A Comparison of Cardiovascular and Catecholamine Responses to 3 Stimuli in Mild Hypertension

In five males with mild essential hypertension, simultaneous hemodynamic and arterial and venous plasma catecholamine responses to three stimulation tests (mental arithmetic, isometric handgrip exercise, and cold) were studied. Plasma norepinephrine (NE), epinephrine (EPI), and dopamine (DA) were measured radioenzymatically. Isometric exercise was the best stimulus for systolic and diastolic blood pressure and NE. Mental arithmetic produced the highest levels of plasma EPI, but there was great intersubject variability. Dopamine levels did not increase with any of these stimuli. Consistent arterio-venous differences across the forearm were seen for EPI but not NE consistent with local production of NE. Isometric exercise produced the closest correlations between peripheral plasma catecholamine levels, blood pressure, and heart rate. Good correlations were seen with mental arithmetic, but with the stimulus of cold correlation was poor

The green tea polyphenol (-)-epigallocatechin-3-gallate inhibits amyloid-beta evoked fibril formation and neuronal cell death in vitro

Alzheimer’s disease is associated with amyloid-β plaques eliciting neuronal oxidative stress. Many naturally occurring compounds have antioxidant properties, but it is unclear if this alone protects against amyloid-β exposure. This study investigated the protective effects of selected bioactive compounds against amyloid-β and pro-oxidant-evoked neurotoxicity in PC12 cells. Neither resveratrol, (−)-epigallocatechin-3-gallate, cyanidin rutinoside or grape skin extract protected PC12 cells against H2O2 or tert butyl hydroperoxide toxicity. Amyloid-β resulted in a concentration-dependent reduction in PC12 cell viability that was unaffected by resveratrol or cyanidin rutinoside pre-treatment. By contrast, (−)-epigallocatechin-3-gallate and grape skin extract significantly reduced amyloid-β-evoked neurotoxicity (by 40%). Only (−)-epigallocatechin-3-gallate was directly able to inhibit amyloid-β aggregate and fibril formation. These results suggest that (−)-epigallocatechin-3-gallate protects neuronal cells by disrupting amyloid-β fibril formation; bioactive polyphenols which disrupt fibril aggregation may confer additional neuroprotection when compared against antioxidant activity alone

Adulterants and Contaminants in Psychotropic Herbal Medicines Detected with Mass Spectrometry and Next-Generation DNA Sequencing

Introduction: The role of herbal medicine in the treatment of common psychiatric disorders such as anxiety, depression and insomnia has become more established over the past decade. Some herbal preparations such as St John’s wort (Hypericum perforatum) have demonstrated clinical evidence but have also been included in recent reports of widespread adulteration and contamination. Herbal medicines sold in Australia are required to be listed on the Therapeutic Goods Administration’s (TGA) Australian Register of Therapeutic Goods (ARTG) and must comply with strict ingredient and manufacturing guidelines to assure quality and safety. Objective: The aim of this research was to assess whether pharmaceutical adulterants and contaminants were present in psychotropic herbal medicines available in Australia, as a measure of quality, and the effectiveness of regulation. Methods: A two-pronged approach combining next-generation DNA sequencing and small-molecule analysis techniques was undertaken to audit a subset of herbal medicines for the presence of prescription medications, illicit drugs, pesticides, herbicides, heavy metals and contaminant DNA. Small-molecule analysis included liquid chromatography with quadrupole time-of-flight mass spectrometer (LC-QTOF-MS) detection, liquid chromatography with UV/vis diode array (LC-UV) detection, gas chromatography with nitrogen–phosphorus and mass spectrometer detection (GC-NPD/MS) and heavy metal analysis using inductively coupled plasma with mass spectrometer (ICP-MS) detection. Results: In total, 49% (29 of 59) of the investigated herbal medicines had one or more materials not listed on their labels or ARTG registration, including Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)-listed material (one medicine), heavy metals (12%) or components that could trigger food sensitivity, such as wheat (12%). In contrast to previous studies, no prescription pharmaceutical adulterants were detected, although 10% had undeclared caffeine. Twenty-four percent of herbal medicines had DNA from animal species, including mice and bats, indicating poor quality control. The surveyed herbal medicines included both traditional Chinese medicines (TCM) and Western herbals. Ninety-four percent of TCMs were contaminated or adulterated, compared with 37% of the Western herbals. Only two of the 59 samples contained the listed active ingredient(s) without additional adulterants and contaminants, or missing ingredients. Conclusions: The high levels of contamination found in this study suggests that closer surveillance of herbal medicines is needed in order to assure the required level of quality of herbal medicines available in Australia. The results suggest that the TGA’s low-/high-risk system for regulation coupled with post-market auditing is not keeping unapproved and/or unsafe herbal medicines from the market