Estrogenic and cytotoxic potentials of compounds isolated from Millettia macrophylla Benth (Fabaceae): towards a better understanding of its underlying mechanisms

Antiviral Rotenoids and Isoflavones Isolated from Millettia oblata ssp. teitensis

Three new (1-3) and six known rotenoids (5-10), along with three known isoflavones (11-13), were isolated from the leaves of Millettia oblata ssp. teitensis. A new glycosylated isoflavone (4), four known isoflavones (14-18), and one known chalcone (19) were isolated from the root wood extract of the same plant. The structures were elucidated by NMR and mass spectrometric analyses. The absolute configuration of the chiral compounds was established by a comparison of experimental ECD and VCD data with those calculated for the possible stereoisomers. This is the first report on the use of VCD to assign the absolute configuration of rotenoids. The crude leaves and root wood extracts displayed anti-RSV (human respiratory syncytial virus) activity with IC50 values of 0.7 and 3.4 μg/mL, respectively. Compounds 6, 8, 10, 11, and 14 showed anti-RSV activity with IC50 values of 0.4-10 μM, while compound 3 exhibited anti-HRV-2 (human rhinovirus 2) activity with an IC50 of 4.2 μM. Most of the compounds showed low cytotoxicity for laryngeal carcinoma (HEp-2) cells; however compounds 3, 11, and 14 exhibited low cytotoxicity also in primary lung fibroblasts. This is the first report on rotenoids showing antiviral activity against RSV and HRV viruses.

Cytotoxic effect and antioxidant activity of pterocarpans from Millettia aboensis root

Chemical analysis of the methanol extract of the root bark of Millettia aboensis led to the isolation of homopterocarpin (1), secundiflorol I (2), and maackain (3). The structures of these compounds were elucidated based on their MS and NMR spectra. The crude methanol root extract was screened for its cytotoxic activity on mouse lymphoma cell line (L5178Y), and the isolated compounds were tested for their antioxidant activity using a 2, 2-diphenylhydrazyl (DPPH) radical scavenging model. The crude methanol root extract gave a percentage growth inhibition of 87.5% on the mouse lymphoma cell line (L5178Y). Compound 3 gave the highest antioxidant activity with an IC₅₀ of 83 µg/ml. These compounds can serve as leads for anticancer agents.

Comparison of Phytochemical Constituents and Pharmacological Activities of Various Solvent Extracts Obtained from Millettia speciosa Stem Powder

Millettia speciosa is a plant extensively used as an important component in Chinese herbal medicine and food-based medicines. The present study was carried out to determine the total flavonoid content (TFC), volatile phytoconstituents, and pharmacological activities, i.e., antityrosinase, sunscreen, and anticancer activity, of different fractions of M. speciosa stem. Different organic solvents of increasing polarity, i.e., petroleum ether (PE), ethyl acetate (EtOAc), and methanol (MeOH), were used for extraction. The highest total flavonoid content, i.e., 48.30 ± 0.90%, was reported for PE extract. Various important phytocomponents were revealed by gas chromatography-mass spectroscopy (GC-MS) analysis. Based on abundance, the major compounds were n-hexadecanoic acid (16.654%), n-hexadecanoic acid (14.808%), and beta-sitosterol (6.298%) for PE, EtOAc, and MeOH extract, respectively. The significant antityrosinase activity, i.e., 70.97 ± 0.66%, with an IC₅₀ value of 4.58 mg/mL was noted for PE extract followed by EtOAc extract, i.e., 59.84 ± 0.67%, with IC₅₀ value of 6.10 mg/mL. The maximum sunscreen activity was reported for PE extract exhibiting the maximum absorbance value (0.633 ± 0.06) in the ultraviolet (UV) region, i.e., UVC, while EtOAc extract showed the second highest level of absorbance in the UVB range, i.e., 0.632 ± 0.07. The strongest anticancer activity (49.73 ± 0.49% cell viability) towards MCF-7 breast cancer cell line was reported for PE extract with IC₅₀ 197.51 μg/mL. Our results confirmed the presence of potential therapeutic components for each extract with significant biological functions, showing the importance of the M. speciosa stem as a source of biomedicine. To our knowledge, this is the first report on M. speciosa stem extending comprehensive research about its phytochemical profile and various significant pharmacological activities.

Chemical Constituents of the Flowers of Pueraria lobata and Their Cytotoxic Properties

The flower of Pueraria lobata (Puerariae Flos) is a reddish-purple to violet-purple flower that blooms between July and September. In our preliminary study, Puerariae Flos extract exhibited significant activity against a human ovarian cancer cell line. This research aims to identify the active compounds in Pueraria Flos. By repeated chromatography, one new tryptophan derivative (1), two new flavanones (4 and 5), and 19 known compounds, including tryptophan derivatives (2 and 3), flavonoids (6–9), isoflavonoids (10–20), a flavonolignan (21), and a phenolic compound (22), were isolated from a methanol extract of Puerariae Flos. The structures of new compounds were elucidated as 13-N-benzoyl-l-tryptophan-1-N-β-d-glucopyranoside (1), 2-hydroxy-5-methoxy-naringenin (4), and 2-hydroxy-5-methoxy-naringenin 7-O-β-d-glucopyranoside (5). Among the isolates, afromosin (17), tectorigenin (11), apigenin (8), glycitein (16), (-)-hydnocarpin (21), irilin D (12), irisolidone 7-O-glucoside (14), and genistein (10) showed cytotoxicity against human ovarian cancer cell line A2780. Apigenin (8) and (-)-hydnocarpin (21) were the most active (IC₅₀ values of 9.99 and 7.36 μM, respectively).

A new isoflavone glucoside and other compounds from Poiretia bahiana C. Mueller: Chemophenetics, fragmentation pattern and biogenetic implications

The genus Poiretia belongs to the Fabaceae (Leguminosae) family and it encompasses twelve species of flowering plants. The chemistry of this genus is scarcely investigated, although some studies have demonstrated the potential of Poiretia species to produce important bioactive compounds. Herein, we describe the phytochemical investigation of P. bahiana C. Mueller leaves. A new isoflavone glucoside named as 2',4',5'-trimethoxyisoflavone-7-O-β-D-glucopyranoside (1), along with six known isoflavones (2-7), two rotenones (8-9), cyclitol 3-O-methyl-chiro-inositol (10), the amino acid proline (11), a mixture of sitosterol (12) and stigmasterol (13), and a mixture of the triterpenes lupeol (14) and β-amirine (15) were obtained from P. bahiana leaves. The structures were established by extensive analysis of their spectroscopic data, which included ¹H NMR, ¹³C NMR, DEPT, and 2D-NMR (¹³C¹H HETCOR and ¹³C¹H COLOC). Two isoflavones (3 and 5) and two rotenones (8-9) exhibited antifungal activity against the plant pathogenic fungus Cladosporium sphaerospermum. Furthermore, the biogenetic implications of the oxygenation pattern of the B-ring of the isoflavones, and the chemophenetics and fragmentation pattern of the isoflavones and rotenones are discussed.

New 5-carba-pterocarpans: Synthesis and preliminary antiproliferative activity on a panel of human cancer cells

Natural pterocarpans and synthetic 5-carba-pterocarpans are isosteres in which the oxygen atom at position 5 in the pyran-ring of pterocarpans is replaced by a methylene group. These 5-carba-analogues were obtained in good yields through the palladium-catalyzed oxyarylation of alcoxy-1,2-dihydronaphthalens with o-iodophenols in PEG-400. They were evaluated on human cancer cell lineages derived respectively from prostate tumor (PC3, IC₅₀ = 11.84 μmol L^-1, SI > 12)) and acute myeloid leukemia (HL-60, IC₅₀ = 8.81 μmol L^-1, SI > 16), highly incident cancer types presenting resistance against traditional chemotherapeutics. Compound 6c (LQB-492) was the most potent (IC₅₀ = 3.85 μmol L^-1, SI > 37) in SF-295 cell lineage (glioblastoma). Such findings suggest that 5-carba-pterocarpan can potentially be new hit compounds for further development of novel antiproliferative agents.

Genetic Variation and Hot Flashes: A Systematic Review

CONTEXT

Approximately 70% of women report experiencing vasomotor symptoms (VMS, hot flashes and/or night sweats). The etiology of VMS is not clearly understood but may include genetic factors.

EVIDENCE ACQUISITION

We searched PubMed and Embase in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. We included studies on associations between genetic variation and VMS. We excluded studies focused on medication interventions or prevention or treatment of breast cancer.

EVIDENCE SYNTHESIS

Of 202 unique citations, 18 citations met the inclusion criteria. Study sample sizes ranged from 51 to 17 695. Eleven of the 18 studies had fewer than 500 participants; 2 studies had 1000 or more. Overall, statistically significant associations with VMS were found for variants in 14 of the 26 genes assessed in candidate gene studies. The cytochrome P450 family 1 subfamily A member 1 (CYP1B1) gene was the focus of the largest number (n = 7) of studies, but strength and statistical significance of associations of CYP1B1 variants with VMS were inconsistent. A genome-wide association study reported statistically significant associations between 14 single-nucleotide variants in the tachykinin receptor 3 gene and VMS. Heterogeneity across trials regarding VMS measurement methods and effect measures precluded quantitative meta-analysis; there were few studies of each specific genetic variant.

CONCLUSIONS

Genetic variants are associated with VMS. The associations are not limited to variations in sex-steroid metabolism genes. However, studies were few and future studies are needed to confirm and extend these findings.

Bioguided identification of daucosterol, a compound that contributes to the cytotoxicity effects of Crateva adansonii DC (capparaceae) to prostate cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Crateva adansonii DC (Capparaceae) is a shrub used to treat tumors in Cameroon. In our previous reports, a Crateva adansonii dichloromethane-methanol (DCM/MeOH) extract was shown to prevent chemically induced tumors in Wistar rats.

AIM OF STUDY

To determine the bioactive principle of Crateva adansonii extract and to elucidate its underlying mechanism.

MATERIALS AND METHODS

An activity-guided fractionation was realized using MTT assay. To investigate if the bioactive compound daucosterol (CA2) accounted for the previously observed anticancer effects of the C. adansonii extract, it was tested on cell growth, cell proliferation, cell cycle, cell death mechanism and cell migration. In addition, cell cycle- and apoptosis-regulating proteins were assessed by Western blotting.

RESULTS

Daucosterol (CA2), a steroid saponin, was identified as major anticancer principle of the C. adansonii extract. Daucosterol significantly inhibited LNCaP, DU145 and PC3 prostate carcinoma cell growth and proliferation at the optimal concentration of 1 μg/mL. It also significantly increased the number of late apoptotic (DU145) and apoptotic (PC3) cells. The number of cells in S phase increased in DU145, while the number of G0/G1 cells decreased. Cell cycle proteins (cdk1, pcdk1, cyclin A and B) were down-regulated in DU145 and PC3 cells, whereas only cdk2 was down-regulated in PC3 cells. Moreover, the anti-apoptotic Akt, pAKT and Bcl-2 proteins were down-regulated, while the pro-apoptotic protein Bax was up-regulated. CA2 induced anti-metastatic effects by decreasing chemotaxis and cell migration, while it increased cell adhesion to fibronectin and collagen matrix.

CONCLUSION

These results suggest that daucosterol is the major active principle responsible at least in part for the anticancer effect of the extract of Crateva adansonii.

The Effects of Trifolium pratense L. Sprouts' Phenolic Compounds on Cell Growth and Migration of MDA-MB-231, MCF-7 and HUVEC Cells

Uncontrolled growth and migration and invasion abilities are common for cancer cells in malignant tumors with low therapeutic effectiveness and high mortality and morbidity. Estrogen receptor β (ERβ), as a member of the nuclear receptor superfamily, shows potent tumor suppressive activities in many cancers. Phytoestrogens’ structural resemblance to 17 β-estradiol allows their binding to ERβ isoform predominantly, and therefore, expression of genes connected with elevated proliferation, motility and invasiveness of cancer cells may be downregulated. Among polyphenolic compounds with phytoestrogenic activity, there are isoflavones from Trifolium pratense L. (red clover) sprouts, containing high amounts of formononetin and biochanin A and their glycosides. To determine the source of the most biologically active isoflavones, we obtained four extracts from sprouts before and after their lactic fermentation and/or β-glucosidase treatment. Our previous results of ITC (isothermal titration calorimetry) modelling and a docking simulation showed clover isoflavones’ affinity to ERβ binding, which may downregulate cancer cell proliferation and migration. Thus, the biological activity of T. pratense sprouts’ extracts was checked under in vitro conditions against highly invasive human breast cancer cell line MDA-MB-231 and non-invasive human breast cancer cell line MCF-7 cells. To compare extracts’ activities acquired for cancer cells with those activities against normal cells, as a third model we choose human umbilical vein endothelial cells (HUVEC), which, due to their migration abilities, are involved in blood vessel formation. Extracts obtained from fermented sprouts at IC₀ dosages were able to inhibit migration of breast cancer cells through their influence on intracellular ROS generation; membrane stiffening; adhesion; regulation of MMP-9, N-cadherin and E-cadherin at transcriptional level; or VEGF secretion. Simultaneously, isolated phenolics revealed no toxicity against normal HUVEC cells. In the manuscript, we proposed a preliminary mechanism accounting for the in vitro activity of Trifolium pratense L. isoflavones. In this manner, T. pratense sprouts, especially after their lactic fermentation, can be considered a potent source of biological active phytoestrogens and a dietary supplement with anti-cancer and anti-invasion properties.

Anthonotha macrophylla P. Beauv (Caesalpiniaceae) aqueous extract exhibits antiestrogenic effects in vitro and in vivo

Background Phytoestrogens are natural compounds known as natural selective estrogen receptor modulators used as alternatives against estrogen-dependent cancers. This study aims to evaluate the antiestrogenic effects of Anthonotha macrophylla, a plant used to treat cancer in Cameroon. Methods The estrogenic/antiestrogenic activities of A. macrophylla aqueous extract were evaluated in vitro using MCF-7 cell proliferation assay. Moreover, a classical uterotrophic test was carried out to evaluate the antiestrogenic effects of A. macrophylla in rats. Changes in the uterus, vagina, and mammary glands were used as endpoints of estrogenicity. Results Anthonotha macrophylla induced antiestrogenic effects in vitro at all the tested concentrations by inhibiting estradiol-induced MCF-7 cell proliferation (p < 0.001). In vivo, a coadministration of estradiol with A. macrophylla extract led to the decrease of uterine [150 (p < 0.05) and 300 (p < 0.01) mg/kg body weight (BW)] and vaginal [75 (p < 0.01) and 300 (p < 0.05) mg/kg BW] epithelial thickness. In addition, a reduction in the mammary gland acini lumen's diameter was also observed at 75 and 150 mg/kg. Gas chromatography-time-of-flight-mass spectrometry analysis showed that phenolic acid derivatives are present in A. macrophylla extract, which are well known to be endowed with estrogenic/antiestrogenic properties. The LD50 of A. macrophylla was estimated to be less than 2000 mg/kg. Conclusions Anthonotha macrophylla aqueous extract has antiestrogenic properties. This could promote more studies to explore its ability to prevent estrogen-dependent cancers.

Millettia macrophylla (Fabaceae) phenolic fraction prevents differentiation of 3T3-L1 adipocytes and the increased risks of cardiovascular diseases in ovariectomized rats

ETHNOPHARMACOLOGICAL RELEVANCE

A prolonged estrogen deficiency alters lipid metabolism and increases risks of cardiovascular diseases. Phytoestrogens, naturally occurring compounds with estrogenic properties are reported to have cardiovascular protective effects. Millettia macrophylla used in the Cameroonian traditional system to treat physiological disorders related to menopause, was previously reported to have estrogenic effects.

AIM

We, therefore, proposed evaluating the in vitro and in vivo effects of M. macrophylla phenolic fraction on some risk factors for cardiovascular diseases.

MATERIAL AND METHODS

In vitro, the ability of the M. macrophylla phenolic fraction (PF) as well as the 9 isolates to prevent the 3T3-L1 preadipocytes differentiation was assessed. Further, the preventive effects of PF on abdominal fat accumulation, body weight gain, lipid profile, nitric oxide level, superoxide dismutase (SOD) and catalase activities, reduced glutathione (GSH) and malondialdehyde (MDA) levels were assessed in a postmenopausal rat model.

RESULTS

In vitro, PF and its isolate secundiferol I inhibited lipid accumulation in 3T3-L1 cells. Moreover, all the isolates except daidzein dimethylether prevented the interleukin IL-6 production in 3T3-L1 cells. In vivo, PF prevented ovariectomy-induced abdominal fat accumulation, body weight gain, dyslipidemia, glucose intolerance and decreased atherogenic index. In addition, it induced a vasorelaxant effect by preventing the low level of nitric oxide in the aorta. PF also exhibited antioxidant effects as it increased aorta GSH level, SOD, and catalase activities and decreased MDA level.

CONCLUSIONS

Taken together, our data suggest that PF prevents the increased risks of cardiovascular diseases in ovariectomized rats.

Application of ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in identification of three isoflavone glycosides and their corresponding metabolites

RATIONALE

Metabolites of isoflavones have attracted much attention in recent years due to their potential bioactivities. However, the complex constituents of the metabolic system and the low level of metabolites make them difficult to analyze. A mass spectrometry (MS) method was applied in our identification of metabolites and study of their fragmentation pathways due to the advantages of rapidity, sensitivity, and low level of sample consumption.

METHODS

Three isoflavone glycosides and their metabolites were identified using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/QTOF-MS). These metabolites were obtained by anaerobically incubating three isoflavone glycosides with human intestinal flora. The characteristic fragments of isoflavone glycosides and their metabolites were used for the identification work.

RESULTS

Two metabolites from ononin, three metabolites from irilone-4'-O-β-D-glucoside, and five metabolites from sissotrin were identified respectively by the retention time (RT), accurate mass, and mass spectral fragmentation patterns. The losses of the glucosyl group, CO from the [M+H]⁺ ion were observed for all the three isoflavone glycosides. The characteristic retro-Diels-Alder (RDA) fragmentation patterns were used to differentiate the compounds. The metabolic pathways of the three isoflavone glycosides were proposed according to the identified chemical structures of the metabolites.

CONCLUSIONS

A selective, sensitive and rapid method was established for detecting and identifying three isoflavone glycosides and their metabolites using UPLC/QTOF-MS. The established method can be used for further rapid structural identification studies of metabolites and natural products. Furthermore, the proposed metabolic pathways will be helpful for understanding the in vivo metabolic process of isoflavone.

Lannea acida A. Rich. (Anacardiaceae) Ethanol Extract Exhibits Estrogenic Effects and Prevents Bone Loss in an Ovariectomized Rat Model of Osteoporosis

Phytoestrogens have been shown to prevent postmenopausal osteoporosis. Lannea acida is a medicinal plant traditionally used in Cameroon to treat infertility, gynaecological complaints, and rheumatism. These uses prompted us to evaluate estrogenic activity of Lannea acida bark ethanolic extract and its antiosteoporotic potential in ovariectomized Wistar rats. In vitro, the E-screen assay was used to assess the ability of L. acida extract to induce MCF-7 cells proliferation. In vivo, a 3-day uterotrophic assay and a 12-week oral treatment in ovariectomized adult rats were carried out to evaluate the ability of L. acida extract to prevent bone mass loss. L. acida extract induced MCF-7 cell proliferation. In vivo, it significantly increased the uterine wet weight, uterine and vaginal epithelial heights, and mammary glands differentiation. At 200 mg/kg, a long-term treatment with the extract prevented body weight gain (p < 0.05) and loss of bone mass and/or density (p < 0.05) induced by ovariectomy. Also, a significant (p < 0.001) decrease of alkaline phosphatase activity was observed with 50 mg/kg. L. acida extract improved bone microarchitecture and could restore normal bone mineralization by increasing the inorganic phosphorus and calcium level in bone. These findings provide evidence that Lannea acida is a potential alternative for the prevention of postmenopausal osteoporosis.

Estrogen-like and tissue-selective effects of 7-methoxycoumarin from Ficus umbellata (Moraceae): an in vitro and in vivo study

BACKGROUND

Ficus umbellata is a medicinal plant previously shown to endow estrogenic properties. Its major component was isolated and characterized as 7-methoxycoumarin (MC). Noteworthy, coumarins and the respective active metabolite 7-hydroxycoumarin analogs have shown aromatase inhibitory activity, which is of particular interest in the treatment of estrogen-dependent cancers. The present work aimed at evaluating the estrogenic/antiestrogenic effects of MC in vitro and in vivo.

METHODS

To do so, in vitro assays using E-screen and reporter gene were done. In vivo, a 3-day uterotrophic assay followed by a postmenopausal-like rat model to characterize MC as well as F. umbellata aqueous extract in ovariectomized Wistar rats was performed. The investigations focused on histological (vaginal and uterine epithelial height) and morphological (uterine wet weight, vagina stratification and cornification) endpoints, bone mass, biochemical parameters and lipid profile.

RESULTS

MC induced a significant (p < 0.05) MCF-7 cell proliferation at a concentration of 0.1 μM, but did not inhibit the effect induced by estradiol in both E-screen and reporter gene assays. In vivo, MC treatment did not show an uterotrophic effect in both rat models used. However, MC (1 mg/kg) induced a significant increase (p < 0.01) of vaginal epithelial height. No significant change was observed with MC in abdominal fat weight, serum lipid levels and bone weight.

CONCLUSION

These results suggest that MC has a weak estrogenic activity in vitro and in vivo that accounts only in part to the estrogenicity of the whole plant extract. MC could be beneficial with regard to vagina dryness as it showed a tissue specific effect without exposing the uterus to a potential tumorigenic growth.

Cytotoxicity of the methanol extracts of Elephantopus mollis, Kalanchoe crenata and 4 other Cameroonian medicinal plants towards human carcinoma cells

BACKGROUND

Cancer still constitutes one of the major health concerns globally, causing serious threats on patients, their families, and the healthcare system.

METHODS

In this study, the cytotoxicity of the methanol extract of Elephantopus mollis whole plant (EMW), Enantia chlorantha bark (ECB), Kalanchoe crenata leaves (KCL), Lophira alata bark (LAB), Millettia macrophylla leaves (MML) and Phragmanthera capitata leaves (PCL) towards five human solid cancer cell lines and normal CRL2120 fibroblasts, was evaluated. Extracts were subjected to qualitative chemical screening of their secondary metabolite contents using standard methods. The cytotoxicity of samples was evaluated using neutral red uptake (NR) assay meanwhile caspase activation was detected by caspase-Glo assay. Flow cytometry was used to analyze the cell cycle distribution and the mitochondrial membrane potential (MMP) whilst spectrophotometry was used to measure the levels of reactive oxygen species (ROS).

RESULTS

Phytochemical analysis revealed the presence of polyphenols, triterpenes and sterols in all extracts. The IC₅₀ values of the best samples ranged from 3.29 μg/mL (towards DLD-1 colorectal adenocarcinoma cells) to 24.38 μg/mL (against small lung cancer A549 cells) for EMW, from 2.33 μg/mL (mesothelioma SPC212 cells) to 28.96 μg/mL (HepG2 hepatocarcinoma) for KCL, and from 0.04 μg/mL (towards SPC212 cells) to 0.55 μg/mL (towards A549 cells) for doxorubicin. EMW induced apoptosis in MCF-7 cells mediated by MMP loss and increased ROS production whilst KCL induced apoptosis via ROS production.

CONCLUSION

This study provides evidences of the cytotoxicity of the tested plant extract and highlights the good activity of Elephantopus mollis and Kalanchoe crenata. They deserve more exploration to develop novel cytotoxic drugs.