Undescribed Amaryllidaceae Alkaloids from Zephyranthes citrina and Their Cytotoxicity

This phytochemical study presents the isolation of eight alkaloids from Zephyranthes citrina Baker. The structures of the new alkaloids, zephycitrine (1) and 6-oxonarcissidine (2), were established by analysis of spectroscopic and spectrometric data. Processing the EtOH extract under acid-base conditions yielded the unreported isolation artifacts 3 and 4. This work also provides analytical data for alkaloids not properly described in the literature (5 and 6). The hippeastidine/zephyranine scaffolds in derivatives 3, 4, and 8-10 are also thoroughly discussed. Furthermore, a cytotoxicity screening of 25 Amaryllidaceae alkaloids isolated from Z. citrina was performed. Only the known alkaloids haemanthamine (12), haemanthidine (13), and lycorine (27) showed significant cell growth inhibition.

Studies on the Nonalkaloidal Secondary Metabolites of Hippeastrum vittatum (L'Her.) Herb. Bulbs

Sixteen chemically varied metabolites were isolated from the bulbs of Hippeastrum vittatum (L'Her.) Herb., including eight flavonoids [3'-methyl isoliquiritigenin (2), 7-hydroxyflavan (8), 7-hydroxyflavanone (9), 7-hydroxyflavan-3-ol (10), 7-methoxy-3',4'-methylenedioxyflavan-3-ol (11), 7-hydroxy-3',4'-methylenedioxy flavan (12), 2',4'-dihydroxy-3'-methyl-3,4-methylenedioxychalcone (13), and isoliquiritigenin (14)], four acetophenones [2,6-dimethoxy-4-hydroxyacetophenone (3), 2,4-dihydroxyacetophenone (4), 2,4-dihydroxy-6-methoxy-3-methylacetophenone (6), and 2,4,6-trimethoxyacetophenone (7)], two alkaloids [lycorine (1) and narciprimine (15)], one phenol derivative [p-nitrophenol (5)], and one steroid [β-sitosterol 3-O-β-glucopyranoside (16)]. Their structures were elucidated by combining one- and two-dimensional NMR and ESI-MS techniques and by comparison with the reported literature data and some authentic samples. Except for lycorine (1), the isolated metabolites were obtained herein for the first time from Hippeastrum plants, among which compound 13 was identified as a new chalcone derivative. Additionally, the total phenolic and flavonoid contents of the total ethanol extract and different fractions of the bulbs were determined by the Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively, whereas their antioxidant potential was compared using the phosphomolybdenum and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays. Finally, the binding affinities of compounds 1-16 to some key target proteins of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), namely, main protease (Mpro), papain-like protease (PLpro), and RNA-dependent RNA polymerase (RdRp), were screened and compared using molecular docking analysis. The possible chemotaxonomic significance of the identified metabolites was also discussed.

Advances on the Amaryllidacea Alkaloids Collected in South Africa, Andean South America and the Mediterranean Basin

The alkaloids are one of the most represented family of natural occurring biological active compounds. Amaryllidaceae are also very well known for their beautiful flower and are thus used as ornamental plants in historic and public gardens. The Amaryllidacea alkaloids constitute an important group that is subdivided into different subfamilies with different carbon skeletons. They are well known from ancient times for their long application in folk medicine, and in particular, Narcissus poeticus L. was known to Hippocrates of Cos (ca. B.C. 460-370), who treated uterine tumors with a formulate prepared from narcissus oil. To date, more than 600 alkaloids of 15 chemical groups exhibiting various biological activities have been isolated from the Amaryllidaceae plants. This plant genus is diffused in regions of Southern Africa, Andean South America and the Mediterranean basin. Thus, this review describes the chemical and biological activity of the alkaloids collected in these regions in the last two decades as weel those of isocarbostyls isolated from Amaryllidaceae in the same regions and same period.

Prenylated flavonoids with significant anti-hepatoma activity from Daphne giraldii and effects on Fibroblast Growth Factor Receptor 1 (FGFR1)

We report here the orchestration of molecular ion networking (MoIN) and a set of computational and informatics assisted structural elucidation approaches in the discovery of 23 new prenyl-flavonoids and 13 known molecules from Daphne giraldii Nitsche (Thymelaeaceae), some of which possess significant bioactivity against hepatoma carcinoma. Daphnegiratriprenylone A (DPTP-A) represents the class of polyprenyl-flavonoids possessing a triprenyl substitution, and was identified with the guidance of mass spectrometry and nuclear magnetic resonance combined with computational approaches. This approach illustrates a paradigm shift in the application of computational tools for the direct assignment of new natural product structures and it was demonstrated to be reliable compared to conventional 2D-NMR techniques. Seventeen compounds exhibited potent and selective activity against Hep3B cells (IC50 ranging from 0.42 to 7.08 μM). Tyrosine kinase FGFR1 has emerged as a potential target of polyprenyl-flavonoids by a reverse pharmacophore mapping approach. We validated that the prenyl-flavonoids effectively inhibit FGFR1 using the Mobility Shift Assay, Western blot and molecular dynamics simulations, and the results suggest significant potency of the compounds towards FGFR1. These findings provide a new chemical class with strong links to traditional medicines, possessing reasonable safety for developing potential therapeutic agents for FGFR1-related diseases.

Flavanols and Flavanes from Crinum asiaticum and Their Effects on LPS Signaling Pathway Through the Inhibition of NF-κB Activation

Three new flavanols, (2R,3S)-7-methoxy-flavan-3-ol (1: ), (2R,3S)-7-hydroxy-flavan-3-ol (2: ), and (2R,3S)-2'-hydroxy-7-methoxy-flavan-3-ol (3: ), together with two known flavans (4: and 5: ), were isolated from the chloroform extract of Crinum asiaticum. Their structures were elucidated by various spectroscopic methods, including 1D and 2D NMR, HR-ESI-MS, and CD data. The isolated compounds 1: and 3: -5: showed inhibitory activity toward LPS-induced nitric oxide (NO) production. Further investigation of the NF-κB pathway mechanisms indicated that 1: and 3: -5: inhibited the LPS-induced IL-6 production and p65 subunit phosphorylation of NF-κB in RAW264.7 cells, with an effective dose of 10 µM.

Anti-Trypanosoma cruzi activity of alkaloids isolated from Habranthus brachyandrus (Amaryllidaceae) from Argentina

BACKGROUND

Chagas disease, caused by the parasite Trypanosoma cruzi, affects over six million people worldwide, mainly in Latin American countries. Currently available drugs have variable efficacy in the chronic phase and significant side effects, so there is an urgent need for safer chemotherapeutic treatments. Natural products provide privileged structures that could serve as templates for the synthesis of new drugs. Among them, Amaryllidaceae plants have proved to be a potential natural source of therapeutical agents due to their rich diversity in alkaloids.

PURPOSE

To identify alkaloids with anti-T. cruzi activity from Habranthus brachyandrus (Baker) Sealy (Amaryllidaceae, subfamily Amaryllidoideae) collected in Argentina.

METHODS

An H. brachyandrus alkaloid extract was tested against T. cruzi, and its cytotoxicity profile was evaluated against two mammalian cell lines to ascertain its selectivity against the parasite and potential liver toxicity. It was also assessed by a stage-specific anti-amastigote assay and analysed by GC/MS to determine its alkaloid profile. The isolated alkaloids were also tested using the aforementioned assays.

RESULTS

The extract showed high and specific activity against T. cruzi. The alkaloids lycoramine, galanthindole, 8-O-demethylmaritidine, 8-O-demethylhomolycorine, nerinine, trisphaeridine, deoxytazettine, and tazettamide were identified by means of GC-MS. In addition, hippeastidine (also named aulicine), tazzetine, ismine, and 3-epimacronine were isolated. The alkaloid ismine was specifically active against the parasite and had low toxicity against HepG2 cells, but did not show anti-amastigote activity.

CONCLUSION

The extract had specific anti-T. cruzi activity and the isolated alkaloid ismine was partially responsible of it. These results encourage further exploration of H. brachyandrus alkaloids in search of novel starting points for Chagas disease drug development.

Flavonoids and alkaloids from the rhizomes of Zephyranthes ajax Hort. and their cytotoxicity

A new flavanol derivative, (2R,3R)-3-acetoxy-7-hydroxy-3′,4′-methylenedioxyflavan (1), was co-isolated from the rhizomes of Zephyranthes ajax Hort. with the following seven known compounds: 7-hydroxyflavan (2), 7,4′-dihydroxyflavan (3), 7,4′-dihydroxy-8-methylflavan (4), 7,3′-dihydroxy-4′-methoxyflavan (5), 5,4′-dihydroxy-7-methoxy-6-methylflavan (6), 7-hydroxy-3′,4′-methylenedioxyflavanone (7) and haemanthamine (8). Their structures were elucidated by combining 1D-/2D-NMR, CD, UV and HRESIMS data, and comparisons with reported data in literature were made. Among these known compounds, 2, 3, 4, 6 and 7 were isolated from the genus Zephyranthes for the first time. In addition, the cytotoxicity assay indicated that compound 8 has potent cytotoxic activity against human hepatocellular carcinoma (the HepG2 cell line), human lung carcinoma (the SK-LU-1 cell line), human carcinoma in the mouth (the KB cell line), human colon carcinoma (the SW480 cell line) and human stomach gastric adenocarcinoma (the AGS cell line), with IC₅₀ values ranging from 4.4 to 11.3 µM. This is the first study reporting the cytotoxicity of compound 8 against the SK-LU-1 cancer cell lines.

Phosphine-Catalyzed Sequential [3+3]/Aza-6π-Electrocyclization Reaction of Cross-Conjugated Azatrienes and δ-Sulfonamido-Allenoates

An unprecedented sequential [3+3]/aza-6π-electrocyclization between cross-conjugated azatrienes and δ-sulfonamido-allenoates, catalyzed by phosphine, has been developed, which provides efficient and facile access to highly functionalized tetrahydroisoquinoline derivatives. The products can be easily transformed into (dihydro)isoquinolines and their fused polycyclic compounds. The reactivity of both azatrienes and δ-sulfonamido-allenoates in this text, acting as a five-atom unit, is unique in the phosphine-catalyzed annulations of allenoates.

In vitro Cell Viability by CellProfiler® Software as Equivalent to MTT Assay

Objective:

This study evaluated in vitro cell viability by the colorimetric MTT stands for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) assay compared to image analysis by CellProfiler^® software.

Materials and Methods:

Hepatoma (Hepa-1c1c7) and fibroblast (L929) cells were exposed to isolated substances, camptothecin, lycorine, tazettine, albomaculine, 3-epimacronine, trispheridine, galanthine and Padina gymnospora, Sargassum sp. methanolic extract, and Habranthus itaobinus Ravenna ethyl acetate in different concentrations. After MTT assay, cells were stained with Panotic dye kit. Cell images were obtained with an inverted microscope equipped with a digital camera. The images were analyzed by CellProfiler^®.

Results:

No cytotoxicity at the highest concentration analyzed for 3-epimacronine, albomaculine, galanthine, trispheridine, P. gymnospora extract and Sargassum sp. extract where detected. Tazettine offered cytotoxicity only against the Hepa1c1c7 cell line. Lycorine, camptothecin, and H. itaobinus extract exhibited cytotoxic effects in both cell lines. The viability methods tested were correlated demonstrated by Bland–Atman test with normal distribution with mean difference between the two methods close to zero, bias value 3.0263. The error was within the limits of the confidence intervals and these values had a narrow difference. The correlation between the two methods was demonstrated by the linear regression plotted as R².

Conclusion:

CellProfiler^® image analysis presented similar results to the MTT assay in the identification of viable cells, and image analysis may assist part of biological analysis procedures. The presented methodology is inexpensive and reproducible.

SUMMARY

In vitro cell viability assessment with MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) assay may be replaced by image analysis by CellProfiler^®.

The viability methods tested were correlated demonstrated by Bland-Atman test with normal distribution with mean difference between the two methods close to zero, bias value 3.0263. The correlation between the two methods was demonstrated by the linear regression plotted as R2.

Abbreviations: HPLC: High pressure liquid chromatography MTT: (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide)

Amaryllidaceae alkaloids: Absolute configuration and biological activity

Plants belonging to the Amaryllidaceae family are well known for their ornamental and medicinal use. Plant members of this group are distributed through both tropical and subtropical regions of the world and are dominant in Andean South America, the Mediterranean basin, and southern Africa. Amaryllidaceae plants have been demonstrated to be a good source of alkaloids with a large spectrum of biological activities, the latter being strictly related to the absolute stereochemistry of the alkaloid scaffold. Among them, great importance for practical applications in medicine has galanthamine, which has already spawned an Alzheimer's prescription drug as a potent and selective inhibitor of the enzyme acetylcholinesterase. Furthermore, lycorine as well as its related isocarbostyryl analogs narciclasine and pancratistatine have shown a strong anticancer activity in vitro against different solid tumors with malignant prognosis. This review addresses the assignment of the absolute configuration of several Amaryllidaceae alkaloids and its relationship with their biological activities.

Phytochemical and biological investigations of Amaryllidaceae alkaloids: a review

Amaryllidaceae is a family that includes 75 genera and about 1100 species, which have a long history of medicinal use. Many plants have been proven to possess efficacy for neurological injury and inflammatory conditions. This article summarizes 357 Amaryllidaceae alkaloids, and cites 166 174 references over the last three decades. These alkaloids are classified into 14 skeleton types, and their abundant sources are also included. Modern pharmacology studies demonstrate that alkaloids that exclusively occur in Amaryllidaceae plant possess wide-ranging pharmacological actions, especially effects on the central nervous system, as well as antitumor, antimicrobial, and anti-inflammatory activities. Effective monomeric compounds from Amaryllidaceae screened for pharmacological activity in vivo and in vitro are also summarized.

Three spirostanol saponins and a flavane-O-glucoside from the fresh rhizomes of Tupistra chinensis

Four new compounds, including three new spirostanol saponins [tupistroside G-I (1-3)] and a new flavane-O-glucoside [tupichiside A (4)], together with ten known compounds, were isolated from the fresh rhizomes of Tupistra chinensis. The structures of the new compounds were elucidated by spectroscopic analysis and chemical evidence. All compounds were tested in vitro for their cytotoxic activities against the Human LoVo and BGC-823 cell lines, and six of them were found to possess potent cytotoxicity. Compounds 2, 8 and 9 showed significant cytotoxicity against the tested tumor cell lines with IC50 values ranging from 0.2 to 0.9μM.

Cytotoxicity Studies of Lycorine Alkaloids of the Amaryllidaceae

The plant family Amaryllidaceae is renowned for its unique alkaloid constituents which possess a significant array of structural diversity. Several of these alkaloids are known for their interesting biological properties, of which galanthamine and pancratistatin have acquired a privileged status due to their relevance in the pharmaceutical arena. In particular, galanthamine represents the first prescription drug emanating from the Amaryllidaceae after its approval by the FDA in 2001 for the treatment of Alzheimer's disease. Following on this commercial success there have been sustained projections for the emergence of an anticancer agent related to pancratistatin due to the potency, selectivity, low toxicity and high tolerability typifying targets of this series of alkaloids. The lycorine series of alkaloids have also garnered widespread interest as cytotoxic agents and were amongst the earliest of the Amaryllidaceae constituents to exhibit such activity. To date over 100 of such naturally-occurring or synthetically-derived alkaloids have been screened for cytotoxic effects against a number of cancer cell lines. This survey examines the cytotoxic properties of lycorine alkaloids, highlights the outcomes of structure-activity relationship orientated studies and affords plausible insights to the mechanistic rationale behind these effects.

Revised NMR Data for 9-O-Demethylgalanthine: An Alkaloid from Zephyranthes robusta (Amaryllidaceae) and its Biological Activity

Ongoing studies of Zephyranthes robusta resulted in the isolation of the lycorine-type alkaloid previously called carinatine and 10- O-demethylgalanthine. The NMR data given previously for this compound were revised and completed by two-dimensional 1H-1H and 1H-13C chemical shift correlation experiments. The name of the isolated compound was corrected to 9- O-demethylgalanthine in accordance with the currently used system of numbering of lycorine-type alkaloids. 9- O-Demethylgalanthine and galanthine, a previously isolated alkaloid from Z. robusta, were inactive in acetylcholinesterase/butyrylcholinesterase assays (IC50 > 500 μM), but showed important prolyl oligopeptidase inhibition activity.

Isoflavonoids in the Amaryllidaceae family

Plants of the Amaryllidaceae family are known as producers of biologically active alkaloids. Besides these a variety of flavonoids, including flavones, chalcones and chromones, have been detected in the Amaryllidaceous plants. In this study, we have analysed 16 representatives of the family for the presence of isoflavonoids. The water/ethanolic extracts were analysed with HPLC-ESI-MS both without any pre-treatment and after immunoaffinity chromatography as a clean-up step. Four individual immunosorbents specific for biochanin A, daidzein and genistein were used. In addition, five enzyme-linked immunosorbent assays specific for the above-mentioned isoflavonoids and their derivatives have been used for the analysis of the extracts after fractionation by semi-preparative HPLC. Fifteen selected isoflavonoids were detected in the studied samples, and the amount of individual compounds ranged between ca. 0.8 and 400 ng/g of dry weight. This study extends the number of known isoflavonoid-producing families within the monocotyledonous plants.

Isolation and Cholinesterase Inhibitory Activity of Narcissus Extracts and Amaryllidaceae Alkaloid

Alkaloid extracts of eleven Narcissus (Amaryllidaceae) species and varieties were studied with respect to their acetylcholinesterase (HuAChE) and butyrylcholinesterase (HuBuChE) inhibitory activity and alkaloid patterns. Forty-two alkaloids were determined by GC/MS, and thirty of them identified from their mass spectra, retention times and retention indexes. Promising HuAChE inhibition activity was demonstrated by nine Narcissus taxa and HuBuChE inhibition by Narcissus poeticus cv. Pink Parasol with an IC50 value of 3.3 ± 0.5 μg/mL. The alkaloid identified as (11C- S)-homolycorine was isolated in pure form from Narcissus Sir W. Churchill using preparative TLC and was tested for its biological activity. Homolycorine inhibited HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 63.7±4.3 μM and 151.0±15.2 μM, respectively.

New Flavan and Alkyl α,β-Lactones from the Stem Bark of Horsfieldia Superba

In the present study phytochemical investigation of the methanol extract of the stem bark of Horsfieldia superba led to the isolation of twenty compounds (1-20), of which three (1-3) were new. However, compounds 2 and 3 were previously reported as synthetic α, β-lactones. The compounds were characterized as (-)-3,4′,7-trihydroxy-3′-methoxyflavan (1), (-)-5,6-dihydro-6-undecyl-2 H-pyran-2-one (2), and (-)-5,6-dihydro-6-tridecyl-2 H-pyran-2-one (3). Seventeen other known compounds were also isolated and identified as (-)-viridiflorol (4), hexacosanoic acid (5), β-sitosterol (6), methyl 2,4-dihydroxy-6-methylbenzoate (methylorsellinate) (7), methyl 2,4-dihydroxy-3,6-dimethylbenzoate (8), (-)-4′-hydroxy-7-methoxyflavan (9), (-)-4′,7-dihydroxyflavan (10), (-)-4′,7-dihydroxy-3′-methoxyflavan (11), (+)-3,4′,7-trihydroxyflavan (12), (-)-catechin (13), (-)-epicatechin (14), (-)-7-hydroxy-3′,4′-methylenedioxyflavan (15), 2′,3,4-trihydroxy-4′-methoxydihydrochalcone (16), 3′,4′,7-trihydroxyflavone (17), (+)-4′-hydroxy-7-methoxyflavanone (18), hexadecanoic acid (palmitic acid) (19) and 3,4-dihydroxybenzoic acid (20). The structures of the compounds were fully characterized by various physical methods (melting point, optical rotation), spectral (UV, IR, ID and 2D NMR) and mass spectrometric techniques. In vitro assay of compounds 2 and 3 demonstrated moderate cytotoxic activities against human prostate (PC-3), colon (HCT-116) and breast (MCF-7) cancer cells, while the chloroform and ethyl acetate fractions of H. superba were found to exhibit moderate AChE inhibitory activity (IC50 72 and 60 μg/mL).

Wild Argentinian Amaryllidaceae, a new renewable source of the acetylcholinesterase inhibitor galanthamine and other alkaloids

The Amaryllidaceae family is well known for its pharmacologically active alkaloids. An important approach to treat Alzheimer’s disease involves the inhibition of the enzyme acetylcholinesterase (AChE). Galanthamine, an Amaryllidaceae alkaloid, is an effective, selective, reversible, and competitive AChE inhibitor. This work was aimed at studying the alkaloid composition of four wild Argentinian Amarillydaceae species for the first time, as well as analyzing their inhibitory activity on acetylcholinesterase. Alkaloid content was characterized by means of GC-MS analysis. Chloroform basic extracts from Habranthus jamesonii, Phycella herbertiana, Rhodophiala mendocina and Zephyranthes filifolia collected in the Argentinian Andean region all contained galanthamine, and showed a strong AChE inhibitory activity (IC₅₀ between 1.2 and 2 µg/mL). To our knowledge, no previous reports on alkaloid profiles and AChEIs activity of wild Argentinian Amarillydaceae species have been publisihed. The demand for renewable sources of industrial products like galanthamine and the need to protect plant biodiversity creates an opportunity for Argentinian farmers to produce such crops.

Bulbispermine: a crinine-type Amaryllidaceae alkaloid exhibiting cytostatic activity toward apoptosis-resistant glioma cells

The Amaryllidaceae alkaloid bulbispermine was derivatized to produce a small group of synthetic analogues. These, together with bulbispermine's natural crinine-type congeners, were evaluated in vitro against a panel of cancer cell lines with various levels of resistance to pro-apoptotic stimuli. Bulbispermine, haemanthamine, and haemanthidine showed the most potent antiproliferative activities as determined by the MTT colorimetric assay. Among the synthetic bulbispermine analogues, only the C1,C2-dicarbamate derivative exhibited notable growth inhibitory properties. All active compounds were found not to discriminate between the cancer cell lines based on the apoptosis sensitivity criterion; they displayed similar potencies in both cell types, indicating that the induction of apoptosis is not the primary mechanism responsible for antiproliferative activity in this series of compounds. It was also found that bulbispermine inhibits the proliferation of glioblastoma cells through cytostatic effects, possibly arising from rigidification of the actin cytoskeleton. These findings lead us to argue that crinine-type alkaloids are potentially useful drug leads for the treatment of apoptosis-resistant cancers and glioblastoma in particular.

Chemical Constituents of Lycoris albiflora and their Cytotoxic Activities

An alcoholic extract of Lycoris albiflora (Amaryllidaceae) showed potent cytotoxic activity against HL-60 cells with an IC50 value of 1.7 μg/mL. Phytochemical examination of the extract resulted in the isolation of 15 alkaloids, including two phenanthridine-type alkaloids (1, 2), one benzylphenethylamine-type alkaloid (3), two crinane-type alkaloids (4, 5), one pyrrolophenanthridine-type alkaloid (6), six lycorenan-type alkaloids (7–12), and three galanthamine-type alkaloids (13–15), together with three neolignans (16–18), two flavans (19, 20), and two acetophenone derivatives (21, 22). Compound 3 (hostasinine A) has not been isolated from Amaryllidaceae plants, and 1, 2, 4, 5, 7–9, 11, 12 and 14–22 are the first isolation and identification from L. albiflora. The phenanthridine-type alkaloids (1, 2), as well as the alkaloids (3–5), exhibited potent cytotoxic activities against not only HL-60 cells but also HSC-2 cells, thus leading to the conclusion that these alkaloids are mainly responsible for the cytotoxicity of the L. albiflora extract. Compound 1 (lycoricidinol), with the most potent cytotoxic activities, induced apoptosis in both HL-60 cells and HSC-2 cells. It is notable that 1 induced transient autophagy and morphological changes in mitochondria in the early stages of the apoptotic cell death process in HSC-2 cells.

Antioxidant flavanes from Livistona chinensis

Three new flavanes and eight known flavonoids were isolated from the fruits of Livistona chinensis. The structure of the new flavanes were established as 2S,3S-3,5,7,3',5'-pentahydroxyflavane (1), 2R,3R-3,5,6,7,8,4'-hexahydroxyflavane (2) and 2R,3R-3,5,6,7,8,3',5'-heptahydroxyflavane (3), respectively, on the basis of chemical and spectroscopic data. The antiproliferative activity against four human tumor cell lines (HL-60, Mata, HepG2 and CNE-1) was evaluated. 1 had significantly antiproliferative effects against HL-60 and CNE-1 with the IC(50) of 0.2 ± 0.01 and 1.0 ± 0.1 μM, respectively, overpowering the reference compound in the assay (cisplatin). Most compounds also exhibited potent antioxidant activity.

Triterpene glycosides from the aerial parts of Larrea tridentata

Chemical study of the aerial parts of Larrea tridentata (Zygophyllaceae) resulted in the isolation of 25 triterpene glycosides, 13 of which were previously unknown. Their structures were determined on the basis of comprehensive spectroscopic analyses, including 2D NMR spectroscopy, and hydrolytic cleavage followed by chromatographic and spectroscopic analyses. This is the first systematic phytochemical study of L. tridentata with attention paid to its triterpene glycoside constituents. The isolated compounds were evaluated for their cytotoxic activity against HL-60 human promyelocytic leukemia cells.