Jaboticaba (Plinia jaboticaba (Vell.) Berg) polyphenols alleviate skeletal muscle insulin resistance by modulating PI3K/Akt/GLUT-4 and AMPK signaling pathways in diet-induced obese mice

Abstract Skeletal muscle responds for most of the insulin-stimulated glucose disposal at postprandial state, impacting glucose homeostasis. Polyphenols were shown to prevent obesity-associated glucose intolerance and peripheral insulin resistance in animal models, but the implication of skeletal muscle to these effects is unclear. We investigated the role of polyphenolic extracts from jaboticaba (Plinia jaboticaba (Vell.) Berg) (PEJ), a Brazilian native species, on skeletal muscle insulin resistance in diet-induced obese mice. PEJ administration was associated with an increase in skeletal muscle protein content of glucose transporter-4 (GLUT-4) and AMP-activated protein kinase (AMPK) phosphorylated at Thr172. PEJ also reduced skeletal muscle mRNA levels of inflammatory genes nuclear factor-ҡB (NF-κB), tumoral necrose factor-α (TNF-α), interleukin 1β (IL-1β), and c-Jun N-terminal kinase (JNK). This study demonstrates that polyphenols from jaboticaba may be a valuable therapeutic agent in the management and prevention of obesity-associated metabolic disorders by reducing skeletal muscle obesity-associated insulin resistance and inflammation. Graphical Abstrac

Bioactive Compounds of Camu-Camu (Myrciaria dubia (Kunth) McVaugh)

Camu-camu is a shrub, native to the Amazon that thrives in areas where flooding is frequent. Genetically, the plant is characterized by a diploid genome and moderate genetic diversity. Several parts of the plant are used in traditional folk medicine to treat a variety of acute and chronic diseases. For over 50 years, the exceptionally high vitamin C content of camu-camu has attracted worldwide attention that continues today because of the recent discovery of several health-promoting phytochemicals with corroborated biological activities (e.g., antioxidant, anti-obesity, antidiabetic). All of these beneficial attributes are well supported by in vitro and in vivo studies as well as human clinical trials. The metabolic precursors of these phytochemicals are synthesized in key metabolic pathways (i.e., the shikimate pathway, the mevalonate pathway). Of these metabolic pathways, we show details for the biosynthesis of betulinic acid, trans-resveratrol, and syringic acid. In conclusion, camu-camu is an exceptional plant for its ability to produce and accumulate significant amounts of a variety of health-promoting phytochemicals. Although several metabolic pathways responsible for the biosynthesis of these phytochemicals have been reconstructed based on fruit and seedling transcriptomes, detailed knowledge of the vast majority of metabolic pathways and their molecular regulatory mechanisms is lacking. Consequently, we must increase our knowledge of the metabolic processes using multi-omic approaches so that we can acquire the skills necessary to develop genetically improved varieties of camu-camu and implement biotechnological applications for the production of these bioactive phytochemicals