The Effects of Acute Rauwolscine (α-Yohimbine) Ingestion on Repeated Wingate Sprint Performance in Healthy Males

Topics in Exercise Science and Kinesiology Volume 4: Issue 1, Article 1, 2023. Background: Rauwolscine (RW), also known as α-Yohimbine, is an α-2-adrenergic receptor antagonist which possesses sympathomimetic properties. RW is commercially sold in pre-workout and energy supplements. However, the ergogenic potential of RW has not been determined. The purpose of this study was to investigate the effects of acute RW supplementation on repeated sprint performance. Methods: Healthy male participants (n=12) completed 3 × 15-second Wingate anaerobic tests (WAnT) separated by 2 minutes of active recovery. Blood lactate (La) was collected before exercise (Pre) and immediately following exercise (Post). Mean power, peak power, fatigue index, heart rate (HR), and rate of perceived exertion (RPE) were taken immediately after each WAnT. Point of application #1: Acute RW supplementation does not result in the enhancement of repeated anaerobic sprint performance. Point of application #2: HR and RPE are not altered during repeated sprints with RW ingestion. Point of application #3: RW ingestion results in higher La levels post-exercise despite no changes in fatigue index

Steroid drugs inhibit bacterial respiratory oxidases and are lethal towards methicillin-resistant Staphylococcus aureus

Background: Cytochrome bd complexes are respiratory oxidases found exclusively in prokaryotes that are important during infection for numerous bacterial pathogens. Methods: In silico docking was employed to screen approved drugs for their ability to bind to the quinol site of Escherichia coli cytochrome bd-I. Respiratory inhibition was assessed with oxygen electrodes using membranes isolated from E. coli and Methicillin-resistant Staphylococcus aureus strains expressing single respiratory oxidases (i.e., cytochromes bd, bo or aa3). Growth/viability assays were used to measure bacteriostatic and bactericidal effects. Results: The steroid drugs ethinylestradiol and quinestrol inhibited E. coli bd-I activity with IC50 values of 47 ± 28.9 µg/mL (158 ± 97.2 µM) and 0.2 ± 0.04 µg/mL (0.5 ± 0.1 µM), respectively. Quinestrol inhibited growth of an E. coli ‘bd-I only’ strain with an IC50 of 0.06 ± 0.02 µg/mL (0.2 ± 0.07 µM). Growth of a S. aureus ‘bd only’ strain was inhibited by quinestrol with an IC50 of 2.2 ± 0.43 µg/mL (6.0 ± 1.2 µM). Quinestrol exhibited potent bactericidal effects against S. aureus but not E. coli. Conclusions: Quinestrol inhibits cytochrome bd in E. coli and S. aureus membranes and inhibits the growth of both species yet is only bactericidal towards S. aureus