Introduction ! The fruits of Mangifera indica L. (Anacardiaceae) are known to contain high levels of bioactive com- pounds such as vitamins, carotenoids, and poly- phenols. The occurrence of high levels of polyphe- nols, such as the xanthonoid mangiferin, flavo- noids, phenolic acids, and different derivatives, provide a good basis for M. indica fruits as a healthy food [1]. Recently, it could be demonstrated that Careless™ activates the evolutionary conserved metabolic sensors sirtuin 1 (Sirt1) and AMP-activated pro- tein kinase (AMPK) and, furthermore, stimulates mitochondrial biogenesis and has antioxidative effects based on an increase in superoxide dismu- tase activity [2]. Sirt1 and AMPK are key players in regulating energy metabolism [3, 4]. They are ac- tivated in response to a variety of stimuli, includ- ing cellular stress, exercise, calorie restriction, and a wide range of hormones and agents that ex- ert impacts on cellular metabolism [3, 4]. Once ac- tivated, Sirt1 or AMPK stimulate a cascade of metabolic processes, e.g., increased fatty acid oxi- dation, inhibition of cholesterol, fatty acid as well as triglyceride synthesis, enhanced muscle glu- cose uptake, and modulation of insulin secretion [3, 5]. AMPK in endothelial cells has been implicated in the regulation of fatty acid oxidation, small G pro- tein activity, inflammation, and angiogenesis [6]. Endothelium-dependent vascular relaxation via the activation of endothelial nitric oxide synthase (eNOS) and nitric oxide production has been shown to be stimulated by AMPK [6]. Moreover, there is evidence indicating that the activation of the AMPK pathway may help to prevent the vas- cular complications associated with insulin sensi- tivity [7]. The prevalence of metabolic syndrome, type 2 diabetes, and being overweight has reached epi- demic proportions in Western society [8]. Being overweight is associated with impaired microcir- culation through alterations in endocrine and vasocrine signals that cause alterations in micro- vascular endothelial and skeletal muscle signal- Abstract ! Mangifera indica fruit preparation (Careless™) ac- tivates the evolutionary conserved metabolic sen- sors sirtuin 1 and adenosine monophosphate-ac- tivated protein kinase, which have been identified as playing a key role in microcirculation and en- dothelial function. Here, an acute effect of a single dose of 100 mg or 300 mg Careless™ on microcir- culation was investigated in a randomized, dou- ble-blind, crossover pilot study in ten healthy women to determine the effective dosage. Micro- circulation and endothelial function were as- sessed by the Oxygen-to-see system and pulse amplitude tonometry (EndoPAT™), respectively. Cutaneous blood flow was increased over time by 100 mg (54% over pre-values, p = 0.0157) and 300 mg (35% over pre-value, p = 0.209) Careless™. The EndoPAT™ reactive hyperemia response was slightly improved 3 h after intake compared to pretesting with 300 mg Careless™. Furthermore, activation of endothelial nitric oxide synthase, as an important regulator for endothelial function, was tested in vitro in primary human umbilical vein endothelial cells. Careless™, after simulation of digestion, increased the activated form of en- dothelial nitric oxide synthase dose-dependently by 23 % (300 μg/mL), 42% (1500 μg/mL), and 60 % (3000 μg/mL) compared to the untreated control. In conclusion, the study suggests moderate bene- ficial effects of Careless™ on microcirculation, which is at least partly mediated by endothelial nitric oxide synthase activation. In Vitro Activation of eNOS by Mangifera indica (Careless™) and Determination of an Effective Dosage in a Randomized, Double-Blind, Human Pilot Study on Microcirculation Authors Alexandra Gerstgrasser 1 , Sigrid Röchter 1 , Dirk Dressler 2 , Christiane Schön 2 , Claudia Reule 2 , Sybille Buchwald-Werner 1 Affiliations 1 Vital Solutions Swiss AG, Romanshorn, Schweiz 2 BioTeSys GmbH, Esslingen Key words l " Mangifera indica l " Anacardiaceae l " Careless™ l " microcirculation l " endothelial function l " human study l " eNOS l " HUVEC received Sept. 2, 2015 revised October 9, 2015 accepted October 12, 2015 Bibliography DOI http://dx.doi.org/ 10.1055/s-0035-1558219 Published online November 19, 2015 Planta Med 2016; 82: 298–304 © Georg Thieme Verlag KG Stuttgart · New York · ISSN 0032‑0943 Correspondence Alexandra Gerstgrasser Vital Solutions Swiss AG Neustrasse 18 8590 Romanshorn Schweiz Phone: + 49 2 17 31 09 82 02 Fax: + 49 2 17 31 09 82 10 Alexandra.gerstgrasser@ vitalsolutions.biz 298 Gerstgrasser A et al. In Vitro Activation … Planta Med 2016; 82: 298–304 Original Papers This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.