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Comprehensive Summary: Eight rare capnosane‐type cembranoids, sarcocinerenoids A—H (1—8) and two new cage‐type cembranoids sarcocinerenoids I—J (9—10) were isolated from the soft coral Sarcophyton cinereum. The 5/11 bicyclic carbon skeleton is the same in Sarcocinerenoids A—H (1—8), and they collocate distinctive oxygen rings. Sarcocinerenoids I—J (9—10) with a cage‐type structure have been discovered to have an oxygen bridge and an uncommon seven‐membered ring. Extensive spectroscopic investigation, X‐ray diffraction analysis, estimated ECD, and DP4+ probability assessments were used to ascertain the structures of the two types of diterpenoids. Moreover, compounds 1, 4 showed promoting angiogenesis activity in zebrafish assays. [ABSTRACT FROM AUTHOR]

Two new eudesmane sesquiterpenoids [(−)-(1 R ,5 S ,6 R ,8 S)−1-hydroxy- nor -eudesm-11-ene-2-one (1) and (−)-(1 S ,5 S ,6 R ,8 R)−6-hydroxyeudesm-11-ene-2-one (2)] were isolated from the aerial parts of Pogostemon cablin. Compound 1 is an unusual 1- nor -eudesmane, and its skeleton structure is similar to that of compound 2. The molecular structures and absolute conformations of the two new sesquiterpenoids were determined by NMR spectroscopy, X-ray diffraction analysis, NMR data calculations and electronic circular dichroism (ECD) calculations. The neuroprotective activity of the isolates in an H 2 O 2 -induced PC12 cell model was also assessed, and the results show that both compounds exhibit good neuroprotective effects. [Display omitted] • Two new eudesmane sesquiterpenoids were isolated from Pogostemon cablin. • Their absolute configurations were elucidated by NMR data, X-ray diffraction, NMR data calculations and ECD calculations. • Compounds 1 and 2 may play a role in reducing the cytotoxicity of H 2 O 2 on PC12 cells. [ABSTRACT FROM AUTHOR]

Diarylheptanoids, potential therapeutic agents and dietary supplements, are the main active compounds in the genus Curcuma, however, determination of the absolute configurations of the flexible polyhydric main chains in linear diarylheptanoids is still a challenge. In this study, an exploration of the phytochemical constituents of Curcuma phaeocaulis led to the isolation of eight novel linear diarylheptanoids (1–8). Enzymatic hydrolysis, preparation of acetonide derivatives, preparation of MTPA esters, and electronic circular dichroism calculations were comprehensively performed in order to determine their absolute configurations. In in vitro assays, compounds 2, 3, and 6 exhibited anti-angiogenic activities, and compounds 2, 3, and their aglycones inhibited the proliferation of HepG2 cells. These findings suggest that diarylheptanoid glucosides of C. phaeocaulis may be useful for suppression of hepatoma growth and metastasis.

Comprehensive Summary: Thirteen new nitrogen‐containing nardosinane‐type sesquiterpenoids, clavukoelloids A—M (1—13) with unique acrylamide fragments vs. the reported general nardosinane‐type sesquiterpenoids containing lactone, were isolated from the soft coral Clavularia koellikeri collected from the South China Sea. The structures and absolute configurations of new compounds were unambiguously determined by analysis of spectroscopic data, CP3, DP4+, ECD spectra, and X‐ray diffraction. Compound 6 showed anti‐inflammatory activities and hepatoprotective activities in transgenic fluorescent zebrafish. [ABSTRACT FROM AUTHOR]

Cyclopeptides are considered as one of the most important classes of compounds derived from marine sources, due to their structural diversity and a myriad of their biological and pharmacological activities. Since marine-derived cyclopeptides consist of different amino acids, many of which are non-proteinogenic, they possess various stereogenic centers. In this respect, the structure elucidation of new molecular scaffolds obtained from natural sources, including marine-derived cyclopeptides, can become a very challenging task. The determination of the absolute configurations of the amino acid residues is accomplished, in most cases, by performing acidic hydrolysis, followed by analyses by liquid chromatography (LC). In a continuation with the authors' previous publication, and to analyze the current trends, the present review covers recently published works (from January 2018 to November 2022) regarding new cyclopeptides from marine organisms, with a special focus on their biological/pharmacological activities and the absolute stereochemical assignment of the amino acid residues. Ninety-one unreported marine-derived cyclopeptides were identified during this period, most of which displayed anticancer or antimicrobial activities. Marfey's method, which involves LC, was found to be the most frequently used for this purpose. [ABSTRACT FROM AUTHOR]

Two new compounds, ardisiapunine B (1) and ardisiapunine C (2), were isolated from Ardisia lindleyana D. Dietr. Their structures were examined using HR–ESI–MS, IR, (1D, 2D) NMR spectroscopic analyses, single–crystal X–ray diffraction, and ECD calculation. It was found that the two new compounds belong to unusual oleanane-type triterpenes, with compound 1 bearing an acetal unit and a C–13–C–18 double bond, and compound 2 bearing a C–28 aldehyde group and a C–18–C–19 double bond. The anti-inflammatory properties of compounds 1 and 2 were tested on NO production and cellular morphology using RAW264.7 cells, and their anti-tumor properties were tested on cytotoxic activities, cellular morphology, cell apoptosis, and cell cycle. The results showed that compound 1 exhibited a potent cytotoxicity against HepG2 cell lines with an IC50 of 12.40 μM. Furthermore, it is possible that compound 1 inhibits cell proliferation by blocking the cell G2/M phase and promoting cell apoptosis. Compound 2 exhibited a potential anti-inflammatory activity by decreasing the production of NO in LPS–stimulated RAW264.7 cells. Comparative analysis of the structures of compounds 1 and 2 revealed that the acetal structure and double bond positions were the main differences between them, and these are presumed to be the main reasons for the extreme differences in their cytotoxicity and anti-inflammatory activities. From these new findings, two promising lead compounds were identified for the future development of potential anti–inflammatory or anti–tumor agents. [ABSTRACT FROM AUTHOR]

Three new lignan glycosides, piperhancosides A−C (1 − 3), and two known compounds (4 − 5) were isolated from the n -BuOH extract of the stems of Piper hancei Maxim. The planar structures of the new compounds were elucidated by extensive spectroscopic analyses. Their relative and absolute configurations were determined by coupling constants, chemical shift differences, acid hydrolysis, enzymatic hydrolysis, and experimental ECD spectra. All the isolates were evaluated for their antineuroinflammatory and antioxidant activities, and compounds 4 and 5 showed significant DPPH.+ radical scavenging ability with EC 50 value of 14.07 and 16.48 μ M, respectively. [Display omitted] • Three new (1 − 3) and two known (4 − 5) lignan glycosides were isolated from Piper hancei. • Their structures were elucidated by spectroscopic analyses, hydrolysis, and ECD data. • Compounds 4 and 5 showed significant DPPH.+ radical scavenging abilities. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three new sesquiterpenes and three new viridin derivatives were isolated from Penicillium sp. SMU0102. • Peniviridiol A (4) is a novel 13, 17- seco -13-methyl viridin with 6/6/6/5 ring fused skeleton. • Peniviridiol B (5) is novel nor - seco -viridin with 6/6/5 ring fused skeleton. • Compound 1 primarily alleviated lipid accumulation through selective activation of the PINK1/Parkin mitophagy signaling pathway. Fungi from the plant rhizosphere microbiome are considered an important source of bioactive novel natural compounds. In this study, three new sesquiterpenes, penisterpenoids A–C (1 – 3), and three new viridin derivatives, peniviridiols A–C (4 – 6), along with twenty one known compounds (7 – 27), were isolated from the rhizosphere fungus Penicillium sp. SMU0102 of medicinal plant Bupleurum chinense DC. Their structures were elucidated by extensive spectroscopic analysis. The absolute configurations of compounds 1 – 6 were determined by experimental and calculated ECD spectra, DP4 + probability analysis, modified Mosher's method, and X-ray crystallography. All new compounds were screened for their cytotoxic and lipid-lowering activities in vitro. Among them, compound 1 (20 μM) remarkably alleviated lipid accumulation both in FFA-induced LO2 cells and TAA-induced zebrafish NAFLD models. Furthermore, compound 1 enhanced ATP production and mitochondrial membrane potential (MMP), suppressed reactive oxygen species (ROS) formation, restored mitochondrial structure, and induced autophagosome formation. Moreover, compound 1 significantly upregulated the expression of representative proteins for the mitochondrial homeostasis, including OPA1, DRP1, MFF, and Fis1, as well as mitophagy representative proteins PINK1, Parkin, and P62. Further mechanistic investigations indicated that compound 1 primarily alleviated lipid accumulation through selective activation of the PINK1/Parkin mitophagy signaling pathway. [ABSTRACT FROM AUTHOR]

Eight previously undescribed chromones eleusineketones A–H (1 – 8), as well as eight known compounds (9 – 16), were isolated from the endophytic fungus Bipolaris eleusines. These planar structures were created using an in-depth analysis of their spectral data, which included 1D, 2D, and HRESIMS data. Furthermore, the absolute configurations of compounds 1 , 2 , and 6 were determined by spectroscopic analysis and quantum chemical computational approaches, and compound 5 was determined by single-crystal X-ray diffraction analysis. The cytotoxic activity assay revealed that compounds 1 and 5 both inhibited MDA-MB-231 cells with IC 50 values of 14.48 μM and 17.99 μM, respectively. [Display omitted] • Eight undescribed chromones were isolated from the endophytic fungus B. eleusines. • Their configurations were determined through X-ray, ECD and 13C NMR calculation. • Compounds 1 and 5 displayed cytotoxic activities against MDA-MB-231 cells. [ABSTRACT FROM AUTHOR]

Cyclopeptides are considered as one of the most important classes of compounds derived from marine sources, due to their structural diversity and a myriad of their biological and pharmacological activities. Since marine-derived cyclopeptides consist of different amino acids, many of which are non-proteinogenic, they possess various stereogenic centers. In this respect, the structure elucidation of new molecular scaffolds obtained from natural sources, including marine-derived cyclopeptides, can become a very challenging task. The determination of the absolute configurations of the amino acid residues is accomplished, in most cases, by performing acidic hydrolysis, followed by analyses by liquid chromatography (LC). In a continuation with the authors’ previous publication, and to analyze the current trends, the present review covers recently published works (from January 2018 to November 2022) regarding new cyclopeptides from marine organisms, with a special focus on their biological/pharmacological activities and the absolute stereochemical assignment of the amino acid residues. Ninety-one unreported marine-derived cyclopeptides were identified during this period, most of which displayed anticancer or antimicrobial activities. Marfey’s method, which involves LC, was found to be the most frequently used for this purpose.

Two new compounds, ardisiapunine B (1) and ardisiapunine C (2), were isolated from Ardisia lindleyana D. Dietr. Their structures were examined using HR–ESI–MS, IR, (1D, 2D) NMR spectroscopic analyses, single–crystal X–ray diffraction, and ECD calculation. It was found that the two new compounds belong to unusual oleanane-type triterpenes, with compound 1 bearing an acetal unit and a C–13–C–18 double bond, and compound 2 bearing a C–28 aldehyde group and a C–18–C–19 double bond. The anti-inflammatory properties of compounds 1 and 2 were tested on NO production and cellular morphology using RAW264.7 cells, and their anti-tumor properties were tested on cytotoxic activities, cellular morphology, cell apoptosis, and cell cycle. The results showed that compound 1 exhibited a potent cytotoxicity against HepG2 cell lines with an IC50 of 12.40 μM. Furthermore, it is possible that compound 1 inhibits cell proliferation by blocking the cell G2/M phase and promoting cell apoptosis. Compound 2 exhibited a potential anti-inflammatory activity by decreasing the production of NO in LPS–stimulated RAW264.7 cells. Comparative analysis of the structures of compounds 1 and 2 revealed that the acetal structure and double bond positions were the main differences between them, and these are presumed to be the main reasons for the extreme differences in their cytotoxicity and anti-inflammatory activities. From these new findings, two promising lead compounds were identified for the future development of potential anti–inflammatory or anti–tumor agents.

Diarylheptanoids, potential therapeutic agents and dietary supplements, are the main active compounds in the genus Curcuma , however, determination of the absolute configurations of the flexible polyhydric main chains in linear diarylheptanoids is still a challenge. In this study, an exploration of the phytochemical constituents of Curcuma phaeocaulis led to the isolation of eight novel linear diarylheptanoids (1 – 8). Enzymatic hydrolysis, preparation of acetonide derivatives, preparation of MTPA esters, and electronic circular dichroism calculations were comprehensively performed in order to determine their absolute configurations. In in vitro assays, compounds 2 , 3 , and 6 exhibited anti-angiogenic activities, and compounds 2 , 3 , and their aglycones inhibited the proliferation of HepG2 cells. These findings suggest that diarylheptanoid glucosides of C. phaeocaulis may be useful for suppression of hepatoma growth and metastasis. [ABSTRACT FROM AUTHOR]

BACKGROUND Pyrisoxazole is a fungicide that has two chiral carbon atoms and four isomers: (3S,5R)‐, (3R,5S)‐, (3S,5S)‐, and (3R,5R)‐pyrisoxazole. RESULTS: Pure crystals of four pyrisoxazole isomers were prepared by chiral separation and single‐crystal cultivation. Their absolute configurations were established by X‐ray single crystal diffraction analysis. Bioassays indicated that compound (3S,5R)‐pyrisoxazole showed excellent fungicidal activity with a median effective concentration (EC50) value of 0.14 μg mL−1 and protective activity with an EC50 value of 13.29 μg mL−1. These values are superior to the commercial fungicides boscalid and racemic pyrisoxazole. CONCLUSIONS: The biological activity of racemic pyrisoxazole is due almost exclusively to the isomer (3S,5R)‐pyrisoxazole; the other three isomers had very low activity. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A new xanthyletin-type coumarin, neopeucedalactone (1), was isolated from the roots of Peucedanum praeruptorum Dunn. Its chemical structure was elucidated based on extensive spectroscopic interpretation. The absolute configurations of xanthyletin-type coumarin were determined by comparing experimental and calculated ECD spectra for the first time. Compound 1 exhibited moderate cell growth inhibitory activities in vitro against human leukemic HL-60, THP-1 cell lines, and human prostate cancer PC-3 cell lines, with IC50 values of 9.97, 27.80, and 48.68 µM, respectively. [ABSTRACT FROM AUTHOR]

Seventeen new carbazole alkaloid derivatives, including a trimeric carbazole racemate, (±)-microphyltrine A (1), 15 dimeric carbazole racemates, (±)-microphyldines A–O (2–16), and a C-6–C-3″-methyl-linked dimeric carbazole, microphyldine P (17), were isolated from the leaves and stems of Murraya microphylla (Merr. et Chun) Swingle. The structures of the new compounds were elucidated on the basis of HRESIMS and NMR data analysis. The optically pure isomers of these isolated carbazole alkaloids were obtained by chiral HPLC separation and their absolute configurations were determined by electronic circular dichroism (ECD) data analysis.

Two new diterpenoids, hypoxyterpoids A (1) and B (2), and four new isocoumarin derivatives, hypoxymarins A–D (4–7), together, with seven known metabolites (3 and 8–13) were obtained from the crude extract of the mangrove-derived fungus Hypoxylon sp. The structures of the new compounds were elucidated on the basis of 1- and 2-dimensional (1D/2D) nuclear magnetic resonance (NMR) spectroscopic and mass spectrometric analysis. The absolute configurations of compounds 1, 2, 4, 5, and 7 were determined by comparison of experimental and calculated electronic circular dichroism (ECD) spectra, and the absolute configurations of C-4′ in 6 and C-9 in 7 were determined by [Rh2(OCOCF3)4]-induced ECD spectra. Compound 1 showed moderate α-glucosidase inhibitory activities with IC50 values of 741.5 ± 2.83 μM. Compounds 6 and 11 exhibited DPPH scavenging activities with IC50 values of 15.36 ± 0.24 and 3.69 ± 0.07 μM, respectively.

Three new andrastin-type meroterpenoids penimeroterpenoids A–C (1–3) together with two known analogs (4 and 5) were isolated from the cultures of the marine-derived Penicillium species (sp.). The structures of the new compounds were elucidated on the basis of 1- and 2-dimensional (1D/2D) Nuclear Magnetic Resonance (NMR) spectroscopic and mass spectrometric analysis. The absolute configurations of 1–3 were determined by comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Compound 1 showed moderate cytotoxicity against A549, HCT116, and SW480 cell lines.

Abstract Tetraconazole, a chiral triazole fungicide, is widely used for the prevention of plant disease in wheat fields. However, the chirality of pesticides like tetraconazole can cause diverse biological responses. Therefore, it is important that research is conducted to investigate the enantioselective effects of chiral enantiomers in this regard. The absolute configurations of two tetraconazole enantiomers were initially confirmed by ECD (Electrostatic circular dichroism). The bioassay test showed that the fungicidal activity of (R)-(+)-tetraconazole against two pathogens (R. cerealis and F. graminearum) was approximately 1.49–1.98 times greater than that for (S)-(−)- tetraconazole. Following recovery experiments, a modified QuEchERS (Quick, easy, cheap, effective, rugged, safe) method was established using UPLC-MS/MS (ultra-performance liquid chromatography tandem mass spectrometry). The mean recoveries from plant and soil sample ranged from 78.9% to 100.5% with intraday relative standard (RSD r) values of 0.8%–6.9% and interday relative standard (RSD R) values of 3.0%–5.2% respectively. The stereoselective degradation of tetraconazole in wheat meant that (S)-(−)-tetraconazole was more rapidly degraded than (R)-(+)-tetraconazole. Conversely, (R)-(+)-tetraconazole was preferentially degraded in wheat soil. These results will provide us with a greater understanding when assessing future environmental risk assessments and strategies that invoke pesticide reduction. Graphical abstract Image 1 Highlights • Absolute configurations of tetraconazole was confirmed. • A UPLC-MS/MS method for tetraconazole enantiomers was established in wheat plant and soil. • Enantioselective degradation behavior of tetraconazole in wheat plant and soil was found. • Enantioselective fungicidal activity of tetraconazole against R.cerealis and F.graminearum was investigated. [ABSTRACT FROM AUTHOR]

Chirality is the central concept of stereochemistry, but remains neglected at both high school and university levels. It is typically introduced through description of Pasteur's historic resolution of enantiomers of tartaric acid, and teaching is usually centred on correct assignation of configurations R and S. This "classical" approach rarely proceeds further, thus leaving serious gaps in the students' knowledge. In this paper, new and systematic approach to the introduction of the concept of chirality, is described. We start with every-day objects (shoes, mirrors, snails, etc.), from which a generalised concept of chirality is introduced. Once this groundwork is laid, molecular chirality is deduced; its commonly occurring special cases (such as R and S configurations of the tetrahedral carbon atom) are discussed later. This method of teaching basic concepts of stereochemistry can be easily adopted to learning through experiments. [ABSTRACT FROM AUTHOR]

A pair of novel lipopeptide epimers, sinulariapeptides A (1) and B (2), and a new phthalide glycerol ether (3) were isolated from the marine algal-associated fungus Cochliobolus lunatus SCSIO41401, together with three known chromanone derivates (4–6). The structures of the new compounds, including the absolute configurations, were determined by comprehensive spectroscopic methods, experimental and calculated electronic circular dichroism (ECD), and Mo2 (OAc)4-induced ECD methods. The new compounds 1–3 showed moderate inhibitory activity against acetylcholinesterase (AChE), with IC50 values of 1.3–2.5 μM, and an in silico molecular docking study was also performed.

Ionone alkaloid 9-( N , N -dimethyl)-4,7-megastigmedien-3-one (compound 1 ) is a new anti-metastatic natural product. However, it was previously reported as optical isomers mixture. Herein, the optical isomers ( 6a-6d ) of compound 1 were synthesized. The absolute configurations of 6a-6d were determined by ECD experiments and calculated spectra with time-dependent density functional theory (TDDFT). The anti-metastatic effects of the optical isomers were examined by transwell assay. These results revealed that compound 6a had potential anti-metastatic activity with an IC 50 value of 0.512 ± 0.093 μM. [ABSTRACT FROM AUTHOR]

Six pairs of previously undescribed 6-monosubstituted dihydrobenzophenanthridine alkaloids were separated as corresponding six scalemic mixtures from the aerial part of Chelidonium majus . The elucidation for the 2D structures of these alkaloids was achieved using regular spectroscopic and chemical methods. The assignment of scalemic-mixture nature was achieved using combined examinations of their NMR data, CD spectra, calculation of specific rotations, and chiral HPLC profiles. The identification for the relative configurations of alkaloids possessing two asymmetric carbons directly connected up by a rotatable sp 3 - sp 3 carbon-carbon single bond was significantly facilitated by discussing the erythro and threo relative configurations defined by the mutuality of the orders of decreasing steric hindrances between the two sets of ligands linked to the two chiral centers. Two scalemic mixtures were assigned as (1′ R ,6 R /1′ S ,6 S )- and (1′ S ,6 R /1′ R ,6 S )-1-(dihydrochelerythrine-6-yl)ethanols, two as (1′ R ,6 R )/(1′ S ,6 S )- and (1′ S ,6 R )/(1′ R ,6 S )-1-(dihydrosanguinarine-6-yl)ethanols, one as (±)-ethyl 2-(dihydrosanguinarine-6-yl)acetate, and one as (±)-ethyl dihydrosanguinarine-6-carboxylate, respectively. The resolution of three scalemic mixtures was achieved and the absolute configurations of the three pairs of enantiomers were assigned via time-dependent Density Functional Theory calculations of electronic circular dichroism (ECD) data. The assignment for the absolute configurations of the other three scalemic mixtures was achieved via a chiral HPLC-UV/CD method plus analyzing their ECD data. The findings of this paper demonstrated that the relevant biochemical reactions concerning the construction of these 6-monosubstituted dihydrobenzophenanthridine alkaloids in the test plant are very nonselective. Scalemic mixture of (1′ R ,6 R )/(1′ S ,6 S )-1-(dihydrosanguinarine-6-yl)ethanol exhibited biological activity. It inhibited the growth of human MDA-MB-231 cell line at a moderate level with IC 50 value of 5.12 μ M. [ABSTRACT FROM AUTHOR]

Three new diketopiperazine alkaloids, including two oxepine-containing diketopiperazines, chrysopiperazines A and B (1 and 2), and one quinazoline-containing diketopiperazine, chrysopiperazine C (5), together with three known analogues (3, 4, and 6), were isolated from the gorgonian-derived Penicillium chrysogenum fungus. The relative and absolute configurations of C-3 and C-15 in 1 and 2, C-3 and C-14 in 5 were established by NOE modified Marfey’s analysis and electronic circular dichroism (ECD) calculations. Particularly, the absolute configurations of C-19 in 1 and 3, which was very challenging to be identified due to the flexible conformation in a short aliphatic chain, were successfully determined by the vibrational circular dichroism (VCD) method, supplying with a reliable and optional method to define the absolute configurations. Additionally, this is the first report on oxepine-containing diketopiperazines from the genus Penicillium.

Three novel enantiomeric pairs of bromolactones possesing a 2,5-dimethylphenyl substituent at the β-position of the lactone ring have been synthesized from corresponding enantiomeric (E)-3-(2′,5′-dimethylphenyl)hex-4-enoic acids (4) by kinetically controlled bromolactonization with N-bromosuccinimide (NBS). γ-Bromo-δ-lactones (5) were isolated as the major products. Absolute configurations of stereogenic centers of γ-bromo-δ-lactones (5) were assigned based on X-ray analysis; configurations of cis δ-bromo-γ-lactones (6) and trans δ-bromo-γ-lactones (7) were determined based on mechanism of bromolactonization. Synthesized compounds exhibited significant antiproliferative activity towards the four canine cancer cell lines (D17, CLBL-1, CLB70, and GL-1) and one human cancer line (Jurkat). Classifying the compounds in terms of activity, the most active were enantiomers of trans δ-bromo-γ-lactones (7) followed by enantiomers of cis isomer (6) and enantiomeric γ-bromo-δ-lactones (5). Higher activity was observed for all stereoisomers with S configuration at C-4 in comparison with their enantiomers with 4R configuration. Synthesized compounds did not induce hemolysis of erythrocytes. The results of the interaction of bromolactones with red blood cell membranes suggest that these compounds incorporate into biological membranes, concentrating mainly in the hydrophilic part of the bilayer but have practically no influence on fluidity in the hydrophobic region. The differences in interactions with the membrane between particular enantiomers were observed only for γ-lactones: stronger interactions were found for enantiomer 4R,5R,6S of cis γ-lactone (6) and for enantiomer 4S,5R,6S of trans γ-lactone (7).

Using a cell-based cytotoxicity assay three new cytotoxic azaphilones, including two stereoisomers and designated monapurones A-C (1-3), were isolated from the extract of Monascus purpureus-fermented rice (red yeast rice). Their structures were elucidated by detailed interpretation of spectroscopic and chemical data. The relative configurations were assigned on the basis of analysis of NOE data, and the absolute configurations were determined by direct comparison of their CD spectra with those of known azaphilones and chemical correlations. In the in vitro assays, monapurones A-C (1-3) showed selective cytotoxicity against human cancer cell line A549 with IC50 values of 3.8, 2.8 and 2.4mM respectively, while exhibiting no significant toxicity to normal MRC-5 and WI-38 cells at the same concentration.

A document investigation on the fungus Trichoderma virens led to the isolation of thirteen undescribed carotane sesquiterpenes and homologous. All structures were elucidated on the basis of NMR and HRESIMS data, and their absolute configurations were assigned by ECD calculation. Especially, virenscarotins A and B were first ramifications forged by aldol condensation of 4-hydroxy-3-isopentenyl-benzaldehyde with two hydroxyl groups in ring A of traditional carotane sesquiterpenes. Ring rearrangement/expansion and oxidative cleavage of normal carotane sesquiterpenes lead to the six-membered ring A of compound virenscarotin C and the ring A cleavage of compound virenscarotin D. All compounds were evaluated for cytotoxic, anti-inflammatory, and seed germination inhibitory activities. Thirteen undescribed carotane sesquiterpenes were isolated from the fungus of Trichoderma virens. Their structures were elucidated based on NMR, HRESIMS, and ECD calculation. [Display omitted] • Thriteen undescribed carotane sesquiterpenes were isolated from Trichoderma virens. • Virenscarotins A and B were from condensation of benzene derivative with carotanes. • Virenscarotin C was from the rearrangement/expansion of the normal carotane. • Ring oxidative cleavage of normal carotane lead to compound virenscarotin D. [ABSTRACT FROM AUTHOR]

[Display omitted] • Six pairs of enantiomeric phthalide dimers were isolated from Ligusticum chuanxiong. • Their absolute configurations were clarified by X-ray diffractions and ECD calculations. • Nine compounds have inhibitory effects against LPS-induced NO production in RAW264.7 cells. Six pairs of enantiomeric phthalide dimers (1 – 6) were isolated from the rhizomes of Ligusticum chuanxiong. Their structures and absolute configurations were elucidated by NMR spectroscopy, X-ray diffraction analyses, and electronic circular dichroism calculations. Compounds (+)- 1 and (−)- 1 are new phthalide dimers, featuring two classes of monomeric units (a phthalide and an unusual 2,3- seco -phthalide) with an uncommon linkage (3,6ʹ/8,3ʹa). Compounds (+)- 2 and (−)- 3 are also novel phthalide dimers that had not been reported previously. Although (−)- 2 and (+)- 3 have been successfully isolated in previous studies, their absolute configurations were not unambiguously determined. As for compound 4 , it was reported as a racemate in one study, and one of its enantiomers was identified in a subsequent study. Herein, all enantiomeric phthalide dimers were successfully separated, and their absolute configurations were determined. The inhibitory effects of all isolates against lipopolysaccharide-induced nitric oxide production were tested using RAW264.7 cells. The results show that compounds (+)- 2 , (−)- 2 , (+) -3 , (−)- 3 , (+)- 4 , (−)- 4 , (+)- 5 , (+)- 6 , and (−)- 6 have inhibitory activities, with compound (+)- 5 being the most active (IC 50 value of 4.3 ± 1.3 μM). [ABSTRACT FROM AUTHOR]

Five new nor-ursane type triterpenoids, gelse-norursane A–E, together with twenty known compounds, were isolated from the whole plant of Gelsemium elegans . The structures of new compounds were established as (2 R ,3 R ,7 R ,17 S ,19 R )-2,3,7,19-tetrahydroxy-6-oxo-24-norurs-4(23),12-dien-28-oic acid ( 1 ), (2 R ,3 R ,7 R ,17 S )-2,3,7-trihydroxy-6-oxo-24-norurs-4(23), 12-dien-28-oic acid ( 2 ), (2 R ,3 R ,7 R ,17 S )-2,3,4-trihydroxy-23-norurs-20(30),12-dien-28-oic acid ( 3 ), (2 R ,3 R ,30 R )-2,3-dihydroxy-24-norurs-4(23),12-dien-30-oic acid ( 4 ), and (2 R ,3 R ,30 R )-2, 3-dihydroxy-24-norurs-4,12-dien-30-oic acid ( 5 ), using spectroscopic analysis, including HRESIMS, 1D and 2D NMR. The absolute configurations of 1 and 4 were established through comparison of experimental and calculated ECD spectra. The gelse-norursane A–E are isolated as the 24-nor-ursane type triterpenoids from the family Loganiaceae for the first time. The cytotoxicities of the selected compounds against a panel of four human cancer HL60, Hela, Hep-G2, and Smmc 7221 cell lines were evaluated using the MTT assay in vitro . [ABSTRACT FROM AUTHOR]

A stereoselective free radical introduction of a phenylthio group onto a nonactivated methyl group in the d-position, adjacent to a prochiral carbon atom, was achieved by photolysis of (-)-menthyl benzenesulfenate in the presence of hexabutylditin and (1R, 3R, 4S, 8S)-9-phenylthiomenthol (4) was obtained with 91 % optical purity. High stereoselectivity of the reaction was calculated (ab initio MP2/6-31G**) to be the consequence of the difference in the transition state eneregies (DDG# = 5.08 kJ/mol) favouring 4 relative to (1R,3R,4S,8R)-9-phenylthiomenthol (5). The absolute configuration of a the new chiral carbon atom was confirmed by its correlation with the corresponding menthane-3,9-diol of known stereochemistry.

A stereoselective free radical introduction of a phenylthio group onto a nonactivated methyl group in the δ-position, adjacent to a prochiral carbon atom, was achieved by photolysis of (-)-menthyl benzenesulfenate in the presence of hexabutylditin and (1R, 3R, 4S, 8S)-9-phenylthiomenthol (4) was obtained with 91%optical purity. High stereoselectivity of the reaction was calculated (ab initio MP2/6-31G**) to be the consequence of the difference in the transition state eneregies (ΔΔG# = 5.08 kJ/mol) favouring 4 relative to (1R,3R,4S,8R)-9-phenylthiomenthol (5). The absolute configuration of a the new chiral carbon atom was confirmed by its correlation with the corresponding menthane-3,9-diol of known stereochemistry.

The octahedral cobalt(III) complexes with ( S , S )-ethylenediamine- N , N ′-di-2 - propionic ( S , S -eddp) and ( S , S )-ethylenediamine- N , N ′-di-2-(3-methyl)-butanoic ( S , S -eddv) acids and oxalato and malonato ligands, as additional bidentate ligands, were prepared and characterized. The complexes were purified by ion-exchange chromatography. The geometry of the complexes has been supposed on the basis of the infrared, electronic absorption and NMR spectra. The Δ absolute configurations of the isolated complexes have been predicted on the basis of their circular dichroism (CD) spectra and it was confirmed by single-crystal X-ray analysis of potassium-Δ-(−) 589 - s-cis -oxalato-( S , S )-ethylenediamine- N , N ′-di-(2-propanoato)-cobaltate(III)-semihydrate, K-Δ-(−) 589 - s-cis -[Co( S , S- eddp)(ox)]·0.5H 2 O. Antimicrobial activity of ligands and obtained cobalt(III) complexes was evaluated by determining the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) in relation to 13 species of microorganisms (five strains of pathogenic bacteria, five species pathogenic fungi and three species of probiotic). Tested ligands and complexes demonstrated moderate and low antibacterial and antifungal activity. There was no difference in activities between the ligands and complexes. [ABSTRACT FROM AUTHOR]

A new caryolane-type sesquiterpene ( 1 ) and its isomer at C-12 ( 2 ), as well as seven previously known compounds, including a labdane diterpene, an aromatic derivative, and four steroids, were isolated from the aerial parts of Cirsium souliei . The structures of compounds 1 and 2 were established using spectroscopic analysis including one- and two-dimensional NMR, HRESIMS, and IR results. Their absolute configurations were assigned for the first time by comparison of the experimental results with calculated optical rotations. The cytotoxicities of 1 and 2 against a panel of four human cancer cell lines (HL60, Hela, Hep-G2, and Smmc 7721) were evaluated using the MTT assay. The caryolane-type sesquiterpenes are isolated from the genus Cirsium for the first time. [ABSTRACT FROM AUTHOR]

• The synthetic route of the Xanthine-Quinazoline analogs were designed and synthesized by substitution, cyclization, alkylation, bromination and deprotection reactions. • Compound 6 were separated by chiral column chromatography. • The relative configurations of title compounds were studied by means of NMR, ECD, FT-IR, DFT and molecular simulation. • Notwithstanding some small discrepancies exist in ECD, OR, NMR, these results support the assignment of an R configuration to A and an S configuration to B. Originating from the xanthine derivatives, a class of potent dipeptidyl peptidase IV (DPP-4) inhibitors for the treatment of type 2 diabetes have been discovered. These inhibitors play a vital role in maintaining the levels of endogenous GLP-1. In this study, Xanthine-Quinazoline derivatives have been designed and synthesized. R - and S -isomers of the target compound were separated by chiral column chromatography and the relative configurations were studied by means of NMR (nuclear magnetic resonance), ECD (electronic circular dichroism), FT-IR (fourier transform infrared spectroscopy), and DFT (density functional theory) calculations. In addition, the absolute configurations (ACs) of the title compound were confirmed by ECD, PES (Potential Energy Surface), optical rotation (OR), and theoretical calculations. [ABSTRACT FROM AUTHOR]

Abstract: Chemical examination of the soft coral Sinularia capillosa resulted in the isolation of eight new sesquiterpenoids named capillosananes S–Z (1–8) and six known sesquiterpenes. The structures of the new compounds were determined on the basis of extensive spectroscopic analysis, including CD effects and Mosher method for the assignment of their absolute configurations. Capillosananes S–U (1–3) presented as the novel carbon skeletons with bicyclo[3,6,0] and bicyclo[4,5,0] systems, while capillosanane V (4) was characteristic of an unprecedented tricyclic skeleton. Capillosananes W–X (5–6) were assigned to the unusual dumortane-type sesquiterpenes. In addition, the absolute configurations of the stereoisomers of isodaucene-9,14-diol were assigned for the first time. [Copyright &y& Elsevier]

Abstract: Three new clerodane diterpenoid glycosides with l-arabinose (1–3), together with ten known compounds including phytol-type diterpenes, cycloartane-type, ursane-type, and oleanane-type triterpenes, were isolated from the aerial parts of Nannoglottis carpesioides which a Chinese endemic genus. The structures of the new compounds 1–3 were identified based on chemical and spectroscopic studies, including one- and two-dimensional NMR, HRESIMS, UV, and IR results. Their absolute configurations were determined by the application of theory calculations of optical rotation, which were compared with the experimental data. New aglycone 1a and l-arabinose were obtained by acid hydrolysis of 1 and GC–MS analysis. The cytotoxicities of some isolated compounds against a panel of human cancer cell lines were evaluated by the MTT assay. Clerodane diterpenoides are the characteristic chemical constituents and may be used as chemical markers of the genus Nannoglottis. [Copyright &y& Elsevier]

ABSTRACT The absolute configurations (AC) of azaheterocylic compounds resulting from the cascade of enediynes involving only light atoms were unambiguously assigned by the joint use of vibrational circular dichroism (VCD) and copper radiation single crystal X-ray diffraction (XRD). These AC determinations proved that the of enediynes proceeded with memory of chirality and of configuration. Chirality 25:832-839, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Phaeosphspirone, an undescribed polyketide with a unique 6/5/5/6-fused tetracyclic system, and two known analogues, herbarin and O -methylherbarin, were purified from the endophytic fungus Phaeosphaeriaceae sp. isolated from the desert plant Bassia dasyphylla. The connectivity and relative configuration of phaeosphspirone was elucidated by comprehensive HR-ESI-MS and NMR analysis together with a computer-assisted structure elucidation (CASE) method. A pair of enantiomers existing in phaeosphspirone were separated by HPLC chromatography after reacting with chiral reagents, from which the absolute configuration of phaeosphspirone was simultaneously determined based on Mosher's rule. This tandem strategy provides a useful approach for the separation and stereochemical determination of enantiomers possessing secondary hydroxyl groups. The structural feature of phaeosphspirone, herbarin and O -methylherbarin together with gene cluster analysis suggested their polyketide biosynthetic origin. Herbarin and O -methylherbarin exhibited moderate cytotoxicity against three cancer cell lines. A pair of novel polyketide enantiomers were isolated and their ab solute configurations were determined by a unique tandem strategy. [Display omitted] • Phaeosphspirone (1) possessing a unique 6/5/5/6-fused tetracyclic system, and herbarin (2) and O -methylherbarin (3), were isolated. • A pair of enantiomers (1/1′) were separated by HPLC chromatography after reacting with chiral reagents. • The biosynthetic pathway of 1 – 3 was suggested according to their structural features and gene cluster analysis. • Compounds 2 and 3 exhibited moderate cytotoxicity against three cancer cells. [ABSTRACT FROM AUTHOR]

Abstract: Five antiplasmodial bisabololoxide sesquiterpene diesters were isolated from an EtOAc extract of the aerial parts of Artemisia persica following an HPLC-time-based activity profiling of the extract. Structure elucidation was achieved by 1D and 2D NMR experiments. Relative configurations of cyclohexenone/cyclohexene and tetrahydropyran moieties of 1–5 were established on the basis of 3 J H–H coupling constants and NOE difference spectra. Stereochemical correlation of the two rings, and assignment of absolute configuration of 1–5 were achieved by comparison of experimental ECD spectra with simulated ECD data for possible stereoisomers, by using time dependent density function theory (TDDFT). Bisaboloids 1–4 exhibited in vitro antimalarial activity against Plasmodium falciparum, with IC50 values ranging from 2.8 to 20.1μM, and selectivity indices (SI) in L-6 cells of 3.7–11.9. [Copyright &y& Elsevier]

Using a cell-based cytotoxicity assay three new cytotoxic azaphilones, including two stereoisomers and designated monapurones A-C (1-3), were isolated from the extract of Monascus purpureus-fermented rice (red yeast rice). Their structures were elucidated by detailed interpretation of spectroscopic and chemical data. The relative configurations were assigned on the basis of analysis of NOE data, and the absolute configurations were determined by direct comparison of their CD spectra with those of known azaphilones and chemical correlations. In the in vitro assays, monapurones A-C (1-3) showed selective cytotoxicity against human cancer cell line A549 with IC50 values of 3.8, 2.8 and 2.4 μM respectively, while exhibiting no significant toxicity to normal MRC-5 and WI-38 cells at the same concentration. [ABSTRACT FROM AUTHOR]

A pair of new 3′,7-epoxy-8,4′-oxyneolignan enantiomers [(+)- 1 and (−)- 1 ] as well as a known phenylpropanoid (2) were isolated from the seeds of Croton tiglium Linn. Their structures were established based on extensive spectroscopic analyses. The absolute configurations of (+)- 1 and (−)- 1 were determined by NMR data calculations and electronic circular dichroism calculations. All compounds were isolated from the genus Croton for the first time. Particularly, (+)- 1 and (−)- 1 were the first 3′,7-epoxy-8,4′-oxyneolignanes reported in Croton. The chemotaxonomic significance of these compounds was discussed. [Display omitted] ● A pair of new lignan enantiomers and a known phenylpropanoid were isolated from Croton tiglium. ● All compounds were isolated from the genus Croton for the first time. ● This is the first time 3′,7-epoxy-8,4′-oxyneolignanes have been isolated from the genus Croton. ● This study revealed the chemotaxonomic significance of the isolated compounds in Croton. [ABSTRACT FROM AUTHOR]

Thirteen undescribed diterpenoid quinones were isolated from the dried roots of Salvia miltiorrhiza. Their structures were determined by extensive analysis, including NMR, HRESIMS, and IR. Their absolute configurations were determined by X-ray diffraction, calculated and experimental circular dichroism spectroscopy, and optical rotation. In the evaluation of bioactivities, salviadionether obviously inhibited the proliferation of HCT-116 cells. R -(+)-salmiltiorin E and R -(+)-grandifolia D both showed inhibitory activities on a variety of tumor cells. Salvianone ester A showed strong cytotoxicity to tumor-repopulating cells (TRCs) with an IC 50 value of 2.19 μ M. [Display omitted] • Thirteen undescribed diterpenoid quinones were isolated from the roots of Salvia miltiorrhiza. • Salviadionether, R -(+)-salmiltiorin E and R -(+)-grandifolia D showed obvious anti-cancer activities in vitro. • Salvianone ester A showed significant cytotoxicity to A375 TRCs (IC 50 = 2.19 μ M). • Their structures were elucidated using various spectroscopy data and chemical evidence. [ABSTRACT FROM AUTHOR]

Empirical force-field calculations were performed on [Ag{Co(aet)(en) 2 }](NO 3 ) 3 (aet = H 2 NCH 2 CH 2 S - ) systems to further understand the occurrence of spontaneous resolution [1] . Results of the calculations reveal that the ΛΛΛΛ strand is more stable than the ΛΔΛΔ strand. Furthermore, the spontaneously crystallized system ΛΛΛΛ, with six constitutional repeating units (CRUs), ΛΛΛΛΛΛ, was more stable than the hetero-chiral system, ΔΔΔΔ, with the same six units as above. In addition, the calculations revealed that electrostatic interactions contributed most of the stability to the system. [ABSTRACT FROM AUTHOR]