Microencapsulated pomegranate peel extract induces mitochondrial complex IV activity and prevents mitochondrial cristae alteration in brown adipose tissue in mice fed on a high-fat diet

Abstract

Pomegranate peel is an agro-industrial residue obtained after fruit processing with high total polyphenol (TP) content, making it an attractive by-product for its reuse. Pomegranate peel extract (PPE) and its bioactive compounds have shown positive effects on obesity models. Effects on favouring mitochondrial biogenesis and function have also been described. However, once phenolic compounds are extracted, their stability can be affected by diverse factors. Microencapsulation could improve PPE stability, allowing its incorporation into functional foods. Nevertheless, studies on the potential biological effects of PPE microparticles (MPPE) in obesity models are lacking. This study aims to evaluate the effect of MPPE on BAT mitochondrial structure and function and metabolic alterations related to obesity in mice fed a high-fat diet (HFD). PPE was microencapsulated by spray drying using inulin (IN) as a wall material and physically-chemically characterized. Eight-week-old male C57BL/6J mice (n=40) were randomly distributed into five groups: control diet (CD), HFD, HFD+IN, HFD+PPE (50 mg/kg/d TP), and HFD+MPPE (50 mg/kg/d TP), for 14 weeks. A glucose tolerance test and indirect calorimetry were conducted. Blood and adipose tissue samples were obtained. MPPE supplementation prevented HFD-induced body weight gain (p<0.001), fasting glycemia (p=0.007), and total cholesterol rise (p=0.001). MPPE resulted in higher BAT mitochondrial complex IV activity (p=0.03) and prevented HFD-induced mitochondrial cristae alteration (p=0.02). In conclusion, MPPE prevented HFD-induced excessive body weight gain and associated metabolic disturbances, potentially by activating complex IV activity and preserving mitochondrial cristae structure in BAT in mice fed with an HFD.

Ameliorative Effect of Neem Leaf and Pomegranate Peel Extracts in Coccidial Infections in New Zealand and V-Line Rabbits: Performance, Intestinal Health, Oocyst Shedding, Carcass Traits, and Effect on Economic Measures

“…In general, pomegranate peel extract has been confirmed as a highly valuable source of bioactive compounds that can be used to improve the functional characteristics of food when used in ethanolic form [ 76 ]. The mix of flavonoids, polyphenols, and other active ingredients found in pomegranate peel have been published previously, confirming that the antioxidant activity in the pomegranate can be attributed mainly to its polyphenol, quercetin, and rutin contents [ 77 ].…”

The fasting‐feeding metabolic transition regulates mitochondrial dynamics

“…Previous studies have suggested that the alignment of mitochondrial cristae and mitochondrial cristae density are a dynamic process associated with OXPHOS activity 30–32 . Here, our results show that glucose consumption after fasting reduces mitochondrial cristae alignment, length and number, as well as reduces mitochondria‐ER interaction, Mfn2 protein and CV‐ATP5A levels.…”

“…28,29 Previous studies have suggested that the alignment of mitochondrial cristae and mitochondrial cristae density are a dynamic process associated with OXPHOS activity. [30][31][32] Here, our results show that glucose consumption after fasting reduces mitochondrial cristae alignment, length and number, as well as reduces mitochondria-ER interaction, Mfn2 protein and CV-ATP5A levels. Once again, similar observations were previously made in the liver, as the postprandial state was associated with reduced mitochondria cristae length through a Mfn2 and Opa1dependent mechanism.…”

Low abundance of Mfn2 protein correlates with reduced mitochondria‐SR juxtaposition and mitochondrial cristae density in human men skeletal muscle: Examining organelle measurements from TEM images

“…MIC60 is the core component of the mitochondrial contact site and cristae organizing system and interacts with several inner and OMM proteins to maintain inner mitochondrial membrane morphology and density 25 . It has been suggested that the typical architecture of cristae provides a specific microenvironment that enhances the catalytic capacity of the OXPHOS system 26 . It was previously shown in HeLa cells that MIC60 knockout, decreases the activity of mitochondrial OXPHOS complexes I, III and IV 27 .…”