Evaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols

The original publication is available at http://pubs.acs.org/Unfermented C. genistoides methanol extracts of different harvestings and selected polyphenols were evaluated for phytoestrogenic activity by comparing binding to both ER subtypes, transactivation of an ERE-containing promoter reporter, proliferation of MCF-7-BUS and MDA-MB-231 breast cancer cells, and binding to SHBG. The extracts from one harvesting of C. genistoides (P104) bound to both ER subtypes. All extracts transactivated ERE-containing promoter reporters via ERβ but not via ERα. All extracts, except P122, caused proliferation of the estrogen-sensitive MCF-7-BUS cells. Proliferation of MCF-7-BUS cells was ER-dependent as ICI 182,780 reversed proliferation. Physiologically more relevant, extracts antagonized E2-induced MCF-7-BUS cell proliferation. Furthermore, all extracts, except P122, induced proliferation of the estrogen-insensitive MDA-MB-231 cells, suggesting that the extracts are able to induce ER-dependent and ER-independent cell proliferation. Binding to SHBG by extracts was also demonstrated. These results clearly show that C. genistoides methanol extracts display phytoestrogenic activity and act predominantly via ERβ. HPLC and LC-MS analysis, however, suggests that the observed phytoestrogenic activity cannot be ascribed to polyphenols known to be present in other Cyclopia species. © 2007 American Chemical Society.Publishers' versio

Maceration Before and During Fermentation: Effect on Pinotage Wine Phenolic Composition, Total Antioxidant Capacity and Objective Colour Parameters

Low-temperature maceration treatments (1, 2 and 4 days at 10 and 15°C) before fermentation and juice/skin mixing treatments (punching-down, pumping-over and rotor action every hour and every 3 hours) duringfermentation were investigated in terms of their effects on Pinotage wine phenolic composition, total antioxidant capacity (TAC) and colour over three vintages (2000 to 2002). Results for pre-fermentation maceration were notconsistent between vintages. Very few significant differences in the phenolic content, TAC and objective colour parameters were observed between the control wines and wines subjected to different pre-fermentation macerationtreatments. Pre-fermentation maceration, especially at 15°C, resulted in wines with increased vitisin A content.  Improvement of wine quality when using pre-fermentation maceration treatments at 10°C was noted previously, while no detrimental effect on the wine TAC was observed. The pumping-over treatment yielded wines with lower TAC and phenol content, as well as less favourable objective colour values, indicating that the punching-down or rotor treatment would be preferred. Although mixing at hourly intervals yielded a higher content of some phenolic compounds compared to the 3-hour interval mixing, mixing frequency did not affect the TAC of the wine. The objective colour parameters, h* and b*, were slightly lower at the higher mixing frequency in 2002 indicating a shift in the direction of a magenta hue

Climatic Region and Vine Structure: Effect on Pinotage Wine Phenolic Composition, Total Antioxidant Capacity and Colour

The phenolic composition, total antioxidant capacity (TAC) and colour of Pinotage wines of the 2001, 2002 and 2003 vintages were investigated, using spectrophotometric, high-performance liquid chromatography (HPLC), free radical scavenging and objective colour analyses. Grapes were harvested from grapevines in three climatic regions ranging from cool to warm, with bush (20- and 30-cm trunk height) and trellised (30- and 60-cm trunk heights) vine treatments, on several vineyard sites in each climatic area. Climatic region had a significant effect on the content of several phenolic compounds; the concentration of anthocyanin monoglucosides, flavonols, flavan-3-ols and tartaric acid esters of hydroxycinnamic acids generally increased as the climatic region becomes cooler, while concentrations of acylated derivatives and free hydroxycinnamic acids decreased. Wines made from bush vines contained higher concentrations of flavonols, gallic acid and flavan-3-ols than those from trellised vines, but lower concentrations of some anthocyanin monoglucosides and acylated derivatives, as well as non-coloured polymers.  These trends resulted in differences in TAC and objective colour parameters, although the different vintages did not show the same trends in all cases. More vintages should therefore be investigated to clarify these effects. Wines from the cool climatic regions and from bush vines were generally darker coloured, with higher TAC than those from the warm climatic regions and bush vines, respectively. High TAC, therefore, coincided with higher colour quality. Variations in TAC were partly explained by trends for individual phenolic compounds, although unknown compounds played a major role

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South Africa’s vital statistics are currently not suitable for monitoring progress towards injury and violence Sustainable Development Goal

Comparison of Post-Activation Potentiating Stimuli on Jump and Sprint Performance

Post-activation potentiation (PAP) is a phenomenon characterized by improved muscle performance based on the previous contractile activity of the muscle. The purpose of this study was to determine the effect of different potentiating stimuli on jump and sprint performance in 13 resistance trained, college-aged men and women. After determining back squat 1 repetition max, subjects returned for testing on separate days to complete one of four interventions (dynamic resistance, weighted plyometric, isometric, or control) in a randomized order. A standardized warmup was performed, followed by a baseline countermovement jump (CMJ) and 20m sprint. Following warm-up and baseline measurements, subjects performed one of the four experimental conditions. CMJ and 20m sprint measurements were completed again at 20-seconds, 4, 8, 12, 16, and 20-minutes. Results revealed significantly faster 0-20m sprint times (p \u3c .05) at the 4, 8, 12, 16, and 20-minute time points compared to baseline and 20-second time points. Significantly faster 0-20m sprint times (p \u3c .05) were also shown for the squat intervention compared to control at 4-minutes, the plyometric and squat intervention compared to control at 8-minutes, the isometric intervention compared to control at 12 and 16- minutes, and the isometric intervention compared to the squat at 20-minutes. These findings indicate that while all PAP stimuli utilized can be effective at improving sprint performance, specific optimal time points may exist

Attempting to Acutely Manipulate Ground Contact Time Imbalances Impairs Running Economy

Running economy (RE) is a key performance determinant. Biomechanical markers have been linked to RE, including ground contact time (GCT), cadence, and vertical oscillation (VO). Recently, we showed a strong relationship between GCT imbalances and RE. Because these markers can be tracked real-time with consumer-wearable devices, runners now have access to instant feedback concerning their mechanics. PURPOSE: Determine if attempting to correct GCT imbalances real-time alters mechanics and RE. METHODS: 7 recreational runners (38 ± 15 years, 24.7 ± 2.8 kg/m2, 5 male) completed 2, 10-minute running trials (9.65 km/hr) on separate days. For both trials, subjects ran with a heart rate (HR) monitor/watch that measured GCT, GCT imbalances, cadence, and VO. For the control (CT) trial, subjects were not permitted to receive feedback from the watch. During the feedback (FB) trial, the watch was set to display GCT imbalances, and subjects were prompted every 20-30 seconds to monitor/attempt to correct any imbalances. Both trials were preceded by a dynamic warmup and 5-minute jog. For the FB trial warmup, subjects were acclimated to the watch and allowed to experiment with manipulating their GCT imbalances. VO2 was monitored continuously throughout each 10-minute trial, and average values from 6 to 9 minutes were determined for each trial. Average values for all running biomechanical variables were calculated from 0.5 minutes to 9.5 minutes. Comparisons between trials were made with a dependent sample t-test. RESULTS: The FB trial elicited a significantly higher (p = .011) working VO2 (35.5 ± 1.6 ml/kg/min) compared to the CT trial (33.4 ± 1.8 ml/kg/min). There were no other significant differences between trials for the other measured variables. Average values for each variable by trial were as follows: RER (CT: .91 ± .04; FB: .92 ± .05), HR (CT: 159 ± 26 bpm; FB: 163 ± 24 bpm), GCT % difference (CT: 1.69 ± .67%; FB: 1.70 ± 1.70%), GCT absolute difference (CT: 9 ± 3 ms; FB: 8 ± 7 ms), GCT (CT: 272 ± 26 ms; FB: 268 ± 31 ms), Cadence (CT: 165 ± 9 steps/min; FB: 167 ± 9 steps/min); VO (CT: 9.3 ± 2.0 cm; FB: 9.2 ± 1.9 cm), VO ratio (CT: 9.5 ± 1.6 cm/m; FB: 9.5 ± 1.6 cm/m). CONCLUSIONS: Acutely attempting to correct GCT imbalances did not result in improved mechanics and actually impaired RE. Altering mechanics based on real-time feedback from consumer-wearable devices may impair performance in the short term. Given that GCT imbalances have been linked to impaired RE, future research should determine how to better correct these imbalances rather than attempting to acutely manipulate them

A Validation Study of a Noninvasive Lactate Threshold Device

International Journal of Exercise Science 12(2): 221-232, 2019. The lactate threshold is considered a key marker of endurance exercise performance and identification of this threshold is important in writing an exercise training program. Unfortunately, assessment of the lactate threshold has traditionally required venous or capillary blood samples and a specialized meter to assess blood lactate concentrations. Recently, a consumer grade, non-invasive device was developed to determine muscle oxygenation and estimate the lactate threshold. Purpose: The aim of this study was to assess the validity of a noninvasive lactate threshold device (NID) to determine lactate threshold heart rate (LTHR). Methods: Twenty-one recreational athletes (14 females, 39 ± 7 years, 29.1 ± 5.2% fat, 37.8 ± 6.0 ml·kg-1·min-1; 7 males, 42 ± 9 years, 16.8 ± 2.2% fat, 45.9 ± 6.4 ml·kg-1·min-1) completed a personalized graded exercise test on a treadmill. All participants wore the NID and blood lactate samples were taken at the end of 3-minute stages. LTHR was then calculated using two traditional methods (4 mmol/L and \u3e1 mmol/L increase) and compared against the same heart rate values calculated by the NID. Results: No significant differences (p = .87) were found in LTHR between the NID and the traditional lactate methods (NID: 167 ± 9 bpm, 4 mmol/L: 167 ± 12 bpm, \u3e1 mmol/L: 167 ± 12 bpm). Conclusions: This study provides preliminary support for the validity of the NID for estimation of LTHR

Characterisation of Pinotage Wine During Maturation on Different Oak Products

The effect of oak contact on the phenolic composition, total antioxidant capacity (TAC) and colour of Pinotage wineswas investigated during maturation. Oak maturation included traditional treatments, such as new, second-fill andthird-fill barrels, as well as alternative treatments (oak chips, staves, extract and dust) applied in old barrels over aperiod of 28 weeks. Oak maturation using traditional and alternative treatments improved the objective colour ofPinotage wine by decreasing the L* value. Losses in TAC caused by decreased concentrations of monomeric phenoliccompounds (most anthocyanins, flavan-3-ols, flavonols and hydroxycinnamic acids) during oak maturation werenegated by increased concentrations of gallic acid and the formation of new oligomeric and polymeric pigments.Wine maturation in stainless steel containers also resulted in a decrease in anthocyanin content. The decreasein phenolic acid content for wines matured in stainless steel was less pronounced, while their flavan-3-ol contentremained stable. The new-barrel treatment had the most pronounced effect on all parameters. Oak maturation canbe used for the production of Pinotage wine when the retention of TAC is a high priority