The Effects of a Cultivar and Production System on the Qualitative and Quantitative Composition of Bioactive Compounds in Spring Wheat (Triticum sp.).

Spelt Triticum aestivum L. subsp. spelta (cv. Wirtas), einkorn Triticum monococcum L. (cv. Samopsza) and emmer Triticum dicoccum Schrank (Schuebl) (cv. Plaskurka biala and Plaskurka ciemna) spring wheat cultivars were analyzed and compared to common wheat Triticum aestivum L. subsp. aestivum (cv. Harenda, Kandela, Mandaryna, Serenada, Goplana, Kamelia, Nimfa, Rusalka, Struna, Zadra) cultivated in an organic production system. Moreover, the performance of four common wheat cultivars (cv. Harenda, Kandela, Mandaryna, Serenada) grown in organic, conventional and integrated production systems were compared. The UHPLC-DAD-MS and TLC-DPPH• analyses of specific substances (phenolic acids and alkylresorcinols) were evaluated to ascertain the potential of spring wheat cultivars for promoting human health and suitability for cultivation in an organic production system. The highest yield was observed for the T. aestivum L. subsp. aestivum (modern hull-less) cv. Nimfa (4.45 t/ha), which also demonstrated the lowest resistance to Fusarium spp. infection. Among the contemporary hull-less cultivars, cv. Mandaryna and cv. Harenda exhibited the highest resistance to this pathogen (2.4% and 3.7% of grains infected by Fusarium, respectively), while simultaneously displaying the highest organic phenolic acid content (900.92 and 984.55 µg/g of the grain) and the highest antioxidant potential. It is noteworthy that the cereal hulls of T. monococcum L. (old hulled) (cv. Samopsza) exhibited a markedly elevated content of phenolic acids (approximately 4000 µg/g of the grain). This may have contributed to the reduced incidence of Fusarium infection (9.3% of grains infected) observed in the grains of this cultivar. Furthermore, the hulls proved to be a rich source of phenolics with high antioxidant activity, which is beneficial for human and animal health.

Selectivity Screening and Structure-Cytotoxic Activity Observations of Selected Oleanolic Acid (OA)-Type Saponins from the Amaranthaceae Family on a Wiade Panel of Human Cancer Cell Lines.

Plants from the Amaranthaceae family are a source of oleanolic acid (OA)-type saponins with cytotoxic activity. Two known OA-type saponins, calenduloside E and chikusetsusaponin IVa, were isolated from the roots of Chenopodium strictum Roth. Their structures were confirmed using MS and NMR techniques. This constitutes the inaugural report of the saponins in Ch. strictum. Both the isolated saponins and structurally similar compounds, momordin Ic and OA, were compared for their cytotoxicity against various cancer and normal cell lines (including skin, breast, thyroid, gastrointestinal, and prostate panels). Their effects were dose- and time-dependent, varying with the specific cell line and compound structure. A chemometric approach demonstrated the effects of the compounds on the cell lines. The study discusses the structure-activity observations. The key structural elements for potent cytotoxic activity included the free carboxyl group 28COOH in the sapogenin structure (OA) and the presence of a sugar moiety. The monodesmosides with glucuronic acid (GlcA) at the C3 position of OA were generally more cytotoxic than bidesmosides or OA alone. The addition of xylose in the sugar chain modified the activity towards the cancer cells depending on the specific cell line. OA-type saponins with GlcA (particularly calenduloside E and momordin Ic) represent a promising avenue for further investigation as potential anticancer agents.

Spiro-Flavonoids in Nature: A Critical Review of Structural Diversity and Bioactivity.

Based on the literature data from 1973 to 2022, this work summarizes reports on spiro-flavonoids with a spiro-carbon at the center of their structure and how this affects their isolation methods, stereochemistry, and biological activity. The review collects 65 unique structures, including spiro-biflavonoids, spiro-triflavonoids, spiro-tetraflavonoids, spiro-flavostilbenoids, and scillascillin-type homoisoflavonoids. Scillascillin-type homoisoflavonoids comprise spiro[bicyclo[4.2.0]octane-7,3'-chromane]-1(6),2,4-trien-4'-one, while the other spiro-flavonoids contain either 2H,2'H-3,3'-spirobi[benzofuran]-2-one or 2'H,3H-2,3'-spirobi[benzofuran]-3-one in the core of their structures. Spiro-flavonoids have been described in more than 40 species of eight families, including Asparagaceae, Cistaceae, Cupressaceae, Fabaceae, Pentaphylacaceae, Pinaceae, Thymelaeaceae, and Vitaceae. The possible biosynthetic pathways for each group of spiro-flavonoids are summarized in detail. Anti-inflammatory and anticancer activities are the most important biological activities of spiro-flavonoids, both in vitro and in vivo. Our work identifies the most promising natural sources, the existing challenges in assigning the stereochemistry of these compounds, and future research perspectives.

Pioneering Metabolomic Studies on Diaporthe eres Species Complex from Fruit Trees in the South-Eastern Poland.

Fungi from the genus Diaporthe have been reported as plant pathogens, endophytes, and saprophytes on a wide range of host plants worldwide. Their precise identification is problematic since many Diaporthe species can colonize a single host plant, whereas the same Diaporthe species can inhabit many hosts. Recently, Diaporthe has been proven to be a rich source of bioactive secondary metabolites. In our initial study, 40 Diaporthe isolates were analyzed for their metabolite production. A total of 153 compounds were identified based on their spectroscopic properties-Ultraviolet-visible and mass spectrometry. From these, 43 fungal metabolites were recognized as potential chemotaxonomic markers, mostly belonging to the drimane sesquiterpenoid-phthalide hybrid class. This group included mainly phytotoxic compounds such as cyclopaldic acid, altiloxin A, B, and their derivatives. To the best of our knowledge, this is the first report on the metabolomic studies on Diaporthe eres species complex from fruit trees in the South-Eastern Poland. The results from our study may provide the basis for the future research on the isolation of identified metabolites and on their bioactive potential for agricultural applications as biopesticides or biofertilizers.

Isolation of Mirificin and Other Bioactive Isoflavone Glycosides from the Kudzu Root Lyophilisate Using Centrifugal Partition and Flash Chromatographic Techniques.

Pueraria lobata (Willd.) Ohwi is a legume taxon native to Southeast Asia and widely used in traditional medicine systems of that region. The therapeutic applications of the underground parts of this species (known as kudzu root) are related to its high content of isoflavones, mainly the characteristic C-glycoside derivatives. Within this group, the most explored compound both phytochemically and pharmacologically is puerarin. However, current scientific findings document important anti-biodegenerative effects for some of the minor isoflavones from kudzu roots. Therefore, the main objective of the study was to develop an original preparative method that allowed the efficient isolation of closely related hydrophilic daidzein C-glycosides, including mirificin, from vacuum-dried aqueous-ethanolic extracts of kudzu roots. For this purpose, the combined centrifugal partition (CPC) and flash chromatographic (FC) techniques were elaborated and used. The optimized biphasic solvent system in CPC, with ethyl acetate, ethanol, water, and 0.5% (V/V) acetic acid as a mobile phase modifier, enabled the purification and separation of the polar fraction containing bioactive isoflavones and ultimately the isolation of mirificin, 3'-hydroxy- and 3'-methoxypuerarin, puerarin, and daidzin using FC. The identity of isoflavones was confirmed using spectroscopic (UV absorption and nuclear magnetic resonance) and mass spectrometric methods. The determined purity of isolated mirificin was 63%.

Special Issue "Natural Plant Substances-Structural and Application Aspects: A Theme Issue in Honor of Professor Wieslaw Oleszek".

Dear Colleagues, [...].

Qualitative and Quantitative Analysis of Secondary Metabolites in Morphological Parts of Paulownia Clon In Vitro 112® and Their Anticoagulant Properties in Whole Human Blood.

It is not easy to find data in the scientific literature on the quantitative content of individual phytochemicals. It is possible to find groups of compounds and even individual compounds rather easily, but it is not known what their concentration is in cultivated or wild plants. Therefore, the subject of this study was to determine the content of individual compounds in the new Paulownia species, Oxytree, developed in a biotechnology laboratory in 2008 at La Mancha University in Spain. Six secondary metabolites were isolated, and their chemical structure was confirmed by spectral methods. An analytical method was developed, which was then used to determine the content of individual compounds in leaves, twigs, flowers and fruits of Paulownia Clon in Vitro 112®. No flavonoids were found in twigs and fruits of Oxytree, while the highest phenylethanoid glycosides were found in twigs. In this study, we also focused on biological properties (anticoagulant or procoagulant) of extract and four fractions (A-D) of different chemical composition from Paulownia Clon in Vitro 112 leaves using whole human blood. These properties were determined based on the thrombus-formation analysis system (T-TAS), which imitates in vivo conditions to assess whole blood thrombogenecity. We observed that three fractions (A, C and D) from leaves decrease AUC10 measured by T-TAS. In addition, fraction D rich in triterpenoids showed the strongest anticoagulant activity. However, in order to clarify the exact mechanism of action of the active substances present in this plant, studies closer to physiological conditions, i.e., in vivo studies, should be performed, which will also allow to determine the effects of their long-term effects.

Iphiona mucronata (Forssk.) Asch. & Schweinf. A Comprehensive Phytochemical Study via UPLC-Q-TOF-MS in the Context of the Embryo- and Cytotoxicity Profiles.

Iphiona mucronata (Family Asteraceae) is widely distributed in the Eastern desert of Egypt. It is a promising plant material for phytochemical analysis and pharmacologic studies, and so far, its specific metabolites and biological activity have not yet been thoroughly investigated. Herein, we report on the detailed phytochemical study using UPLC-Q-TOF-MS approach. This analysis allowed the putative annotation of 48 metabolites belonging to various phytochemical classes, including mostly sesquiterpenes, flavonoids, and phenolic acids. Further, zebrafish embryotoxicity has been carried out, where 100 µg/mL extract incubated for 72 h resulted in a slow touch response of the 10 examined larvae, which might be taken as a sign of a disturbed peripheral nervous system. Results of in vitro testing indicate moderate cytotoxicity towards VERO, FaDu, and HeLa cells with CC50 values between 91.6 and 101.7 µg/mL. However, selective antineoplastic activity in RKO cells with CC50 of 54.5 µg/mL was observed. To the best of our knowledge, this is the first comprehensive profile of I. mucronata secondary metabolites that provides chemical-based evidence for its biological effects. A further investigation should be carried out to precisely define the underlying mechanisms of toxicity.

Neuroprotective Effect of Yucca schidigera Roezl ex Ortgies Bark Phenolic Fractions, Yuccaol B and Gloriosaol A on Scopolamine-Induced Memory Deficits in Zebrafish.

Y. schidigera contains a number of unusual polyphenols, derivatives of resveratrol and naringenin, called spiro-flavostilbenoids, which have potent in vitro anti-inflammatory, antioxidant, and moderate cholinesterase inhibitory activities. To date, these compounds have not been tested in vivo for the treatment of neurodegenerative diseases. The aim of the present study was to evaluate the effects of both single spiro-flavostilbenoids (yuccaol B and gloriosaol A) and phenolic fractions derived from Y. schidigera bark on scopolamine-induced anxiety and memory process deterioration using a Danio rerio model. Detailed phytochemical analysis of the studied fractions was carried out using different chromatographic techniques and Nuclear Magnetic Resonance (NMR). The novel tank diving test was used as a method to measure zebrafish anxiety, whereas spatial working memory function was assessed in Y-maze. In addition, acetylcholinesterase/butyrylcholinesterase (AChE/BChE) and 15-lipooxygenase (15-LOX) inhibition tests were performed in vitro. All pure compounds and fractions under study exerted anxiolytic and procognitive action. Moreover, strong anti-oxidant capacity was observed, whereas weak inhibition towards cholinesterases was found. Thus, we may conclude that the observed behavioral effects are complex and result rather from inhibition of oxidative stress processes and influence on cholinergic muscarinic receptors (both 15-LOX and scopolamine assays) than effects on cholinesterases. Y. schidigera is a source of substances with desirable properties in the prevention and treatment of neurodegenerative diseases.

Serjanic Acid Glycosides from Chenopodium hybridum L. with Good Cytotoxicity and Selectivity Profile against Several Panels of Human Cancer Cell Lines.

Two triterpene saponins, including a novel serjanic acid derivative, were isolated from Chenopodium hybridum L. (Amaranthaceae) aerial parts. Their structures were elucidated by a combination of spectroscopic methods (MS, 1D and 2D NMR). Both compounds were evaluated for cytotoxicity and selectivity on skin, prostate, gastrointestinal, thyroid and lung cancer cells. Their effect was dose and time-dependent with varied potency, the highest against prostate PC3 and melanoma WM793, where IC50 was lower than the reference drug doxorubicin. Structure-activity relationship is briefly discussed.

Pulmonaria obscura and Pulmonaria officinalis Extracts as Mitigators of Peroxynitrite-Induced Oxidative Stress and Cyclooxygenase-2 Inhibitors-In Vitro and In Silico Studies.

The Pulmonaria species (lungwort) are edible plants and traditional remedies for different disorders of the respiratory system. Our work covers a comparative study on biological actions in human blood plasma and cyclooxygenase-2 (COX-2) -inhibitory properties of plant extracts (i.e., phenolic-rich fractions) originated from aerial parts of P. obscura Dumort. and P. officinalis L. Phytochemical profiling demonstrated the abundance of phenolic acids and their derivatives (over 80% of the isolated fractions). Danshensu conjugates with caffeic acid, i.e., rosmarinic, lithospermic, salvianolic, monardic, shimobashiric and yunnaneic acids were identified as predominant components. The examined extracts (1-100 µg/mL) partly prevented harmful effects of the peroxynitrite-induced oxidative stress in blood plasma (decreased oxidative damage to blood plasma components and improved its non-enzymatic antioxidant capacity). The cellular safety of the extracts was confirmed in experimental models of blood platelets and peripheral blood mononuclear cells. COX-2 inhibitor screening evidently suggested a stronger activity of P. officinalis (IC50 of 13.28 and 7.24 µg/mL, in reaction with synthetic chromogen and physiological substrate (arachidonic acid), respectively). In silico studies on interactions of main components of the Pulmonaria extracts with the COX-2 demonstrated the abilities of ten compounds to bind with the enzyme, including rosmarinic acid, menisdaurin, globoidnan A and salvianolic acid H.

Phytochemical Profile, Antioxidant Activity, and Cytotoxicity Assessment of Tagetes erecta L. Flowers.

Tagetes erecta L. is a popular ornamental plant of the Asteraceae family, which is widely cultivated not only for its decorative use, but also for the extraction of lutein. Besides carotenoid representatives, which have been extensively studied, other important classes of secondary metabolites present in the plant, such as polyphenols, could exhibit important biological activities. The phytochemical analysis of a methanolic extract obtained from T. erecta inflorescences was achieved using liquid chromatography-mass spectrometry (LC-MS) techniques. The extract was further subjected to a multistep purification process, which allowed the separation of different fractions. The total extract and its fractions contain several polyphenolic compounds, such as hydroxybenzoic and hydroxycinnamic acid derivatives, flavonols (especially quercetagetin glycosides), and several aglycons (e.g., quercetin, patuletin). One of the fractions, containing mostly quercetagitrin, was subjected to two different antioxidant assays (metal chelating activity and lipoxygenase inhibition) and to in vitro cytotoxicity assessment. Generally, the biological assays showed promising results for the investigated fraction compared to the initial extract. Given the encouraging outcome of the in vitro assays, further purification and structural analysis of compounds from T. erecta extracts, as well as further in vivo investigations are justified.

Norditerpenoids with Selective Anti-Cholinesterase Activity from the Roots of Perovskia atriplicifolia Benth.

Inhibition of cholinesterases remains one of a few available treatment strategies for neurodegenerative dementias such as Alzheimer's disease and related conditions. The current study was inspired by previous data on anticholinesterase properties of diterpenoids from Perovskia atriplicifolia and other Lamiaceae species. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by the three new natural compounds-(1R,15R)-1-acetoxycryptotanshinone (1), (1R)-1-acetoxytanshinone IIA (2), and (15R)-1-oxoaegyptinone A (3)-as well as, new for this genus, isograndifoliol (4) were assessed. Three of these compounds exhibited profound inhibition of butyrylcholinesterase (BChE) and much weaker inhibition of acetylcholinesterase (AChE). All compounds (1-4) selectively inhibited BChE (IC50 = 2.4, 7.9, 50.8, and 0.9 µM, respectively), whereas only compounds 3 and 4 moderately inhibited AChE (IC50 329.8 µM and 342.9 µM). Molecular docking and in silico toxicology prediction studies were also performed on the active compounds. Natural oxygenated norditerpenoids from the traditional Central Asian medicinal plant P. atriplicifolia are selective BChE inhibitors. Their high potential makes them useful candidate molecules for further investigation as lead compounds in the development of a natural drug against dementia caused by neurodegenerative diseases.

Water Soldier Stratiotes aloides L.-Forgotten Famine Plant With Unique Composition and Antioxidant Properties.

Stratiotes aloides L. is common water plant in central Poland. Due to its expansive character, S. aloides L. can strongly affect the functioning of aquatic ecosystems. S. aloides L. was an important famine plant in central Poland. This plant was commonly collected and cooked until the turn of the 20th century. It has also been used to heal wounds, especially when these are made by an iron implement. The objective of the present work was to study the phenolic profile in the leaves and roots of S. aloides as well as their antioxidant potential and ability to inhibit lipoxygenase (LOX) in the light of their potential bioaccessibility. The dominant compound in its leaves was luteolin-7-O-hexoside-glucuronide (5.84 mg/g DW), whereas the dominant root component was chrysoeriol-7-O-hexoside-glucuronide (0.83 mg/g DW). Infusions from leaves, roots, and their 1:1 (v/v) mixture contained potentially bioaccessible antiradical compounds. S. aloides is a good source of water-extractable reductive compounds. Especially valuable are the leaves of this plant. The roots of S. aloides contained very active hydrophilic compounds able to chelate metal ions. However, their potential bioaccessibility was relatively low. The hydrophilic compounds from the leaves were the most effective XO inhibitors (EC50 = 9.91 mg DW/mL). The water-extractable compounds derived from the leaves and roots acted as uncompetitive LOX inhibitors.

Anticancer Potential and Capsianosides Identification in Lipophilic Fraction of Sweet Pepper (Capsicum annuum L.).

This study aimed to determine the health-promoting properties of sweet pepper by comparing the activity of fractions with variable lipophilicity. Fractions from red pericarp: aqueous (F1), 40% MeOH (F2), and 70% MeOH (F3) were analyzed for antiradical activity (with DPPH• and ABTS+•), and the contents of total phenolic compounds (TP), flavonoids (TF), and dihydroxycinnamic acids (TDHCA). The anticancer potential of the fractions was evaluated in vitro using different cancer cell lines: human colorectal carcinoma (HCT116) and PC-3 (prostate cancer cell). Fibroblast-like cells of L929 obtained from subcutaneous adipose tissue of mouse were used as normal cells. The highest content of TP, TF, and TDHCA along with the strongest antiradical activity was observed for fraction F2, while the strongest anticancer properties against PC-3 were observed in fraction F3. Fraction F3 primarily contained capsianoside derivatives, which had been isolated through chromatographic methods and identified by spectral methods. These analyses helped in identifying 8 compounds, including 3 new compounds.

Cytotoxic Cardenolides from the Leaves of Acokanthera oblongifolia.

Three previously undescribed cardenolides, acovenosigenin A 3-O-α-L-acofriopyranoside (1: ), 14-anhydroacovenosigenin A 3-O-[ß-D-glucopyranosyl-(1″→4')-O-α-L-acofriopyranoside] (2: ), and 14-anhydroacovenosigenin A 3-O-[ß-D-glucopyranosyl-(1″→4')-O-α-L-acovenopyranoside] (3: ), together with the two already known ones, 14-anhydrodigitoxigenin 3-O-ß-D-glucopyranoside (4: ) and acospectoside A (5: ), were isolated from the leaves of Acokanthera oblongifolia. The influence of cardenolides 1:  - 3: and acovenoside A (found in the Acokanthera genus) on three cancer cell lines (HT29, HCT116, and AGS) was also investigated. The most promising results, in comparison with oxaliplatin, were obtained for compound 1: , which was found to be highly cytotoxic for all tested cell lines, HT29 (IC50 = 63.49 nM), HCT116 (IC50 = 67.35 nM), and AGS (IC50 = 80.92 nM). Unfortunately, 1: also showed similar toxicity towards normal lymphocytes (IC50 = 98.03 nM).

Phenolic Content and Antioxidant Activity in Trifolium Germplasm from Different Environments.

Phenolics are important mediators in plant-environment interactions. The presence and concentration of phenolic compounds and their antioxidant activity were evaluated in leaves and flowers of a set of Trifolium species originating from contrasting environments encompassing lowland and mountain sites. The current germplasm proved a great reservoir of phenolic compounds, with different chemical structure and, possibly, diversified biological activity. Germplasm groups with specific phenolic composition were observed. In some cases, different patterns bore a taxonomic meaning. Lowland germplasm showed higher concentration of total phenolics in leaves than mountain accessions (50.30 vs. 34.19 mg/g dry matter (DM)), while the latter had higher concentration in flowers (114.16 vs. 57.44 mg/g DM). Outstanding concentration of isoflavones was observed in leaves of lowland germplasm (24.19 mg/g DM), and of both proanthocyanidins and flavonoids in flowers of mountain germplasm (53.81 and 56.62 mg/g DM, respectively). The pattern of phenolic composition in lowland and mountain germplasm was suggestive of different adaptive strategies. Three assays of antioxidant activity were tested, which were characterised by rather different reactivity towards phenolic composition. The scavenging activity was higher for leaf extracts of lowland germplasm, and for flower extracts of mountain germplasm. Besides identifying germplasm of interest, this study also suggested possible links between environmental factors and concentration and composition of phenolic compounds.

Antioxidative and Potentially Anti-inflammatory Activity of Phenolics from Lovage Leaves Levisticum officinale Koch Elicited with Jasmonic Acid and Yeast Extract.

The effect of elicitation with jasmonic acids (JA) and yeast extract (YE) on the production of phenolic compounds as well as the antioxidant and anti-inflammatory properties of phenolic extracts of lovage was evaluated. The analysis of phenolic compounds carried out with the UPLC-MS technique indicated that rutin was the dominant flavonoid, while 5-caffeoylquinic acid was the main component in the phenolic acid fraction in the lovage leaves. The application of 10 µM JA increased the content of most of the identified phenolic compounds. The highest antioxidant activities estimated as free radical scavenging activity against ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and reducing power were determined for the sample elicited with 10 µM JA, while this value determined as iron chelating ability was the highest for the 0.1% YE-elicited lovage. The 0.1% and 1% YE elicitation also caused significant elevation of the lipoxygenase (LOX) inhibition ability, while all the concentrations of the tested elicitors significantly improved the ability to inhibit cyclooxygenase 2 (COX2) (best results were detected for the 10 µM JA and 0.1% YE2 sample). Thus, 0.1% yeast extract and 10 µM jasmonic acid proved to be most effective in elevation of the biological activity of lovage.

Chemical Profile and Antioxidant Activity of Zinnia elegans Jacq. Fractions.

Zinnia elegans (syn. Zinnia violacea) is a common ornamental plant of the Asteraceae family, widely cultivated for the impressive range of flower colors and persistent bloom. Given its uncomplicated cultivation and high adaptability to harsh landscape conditions, we investigated the potential use of Z. elegans as a source of valuable secondary metabolites. Preliminary classification of compounds found in a methanolic extract obtained from inflorescences of Z. elegans cv. Caroussel was accomplished using HR LC-MS techniques. The extract was then subjected to solid-phase extraction and separation using Sephadex LH-20 column chromatography, which resulted in several fractions further investigated for their antioxidant properties through lipoxygenase inhibition and metal chelating activity assays. Moreover, following additional purification procedures, structures of some active ingredients were established by NMR spectroscopy. The investigated fractions contained polyphenolic compounds such as chlorogenic acids and apigenin, kaempferol, and quercetin glycosides. Antioxidant assays showed that certain fractions exhibit moderate 15-LOX inhibition (Fr 2, IC50 = 18.98 µg/mL) and metal chelation (e.g., Fr 1-2, EC50 = 0.714-1.037 mg/mL) activities as compared to positive controls (20.25 µg/mL for kaempferol and 0.068 mg/mL for EDTA, respectively). For Fr 2, the 15-LOX inhibition activity seems to be related to the abundance of kaempferol glycosides. The NMR analyses revealed the presence of a kaempferol 3-O-glycoside, and a guanidine alkaloid previously not described in this species.

Yuccalechins A-C from the Yucca schidigera Roezl ex Ortgies Bark: Elucidation of the Relative and Absolute Configurations of Three New Spirobiflavonoids and Their Cholinesterase Inhibitory Activities.

The ethyl acetate fraction of the methanolic extract of Yucca schidigera Roezl ex Ortgies bark exhibited moderate acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity (IC50 47.44 and 47.40 µg mL-1, respectively). Gel filtration on Sephadex LH-20 and further RP-C18 preparative HPLC of EtOAc fraction afforded 15 known and 3 new compounds, stereoisomers of larixinol. The structures of the isolated spirobiflavonoids 15, 26, and 29 were elucidated using 1D and 2D NMR and MS spectroscopic techniques. The relative configuration of isolated compounds was assigned based on coupling constants and ROESY (rotating-frame Overhauser spectroscopy) correlations along with applying the DP4+ probability method in case of ambiguous chiral centers. Determination of absolute configuration was performed by comparing calculated electronic circular dichroism (ECD) spectra with experimental ones. Compounds 26 and 29, obtained in sufficient amounts, were evaluated for activities against AChE and BChE, and they showed a weak inhibition only towards AChE (IC50 294.18 µM for 26, and 655.18 µM for 29). Furthermore, molecular docking simulations were performed to investigate the possible binding modes of 26 and 29 with AChE.