Phytochemical profiling of Striga asiatica; characterisation and anti-microbial assessment of the isolates.

One undescribed compound, striasinol (1), and twelve previously described compounds were isolated from the aerial parts of Striga asiatica. Structure elucidation of isolated compounds was achieved by the interpretation of 1D and 2D NMR and HRESIMS data. The absolute configuration (1S,5S) of 1 was ascertained based on GIAO NMR calculations, DP4+ probability analysis, and a comparison of the experimental and calculated specific rotation values. The isolated compounds were evaluated for their antimalarial action, and none was found to be effective against the chloroquine-sensitive (D6) or chloroquine-resistant (W2) strains of Plasmodium falciparum. The isolates were found non-toxic to the Vero cell line as well. Subsequent testing of these metabolites for antimicrobial activities against various bacterial and fungal strains (up to 20 µg/mL), revealed that compounds 6 (chryseriol) and 7 (apigenin) showed a reasonable activity towards methicillin-resistant Staphylococcus aureus ATCC 1708 (MRSA), with IC50 values of 5.81 and 3.60 µg/mL, respectively.

Comprehensive quality assessment of peppermint oils and commercial products: An integrated approach involving conventional and chiral GC/MS coupled with chemometrics.

Peppermint essential oil (EO) has a multitude of applications, such as a fragrance in cosmetics, personal care and industrial products, or as a flavoring ingredient in food and beverages. Despite its popularity and economic significance, peppermint EO is often adulterated to reduce production costs and to increase profits. Although the ISO standard for peppermint EO exists, detecting sophisticated forms of adulteration remains challenging.The current study used conventional and chiral GC/MS analysis of volatiles compounds, and chemometric techniques to evaluate an extensive set of authentic peppermint EO (n = 22) and commercial products (n = 36) purported to contain peppermint EO. Specifically, thirty-six terpenoids were examined in each sample and compared with the ISO standard. Fifty-three percent of the selected commercial products did not meet the ISO specifications and the ratio between menthone/isomenthone was proven to be a good indicator for authentication and adulteration detection. Chiral GC/MS was further employed to measure eight terpenoids: α-pinene, ß-pinene, limonene, menthol, menthone, isomenthone, pulegone, and menthyl acetate. The enantiomeric compositions of 27 commercial products were above or below the norm measured from authentic peppermint EOs. Of the 27 samples, eight met the ISO standard. A sample class prediction (SCP) model based on partial least squares-discriminant analysis (PLS-DA) of conventional GC/MS data was constructed using authentic peppermint EOs and cornmint EOs. The model can distinguish the most common types of peppermint EOs (US, India, and US/India blend) and cornmint EOs sold in the US market. After construction, the SCP model was then used to analyze commercial samples. One sample, which passed both ISO specification and chiral analysis, was identified as outlier by the SCP model. Overall, the applicability of combining both conventional and chiral GC/MS along with chemometric tools has been successfully demonstrated to address the overall quality of peppermint EOs in commerce and may help combat sophisticated adulteration.

Applicability of LC-QToF and Microscopical Tools in Combating the Sophisticated, Economically Motivated Adulteration of Poppy Seeds.

Morphine and codeine are the two principal opiates found in the opium poppy (Papaver somniferum L.) and are therapeutically used for pain management. Poppy seeds with low opiates are primarily used for culinary purposes due to their nutritional and sensory attributes. Intentional adulteration of poppy seeds is common, often combined with immature, less expensive, exhausted, or substituted with morphologically similar seeds, viz., amaranth, quinoa, and sesame. For a safer food supply chain, preventive measures must be implemented to mitigate contamination or adulteration. Moreover, the simultaneous analysis of P. somniferum and its adulterants is largely unknown. Pre- and post-processing further complicate the alkaloid content and may pose a significant health hazard. To address these issues, two independent methods were investigated with eight botanically verified and fifteen commercial samples. Microscopical features were established for the authenticity of raw poppy seeds. Morphine, codeine, and thebaine quantities ranged from 0.8-223, 0.2-386, and 0.1-176 mg/kg, respectively, using LC-QToF. In most cases, conventional opiates have a higher content than papaverine and noscapine. The analytical methodology provided a chemical profile of 47 compounds that can be effectively applied to distinguish poppy seeds from their adulterants and may serve as an effective tool to combat ongoing adulteration.

Assessment of Herb-Drug Interaction Potential of Five Common Species of Licorice and Their Phytochemical Constituents.

The dried roots and rhizomes of Glycyrrhiza species (G. glabra, G. uralensis and G. inflata), commonly known as licorice, have long been used in traditional medicine. In addition, two other species, G. echinata and G. lepidota are also considered "licorice" in select markets. Currently, licorice is an integral part of several botanical drugs and dietary supplements. To probe the botanicals' safety, herb-drug interaction potential of the hydroethanolic extracts of five Glycyrrhiza species and their key constituents was investigated by determining their effects on pregnane X receptor, aryl hydrocarbon receptor, two major cytochrome P450 isoforms (CYP3A4 and CYP1A2), and the metabolic clearance of antiviral drugs. All extracts enhanced transcriptional activity of PXR and AhR (>2-fold) and increased the enzyme activity of CYP3A4 and CYP1A2. The highest increase in CYP3A4 was seen with G. echinata (4-fold), and the highest increase in CYP1A2 was seen with G. uralensis (18-fold) and G. inflata (16-fold). Among the constituents, glabridin, licoisoflavone A, glyasperin C, and glycycoumarin activated PXR and AhR, glabridin being the most effective (6- and 27-fold increase, respectively). Licoisoflavone A, glyasperin C, and glycycoumarin increased CYP3A4 activity while glabridin, glyasperin C, glycycoumarin, and formononetin increased CYP1A2 activity (>2-fold). The metabolism of antiretroviral drugs (rilpivirine and dolutegravir) was increased by G. uralensis (2.0 and 2.5-fold) and its marker compound glycycoumarin (2.3 and 1.6-fold). The metabolism of dolutegravir was also increased by G. glabra (2.8-fold) but not by its marker compound, glabridin. These results suggest that licorice and its phytochemicals could affect the metabolism and clearance of certain drugs that are substrates of CYP3A4 and CYP1A2.Supplemental data for this article is available online at https://doi.org/10.1080/19390211.2022.2050875 .

Modulation of CYP3A4 and CYP2C9 activity by Bulbine natalensis and its constituents: An assessment of HDI risk of B. natalensis containing supplements.

BACKGROUND: Bulbine natalensis is an African-folk medicinal plant used as a dietary supplement for enhancing sexual function and muscle strength in males by presumably boosting testosterone levels, but no scientific information is available about the possible herb-drug interaction (HDI) risk when bulbine-containing supplements are concomitantly taken with prescription drugs. PURPOSE: This study was aimed to investigate the HDI potential of B. natalensis in terms of the pregnane X receptor (PXR)-mediated induction of major drug-metabolizing cytochrome P450 enzyme isoforms (i.e., CYP3A4 and CYP2C9) as well as inhibition of their catalytic activity. RESULTS: We found that a methanolic extract of B. natalensis activated PXR (EC50 6.2 ± 0.6 µg/ml) in HepG2 cells resulting in increased mRNA expression of CYP3A4 (2.40 ± 0.01 fold) and CYP2C9 (3.37 ± 0.3 fold) at 30 µg/ml which was reflected in increased activites of the two enzymes. Among the constituents of B. natalensis, knipholone was the most potent PXR activator (EC50 0.3 ± 0.1 µM) followed by bulbine-knipholone (EC50 2.0 ± 0.5 µM), and 6'-methylknipholone (EC50 4.0 ± 0.5 µM). Knipholone was also the most effective in increasing the expression of CYP3A4 (8.47 ± 2.5 fold) and CYP2C9 (2.64 ± 0.3 fold) at 10 µM. Docking studies further confirmed the unique structural features associated with knipholones for their superior inductive potentials in the activation of PXR compared to other anthraquinones. In a CYP inhibition assay, the methanolic extract as well as the anthraquinones strongly inhibited the catalytic activity of CYP2C9 while, inhibition of CYP3A4 was weak. CONCLUSIONS: These results suggest that consumption of B. natalensis may pose a potential risk for HDI if taken with conventional medications that are substrates of CYP3A4 and CYP2C9 and may contribute to unanticipated adverse reactions or therapeutic failures. Further studies are warranted to validate these findings and establish their clinical relevancy.

Characterization, Quantification and Quality Assessment of Avocado (Persea americana Mill.) Oils.

Avocado oil is prized for its high nutritional value due to the substantial amounts of triglycerides (TGs) and unsaturated fatty acids (FAs) present. While avocado oil is traditionally extracted from mature fruit flesh, alternative sources such as avocado seed oil have recently increased in popularity. Unfortunately, sufficient evidence is not available to support the claimed health benefit and safe use of such oils. To address potential quality issues and identify possible adulteration, authenticated avocado oils extracted from the fruit peel, pulp and seed by supercritical fluid extraction (SFE), as well as commercial avocado pulp and seed oils sold in US market were analyzed for TGs and FAs in the present study. Characterization and quantification of TGs were conducted using UHPLC/ESI-MS. Thirteen TGs containing saturated and unsaturated fatty acids in avocado oils were unambiguously identified. Compared to traditional analytical methods, which are based only on the relative areas of chromatographic peaks neglecting the differences in the relative response of individual TG, our method improved the quantification of TGs by using the reference standards whenever possible or the reference standards with the same equivalent carbon number (ECN). To verify the precision and accuracy of the UHPLC/ESI-MS method, the hydrolysis and transesterification products of avocado oil were analyzed for fatty acid methyl esters using a GC/MS method. The concentrations of individual FA were calculated, and the results agreed with the UHPLC/ESI-MS method. Although chemical profiles of avocado oils from pulp and peel are very similar, a significant difference was observed for the seed oil. Principal component analysis (PCA) based on TG and FA compositional data allowed correct identification of individual avocado oil and detection of possible adulteration.

Safety Assessment of Phytochemicals Derived from the Globalized South African Rooibos Tea ( Aspalathus linearis) through Interaction with CYP, PXR, and P-gp.

Rooibos tea ( Aspalathus linearis) is a well-known South African herbal tea enjoyed worldwide. Limited reports indicate the potential of rooibos tea to alter the activity of certain cytochrome P450 (CYP450) isozymes. In this study, the phytochemical investigation of MeOH extract of A. linearis (leaves and stems) resulted in the isolation and characterization of 11 phenolic compounds. The MeOH extract exhibited significant inhibition of the major human CYP450 isozymes (CYP3A4, CYP1A2, CYP2D6, CYP2C9, and CYP2C19). The strongest inhibition was observed by the extract for CYP3A4 (IC50 1.7 ± 0.1 µg/mL) followed by CYP2C19 (IC50 4.0 ± 0.3 µg/mL). Among the tested phytochemicals, the most potent inhibitors were isovitexin on CYP3A4 (IC50 3.4 ± 0.2 µM), vitexin on CYP2C9 (IC50 8.0 ± 0.2 µM), and thermopsoside on CYP2C19 (IC50 9.5 ± 0.2 µM). The two major, structurally related compounds aspalathin and nothofagin exhibited a moderate pregnane-X receptor (PXR) activation, which was associated with increased mRNA expression of CYP3A4 and CYP1A2, respectively. These results indicate that a high intake of nutraceuticals containing rooibos extracts may pose a risk of herb-drug interactions when consumed concomitantly with clinical drugs that are substrates of CYP enzymes.

Utility of alkaloids as chemical and biomarkers for quality, efficacy, and safety assessment of botanical ingredients.

BACKGROUND: Selecting the appropriate chemical and bio-markers for monitoring the quality, efficacy, and safety is critical for efficient and reliable assessment of traditional medicines derived from botanical sources. Chemical markers have been implicated primarily in establishing the analytical methodologies aiming at verification of the botanical sources of the raw materials, the extracts, and the finished products such as botanical dietary supplements and nutraceuticals. In addition, they have been employed in differentiation between crude or raw (unprocessed) and processed plant extracts, and identification as well as determination of potential toxicants and adulterants in herbal medicines. Additionally, these chemical markers are utilized for selection of efficient methods for extraction of plants. Further, biomarkers have been exploited in determination of the pharmacokinetic properties of bioactive herbal constituents. Alkaloids, unlike other plant constituents, are uniquely characterized by having basic properties, and possessing substantial and diverse pharmacological effects. These features make alkaloids attractive components for functioning as chemical and biomarkers in determining the quality of botanical ingredients where this class of phytochemicals prevail or is responsible for lending biological effects. PURPOSE: The aim of the review is to exhibit the function of alkaloids as biomarkers and chemical markers in the evaluation of quality, efficacy, and safety of medicinal herbs and their commercial products. METHODS: Literature acquisition was accomplished using the most commonly accessed scholarly search engines including SciFinder, PubMed, and Google Scholar. Secondly, the full-texts which are relevant to the topic were included in this review. This was followed by a thorough and detailed analysis of the collected information. RESULTS: The literature search with main emphasis on the roles of alkaloids in the evaluation of quality, efficacy and safety of herbal medicines was evaluated to provide all succinct information in one place. Compilation of such critical information is expected to help the reader to appreciate alkaloids as important markers in the quality control of herbal drugs and products. CONCLUSION: The current review article covers the fundamental roles played by alkaloids as chemical and biomarkers in assessing the essential parameters of the quality of botanical ingredients, as briefly described earlier. The utilization of alkaloids as biomarkers to determine the efficacy-linked pharmacokinetic parameters is limited to reviewing studies on human subjects.

In chemico assessment of potential sensitizers: Stability and direct peptide reactivity of 24 fragrance ingredients.

Twenty-four pure fragrance ingredients of concern as potential skin sensitizers were previously subjected to degradation studies and evaluated using the high throughput with dansyl cysteamine (HTS-DCYA) method. The experimental results showed that two-thirds of the 24 fragrance ingredients underwent chemical degradation. In some cases, such degradation was accompanied by an increase in thio-reactivity. These results prompted us to investigate the reactivity of the same ingredients using the direct peptide reactivity assay (DPRA). In the present work, the 24 chemicals were subjected to forced degradation for 150 days, and evaluated with both DPRA and HTS-DCYA methods. At the end of the study, four and eight compounds remained non-reactive in the DPRA and DCYA assay, respectively. Coumarin, benzyl salicylate, benzyl cinnamate and hexyl cinnamal were found unreactive in both assays, while cinnamal, cinnamyl alcohol, hydroxycitronellal and lilial were found negative in the DCYA but positive in the DPRA method. The incongruity in reactivity of these four compounds was attributed to a possible role of pro-oxidants formed upon degradation, resulting in depletion of peptide without formation of apparent covalent adducts with the test chemical. To validate this hypothesis, the effect of hydrogen peroxide as model pro-oxidant on both lysine- and cysteine-heptapeptide depletion in the DPRA method was thus investigated. The obtained results showed little effect of oxidative conditions on lysine depletion, while cysteine depletion was significantly affected by concentrations above 1.1 mg/L of hydrogen peroxide. Overall, both in chemico methods confirmed chemical instability should be considered when assessing the skin sensitization potential of (un)known chemicals with alternative methods.

In chemico skin sensitization risk assessment of botanical ingredients.

Skin sensitization risk assessment of botanical ingredients is necessary for consumers' protection and occupational hazard identification. There are currently very few available alternative methods that can assist in the evaluation of complex mixtures. Chemical methods can provide essential information in a timely manner and thus help to reduce the need for in vivo testing, and they can complement and facilitate targeted in vitro assays. In the present work, the applicability of the high-throughput screening with dansyl cysteamine (DCYA) method for the systematic evaluation of skin sensitization of complex botanicals was explored. Botanical ingredients of four unrelated plant species were obtained and tested with the high-throughput fluorescence method at three concentrations. To illustrate the minimal matrix effects of the tested extracts on the developed method, the least DCYA-reactive extract (Rosa canina) was spiked with known sensitizers at different concentrations. The data obtained from the four plant extracts and the spiking experiments with known sensitizers, suggest that the high-throughput screening-DCYA method can be successfully applied for estimating the skin sensitization potential of complex botanical matrices. This is the first report of an attempt to develop a versatile in chemico method for the rapid detection of reactive skin sensitizers in complex botanical extracts, which could complement the battery of existing validated, non-animal methods.

Chemical stability and in chemico reactivity of 24 fragrance ingredients of concern for skin sensitization risk assessment.

Twenty-four pure fragrance ingredients have been identified as potential concern for skin sensitization. Several of these compounds are chemically unstable and convert into reactive species upon exposure to air or light. In the present work, a systematic investigation of the correlation between chemical stability and reactivity has been undertaken. The compounds were subjected to forced photodegradation for three months and the chemical changes were studied with GC-MS. At the end of the stability study, two-thirds of the samples were found to be unstable. The generation of chemically reactive species was investigated using the in chemico HTS-DCYA assay. Eleven and fourteen compounds were chemically reactive before and after three months, respectively. A significant increase in reactivity upon degradation was found for isoeugenol, linalool, limonene, lyral, citronellol and geraniol; in the same conditions, the reactivity of hydroxycitronellal decreased. The non-reactive compounds α-isomethyl ionone, benzyl alcohol, amyl cinnamal and farnesol became reactive after photo-oxidative degradation. Overall, forced degradation resulted in four non-reactive fragrance compounds to display in chemico thiol reactivity, while ten out of 24 compounds remained inactive. Chemical degradation does not necessarily occur with generation of reactive species. Non-chemical activation may be involved for the 10 stable unreactive compounds.

Concurrent supercritical fluid chromatographic analysis of terpene lactones and ginkgolic acids in Ginkgo biloba extracts and dietary supplements.

Supercritical fluid chromatography was used to resolve and determine ginkgolic acids (GAs) and terpene lactones concurrently in ginkgo plant materials and commercial dietary supplements. Analysis of GAs (C13:0, C15:0, C15:1, and C17:1) was carried out by ESI (-) mass detection. The ESI (-) spectra of GAs simply displayed only the [M-H](-) pseudo-molecular ions, and selected ion monitoring (SIM) for those ions was used for the quantification. Analysis of terpene lactones (ginkgolides A, B, C, J and bilobalide) was complicated by in-source collision-induced dissociation (IS-CID) in the ESI source. Thus, MS analysis could be influenced by the fragmentation pattern produced by the IS-CID. However, it was established that the fragmentation pattern, measured by ion survival yield (ISY), was independent of analyte concentration or matrix at a fixed cone voltage in the ESI source. Therefore, MS with SIM mode was applicable for the analysis of these analytes. The reported method provided consistent and sensitive analysis for the analytes of interest. The LOQs and LODs were determined to be below 100 and 40 ng/mL for GAs and 1 µg/mL and 400 ng/mL for terpene lactones, respectively. Intra- and inter-day precisions were found to be satisfactory with RSDs being below 5.2 %. Analyte recoveries ranged from 87 to 109 %. The developed method was successfully applied to the analysis of 11 ginkgo plant samples and 8 dietary supplements with an analysis time of less than 12 min.

Quality evaluation of terpinen-4-ol-type Australian tea tree oils and commercial products: an integrated approach using conventional and chiral GC/MS combined with chemometrics.

GC/MS, chiral GC/MS, and chemometric techniques were used to evaluate a large set (n=104) of tea tree oils (TTO) and commercial products purported to contain TTO. Twenty terpenoids were determined in each sample and compared with the standards specified by ISO-4730-2004. Several of the oil samples that were ISO compliant when distilled did not meet the ISO standards in this study primarily due to the presence of excessive p-cymene and/or depletion of terpinenes. Forty-nine percent of the commercial products did not meet the ISO specifications. Four terpenes, viz., α-pinene, limonene, terpinen-4-ol, and α-terpineol, present in TTOs with the (+)-isomer predominant were measured by chiral GC/MS. The results clearly indicated that 28 commercial products contained excessive (+)-isomer or contained the (+)-isomer in concentrations below the norm. Of the 28 outliers, 7 met the ISO standards. There was a substantial subset of commercial products that met ISO standards but displayed unusual enantiomeric+/-ratios. A class predictive model based on the oils that met ISO standards was constructed. The outliers identified by the class predictive model coincided with the samples that displayed an abnormal chiral ratio. Thus, chiral and chemometric analyses could be used to confirm the identification of abnormal commercial products including those that met all of the ISO standards.