Capsaicin ameliorates diet-induced disturbances of glucose homeostasis and gut microbiota in mice associated with the circadian clock

Effects of chili meal supplementation on productive performance, intestinal health, and liver lipid metabolism of laying hens fed low-protein diets

This study aimed to explore the effects of chili meal (CM), a by-product of chili pepper oil extraction, on the productive performance, intestinal health, and lipid metabolism of laying hens fed low-protein (LP) diets. A total of 384 Hy-Line brown laying hens (32 weeks old) were divided into six groups: control (CON) diet with 16.5 % crude protein (CP), LP diet with 15 % CP, and LP diets supplemented with 3 %, 5 %, 7 %, and 9 % CM. Results showed that dietary CM supplementation of up to 5 % did not negatively affect the productive performance of laying hens fed LP diets. However, the groups receiving 7 % and 9 % CM exhibited a significant increase in the feed-to-egg ratio (P < 0.05). Additionally, dietary CM supplementation effectively enhanced egg yolk color in a dose-dependent manner (P < 0.05). Intestinal morphology analysis indicated that the 5 % CM group had a higher villus height-to-crypt depth ratio than the LP and 9 % CM groups (P < 0.05), with no significant differences among the other groups. Dietary supplementation with 3 %-7 % CM did not significantly affect serum and jejunal antioxidant capacity, and the 9 % CM group exhibited the highest levels of serum and jejunal malondialdehyde among the groups (P < 0.05). Dietary CM supplementation significantly increased anti-inflammatory cytokines (IL-4 and IL-10) and decreased pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) in the serum and jejunal tissue of laying hens (P < 0.05). Moreover, CM supplementation significantly altered the cecal microbiota composition in laying hens, increasing the abundance of beneficial bacteria, such as Desulfovibrio and Megamonas. Furthermore, dietary CM supplementation significantly decreased serum triglyceride levels; downregulated liver mRNA levels of ACC, FAS, and SREBP-1C/2; and upregulated the mRNA levels of ACOX1, PPAR-α, Apob, and CPT in laying hens fed LP diets. In conclusion, CM supplementation should not exceed 5 % to avoid negative impacts on performance while supporting intestinal health and lipid metabolism.

Allicin Improves Diet-Induced Nonalcoholic Steatohepatitis and Gut Microbiota Dysbiosis in Mice via the Involvement of the Circadian Clock Gene Rev-erbα

Nonalcoholic Steatohepatitis (NASH) is a progressive liver disease characterized by inflammation and liver damage. Allicin, a bioactive compound derived from garlic, has demonstrated anti-inflammatory and antioxidant properties. This study explores the effects of allicin on NASH and gut microbiota dysbiosis induced by a high-fat, high-fructose diet (HFFD) in mice. Allicin supplementation significantly alleviated hepatic inflammation, improved glucose metabolism, and modulated the circadian rhythm gene Rev-erbα, which plays a critical role in regulating inflammation. The anti-inflammatory effects of allicin were diminished in Si-Rev-erbα-treated HepG2 cells, highlighting the importance of circadian regulation in mediating these effects. Allicin's anti-inflammatory effects were associated with increased levels of short-chain fatty acids (SCFAs) and the restoration of diurnal oscillations in proinflammatory cytokines and gut microbiota composition, particularly in genera, such as Akkermansia, Bacteroidetes, and Lactobacillus. These findings suggest that allicin could be a promising therapeutic approach for managing NASH, liver dysfunction, and related metabolic disorders through the modulation of circadian rhythms and the gut microbiome.

Regulatory Role of Bioactive Compounds from Natural Spices on Mitochondrial Function

Natural spices have gained much attention for their aromatic and pungent flavors as well as their multiple beneficial health effects. As complex organelles that play a central role in energy production, stress response control, cell signal transduction, and metabolism regulation, mitochondria could be regulated by many bioactive components in spices. In this review, the role of mitochondria in maintaining cellular and metabolism homeostasis is summarized. The regulatory effects of mitochondrial function by major bioactive compounds from natural spices are evaluated, including capsaicin, 6-gingerol, 6-shogaol, allicin, quercetin, curcumin, tetrahydrocurcumin, and cinnamaldehyde. The underlying molecular mechanisms are also discussed. This work could enhance our understanding toward health-promoting properties of spice compounds as well as provide new insights into the prevention and treatment of disorders associated with mitochondrial dysfunctions by those nutraceuticals.

Capsaicin Mitigates Reverbα-Involved Lipid Metabolism Disorder in HepG2 Cells and Obese Mice through a Trpv1-Dependent Mechanism

Capsaicin (CAP), the active component of chili peppers, exerts a range of health benefits, including anti-inflammatory, antitumor, obesity-prevention, metabolic control, and biological rhythm-modulating effects, primarily through the activation of the transient receptor potential vanilloid 1 (TRPV1) receptor. The research explores the role of TRPV1 and its interaction with hepatic circadian clock regulation in modulating lipid metabolism and liver health. The effect of CAP on lipid metabolism and the potential mechanism was examined in HepG2 cells and high-fat, high-sugar diet (HFFD)-induced obese mice. In vitro, CAP (50 μM) decreased lipid droplet overaccumulation (from 152.8 ± 2.30 to 110.13 ± 3.91%), enhanced mitochondrial function (from 57.94 ± 1.93 to 86.74 ± 1.83%), and alleviated circadian desynchrony through a Trpv1-dependent mechanism in HepG2 cells. In vivo, CAP (5 mg/kg) reduced the body weight gain (from 50.61 ± 3.77 to 38.36 ± 2.04%), restored the hepatic circadian rhythm, and modulated the expression of lipid-related genes through the involvement of TRPV1 in mice. This study highlighted the potential of CAP to attenuate Reverbα-mediated lipid metabolic dysfunction through a Trpv1-dependent mechanism, revealing a complex interplay between circadian regulation and lipid metabolism.

A Cross Talking between the Gut Microbiota and Metabolites of Participants in a Confined Environment

Certain workplaces, like deep-sea voyages, subject workers to chronic psychological stress and circadian rhythm disorders due to confined environments and frequent shifts. In this study, participants lived in a strictly controlled confined environment, and we analyzed the effects of a confined environment on gut microbiota and metabolites. The results showed that living in confined environments can significantly alter both the gut microbiota and the gut metabolome, particularly affecting lipid metabolism pathways like glycerophospholipid metabolism. There was a significant reduction in the abundance of Faecalibacterium and Bacteroides, while Blautia, Bifidobacterium, and Collinsella showed significant increases. An association analysis revealed a strong correlation between changes in the gut microbiota and the metabolome. Four upregulated lipid metabolites may serve as biomarkers for damage induced by confined environments, and certain gut microbiota alterations, such as those involving Faecalibacterium and Bacteroides, could be potential psychobiotics or therapeutic targets for enhancing mental health in a confined environment.

Signaling pathways regulated by natural active ingredients in the fight against exercise fatigue-a review

Exercise fatigue is a normal protective mechanism of the body. However, long-term fatigue hinders normal metabolism and exercise capacity. The generation and recovery from exercise fatigue involves alterations in multiple signaling pathways, mainly AMPK, PI3K/Akt, Nrf2/ARE, NF-κB, PINK1/Parkin, and BDNF/TrkB, as well as MAPK signaling pathways that mediate energy supply, reduction of metabolites, oxidative stress homeostasis, muscle fiber type switching, and central protective effects. In recent studies, a rich variety of natural active ingredients have been identified in traditional Chinese medicines and plant extracts with anti-fatigue effects, opening up the field of research in new anti-fatigue drugs. In this review we give an overview of the signaling pathways associated with the activity of natural food active ingredients against exercise fatigue. Such a comprehensive review is necessary to understand the potential of these materials as preventive measures and treatments of exercise fatigue. We expect the findings highlighted and discussed here will help guide the development of new health products and provide a theoretical and scientific basis for future research on exercise fatigue.