Evaluation of Lippia scaberrima Sond. and Aspalathus linearis (Burm.f.) R. Dahlgren extracts on human CYP enzymes and gold nanoparticle synthesis: implications for drug metabolism and cytotoxicity.

BACKGROUND: Metabolism is an important component of the kinetic characteristics of herbal constituents, and it often determines the internal dose and concentration of these effective constituents at the target site. The metabolic profile of plant extracts and pure compounds need to be determined for any possible herb-drug metabolic interactions that might occur. METHODS: Various concentrations of the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with fermented and unfermented Aspalathus linearis extract were used to determine the inhibitory potential on placental, microsomal and recombinant human hepatic Cytochrome P450 enzymes. Furthermore, the study investigated the synthesis and characterization of gold nanoparticles from the ethanolic extract of Lippia scaberrima as a lead sample. Confirmation and characterization of the synthesized gold nanoparticles were conducted through various methods. Additionally, the cytotoxic properties of the ethanolic extract of Lippia scaberrima were compared with the gold nanoparticles synthesized from Lippia scaberrima using gum arabic as a capping agent. RESULTS: All the samples showed varying levels of CYP inhibition. The most potent inhibition took place for CYP2C19 and CYP1B1 with 50% inhibitory concentration (IC50) values of less than 0.05 µg/L for the essential oil tested and IC50-values between 0.05 µg/L-1 µg/L for all the other combinations and extracts tested, respectively. For both CYP1A2 and CYP2D6 the IC50-values for the essential oil, the extracts and combinations were found in the range of 1 - 10 µg/L. The majority of the IC50 values found were higher than 10 µg/L and, therefore, were found to have no inhibition against the CYP enzymes tested. CONCLUSION: Therefore, the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with Aspalathus linearis do not possess any clinically significant CYP interaction potential and may be further investigated for their adjuvant potential for use in the tuberculosis treatment regimen. Furthermore, it was shown that the cytotoxic potential of the Lippia scaberrima gold nanoparticles was reduced by twofold when compared to the ethanolic extract of Lippia scaberrima.

Aspalathus linearis (Rooibos) Targets Adipocytes and Obesity-Associated Inflammation.

Excess weight and obesity are the fifth leading cause of death globally, and sustained efforts from health professionals and researchers are required to mitigate this pandemic-scale problem. Polyphenols and flavonoids found in Aspalathus linearis-a plant widely consumed as Rooibos tea-are increasingly being investigated for their positive effects on various health issues including inflammation. The aim of our study was to examine the effect of Rooibos extract on obesity and the associated low-grade chronic inflammatory state by testing antioxidant activity, cytokine secretions, macrophage polarization and the differentiation of human adipocytes through the development of adipospheroids. Rooibos extract significantly decreased ROS production and the secretion of pro-inflammatory cytokines (IFN-γ, IL-12, IL-2 and IL-17a) in human leukocytes. Additionally, Rooibos extract down-regulated LPS-induced macrophage M1 polarization, shown by a significant decrease in the expression of pro-inflammatory cytokines: TNFα, IL-8, IL-6, IL-1ß and CXCL10. In addition, Rooibos inhibited intracellular lipid accumulation and reduced adipogenesis by decreasing the expression of PPARγ, Ap2 and HSL in adipospheroids. A significant decrease in leptin expression was noted and this, more interestingly, was accompanied by a significant increase in adiponectin expression. Using a co-culture system between macrophages and adipocytes, Rooibos extract significantly decreased the expression of all studied pro-inflammatory cytokines and particularly leptin, and increased adiponectin expression. Thus, adding Rooibos tea to the daily diet is likely to prevent the development of obesity associated with chronic low-level inflammation.

Pharmacological activity of Aspalathus linearis extracts: pre-clinical research in view of prospective neuroprotection.

OBJECTIVES: Rooibos tea, a very popular everyday beverage made of Aspalathus linearis plant material and containing multiple polyphenolic compounds, reveals an expectation to positively affect various processes observed in the pathogenesis of neurodegenerative diseases as in the case of consumption of other polyphenol-abundant food products. METHODS: This review is based on available data from pre-clinical in vitro and in vivo studies and presents a broad report on the pharmacological activity of the A. linearis extracts relevant for neurodegenerative diseases. RESULTS: Flavonoids present in herbal infusions are absorbed from gastro-intestinal tract and may affect the central nervous system. The experimental investigations yield the results indicating to supporting role of A. linearis in the prevention of neurodegeneration, primarily owing to anti-oxidative and anti-inflammatory properties, anti-hyperglycaemic and anti-hyperlipidaemic effects as well as favourable impact on neurotransmission with following cognitive and behavioural after-math. DISCUSSION: The multiple pharmacological activities and safety of Aspalathus linearis extracts are commented in the manuscript. The continuous rooibos tea consumption seems to be safe (despite anecdotal liver irritation); however, there is a risk of herbal-drug interactions.

Aspalathin and Other Rooibos Flavonoids Trapped α-Dicarbonyls and Inhibited Formation of Advanced Glycation End Products In Vitro.

The excessive dietary intake of simple sugars and abnormal metabolism in certain diseases contribute to the increased production of α-dicarbonyls (α-DCs), such as methylglyoxal (MGO) and glyoxal (GO), the main precursors of the formation of advanced glycation end products (AGEs). AGEs play a vital role, for example, in the development of cardiovascular diseases and diabetes. Aspalathus linearis (Burman f.) R. Dahlgren (known as rooibos tea) exhibits a wide range of activities beneficial for cardio-metabolic health. Thus, the present study aims to investigate unfermented and fermented rooibos extracts and their constituents for the ability to trap MGO and GO. The individual compounds identified in extracts were tested for the capability to inhibit AGEs (with MGO or GO as a glycation agent). Ultra-high-performance liquid chromatography coupled with an electrospray ionization mass spectrometer (UHPLC-ESI-MS) was used to investigate α-DCs' trapping capacities. To evaluate the antiglycation activity, fluorescence measurement was used. The extract from the unfermented rooibos showed a higher ability to capture MGO/GO and inhibit AGE formation than did the extract from fermented rooibos, and this effect was attributed to a higher content of dihydrochalcones. The compounds detected in the extracts, such as aspalathin, nothofagin, vitexin, isovitexin, and eriodictyol, as well as structurally related phloretin and phloroglucinol (formed by the biotransformation of certain flavonoids), trapped MGO, and some also trapped GO. AGE formation was inhibited the most by isovitexin. However, it was the high content of aspalathin and its higher efficiency than that of metformin that determined the antiglycation and trapping properties of green rooibos. Therefore, A. linearis, in addition to other health benefits, could potentially be used as an α-DC trapping agent and AGE inhibitor.

Network Pharmacology- and Molecular Dynamics Simulation-Based Bioprospection of Aspalathus linearis for Type-2 Diabetes Care.

The medicinal herb Aspalathus linearis (rooibos) is globally recognized in type-2 diabetes mellitus (T2DM) treatment due to its known and distinctive compounds. This work utilized network pharmacology (NP) coupled with molecular dynamics simulation in gaining new insight into the anti-diabetic molecular mechanism of action of rooibos teas. It looked at the interactions between rooibos constituents with various relevant protein receptors and signaling routes associated with T2DM progression. The initial analysis revealed 197 intersecting gene targets and 13 bioactive rooibos constituents linked to T2DM. The interactions between proteins and compounds to the target matrix were generated with the Cystoscope platform and STRING database. These analyses revealed intersecting nodes active in T2DM and hypoxia-inducible factor 1 (HIF-1) as an integral receptors target. In addition, KEGG analysis identified 11 other pathways besides the hub HIF-1 signaling route which may also be targeted in T2DM progression. In final molecular docking and dynamics simulation analysis, a significant binding affinity was confirmed for key compound-protein matrices. As such, the identified rooibos moieties could serve as putative drug candidates for T2DM control and therapy. This study shows rooibos constituents' interaction with T2DM-linked signaling pathways and target receptors and proposes vitexin, esculin and isovitexin as well as apigenin and kaempferol as respective pharmacologically active rooibos compounds for the modulation of EGFR and IGF1R in the HIF-1 signaling pathway to maintain normal homeostasis and function of the pancreas and pancreatic ß-cells in diabetics.

In vitro effects of aqueous extract of fermented rooibos (Aspalathus linearis) on human sperm function.

Aspalathus linearis (rooibos) is a herbal medicinal plant originally from South Africa's fynbos and well known for its medicinal effects in treating different medical conditions. Rooibos contains significant levels of antioxidants capable of inhibiting the production of reactive oxygen species, which may improve seminal parameters. This study focussed on investigating the direct effect of fermented rooibos on human sperm functions in vitro. Semen samples collected by masturbation from unproven fertile donors (n = 25) and infertile patients (n = 25) after 3-5 days' abstinence were liquefied and centrifuged (300 × g; 10 min) in human tubular fluid medium containing 1% bovine serum albumin. Afterwards, semen samples (7.5 × 106 /ml) were incubated at 37°C for one hour with aqueous extract of fermented extract in sperm preparation medium (0, 0.10, 1.0, 10 and 100 µg/ml) and assessed. Our data showed that fermented rooibos did not affect functional sperm parameters (motility, vitality, intracellular reactive oxygen species and acrosome reaction, p > .05), in vitro except in the reduced percentage of intact mitochondrial membrane potential and DNA fragmentation (p < .05). The decrease in DNA fragmentation generates the possibility of using the extract in patients prior to assisted reproductive techniques.

[Literature research and traditional Chinese medicine properties of Aspalathus linearis].

Aspalathus linearis is a needle-shaped shrub that grows in the Cedarberg mountains in southern South Africa, with an extremely high medicinal value. In 2014, China has approved A. linearis as a new food material. Through retrieval in CNKI, Wanfang, VIP, Web of Science, PubMed and Scopus databases, the literatures were excluded, classified and summarized.On the basis of Chinese medicine theory, the traditional Chinese medicine properties were deducted. Finally, 264 relevant li-teratures were included and classified into 6 categories: review, planting, chemical composition, clinical study, pharmacological effects and safety. The traditional Chinese medicinal properties were deducted as sweet flavor and neutral property. It enters kidney, spleen, heart and liver channels. The major functions are to tonify the kidney and benefit the essence, nourish Qi and spleen, nourish Yin and prompt the production of body fluid, tranquilize mind, and relieve pain. It can be used for soreness of the waist and fatigue, sexual disinterest, limbs heaviness, thirst due to insufficiency of fluid and internal heat, irritability and insomnia, forget fulness, stomachache, joint pain, dysmenorrhea, headache. Preparation for external use can treat eczema itching. Water decoction(2-15 g) can also be used as tea directly. This paper defined the traditional Chinese medicine properties of A. linearis, so as to provide the theoretical basis for further clinical application.

Aspalathus linearis infusion affects hole-board test behaviour and amino acid concentration in the brain.

Rooibos tea, brewed using Aspalathus linearis leaves, is a popular South African herbal infusion, but its everyday intake is not fully described in terms of the neuropsychopharmacological outcomes. The cell-protective activity of A. linearis is connected with the ability of reducing glycaemia, inflammation as well as oxidative stress. It was already shown that "fermented" rooibos herbal tea (FRHT), which is rich in phenolic compounds, improves the cognitive performance of rats in the water maze and impacts dopaminergic striatal transmission. The present research was taken to extend the knowledge about the feasible behavioural and neurochemical implications of sustained oral FRHT consumption. We hypothesized that it might affect brain amino acid content and thus induce behaviour and neuroprotection. FRHTs of different leaf to water ratios (1:100, 2:100 and 4:100), analysed by chromatographic methods as regards their flavonoid characteristics, were given to rats as only liquid for 3 months. Their behaviour was evaluated in the hole-board test (HBT). Brain amino acids concentration was analysed in the striatum, hippocampus and prefrontal cortex by HPLC-ECD. The rats drinking rooibos tea presented increased motor activity defined as time spent on moving in the HBT. Their exploration measured by head-dipping and rearing was enhanced. Longer time of the testing-box central zone occupation indicated to reduction in anxiety-related behaviour. Excitatory amino acids (aspartate and glutamate) content was decreased in the striatum of animals drinking the infusions whereas taurine level was increased both in the striatum and hippocampus. In conclusion we suggest that long-term FRHT intake affects exploration and anxiety-related behaviour of the rats as well as exerts biochemical outcomes in the brain that support the neuroprotective impact of rooibos tea.

Comparison of Phenolic Content and Antioxidant Activity for Fermented and Unfermented Rooibos Samples Extracted with Water and Methanol.

Rooibos is brewed from the medicinal plant Aspalathus linearis. It has a well-established wide spectrum of bio-activity properties, which in part may be attributed to the phenolic antioxidant power. The antioxidant capacity (AOC) of rooibos is related to its total phenolic content (TPC). The relation between TPC and AOC of randomly selected 51 fermented (FR) and 47 unfermented (UFR) rooibos samples was studied after extraction using water and methanol separately. The resulted extracts were assessed using two antioxidant assays, trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP). The results were analyzed using both simple statistical methods and machine learning. The analysis showed different trends of TPC and AOC correlations of FR and UFR samples, depending on the solvent used for extraction. The results of the water extracts showed similar TPC and higher AOC of FR than UFR samples, while the methanolic extracted samples showed higher TPC and AOC of UFR than FR. As a result, the methanolic extracts showed better agreement between TPC and AOC than water extracts. Possible explanations are given for these observed results. Although, the current literature demonstrates direct correlations of the TPC and AOC of rooibos water extracts. This study showed deviation and highlighted the importance of solvent selection and analysis methodology as an important factor in determining the TPC/AOC correlation and subsequently the expectation of the actual health benefits of rooibos herbal tea. In particular, unfermented and fermented samples can be accurately identified on the basis of a combination of assays (any two of TPC, FRAP and TEAC), especially if methanol is the solvent used. Machine learning analysis of assay data provides nearly identical results with classical statistical analytical methods. This is the first report on machine learning analysis and comparison of the TPC and AOC of rooibos herbal tea extracted with methanol and water, and highlights the importance of using methanol as a solvent to evaluate its AOC.

Literature research and traditional Chinese medicine properties of Aspalathus linearis / 中国中药杂志

Aspalathus linearis is a needle-shaped shrub that grows in the Cedarberg mountains in southern South Africa, with an extremely high medicinal value. In 2014, China has approved A. linearis as a new food material. Through retrieval in CNKI, Wanfang, VIP, Web of Science, PubMed and Scopus databases, the literatures were excluded, classified and summarized.On the basis of Chinese medicine theory, the traditional Chinese medicine properties were deducted. Finally, 264 relevant li-teratures were included and classified into 6 categories: review, planting, chemical composition, clinical study, pharmacological effects and safety. The traditional Chinese medicinal properties were deducted as sweet flavor and neutral property. It enters kidney, spleen, heart and liver channels. The major functions are to tonify the kidney and benefit the essence, nourish Qi and spleen, nourish Yin and prompt the production of body fluid, tranquilize mind, and relieve pain. It can be used for soreness of the waist and fatigue, sexual disinterest, limbs heaviness, thirst due to insufficiency of fluid and internal heat, irritability and insomnia, forget fulness, stomachache, joint pain, dysmenorrhea, headache. Preparation for external use can treat eczema itching. Water decoction(2-15 g) can also be used as tea directly. This paper defined the traditional Chinese medicine properties of A. linearis, so as to provide the theoretical basis for further clinical application.

A new analytical concept based on chemistry and toxicology for herbal extracts analysis: From phenolic composition to bioactivity.

Studies regarding the bioactivity of teas are mainly based on the phenolic composition and in vitro antioxidant activity of the herbal species used in their preparation. The aim of this study was to compare the in vitro and ex vivo antioxidant activity, cytotoxic/antiproliferative activity against cancer cells, the inhibitory activity of α-amylase, α-glucosidase and angiotensin I-converting enzymes, as well as the inhibition of DNA-induced fission of the peroxyl radical, in relation to aqueous extracts of Camellia sinensis var. sinensis (CS), Ilex paraguariensis (IP), Aspalathus linearis (AL) and an optimised extract (OT) containing the three herb species. A bivariate and multivariate statistical approach was employed to associate functional activities with individual phenolic composition. The CS and OT extracts showed the highest levels of hesperidin, quercetin-3-rutinoside, (-)-epigallocatechin-3-gallate and isoquercitrin. The CS and OT extracts showed the highest antioxidant activity, greater ability to inhibit α-amylase and proliferation of HCT8 cells, and greater ability to reduce Folin-Ciocalteu reagent. The AL extract, which is the major source of quercetin-3-rutinoside, hesperidin and isoquercitrin, showed the highest ability to inhibit α-glucosidase, the inhibition of LDL oxidation and protection of human erythrocytes. The IP extract showed the highest inhibition of lipoperoxidation in brain homogenate of Wistar rats, antihypertensive activity, and A549 cell proliferation; chlorogenic acid was its major phenolic compound. In general, the in vitro functionality of each extract was dependent on its chemical composition and the OT extract presented the most varied phenolic composition, and biological activity similar to the CS sample. In conclusion, the mixture of CS, AL, and IP represents a chemical and functional-based strategy to develop functional teas.

Rooibos (Aspalathus linearis) protects against nicotineinduced vascular injury and oxidative stress in Wistar rats.

BACKGROUND: Rooibos (Aspalathus linearis) is an indigenous South African plant, traditionally used by the local population as a remedy against several ailments. More recently, rooibos was shown to exhibit potent antioxidant properties, attributed to its polyphenols. We assessed whether treatment with fermented rooibos (RF), unfermented rooibos (RUF) and melatonin (Mel), a well-documented antioxidant included for comparison, could counter the harmful vascular and pro-oxidant effects of nicotine. METHODS: Vascular function, antioxidant enzyme activity and lipid peroxidation were assessed in male adult rats treated with nicotine (5 mg/kg body weight/day) and 2% RF, 2% RUF or 4% Mel co-administration. Nitric oxide (NO) production and cell viability were measured in nicotine-exposed rat aortic endothelial cells (AECs) pre-treated with RF (0.015 mg/ml). RESULTS: Vascular studies showed that co-administration with RF or Mel exerted anti-contractile and pro-relaxation responses in aortic rings, and increased hepatic superoxide dismutase and catalase activity in nicotine-exposed animals. Co-treatment with Mel additionally decreased lipid peroxidation in nicotine-exposed rats. RUF exerted anti-contractile responses in aortic rings of nicotine-treated animals, while in nicotine-exposed AECs, RF pre-treatment increased intracellular NO levels. CONCLUSIONS: For the first time, we have shown that rooibos co-treatment exerted beneficial vascular effects in nicotine-exposed rats, and that this was associated with increased antioxidant enzyme activity.

Transcriptomics of the Rooibos (Aspalathus linearis) Species Complex.

Rooibos (Aspalathus linearis), widely known as a herbal tea, is endemic to the Cape Floristic Region of South Africa (SA). It produces a wide range of phenolic compounds that have been associated with diverse health promoting properties of the plant. The species comprises several growth forms that differ in their morphology and biochemical composition, only one of which is cultivated and used commercially. Here, we established methodologies for non-invasive transcriptome research of wild-growing South African plant species, including (1) harvesting and transport of plant material suitable for RNA sequencing; (2) inexpensive, high-throughput biochemical sample screening; (3) extraction of high-quality RNA from recalcitrant, polysaccharide- and polyphenol rich plant material; and (4) biocomputational analysis of Illumina sequencing data, together with the evaluation of programs for transcriptome assembly (Trinity, IDBA-Trans, SOAPdenovo-Trans, CLC), protein prediction, as well as functional and taxonomic transcript annotation. In the process, we established a biochemically characterized sample pool from 44 distinct rooibos ecotypes (1-5 harvests) and generated four in-depth annotated transcriptomes (each comprising on average ≈86,000 transcripts) from rooibos plants that represent distinct growth forms and differ in their biochemical profiles. These resources will serve future rooibos research and plant breeding endeavours.

A histomorphometric study on the hepatoprotective effects of a green rooibos extract in a diet-induced obese rat model.

Obesity, type two diabetes mellitus and insulin resistance are associated with increased oxidative stress and inflammation. Unfermented green rooibos is an aspalathin rich variant of traditional fermented rooibos (Aspalathus linearis) and has a high polyphenol content. The present study aimed to determine the histologically observable effects of a commercially produced, aspalathin-rich green rooibos extract, Afriplex GRT™ (GRE) in a diet-induced obese rat model. Male Wistar rats (N = 28) were randomly assigned to four study groups (n = 7): control (C), green rooibos (GRT), high-fat diet (HFD) and experimental (HFD-GRT) group. Body mass was determined prior to euthanasia and liver mass was determined after death. The left lateral lobe of the liver was processed to wax and stained using haematoxylin and eosin (H & E), Masson's trichrome stain, Gordons and Sweet's reticulin impregnation and periodic acid-Schiff stain. Frozen liver tissue sections were used for Oil red O staining. Morphometric quantification of steatosis, semiquantitative pathology grading and scoring were performed and verified by a veterinary histopathologist. A significant increase in body and liver mass was observed in the HFD groups while co-treatment with green rooibos significantly reduced both. The volume and area of steatosis were significantly increased in the HFD groups while the area of steatosis significantly reduced with green rooibos co-treatment. The percentage, location and type of steatosis as well as presence of inflammation and hepatocellular injury were reduced in the HFD group co-treated with GRE. These findings suggest that a GRE has potential as an anti-steatotic, anti-inflammatory and weight reducing agent in vivo.

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.

Long-term administration of Aspalathus linearis infusion affects spatial memory of adult Sprague-Dawley male rats as well as increases their striatal dopamine content.

ETHNOPHARMACOLOGICAL RELEVANCE: Everyday use of the herbal tea rooibos, produced from Aspalathus linearis (Brum.f) Dahlg. (Fabaceae) is customary in South Africa, a continuation of its historical use by indigenous people. Although evidence of its traditional indications is anecdotal, rooibos tea is regarded as a general health tea. AIMS OF THE STUDY: Available contemporary research indicates to broad cell protective activity of rooibos focusing on its antioxidative, anti-inflammatory, anti-hyperglycaemic and antithrombotic features affecting metabolic syndrome, cardiovascular risk and neuroprotection. Nevertheless little is known about its impact on brain functions. The present experiment aimed to evaluate the possible behavioural and neurochemical effects of long-term oral administration of "fermented"" rooibos herbal tea (FRHT) infusions to adult male Sprague-Dawley rats. MATERIALS AND METHODS: Infusions, prepared using 1, 2 and 4 g of "fermented"" (oxidised) A. linearis leaves for 100 ml of hot water, were characterised in terms of flavonoid content by ultra-high and high performance liquid chromatography (UHPLC-qTOF-MS, HPLC-DAD) and administered to rats as sole drinking fluid for 12 weeks. Spatial memory behaviour was assessed in a modified version of the Morris water maze. Dopamine, noradrenaline, serotonin and their metabolite levels (DOPAC, 3-MT, HVA, MHPG, 5-HIAA) were quantified in prefrontal cortex, hippocampus and striatum by HPLC-ECD. Body weight and blood glucose level were additionally estimated. RESULTS: All FRHT-treated rats showed improvement of long-term spatial memory defined as increased number of crossings over the previous platform position in SE quadrant of the water maze. It was not accompanied by excessive motor activity. Striatal dopamine and its metabolite 3-MT (3-methoxytyramine) levels were increased in treated rats. There were no differences in body weight gain between control and treated animals but blood glucose level was significantly lower in the latter ones. CONCLUSION: The improvement of long-term memory in FRHT-treated rats and stimulating impact of FRHT on their dopaminergic striatal transmission support the wellness enhancing effect of rooibos tea, contributing to a better understanding of the neurological background of traditional habitual consumption of this herbal tea.

The cardiovascular effects of Aspalathus linearis supplementation in male Wistar rats receiving fixed-dose combination first-line antiretroviral therapy.

HIV-infected populations receiving antiretroviral therapy (ART) have an increased risk of cardiovascular disease. The beneficial cardiovascular effects of rooibos are well described; however, it is unknown whether rooibos ameliorates harmful ART-induced cardiovascular side effects. We investigated the cardiometabolic effects of rooibos co-treatment in rats receiving ART (efavirenz, emtricitabine, tenofovir) for nine weeks. Rooibos treatment reduced total cholesterol levels; however, triglyceride, phospholipid and thiobarbituric acidreactive substance levels were unaffected by ART, rooibos or combination treatment. In isolated hearts exposed to ischaemia-reperfusion injury, ART resulted in increased infarct sizes compared to controls, which was not observed when co-treated with rooibos. Vascular studies showed reduced aortic relaxation with ART, and improved relaxation when co-treated with rooibos. In conclusion, we show that rooibos treatment reduced total cholesterol levels in control rats, and that rooibos co-treatment ameliorated the harmful ART-induced cardiovascular effects. These findings are novel and warrant further studies into underlying mechanisms and clinical relevance.

Visualization of Aspalathin in Rooibos (Aspalathus linearis) Plant and Herbal Tea Extracts Using Thin-Layer Chromatography.

Aspalathin, the main polyphenol of rooibos (Aspalathus linearis), is associated with diverse health promoting properties of the tea. During fermentation, aspalathin is oxidized and concentrations are significantly reduced. Standardized methods for quality control of rooibos products do not investigate aspalathin, since current techniques of aspalathin detection require expensive equipment and expertise. Here, we describe a simple and fast thin-layer chromatography (TLC) method that can reproducibly visualize aspalathin in rooibos herbal tea and plant extracts at a limit of detection (LOD) equal to 178.7 ng and a limit of quantification (LOQ) equal to 541.6 ng. Aspalathin is a rare compound, so far only found in A. linearis and its (rare) sister species A. pendula. Therefore, aspalathin could serve as a marker compound for authentication and quality control of rooibos products, and the described TLC method represents a cost-effective approach for high-throughput screening of plant and herbal tea extracts.

Analysis of Phenolic Compounds in Rooibos Tea (Aspalathus linearis) with a Comparison of Flavonoid-Based Compounds in Natural Populations of Plants from Different Regions.

Tea samples from 17 populations of "wild tea" ecotypes Aspalathus linearis (rooibos tea) and 2 populations of Aspalathus pendula were analyzed. Recent advances in column technology together with high-resolution mass spectrometry were applied to improve resolution, facilitating the identification of several new compounds as well as grouping of the wild tea ecotypes according to their chemical composition. The collisional cross-section data obtained from ion mobility-mass spectrometry is reported for the flavonoids in rooibos for the first time. Enzyme pathways for the synthesis of the unique flavonoids found in rooibos tea are also proposed. A. linearis and A. pendula produce similar combinations of main phenolic compounds, with no diagnostically different discontinuities between populations or species. Northern resprouters (Gifberg and Nieuwoudtville) contain higher phenylpropenoic acid glucoside levels while teas from Wupperthal and surrounding areas were found to contain unique dihydrochalcones (phloridzin and a sieboldin analog), which are reported here for the first time.

Minimising variation in aspalathin content of aqueous green rooibos extract: optimising extraction and identifying critical material attributes.

BACKGROUND: High levels of aspalathin, an antidiabetic dihydrochalcone, in green rooibos underpins interest in the production of a standardised extract. Elements of a quality-by-design approach were applied to optimise extraction conditions, aiming at the delivery of a dry matter yield (DMY) ≥ 160 g kg-1 and an extract with an aspalathin content (AC) ≥ 80 g kg-1 . RESULTS: Hot water extraction parameters, namely extraction time, extraction temperature and water-to-plant material ratio, were optimised for DMY and aspalathin extraction efficiency (AEE) using Design of Experiments. Good polynomial prediction models were obtained and multiresponse desirability plots indicated 37 min, 93 °C and 23:1 as optimal conditions. Even when using 30 min and 10:1 instead for practical reasons, the target DMY and AC values could be achieved with the caveat that plant material with an AC ≥ 30 g kg-1 is used. Particle size distribution and stem content were identified as contributing to variation in the AC of raw material. CONCLUSION: By setting raw material specifications in terms of AC, as well as applying practical optimum extraction conditions, 160 g kg-1 extract with an AC ≥ 80 g kg-1 could be consistently achieved from green rooibos plant material. © 2017 Society of Chemical Industry.