Nitrogen-Containing Constituents of Black Cohosh: Chemistry, Structure Elucidation, and Biological Activities

Exploring the Efficacy and Safety of Black Cohosh (Cimicifuga racemosa) in Menopausal Symptom Management

Black cohosh (Cimicifuga racemosa) is a perennial plant used to treat menopause. This plant is known to have a serotonergic rather than estrogenic impact. It has been recommended to treat vasomotor symptoms associated with breast cancer patients. It also relieves symptoms such as night sweats and hot flashes, commonly called vasorelaxation. The variability in the study's results, doses, and assessment methods requires more rigorous research to establish its efficacy and safety. Standardized trials are needed to provide more precise information on the benefits and limitations of menopause treatment, informing women seeking alternatives to hormone therapy. Black cohosh has shown the potential to reduce the frequency and intensity of vasomotor symptoms in breast cancer patients undergoing tamoxifen treatment. In addition to its effectiveness in alleviating night sweats and hot flashes, the vasorelaxation properties contribute to its overall positive impact on menopausal symptoms. Due to discrepancies, varying dosages, and assessment techniques, further comprehensive studies are essential to determine the optimal dosage, long-term safety, and overall efficacy. Only through standardized trials can women make informed decisions about black cohosh as a viable alternative to hormone therapy during menopause.

Non-targeted chemical analysis of consumer botanical products labeled as blue cohosh (Caulophyllum thalictroides), goldenseal (Hydrastis canadensis), or yohimbe bark (Pausinystalia yohimbe) by NMR and MS

Consumers have unprecedented access to botanical dietary supplements through online retailers, making it difficult to ensure product quality and authenticity. Therefore, methods to survey and compare chemical compositions across botanical products are needed. Nuclear magnetic resonance (NMR) spectroscopy and non-targeted mass spectrometry (MS) were used to chemically analyze commercial products labeled as containing one of three botanicals: blue cohosh, goldenseal, and yohimbe bark. Aqueous and organic phase extracts were prepared and analyzed in tandem with NMR followed by MS. We processed the non-targeted data using multivariate statistics to analyze the compositional similarity across extracts. In each case, there were several product outliers that were identified using principal component analysis (PCA). Evaluation of select known constituents proved useful to contextualize PCA subgroups, which in some cases supported or refuted product authenticity. The NMR and MS data reached similar conclusions independently but were also complementary.

Low Energy Collision-Induced Dissociation of Azepine Pictet-Spengler Adducts of Nω-Methylserotonin

Cimitrypazepines are a class of natural products produced by Pictet-Spengler condensation of N_ω-methylserotonin and aldehydes in a manner that produces a seven-membered azepine ring. In this study, the fragmentation behavior of this class of molecules under low-energy CID was investigated in detail. Proposed mechanisms of fragmentation were supported by deuterium labeling and DFT calculations. Loss of methylamine and methylenimine were dominant fragmentation pathways of analogs containing an aliphatic side chain. Loss of methylenimine was found to proceed via unusual methyl cation transfer. Fragmentation of analogs containing an aromatic side chain was strongly influenced by the nature of the substituents and proceeded via a novel retro-Pictet-Spengler pathway and involvement of ion-neutral complexes. In some cases, a gas-phase interconversion between the azepine and β-carboline ring was observed during fragmentation. Detailed analysis of fragmentation behavior provided in this study will serve as a valuable guide for the discovery of new analogs from natural sources.

A cross-sectional clinical study in women to investigate possible genotoxicity and hematological abnormalities related to the use of black cohosh botanical dietary supplements

Black cohosh (BC; Actaea racemosa L.), a top-selling botanical dietary supplement, is marketed to women primarily to ameliorate a variety of gynecological symptoms. Due to widespread usage, limited safety information, and sporadic reports of hepatotoxicity, the Division of the National Toxicology Program (DNTP) initially evaluated BC extract in female rats and mice. Following administration of up to 1000 mg/kg/day BC extract by gavage for 90 days, dose-related increases in micronucleated peripheral blood erythrocytes were observed, along with a nonregenerative macrocytic anemia resembling megaloblastic anemia in humans. Because both micronuclei and megaloblastic anemia may signal disruption of folate metabolism, and inadequate folate levels in early pregnancy can adversely affect neurodevelopment, the DNTP conducted a pilot cross-sectional study comparing erythrocyte micronucleus frequencies, folate and B12 levels, and a variety of hematological and clinical chemistry parameters between women who used BC and BC-naïve women. Twenty-three women were enrolled in the BC-exposed group and 28 in the BC-naïve group. Use of any brand of BC-only supplement for at least 3 months was required for inclusion in the BC-exposed group. Supplements were analyzed for chemical composition to allow cross-product comparisons. All participants were healthy, with no known exposures (e.g., x-rays, certain medications) that could influence study endpoints. Findings revealed no increased micronucleus frequencies and no hematological abnormalities in women who used BC supplements. Although reassuring, a larger, prospective study with fewer confounders (e.g., BC product diversity and duration of use) providing greater power to detect subtle effects would increase confidence in these findings.

Living with a giant, flowering parasite: metabolic differences between Tetrastigma loheri Gagnep. (Vitaceae) shoots uninfected and infected with Rafflesia (Rafflesiaceae) and potential applications for propagation

Metabolites in Rafflesia-infected and non-infected Tetrastigma were compared which may have applications in Rafflesia propagation. Benzylisoquinoline alkaloids, here reported for the first time in Vitaceae, were abundant in non-infected shoots and may be a form of defense. In Rafflesia-infected shoots, oxylipins, which mediate immune response, were elevated. Endemic to the forests of Southeast Asia, Rafflesia (Rafflesiaceae) is a genus of holoparasitic plants producing the largest flowers in the world, yet completely dependent on its host, the tropical grape vine, Tetrastigma. Rafflesia species are threatened with extinction, making them an iconic symbol of plant conservation. Thus far, propagation has proved challenging, greatly decreasing efficacy of conservation efforts. This study compared the metabolites in the shoots of Rafflesia-infected and non-infected Tetrastigma loheri to examine how Rafflesia infection affects host metabolomics and elucidate the Rafflesia infection process. Results from LC-MS-based untargeted metabolomics analysis showed benzylisoquinoline alkaloids were naturally more abundant in non-infected shoots and are here reported for the first time in the genus Tetrastigma, and in the grape family, Vitaceae. These metabolites have been implicated in plant defense mechanisms and may prevent a Rafflesia infection. In Rafflesia-infected shoots, oxygenated fatty acids, or oxylipins, and a flavonoid, previously shown involved in plant immune response, were significantly elevated. This study provides a preliminary assessment of metabolites that differ between Rafflesia-infected and non-infected Tetrastigma hosts and may have applications in Rafflesia propagation to meet conservation goals.

Bioactive Azepine-Indole Alkaloids from Psychotria nemorosa

Phytochemical investigation of the alkaloid extract of the aerial parts of Psychotria nemorosa led to the isolation and characterization of 10 azepine-indole alkaloids, i.e., cimitrypazepine (1), fargesine (2), nemorosines A (3), and B (12), nemorosinosides A-F (4-9), as well as two β-carboline derivatives, 10-hydroxyisodolichantoside (10) and 10-hydroxydolichantoside (11), an isoxazole alkaloid, nemorosinoside G (13), serotonin (14), bufotenine (15), and (S)-gentianol (16). Compounds 3-13 have not yet been described. These compounds were isolated by semipreparative HPLC, and their structures were determined by means of HRMS, NMR, and ECD measurements. In addition, the monoamine oxidase-A (MAO-A), MAO-B, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibitory activities were evaluated. Alkaloids 1-3 inhibited the MAO-A activity with IC₅₀ values of 1.4, 1.4, and 0.9 μM, respectively.

Evaluating Sufficient Similarity of Botanical Dietary Supplements: Combining Chemical and In Vitro Biological Data

Botanical dietary supplements are complex mixtures with numerous potential sources of variation along the supply chain from raw plant material to the market. Approaches for determining sufficient similarity (ie, complex mixture read-across) may be required to extrapolate efficacy or safety data from a tested sample to other products containing the botanical ingredient(s) of interest. In this work, screening-level approaches for generating both chemical and biological-response profiles were used to evaluate the similarity of black cohosh (Actaea racemosa) and Echinacea purpurea samples to well-characterized National Toxicology Program (NTP) test articles. Data from nontargeted chemical analyses and gene expression of toxicologically important hepatic receptor pathways (aryl hydrocarbon receptor [AhR], constitutive androstane receptor [CAR], pregnane X receptor [PXR], farnesoid X receptor [FXR], and peroxisome proliferator-activated receptor alpha [PPARα]) in primary human hepatocyte cultures were used to determine similarity through hierarchical clustering. Although there were differences in chemical profiles across black cohosh samples, these differences were not reflected in the biological-response profiles. These findings highlight the complexity of biological-response dynamics that may not be reflected in chemical composition profiles. Thus, biological-response data could be used as the primary basis for determining similarity among black cohosh samples. Samples of E. purpurea displayed better correlation in similarity across chemical and biological-response measures. The general approaches described herein can be applied to complex mixtures with unidentified active constituents to determine when data from a tested mixture (eg, NTP test article) can be used for hazard identification of sufficiently similar mixtures, with the knowledge of toxicological targets informing assay selection when possible.

Black cohosh extracts and powders induce micronuclei, a biomarker of genetic damage, in human cells

Black cohosh extract (BCE) is a widely used dietary supplement marketed to women to alleviate symptoms of gynecological ailments, yet its toxicity has not been well characterized. The National Toxicology Program (NTP) previously reported significant increases in micronucleated erythrocytes in peripheral blood of female Wistar Han rats and B6C3F1/N mice administered 15-1,000 mg BCE/kg/day by gavage for 90 days. These animals also developed a dose-dependent nonregenerative macrocytic anemia characterized by clinical changes consistent with megaloblastic anemia. Both micronuclei (MN) and megaloblastic anemia can arise from disruption of the folate metabolism pathway. The NTP used in vitro approaches to investigate whether the NTP's test lot of BCE, BCEs from various suppliers, and root powders from BC and other cohosh species, were genotoxic in general, and to gain insight into the mechanism of action of BCE genotoxicity. Samples were tested in human TK6 lymphoblastoid cells using the In Vitro MicroFlow® MN assay. The NTP BCE and a BC extract reference material (XRM) were tested in the MultiFlow^® DNA Damage assay, which assesses biomarkers of DNA damage, cell division, and cytotoxicity. The NTP BCE and several additional BCEs were tested in bacterial mutagenicity assays. All samples induced MN when cells were grown in physiological levels of folic acid. The NTP BCE and BC XRM produced activity patterns consistent with an aneugenic mode of action. The NTP BCE and five additional BCEs were negative in bacterial mutagenicity tests. These findings show that black cohosh preparations induce chromosomal damage and may pose a safety concern. Environ. Mol. Mutagen. 59:416-426, 2018. © 2018 Published 2018. This article is a US Government work and is in the public domain in the USA.