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An ellagitannin monomer, lythracin M (1), and a dimer, lythracin D (2), along with eight known monomers (3 − 10) were isolated from Lawsonia inermis (Lythraceae) leaves. Lythracin M (1) is a C -glycosidic ellagitannin with a flavogallonyl dilactone moiety that participates in the creation of a γ-lactone ring with the anomeric carbon of the glucose core. Lythracin D (2) was determined as an atropisomer of the reported lythcarin D. These newly discovered structures (1 and 2) were determined by intensive spectroscopic experiments and by comparing DFT-calculated 1H 1H coupling, 1H NMR chemical shifts, and ECD data with experimental values. The anti-acetylcholinesterase assay of the compounds 1 – 10 revealed that the C-1 ellagitannin epimers [casuarinin (7 ; IC 50 = 34 ± 2 nM) and stachyurin (8 ; IC 50 = 56 ± 3 nM)], and the new dimer (2 ; IC 50 = 61 ± 4 nM) possess enzyme inhibitory effects comparable to the reference drug (donepezil, IC 50 = 44 ± 3 nM). Molecular docking of compounds 1 – 10 with AChE identified the free galloyl moiety as an important pharmacophore in the anticholinesterase activity of tannins. [Display omitted] • Two new (1 and 2) and eight known ellagitannins (3 – 10) were isolated from leaves of L. inermis. • The stereo-structure of 1 was established based on DFT calculations and intensive spectroscopic studies. • The anti-AChE activity of 1 – 10 was evaluated experimentally and by using molecular docking. • The ellagitannins 2 , 7 , and 8 are promising anti-AChE. [ABSTRACT FROM AUTHOR]

Chromatographic separation of an aqueous acetone extract of the galls from Tamarix aphylla using gels resulted in isolation of an ellagitannin, phyllagallin M1 ( 13 ), a gallo-ellagitannin, phyllagallin D1 ( 14 ), and four gallotannins, phyllagallin M2 ( 15 ) and phyllagallins D2–D4 ( 16 – 18 ), in addition to four known ellagitannins and three phenolics of lower molecular weight structurally related to hydrolyzable tannins. The structures of the six new tannins were elucidated based on spectroscopic and chemical data. Among the phenolics, flavogallonic acid dilactone ( 8 ), which is presumed to be biogenetically produced by C–C oxidative coupling of an ellagic acid unit with a galloyl residue, shows an exceptional oxidative pattern of gallic acid residues in plants of the family Tamaricaceae. Although the ellagitannin tamarixellagic acid ( 4 ) was reported to be a constituent of the galls of T. aphylla , such compounds with anomalous location of the DHDG moiety at O-3 on the glucopyranose core have not been observed among the tannins of tamaricaceous plants. [ABSTRACT FROM AUTHOR]

Abstract: An ellagitannin monomer, nilotinin M1 (1), and three dimers, nilotinins D1 (2), D2 (3), and D3 (4), were isolated from leaves of Tamarix nilotica (Ehrenb.) Bunge. Structures were elucidated based on analysis of spectroscopic data and chemical correlations with known compounds. In addition, six known tannins, hirtellin A (5) (dimer), remurin A (6), remurin B (7), 1,3-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-β-d-glucose (8), gemin D (9), and hippomanin A (10) (monomers), were isolated for the first time from this plant species. The reported 13C NMR assignments of the dehydrodigalloyl moiety and glucose cores of 5 are revised, and the 13C NMR spectroscopic data for 6 and 7 are also reported for the first time. [Copyright &y& Elsevier]

Investigation on tannins having antitumor properties led to the isolation of two new C -glycosidic ellagitannins (1 and 2) along with seven known ellagitannins (3 – 9) and a related polyphenolic constituent (10) from Lawsonia inermis leaves. Our intensive HRESIMS, 1D and 2D NMR, and ECD spectroscopic studies of new tannins have shown that one (1) has a monomer structure of C -glycosidic tannin, and the other (2) has a dimeric structure of 2,3- O -hexahydroxydiphenoyl glucopyranose and a C -glycosidic tannin. Among the known compounds, one (3) is a C -glycosidic tannin that was isolated first of all from nature, five were C -glycosidic tannins, vescalagin (4), 1- O -methylvescalagin (5), castalagin (6), stachyurin (7), and casuarinin (8), and one was an O- glycosidic ellagitannin, tellimagrandin II (9). The remaining phenolic constituent from the leaves was identified as valoneic acid dilactone (10). The ellagitannins 1 , and 3 – 9 demonstrated noticeable cytotoxicity on human oral squamous cell carcinoma cell lines (HSC-2, HSC-4, and Ca9–22), and lower effects on human oral normal cells (HGF, HPC, and HPLF). Tellimagrandin II (9) had the highest tumor-specific cytotoxicity, and also cleaved poly (ADP-ribose) polymerase 1 in HSC-2 cells. These findings showed that L. inermis ellagitannins may be a candidate for the production of anti-oral cancer materials. [Display omitted] • Two new (1 and 2), a first isolated from nature (3), and six knowns (4 – 9) ellagitannins, and a related phenolic (10) were isolated from leaves of L. inermis. • The ellagitannins (1 , 3 – 9) exhibited higher cytotoxicity against human oral cancer cell lines (HSC-2, HSC-4, and Ca9–22) than against human normal oral cells (HGF, HPC, and HPLF). • Tellimagrandin II (9) induced cleavage of PARP1 in HSC-2 cells. [ABSTRACT FROM AUTHOR]

Four flavanolignans, ceibapentains A (1) and B (2) and cinchonains Ia (3) and Ib (4), were isolated for the first time from an ethyl acetate extract of Ceiba pentandra (L) (Bombacaceae) aerial parts. The ceibapentains A (1) and B (2) are new compounds and their structures, including the absolute configurations, were determined by HRESIMS, 1D and 2D NMR, and electronic circular dichroism analyses, then compared with reported data. Compounds 1 – 4 were tested for their anti-Alzheimer's activity via an assessment of their inhibitory effect on amyloid β 42 aggregation using a thioflavin T assay. The results revealed that cinchonain Ia (3) showed a higher inhibitory effect (91%) than the standard curcumin (70%). Compounds 1 , 2 , and 4 exhibited moderate activity, with inhibition ratios of 43%, 47%, and 58%, respectively. A molecular docking study on the binding mode of 3 and curcumin with an amyloid β 1–40 peptide fibril structure indicated a high affinity of cinchonain 1a (3) towards amyloid β 1–40 peptide, in agreement with the experimental results. Unlabelled Image • Isolation of two new and two known flavanolignans from Ceiba pentandra • Investigation of the anti-Alzheimer's activities of the isolated compounds • Assessment of their inhibitory effect on amyloid β 42 aggregation • Molecular docking study on the binding mode of compounds with amyloid β 1–40 [ABSTRACT FROM AUTHOR]