Heat treatment improves the sensory properties of the ultrafiltration by-product of honeybush (Cyclopia genistoides) extract.

BACKGROUND: Ultrafiltration of green honeybush (Cyclopia genistoides) extract results in a by-product (retentate). Application of further separation processes for recovery of polyphenols would entail creation of additional waste. Repurposing the retentate as a food flavour ingredient provides an alternative valorization approach. RESULTS: The retentate, suspended in water (270 g L-1 ), was heat-treated at 80 °C for 2, 4, 8 and 16 h, and at 90 °C for 2, 4, 6 and 8 h to change its sensory profile. The heat-treated retentate, diluted to beverage strength (2.15 g L-1 ), had prominent 'grape/Muscat-like' and 'marmalade/citrus' aroma and flavour notes. Overall, heating for ≤ 4 h increased the intensities of positive flavour and aroma notes, while reducing those of 'green/grass', 'hay' and bitterness, whereafter further heating only had a slight effect on the aroma profile at 80 °C (P < 0.05), but not at 90 °C (P ≥ 0.05). The heat treatments, 80 °C/4 h and 90 °C/4 h, were subsequently applied to different batches of retentate (n = 10) to accommodate the effect of natural product variation. Heating at 90 °C produced higher intensities of positive aroma attributes (P < 0.05), but was more detrimental to the phenolic stability, compared to 80 °C. CONCLUSION: After heat treatment, the phenolic content of C. genistoides retentate, reconstituted to beverage strength, still fell within the range of a typical 'fermented' (oxidized) honeybush leaf tea infusion. The change in phenolic composition will not diminish the benefit of an improved sensory profile for the retentate by-product through heating. © 2021 Society of Chemical Industry.

Mangiferin and Hesperidin Transdermal Distribution and Permeability through the Skin from Solutions and Honeybush Extracts (Cyclopia sp.)-A Comparison Ex Vivo Study.

Polyphenolic compounds-mangiferin and hesperidin-are, among others, the most important secondary metabolites of African shrub Cyclopia sp. (honeybush). The aim of this study was to compare the percutaneous absorption of mangiferin and hesperidin from solutions (water, ethanol 50%, (v/v)) and extracts obtained from green and fermented honeybush (water, ethanol 50%, (v/v)). Research was performed with the Bronaugh cells, on human dorsal skin. The mangiferin and hesperidin distributions in skin layers (stratum corneum, epidermis, and dermis) and in acceptor fluid (in every 2, 4, 6, and 24 h) were evaluated by HPLC-Photodiode Array Coulometric and Coulometric Electrochemical Array Detection. The transdermal distribution of hesperidin was also demonstrated by fluorescence microscopy. Results indicated that mangiferin and hesperidin were able to cross the stratum corneum and penetrate into the epidermis and dermis. An advantage of hesperidin penetration into the skin from the water over ethanol solution was observed (451.02 ± 14.50 vs. 357.39 ± 4.51 ng/cm2), as well as in the mangiferin study (127.56 ± 9.49 vs. 97.23 ± 2.92 ng/cm2). Furthermore, mangiferin penetration was more evident from nonfermented honeybush ethanol extract (189.85 ± 4.11 ng/cm2) than from solutions. The permeation of mangiferin and hesperidin through the skin to the acceptor fluid was observed regardless of whether the solution or the honeybush extract was applied. The highest ability to permeate the skin was demonstrated for the water solution of hesperidin (250.92 ± 16.01 ng/cm2), while the hesperidin occurring in the extracts permeated in a very low capacity. Mangiferin from nonfermented honeybush ethanol extract had the highest ability to permeate to the acceptor fluid within 24 h (152.36 ± 8.57 ng/cm2).

Adipose tissue as a possible therapeutic target for polyphenols: A case for Cyclopia extracts as anti-obesity nutraceuticals.

Obesity is a significant contributor to increased morbidity and premature mortality due to increasing the risk of many chronic metabolic diseases such as type 2 diabetes, cardiovascular disease and certain types of cancer. Lifestyle modifications such as energy restriction and increased physical activity are highly effective first-line treatment strategies used in the management of obesity. However, adherence to these behavioral changes is poor, with an increased reliance on synthetic drugs, which unfortunately are plagued by adverse effects. The identification of new and safer anti-obesity agents is thus of significant interest. In recent years, plants and their phenolic constituents have attracted increased attention due to their health-promoting properties. Amongst these, Cyclopia, an endemic South African plant commonly consumed as a herbal tea (honeybush), has been shown to possess modulating properties against oxidative stress, hyperglycemia, and obesity. Likewise, several studies have reported that some of the major phenolic compounds present in Cyclopia spp. exhibit anti-obesity effects, particularly by targeting adipose tissue. These phenolic compounds belong to the xanthone, flavonoid and benzophenone classes. The aim of this review is to assess the potential of Cyclopia extracts as an anti-obesity nutraceutical as underpinned by in vitro and in vivo studies and the underlying cellular mechanisms and biological pathways regulated by their phenolic compounds.

Impact of steam treatment on shelf-life stability of a xanthone-rich green herbal tea (Cyclopia maculata Andrews Kies) - identifying quality changes during storage.

BACKGROUND: Steam treatment of shredded, fresh C. maculata (honeybush) plant material improves the aroma of this green herbal tea with a slight impact on color and phenolic content, but the effect on storage stability is not known. RESULTS: Steam-treated (60 s before drying) and untreated (control) dried plant material was stored under normal storage conditions in semi-permeable sachets at 25 °C and 60% relative humidity. Reference samples of treated (steamed) and untreated (control) material were stored at 0 °C in impermeable pouches for maximum retention of quality. The stability of the herbal tea was assessed in terms of sensory profile, phenolic composition and color over a storage period of 6 months. Normal storage conditions resulted in a significant (P < 0.05) decrease in green color, especially in steamed samples. Intensities of fruity and sweet-associated aroma attributes increased progressively during storage, while the opposite was observed for vegetal and cereal-like attributes. These changes in the aroma profile were more pronounced in untreated (control) samples. Individual phenolic content remained stable during storage. CONCLUSIONS: Storage of 3 to 6 months may result in a more appealing aroma profile and enhanced product quality, despite loss of green color. © 2018 Society of Chemical Industry.

Evaluation of Cycloferin Supplement on Health Parameters in Experimentally Induced Diabetic Rats with and Without Exogenous Insulin.

Cycloferin is an extract of the chemicals from the Cyclopia species, which grows only in small areas in the southwest and southeast of South Africa and has been consumed traditionally as a nourishing tea to treat numerous health issues and illnesses. Previous studies report that some of the active compounds in Cycloferin, such as pinitol (a modified sugar) and mangiferin (a glucoside), may reduce blood sugar levels and therefore may be used as a treatment for diabetes. Mangiferin, in particular, has been shown to stimulate carbohydrate oxidation and alleviate some effects of insulin resistance and hyperglycemia. Other active components of Cycloferin include flavones, isoflavones, coumestans, luteolin, 4-hydroxycinnamic acid, polyphenols, and xanthones. These active compounds are antioxidants, which can enhance glucose breakdown, lower blood lipids, and reduce the number of highly reactive compounds known as free radicals, which can alter cellular structure and function when present in large amounts. In this study, we explored the ameliorative effects of Cycloferin by treating streptozotocin- (STZ) injected rats with Cycloferin and evaluating its long-term and short-term effect on blood glucose levels and kidney and liver conditions of the diabetic-rendered rats. Our results demonstrated the ability of Cycloferin to both lower the blood glucose levels and reduce evidence of damage in kidney and liver in diabetic rats with and without exogenous insulin treatment for partial control of diabetic state.

The Potential of South African Herbal Tisanes, Rooibos and Honeybush in the Management of Type 2 Diabetes Mellitus.

Diabetes mellitus is a metabolic disease that can lead to high morbidity, mortality and long-term complications. Available treatment strategies, which are mainly based on treating hyperglycemia, with insulin and other pharmacological agents are not completely efficient and can even lead to development of unwanted side effects. Scientific evidence suggests that bioactive compounds from teas and other plant-based foods, which are known source of natural antioxidants, could be an attractive strategy to preferentially treat and manage type 2 diabetes mellitus (T2DM) and thus, have significant therapeutic implications. In this review, we attempt an in-depth analysis and discussion of the current progress in our understanding of the antidiabetic potential of two commercialized South Africa herbal tisanes-Rooibos and Honeybush and their polyphenols.

Phenolic and physicochemical stability of a functional beverage powder mixture during storage: effect of the microencapsulant inulin and food ingredients.

BACKGROUND: The need for a convenience herbal iced tea product with reduced kilojoules merited investigation of the shelf-life of powder mixtures containing a green Cyclopia subternata Vogel (honeybush) extract with proven blood glucose-lowering activity and alternative sweetener mixture. RESULTS: Prior to long-term storage testing, the wettability of powder mixtures containing food ingredients and the compatibility of their components were confirmed using the static sessile drop method and isothermal microcalorimetry, respectively. The powders packed in semi-sealed containers remained stable during storage at 25 °C/60% relative humidity (RH) for 6 months, except for small losses of specific phenolic compounds, namely mangiferin, isomangiferin, 3-ß-d-glucopyranosyliriflophenone, vicenin-2 and 3',5'-di-ß-d-glucopyranosylphloretin, especially when both citric acid and ascorbic acid were present. These acids drastically increased the degradation of phenolic compounds under accelerated storage conditions (40 °C/75% RH). Accelerated storage also caused changes in the appearance of powders and the colour of the reconstituted beverage solutions. Increased moisture content and aw of the powders, as well as moisture released due to dehydration of citric acid monohydrate, contributed to these changes. CONCLUSION: A low-kilojoule honeybush iced tea powder mixture will retain its functional phenolic compounds and physicochemical properties during shelf-life storage at 25 °C for 6 months. © 2017 Society of Chemical Industry.

Polyphenol-Enriched Fractions of Cyclopia intermedia Selectively Affect Lipogenesis and Lipolysis in 3T3-L1 Adipocytes.

Cyclopia species are increasingly investigated as sources of phenolic compounds with potential as therapeutic agents. Recently, we demonstrated that a crude polyphenol-enriched organic fraction (CPEF) of Cyclopia intermedia, currently forming the bulk of commercial production, decreased lipid content in 3T3-L1 adipocytes and inhibited body weight gain in obese db/db mice. The aim of the present study was to determine whether a more effective product and/or one with higher specificity could be obtained by fractionation of the CPEF by purposely increasing xanthone and benzophenone levels. Fractionation of the CPEF using high performance counter-current chromatography (HPCCC) resulted in four fractions (F1-F4), predominantly containing iriflophenone-3-C-ß-D-glucoside-4-O-ß-D-glucoside (benzophenone: F1), hesperidin (flavanone: F2), mangiferin (xanthone: F3), and neoponcirin (flavone: F4), as quantified by high-performance liquid chromatography with diode array detection (HPLC-DAD), and confirmed by LC-DAD with mass spectrometric (MS) and tandem MS (MSE) detection. All fractions inhibited lipid accumulation in 3T3-L1 pre-adipocytes and decreased lipid content in mature 3T3-L1 adipocytes, although their effects were concentration-dependent. F1-F3 stimulated lipolysis in mature adipocytes. Treatment of mature adipocytes with F1 and F2 increased the messenger RNA expression of hormone sensitive lipase, while treatment with F1 and F4 increased uncoupling protein 3 expression. In conclusion, HPCCC resulted in fractions with different phenolic compounds and varying anti-obesity effects. The activities of fractions were lower than the CPEF; thus, fractionation did not enhance activity within a single fraction worthwhile for exploitation as a nutraceutical product, which illustrates the importance of considering synergistic effects in plant extracts.

Anti-Inflammatory Effects of Aspalathus linearis and Cyclopia spp. Extracts in a UVB/Keratinocyte (HaCaT) Model Utilising Interleukin-1α Accumulation as Biomarker.

Ultraviolet B (UVB) radiation is one of the major predisposing risk factors of skin cancer. The anticancer and photoprotective effects of unoxidized rooibos (Aspalathus linearis) and honeybush (Cyclopia) herbal teas, containing high levels of dihydrochalones and xanthones, respectively, have been demonstrated in skin cancer models in vivo. In the current study, the anti-inflammatory effects of methanol and aqueous extracts of these herbal teas were investigated in a UVB/HaCaT keratinocyte model with intracellular interleukin-1α (icIL-1α) accumulation as a biomarker. Extracts of green tea (Camellia sinensis) served as benchmark. Both extracts of green tea and rooibos, as well as the aqueous extract of C. intermedia, enhanced UVB-induced inhibition of cell viability, proliferation and induction of apoptosis, facilitating the removal of icIL-1α. The underlying mechanisms may involve mitochondrial dysfunction exhibiting pro-oxidant responses via polyphenol-iron interactions. The methanol extracts of honeybush, however, protected against UVB-induced reduction of cell growth parameters, presumably via antioxidant mechanisms that prevented the removal of highly inflamed icIL-1α-containing keratinocytes via apoptosis. The dual antioxidant and/or pro-oxidant role of the polyphenolic herbal tea constituents should be considered in developing preventive strategies against UVB-induced skin carcinogenesis. The indirect removal of UVB damaged keratinocytes by herbal tea extracts via apoptosis may find application in the prevention of photo-induced inflammation.

The potential role of polyphenols in the modulation of skin cell viability by Aspalathus linearis and Cyclopia spp. herbal tea extracts in vitro.

OBJECTIVES: The relationship between polyphenol constituents, antioxidant properties of aqueous and methanol extracts of green tea (Camellia sinensis), the herbal teas, rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.), against skin cell viability was investigated in vitro. METHODS: The effect of extracts, characterised in terms of polyphenol content and antioxidant properties, on cell viability of premalignant, normal and malignant skin cells was determined. KEY FINDINGS: Phenolic composition, particularly high levels of potent antioxidants, of rooibos and green tea methanol extracts was associated with a strong reduction in cell viability specifically targeting premalignant cells. In contrast, the aqueous extracts of Cyclopia spp. were more effective in reducing cell viability. This correlated with a relatively high flavanol/proanthocyanidin content and ABTS radical cation scavenging capacity. The major green tea flavanol (epigallocatechin gallate) and rooibos dihydrochalcone (aspalathin) exhibited differential effects against cell viability, while the major honeybush xanthone (mangiferin) and flavanone (hesperidin) lacked any effect presumably due to a cytoprotective effect. The underlying mechanisms against skin cell viability are likely to involve mitochondrial dysfunction resulting from polyphenol-iron interactions. CONCLUSIONS: The polyphenol constituents and antioxidant parameters of herbal tea extracts are useful tools to predict their activity against skin cell survival in vitro and potential chemopreventive effects in vivo.

The phytoestrogenic Cyclopia extract, SM6Met, increases median tumor free survival and reduces tumor mass and volume in chemically induced rat mammary gland carcinogenesis.

SM6Met, a phytoestrogenic extract of Cyclopia subternata indigenous to the Western Cape province of South Africa, displays estrogenic attributes with potential for breast cancer chemoprevention. In this study, we report that SM6Met, in the presence of estradiol, induces a significant cell cycle G0/G1 phase arrest similar to the selective estrogen receptor modulator, tamoxifen. Furthermore, as a proof of concept, in the N-Methyl-N-nitrosourea induced rat mammary gland carcinogenesis model, SM6Met increases tumor latency by 7days and median tumor free survival by 42 days, while decreasing palpable tumor frequency by 32%, tumor mass by 40%, and tumor volume by 53%. Therefore, the current study provides proof of concept that SM6Met has definite potential as a chemopreventative agent against the development and progression of breast cancer.

Antiseptic effect of vicenin-2 and scolymoside from Cyclopia subternata (honeybush) in response to HMGB1 as a late sepsis mediator in vitro and in vivo.

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, which are 2 active compounds from C. subternata that act against high mobility group box 1 (HMGB1)-mediated septic responses in human umbilical vein endothelial cells (HUVECs) and mice. The antiseptic activities of vicenin-2 and scolymoside were determined by measuring permeability, neutrophil adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice. According to the results, vicenin-2 and scolymoside effectively inhibited lipopolysaccharide-induced release of HMGB1, and suppressed HMGB1-mediated septic responses such as hyperpermeability, the adhesion and migration of leukocytes, and the expression of cell adhesion molecules. In addition, vicenin-2 and scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6, and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by HMGB1. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agents for the treatment of various severe vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Ameliorative Effect of Vicenin-2 and Scolymoside on TGFBIp-Induced Septic Responses.

Transforming growth factor ß-induced protein (TGFBIp) is an extracellular matrix protein whose expression in several cell types is greatly increased by TGF-ß. TGFBIp is released by the human umbilical vein endothelial cells (HUVECs) and functions as a mediator of experimental sepsis. Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain in biological processes. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, two active compounds in C. subternata against TGFBIp-mediated septic responses in HUVECs and mice. The anti-inflammatory activities of vicenin-2 or scolymoside were determined by measuring permeability, human neutrophils adhesion and migration, and activation of pro-inflammatory proteins in TGFBIp-activated HUVECs and mice. According to the results, vicenin-2 or scolymoside effectively inhibited lipopolysaccharide-induced release of TGFBIp and suppressed TGFBIp-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, vicenin-2 or scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6 and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by TGFBIp. Vicenin-2 or scolymoside reduced cecal ligation and puncture (CLP)-induced septic mortality and pulmonary injury. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agent for treatment of various severe vascular inflammatory diseases via inhibition of the TGFBIp signaling pathway.

Mangiferin has an additive effect on the apoptotic properties of hesperidin in Cyclopia sp. tea extracts.

A variety of biological pro-health activities have been reported for mangiferin and hesperidin, two major phenolic compounds of Honeybush (Cyclopia sp.) tea extracts. Given their increasing popularity, there is a need for understanding the mechanisms underlying the biological effects of these compounds. In this study, we used real-time cytotoxicity cellular analysis of the Cyclopia sp. extracts on HeLa cells and found that the higher hesperidin content in non-fermented "green" extracts correlated with their higher cytotoxicity compared to the fermented extracts. We also found that mangiferin had a modulatory effect on the apoptotic effects of hesperidin. Quantitative PCR analysis of hesperidin-induced changes in apoptotic gene expression profile indicated that two death receptor pathway members, TRADD and TRAMP, were up regulated. The results of this study suggest that hesperidin mediates apoptosis in HeLa cells through extrinsic pathway for programmed cell death.

Cyclopia maculata (honeybush tea) stimulates lipolysis in 3T3-L1 adipocytes.

We have previously, for the first time, demonstrated that hot water extracts of Cyclopia maculata and Cyclopia subternata, endemic South African plants that are consumed as herbal teas, inhibit adipogenesis in 3T3-L1 adipocytes. The aim of this study was to extend the anti-obesity investigations of these plants by quantifying lipolysis in mature 3T3-L1 adipocytes. Glycerol concentration in culture supernatants was used as a marker of adipocyte lipolysis. Isoproterenol, a ß-adrenergic agonist and a known lipolytic agent, was used as a positive control in our assays. Lipolysis was stimulated by all extracts, although statistical significance was noted for fermented (oxidised) C. maculata only. A concentration of 80µg/ml of C. maculata extract induced maximal lipolysis (1.8-fold, p<0.001). The increased lipolysis was accompanied by an increase in the expression of hormone sensitive lipase (1.6-fold, p<0.05) and perilipin (1.6-fold, p<0.05). The plant extracts, at the concentration range assayed (0-100µg/ml), were not cytotoxic in terms of mitochondrial dehydrogenase and adenosine-5'-triphosphate activity. These results showed that C. maculata stimulates lipolysis in mature 3T3-L1 adipocytes, providing further support for the anti-obesity effects of Cyclopia spp.

Phytoestrogenic potential of Cyclopia extracts and polyphenols.

Cyclopia Vent. species, commonly known as honeybush, are endemic to Southern Africa. The plant is traditionally used as an herbal tea but several health benefits have recently been recorded. This minireview presents an overview of polyphenols found in Cyclopia and focuses on the phytoestrogenic potential of selected polyphenols and of extracts prepared from the plant.

Comparative study of chromatographic medium-associated mass and potential antitumor activity loss with bioactive extracts.

Natural product drug discovery programs often rely on the use of silica (Si) gel, reversed-phase media, or size-exclusion resins (e.g., RP-C18, Sephadex LH-20) for compound purification. The synthetic polymer-based sorbent Diaion HP20SS (cross-linked polystyrene matrix) is used as an alternative to prepare purified natural product libraries. To evaluate the impact of chromatographic media on the isolation of biologically active, yet chromatographically unstable natural products, Diaion HP20SS was evaluated side-by-side with normal-phase sorbents for irreversible binding of extract constituents and their effects on bioactivity. An array of chemically diverse natural product-rich extracts was selected as a test panel, and a cell-based reporter assay for hypoxia-inducible factor-1 (HIF-1) was employed to monitor potential change(s) in bioactivity. Silica gel caused significant irreversible binding of three out of 10 extracts. Curcuma longa, Saururus cernuus, and Citrus reticulata extracts showed decreased HIF-1 inhibitory activity after elution through Si gel. An additional nonpolar column wash of HP20SS with EtOAc retained considerable bioactivities of active extracts. In general, Si gel produced the greatest loss of bioactivity. However, HP20SS elution reduced significantly HIF-1 inhibitory activity of certain extracts (e.g., Asimina triloba).

Cyclopia maculata and Cyclopia subternata (honeybush tea) inhibits adipogenesis in 3T3-L1 pre-adipocytes.

The stems, leaves and flowers of Cyclopia have been consumed as a herbal tea 'honeybush tea' to treat various medical ailments since the 19th century. Plant polyphenols are reported to inhibit adipogenesis in cell and animal models of obesity. The aim of this study was to assess the effect of hot water extracts of two Cyclopia species, C. maculata and C. subternata on obesity in an in vitro model. The total polyphenol content of unfermented C. subternata, unfermented C. maculata and fermented C. maculata extracts was 25.6, 22.4 and 10.8g GAE/100g, respectively. The major compounds present in the extracts were: the flavonoid, phloretin-3',5'-di-C-glucoside in C. subternata, the xanthone, mangiferin in unfermented C. maculata and the flavanone, hesperidin in fermented C. maculata. All of the plant extracts inhibited intracellular triglyceride and fat accumulation, and decreased PPARγ2 expression. The higher concentrations of unfermented C. maculata (800 and 1600µg/ml) and C. subternata (1600µg/ml) were cytotoxic in terms of decreased mitochondrial dehydrogenase activity. Both fermented and unfermented C. maculata, at concentrations greater than 100µg/ml, decreased cellular ATP content. Cyclopia maculata and C. subternata inhibit adipogenesis in vitro, suggesting their potential as anti-obesity agents.

Food ingredient extracts of Cyclopia subternata (Honeybush): variation in phenolic composition and antioxidant capacity.

Cyclopia subternata plants are traditionally used for the production of the South African herbal tea, honeybush, and recently as aqueous extracts for the food industry. A C. subternata aqueous extract and mangiferin (a major constituent) are known to have anti-diabetic properties. Variation in phenolic composition and antioxidant capacity is expected due to cultivation largely from seedlings, having implications for extract standardization and quality control. Aqueous extracts from 64 seedlings of the same age, cultivated under the same environmental conditions, were analyzed for individual compound content, total polyphenol (TP) content and total antioxidant capacity (TAC) in a number of assays. An HPLC method was developed and validated to allow quantification of xanthones (mangiferin, isomangiferin), flavanones (hesperidin, eriocitrin), a flavone (scolymoside), a benzophenone (iriflophenone-3-C-ß-glucoside) and dihydrochalcones (phloretin-3',5'-di-C-ß-glucoside, 3-hydroxyphloretin-3',5'-di-C-hexoside). Additional compounds were tentatively identified using mass spectrometric detection, with the presence of the 3-hydroxyphloretin-glycoside, an iriflophenone-di-O,C-hexoside, an eriodictyol-di-C-hexoside and vicenin-2 being demonstrated for the first time. Variability of the individual phenolic compound contents was generally higher than that of the TP content and TAC values. Among the phenolic compounds, scolymoside, hesperidin and iriflophenone-3-C-ß-glucoside contents were the most variable. A combination of the measured parameters could be useful in product standardization by providing a basis for specifying minimum levels.

Modulating effects of rooibos and honeybush herbal teas on the development of esophageal papillomas in rats.

Widespread consumption of herbal teas has stimulated interest in their role as cancer preventive agents. The present investigation monitored the modulation of methylbenzylnitrosamine (MBN)-induced esophageal squamous cell carcinogenesis by rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia) herbal and Camellia sinensis teas in male F344 rats. The tumor multiplicity was significantly (P < 0.05) inhibited by unfermented honeybush (45.5%), green (50%), and black (36%) teas, while the other teas exhibited weaker effects (<30% inhibition). The mean total papilloma size was reduced by unfermented rooibos (87%), unfermented honeybush (94%), and fermented honeybush (74%) due to the absence of large papillomas (>10 mm(3)). Reduction of the mean total papilloma number correlated with the total polyphenol (TPP) (r = 0.79; P < 0.02) and flavanol/proanthocyanidin (FLAVA) (r = 0.89; P < 0.008) intake (mg/100 g body weight) of the teas and the FLAVA (r = 0.89; P < 0.04) and flavonol/flavones/xanthones (r = 0.99; P < 0.002) intake when considering only the herbal teas. A daily TPP intake threshold of 7 mg/100 g body weight existed below where no inhibition of papilloma development was observed. Fermentation of herbal teas reduced the inhibitory effects on papilloma development associated with a reduction in the polyphenolic constituents. The inhibitory effect of herbal teas on papilloma development is associated with different flavonoid subgroups and/or combination thereof.