Mechanism of antihypertensive effect of Mucuna pruriens L. seed extract and its isolated compounds

Effects of a New Natural Catechol-O-methyl Transferase Inhibitor on Two In Vivo Models of Parkinson's Disease

A tetrahydroisoquinoline identified in Mucuna pruriens ((1R,3S)-6,7-dihydroxy-1-methyl-1,2,3,4-tetrahydroisoquinoline-1,3-dicarboxylic acid, compound 4) was synthesized and assessed for its in vitro pharmacological profile and in vivo effects in two animal models of Parkinson's disease. Compound 4 inhibits catechol-O-methyltransferase (COMT) with no affinity for the dopaminergic receptors or the dopamine transporter. It restores dopamine-mediated motor behavior when it is co-administered with L-DOPA to C. elegans worms with 1-methyl-4-phenylpyridinium-damaged dopaminergic neurons. In a 6-hydroxydopamine rat model of Parkinson's disease, its co-administration at 30 mg/kg with L-DOPA enhances the effect of L-DOPA with an intensity similar to that of tolcapone 1 at 30 mg/kg but for a shorter duration. The effect is not dose-dependent. Compound 4 seems not to cross the blood-brain barrier and thus acts as a peripheral COMT inhibitor. COMT inhibition by compound 4 further validates the traditional use of M. pruriens for the treatment of Parkinson's disease, and compound 4 can thus be considered as a promising drug candidate for the development of safe, peripheral COMT inhibitors.

Exploring a New Natural Treating Agent for Primary Hypertension: Recent Findings and Forthcoming Perspectives

Primary hypertension describes abnormally-high systolic/diastolic blood pressure in a resting condition caused by various genetic or environmental risk factors. Remarkably, severe complications, such as ischemic cardiovascular disease, stroke, and chronic renal disease have led to primary hypertension becoming a huge burden for almost one-third of the total population. Medication is the major regimen for treating primary hypertension; however, recent medications may have adverse effects that attenuate energy levels. Hence, the search for new hypotensive agents from folk or traditional medicine may be fruitful in the discovery and development of new drugs. This review assembles recent findings for natural antihypertensive agents, extracts, or decoctions published in PubMed, and provides insights into the search for new hypotensive compounds based on blood-pressure regulating mechanisms, including the renin-angiotensin-aldosterone system and the sympathetic/adrenergic receptor/calcium channel system.