds, which were identified for the first time in Q. saponaria extracts.

Tandem mass spectrometric characterization of acetylated polyhydroxy hellebosaponins, the principal steroid saponins in Helleborus niger L. roots(#).

RATIONALE: Isolation and extensive nuclear magnetic resonance (NMR) analyses revealed polyhydroxy steroid saponins to be characteristic constituents in Helleborus niger L. roots. A comprehensive study including various multi-stage mass spectrometry (MS(n) ) experiments provided first solid chromatographic and mass spectrometric information facilitating future analysis and structural assessment of polyhydroxy saponins by LC/MS(n) techniques without isolation and NMR analyses. METHODS: The polyhydroxy saponins were analyzed by direct syringe injection or chromatographically separated on a capillary high-performance liquid chromatography (HPLC) system coupled to an electrospray ionization (ESI) source. MS(n) spectra were recorded on an ion trap mass spectrometer including up to four fragmentation stages (LC/ESI-MS/MS). Additionally, high-resolution mass spectra were recorded on an Orbitrap Fourier transform (FT) mass spectrometer equipped with a nanospray-ESI interface. RESULTS: The polyhydroxy hellebosaponins A and D were discovered to be significant constituents from H. niger roots. Extensive study of their MS(n) data revealed that they readily fragmented in the positive ion mode providing diagnostic fragments for elucidation of the steroidal character and number of OH groups. The negative ion mode yielded valuable information on the [M-H](-) ion, number and location of acetyl groups and sugar units. Additionally, fragmentation pathways for positive and negative ion modes were proposed. CONCLUSIONS: These results not only extend the knowledge about H. niger saponins, but also provide a facilitated approach to the analysis of polyhydroxy saponins by LC/MS(n) without prior isolation and extensive NMR identification. Additionally, proposed fragmentation pathways for positive and negative ionization modes provide a solid complementary database for further, more detailed MS(n) studies.

Metabolic fate of depsides and alkaloid constituents in aqueous extracts from Mercurialis perennis L. during fermentation.

Dog's mercury (Mercurialis perennis L.) is an old medicinal plant, nowadays used in complementary medicine. Aqueous fermented extracts of the plant are being mainly applied in remedies to treat external inflammations, but a thorough phytochemical characterization is still lacking. Therefore, the conversion of characteristic compound classes from M. perennis extracts during fermentation and storage was investigated. The microbial transformation of the two main depsides phaselic acid (=(2R)-O-[(E)-caffeoyl]malic acid; 1) and mercurialis acid (=(2R)-[(E)-caffeoyloxy]glutaric acid; 2) was monitored by HPLC-DAD. The degradation followed a second-order kinetic, and the calculated half-life periods of both constituents were 67 and 30 months, respectively. Several depside metabolites were detected by GC/MS in AcOEt extracts as (t) BuMe2 Si (TBDMS) derivatives after derivatization, mainly dihydrocinnamic acids. Moreover, numerous α-hydroxy acids were found, allegedly as degradation products from amino acids or peptides. The microbial alteration of the main alkaloid hermidin was also examined. After three days of fermentation, three novel N-metabolites were formed and thoroughly assigned in CH2 Cl2 extracts as a mixture of 3-ethylhermidin, 3-ethylhermidin quinone, and (E/Z)-3-ethylidenehermidin by GC/MS and NMR methods, as well as by means of total synthesis. A mechanism for the formation of these N-metabolites starting from dimeric hermidin oxidation products is proposed. The obtained results reveal the complex pathways plant constituents may undergo during the fermentation of the extracts.

LC-NMR, NMR, and LC-MS identification and LC-DAD quantification of flavonoids and ellagic acid derivatives in Drosera peltata.

The herb of Drosera peltata, commonly named the shield sundew, is used as an antitussive in phytotherapy, although the plants' composition has not been determined in detail so far. Hence, in this study, we present a validated, sensitive, reliable, and cheap narrow-bore LC-DAD method for the simultaneous quantification of flavonoids and ellagic acid derivatives in this herbal drug. In addition, the structures of 13 compounds have been elucidated by LC-MS, LC-NMR, and offline NMR experiments after isolation: herbacetin-3-O-glucoside (1), gossypitrin (2), ellagic acid (3), quercetin-7-O-glucoside (4), isoquercitrin (5), kaempferol-3-O-(6″-O-galloyl)-glucoside (6), herbacetin-7-O-glucoside (7), astragalin (8), gossypetin (9), herbacetin (10), quercetin (11), 3,3'-di-O-methyl ellagic acid (12), and kaempferol (13). Compounds 1, 2, 4, 5, 6, 7, and 10 have been identified in D. peltata for the first time, and compounds 1, 4, 6, 7, and 10 have not been detected in any Drosera species before.

An approach to the chemotaxonomic differentiation of two European dog's mercury species: Mercurialis annua L. and M. perennis L.

Mercurialis annua and M. perennis are medicinal plants used in complementary medicine. In the present work, analytical methods to allow a chemotaxonomic differentiation of M. annua and M. perennis by means of chemical marker compounds were established. In addition to previously published compounds, the exclusive presence of pyridine-3-carbonitrile and nicotinamide in CH(2) Cl(2) extracts obtained from the herbal parts of M. annua was demonstrated by GC/MS. Notably, pyridine-3-carbonitrile was identified for the first time as a natural product. Further chromatographic separation of the CH(2) Cl(2) extracts via polyamide yielded a MeOH fraction exhibiting a broad spectrum of side-chain saturated n-alkylresorcinols. While the n-alkylresorcinol pattern was similar for both plant species, some specific differences were observed for particular n-alkylresorcinol homologs. Finally, the investigation of H(2) O extracts by LC/MS/MS revealed the presence of depside constituents. Whereas, in M. perennis, a mixture of mercurialis acid (=(2R)-[(E)-caffeoyl]-2-oxoglutarate) and phaselic acid (=(E)-caffeoyl-2-malate) could be detected, in M. annua solely phaselic acid was found. By comparison with synthesized enantiomerically pure (2R)- and (2S)-phaselic acids, the configuration of the depside could be determined as (2S) in M. annua and as (2R) in M. perennis.

Investigations into the phenolic constituents of dog's mercury (Mercurialis perennis L.) by LC-MS/MS and GC-MS analyses.

INTRODUCTION: Dog's mercury (Mercurialis perennis L.) is a traditional European medicinal plant considered as a rich source of bioactive natural products. Yet phytochemical data of the plant are scant. OBJECTIVE: This study aimed to identify the hydrophilic phenolic constituents from M. perennis by aqueous and hydroalcoholic extraction. METHODOLOGY: Extracts of herbal parts were investigated in-depth by HPLC(DAD)-MS/MS and GC/MS analyses. In addition, a novel compound was isolated and fully characterised by 1- and 2D-NMR experiments. RESULTS: Several conjugates of caffeic, p-coumaric and ferulic acids together with glucaric or 2-hydroxyglutaric acids (depsides) were detected in the aqueous extracts from aerial plant parts by use of LC-MS/MS techniques as well UV-spectral data. By implementation of preparative chromatography on polyamide pretreated with formic acid followed by vacuum liquid chromatography on reversed-phase C(18) -silica, one of the predominant depsides was isolated as a pure compound. The NMR spectra ((1) H and (13) C NMR) together with 2D-hetereonuclear multiple bond correlation NMR experiments (gHMBC and gHSQC) and chiral GC investigation, allowed identification of this compound as (-)-(E)-caffeoyl-2-(R)-oxoglutarate. This structure was additionally supported by GC/MS data after silylation and methylation reactions. The hydroalcoholic extract from aerial parts was separated by solvent partition between ethyl acetate and n-butanol. The latter fraction (n-butanol) yielded a mixture of mono- and oligo-glycosides of kaempferol and quercetin, all of them being assigned by LC-MS/MS. CONCLUSIONS: The present investigation constitutes the first comprehensive report on the hydrophilic constituents of the rarely studied plant Mercurialis and thus completes the phytochemical knowledge on M. perennis.

Identification and quantification of flavonoids and ellagic acid derivatives in therapeutically important Drosera species by LC-DAD, LC-NMR, NMR, and LC-MS.

Droserae herba is a drug commonly used for treatment of convulsive or whooping cough since the seventeenth century. Because of the contribution of flavonoids and ellagic acid derivatives to the therapeutic activity of Droserae herba, an LC-DAD method has been developed for quantification of these analytes in four Drosera species used in medicine (Drosera anglica, D. intermedia, D. madagascariensis, and D. rotundifolia). During elaboration of the method 13 compounds, including three substances not previously described for Drosera species, were detected and unambiguously identified by means of extensive LC-MS and LC-NMR experiments and by off-line heteronuclear 2D NMR after targeted isolation. The most prominent component of D. rotundifolia and D. anglica, 2″-O-galloylhyperoside, with myricetin-3-O-ß-glucopyranoside and kaempferol-3-O-(2″-O-galloyl)-ß-galactopyranoside, were identified for the very first time in this genus. The LC-DAD method for quantification was thoroughly validated, and enables, for the first time, separation and precise analysis of these analytes in Droserae herba. Simple sample preparation and use of a narrow-bore column guarantee low cost and simplicity of the suggested system, which is excellently suited to quality control of the drug or herbal medicinal products containing this drug.

Flavonoid glucuronides and a chromone from the aquatic macrophyte Stratiotes aloides.

The first phytochemical analysis of the aquatic macrophyte Stratiotes aloides afforded two new flavonoid glucuronides, luteolin 7-O-beta-D-glucopyranosiduronic acid-(1-->2)-beta-D-glucopyranoside (1) and chrysoeriol 7-O-beta-D-glucopyranosiduronic acid-(1-->2)-beta-D-glucopyranoside (2), as well as the new 2-(2-hydroxypentyl)-5-carboxy-7-methoxychromone (5) and chrysoeriol 7-O-beta-(6-O-malonyl)glucopyranoside (3), which has been assigned via NMR data for the first time. Additionally, free amino acids such as tryptophan, arginine, leucine, isoleucine, phenylalanine, and tyrosine along with choline, cis-aconitic acid, the phenolic glycoside alpha-arbutine, the chlorophyll derivative phaeophorbide a, and the flavonoid glycoside luteolin 7-O-beta-(6-O-malonyl)glucopyranoside (4) were isolated. Despite the low quantities obtained in some cases (between 50-300 microg), the structures of all compounds were unambiguously elucidated by extensive NMR and MS experiments. With a delay of 2 days compound 1 (10 and 50 microM test concentration) strongly inhibited the growth of human SH-SY5Y neuroblastoma cells in a dose-dependent manner, whereas only a moderate growth inhibition of human Patu 8902 carcinoma cells could be observed. Compounds 1 and 2 showed no activities against the bacteria Escherichia coli BW25113, Pseudomonas pudida KT2440, and Enterobacter cloacae subsp. dissolvens.

Anti-inflammatory 5-(11'Z-heptadecenyl)- and 5-(8'Z,11'Z-heptadecadienyl)-resorcinols from mango (Mangifera indica L.) peels.

Bioassay directed extraction and purification of mango peels revealed the 5-(11'Z-heptadecenyl)-resorcinol (1) and the known 5-(8'Z,11'Z-heptadecadienyl)-resorcinol (2) previously not described in Mangifera indica L. The structures of both compounds were determined by extensive 1D and 2D NMR studies and MS. Both compounds exhibited potent cyclooxygenase (COX)-1 and COX-2 inhibitory activity with IC(50) values ranging from 1.9 (2) to 3.5 microM (1) and from 3.5 (2) to 4.4 (1) microM, respectively, coming close to the IC(50) values of reference drugs. 5-Lipoxygenase (5-LOX) catalyzed leukotriene formation was only slightly inhibited. Structure-activity studies by referring to synthetic saturated homologues indicated that the degree of unsaturation in the alkyl chain plays a key role for COX inhibitory activity, whereas the influence of chain length was less significant.

Integerrimides A and B, cyclic heptapeptides from the latex of Jatropha integerrima.

Two new cyclic heptapeptides, integerrimides A and B, have been isolated from the latex of Jatropha integerrima. Their structures were elucidated by using extensive 1D and 2D NMR, MS, and chemical degradation. At 50 microM both peptides 1 and 2 significantly inhibited neurite outgrowth in neuronal cell culture. They also partially inhibited proliferation of human IPC-298 melanoma cells as well as migration of human Capan II pancreatic carcinoma cells, but were inactive in HSV-1, antifungal, and antimalarial assays.

Isolation of carotenoids from plant materials and dietary supplements by high-speed counter-current chromatography.

Methods for the isolation of lipophilic pigments from crude extracts of plant materials (spinach and sweet corn) by high-speed counter-current chromatography (HSCCC) were developed. Particular attention was given to (all-E)-lutein and (all-E)-zeaxanthin. However, the concomitant pigments neoxanthin, violaxanthin and beta-carotene as well as chlorophylls a and b were also considered. Furthermore, for the first time dietary supplements containing lutein and zeaxanthin were also used as a source for the recovery of carotenoids. Due to their simple matrix (oily excipient in soft gelatine capsules), sample preparation was facilitated and consumption of solvents was minimized. The carotenoids were characterized by 1H NMR spectroscopy, by LC/APcI-MS in the positive ionization mode, and by UV-vis spectroscopy. Data showed that the target compounds were of high purity (90 - 93%). Lutein and zeaxanthin may be used as reference substances for analytical purposes.

Screening of mango (Mangifera indica L.) cultivars for their contents of flavonol O- and xanthone C-glycosides, anthocyanins, and pectin.

With respect to their browning potential and in consideration of a combined recovery of pectin and phenolic compounds, peels of 14 cultivars and the flesh of nine cultivars of mango (Mangifera indica L.) fruits were analyzed for their contents of flavonol O- and xanthone C-glycosides by high-performance liquid chromatography (HPLC)-diode array detection-electrospray ionization mass spectrometry (ESI-MS). While total amounts of up to 4860 mg/kg dry matter demonstrated the peels to be a rich source of phenolic compounds, only traces could be detected in the flesh. The profile of flavonol glycosides of the peels proved to be highly characteristic and may therefore serve as a tool for authenticity control of mango puree concentrate, which is often produced from unpeeled fruits and represents an important intermediate for the production of mango nectars. Two compounds were isolated by preparative HPLC, and their structures were elucidated on the basis of ESI-MS as well as NMR spectroscopy, establishing the two compounds as rhamnetin 3-O-beta-galactopyranoside and rhamnetin 3-O-beta-glucopyranoside, respectively. In the peels of red-colored cultivars, cyanidin 3-O-galactoside and an anthocyanidin hexoside so far not reported in mango could tentatively be identified. The contents and degrees of esterification of pectins extracted from the lyophilized peels ranged from 12.2 to 21.2% and from 56.3 to 65.6%, respectively, suggesting mango peels also as a promising source of high-quality pectin.

New flavones from Millettia erythrocalyx.

From the stem bark of Millettia erythrocalyx, three new compounds, namely, millettocalyxins A-C (1-3), and the new natural product pongol methyl ether (4) were isolated, along with 10 other known compounds. The structures of the new isolates were elucidated on the basis of spectroscopic data interpretation.