Natural activators of AMPK signaling: potential role in the management of type-2 diabetes

Tomatine Improves Glucose Metabolism and Mitochondrial Respiration in Insulin-Resistant Hepatocyte Cell Lines AML12 and HepG2 via an AMP-Activated Protein Kinase-Dependent Pathway

Insulin resistance (IR) disrupts hepatic glucose metabolism and mitochondrial function, which contributes to metabolic disorders. The present study examined the effects of tomatine on glucose metabolism in high-glucose-induced IR hepatocytes and explored its underlying mechanisms using AML12 and HepG2 cell models. The results showed that tomatine did not exhibit cytotoxic effects. Under IR conditions, tomatine dose-dependently improved glucose metabolism by enhancing glucose consumption and restoring the mRNA expression of the glucose transporter Glut2 and gluconeogenesis-related genes (Pepck and G6pase). Mechanistically, tomatine activated the phosphorylation of AMP-activated protein kinase (AMPK) and upregulated the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), reversing the IR-induced suppression of the AMPK/PGC1α pathway. In addition, tomatine enhanced mitochondrial oxidative function by restoring the oxygen consumption rate, increasing ATP production, and upregulating mitochondrial oxidative phosphorylation complex proteins. Both genetic and pharmacological inhibition of AMPK abolished these beneficial effects, confirming its central role in mediating tomatine's actions. Overall, our findings suggest that tomatine is a promising therapeutic candidate for enhancing hepatic glucose metabolism and mitochondrial function in IR-associated metabolic disorders through AMPK activation.

Ent-Kaurane Diterpenoids from Coffea Genus: An Update of Chemical Diversity and Biological Aspects

Coffee is one of the most important beverages in the world and is produced from Coffea spp. beans. Diterpenes with ent-kaurane backbones have been described in this genus, and substances such as cafestol and kahweol have been widely investigated, along with their derivatives and biological properties. Other coffee ent-kaurane diterpenoids have been reported with new perspectives on their biological activities. The aim of this review is to update the chemical diversity of ent-kaurane diterpenoids in green and roasted coffee, detailing each new compound and reporting its biological potential. A systematic review was performed using the bibliographic databases (SciFinder, Web of Science, ScienceDirect) and specific keywords such as "coffea diterpenes", "coffee diterpenes", "coffee ent-kaurane diterpenes" and "coffee diterpenoids". Only articles related to the isolation of coffee ent-kaurane compounds were considered. A total of 146 compounds were related to Coffea spp. since the first report in 1932. Different chemical skeletons were observed, and these compounds were grouped as furan-type, oxidation-type, rearrangement-type, lacton-type, and lactam-type, among others. In general, the new coffee diterpenoids showed potential as antidiabetic, antidiapogenic, α-glucosidade inhibition, antiplatelet activity, and Cav.3 inhibitors agents, revealing the possibilities for the design, discovery, and development of new drugs.

Loss of AMPK activity induces organelle dysfunction and oxidative stress during oocyte aging

BACKGROUND

Oocyte quality is critical for the mammalian reproduction due to its necessity on fertilization and early development. During aging, the declined oocytes showing with organelle dysfunction and oxidative stress lead to infertility. AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase which is important for energy homeostasis for metabolism. Little is known about the potential relationship between AMPK with oocyte aging.

RESULTS

In present study we reported that AMPK was related with low quality of oocytes under post ovulatory aging and the potential mechanism. We showed the altered AMPK level during aging and inhibition of AMPK activity induced mouse oocyte maturation defect. Further analysis indicated that similar with its upstream regulator PKD1, AMPK could reduce ROS level to avoid oxidative stress in oocytes, and this might be due to its regulation on mitochondria function, since loss of AMPK activity induced abnormal distribution, reduced ATP production and mtDNA copy number of mitochondria. Besides, we also found that the ER and Golgi apparatus distribution was aberrant after AMPK inhibition, and enhanced lysosome function was also observed.

CONCLUSIONS

Taken together, these data indicated that AMPK is important for the organelle function to reduce oxidative stress during oocyte meiotic maturation.

The potential protective effect of aqueous extract of Acanthophyllum glandulosum root on Streptozotocin-induced diabetes in mice

Purpose

Treatment of diabetes using traditional medicine has attracted attention in recent decades because of its unique benefits. Acanthophyllum glandulosum is known as an herb with therapeutic potential. This research explored the likely protective effects of Acanthophyllum Glandulosum Root (AGR) in mice with Streptozotocin-induced type 2 diabetes mellitus (T2DM) to provide complementary therapy.

Methods

Diabetes was induced by a single injection of Streptozotocin (STZ) in mice. STZ-diabetic mice were treated with oral dosages of AGR (25, 50, 100, and 200 mg/kg) on different experiment days. During the experiment, the effect of a topical extract of AGR on Glucose level, serum lipid profile, and liver and kidney biomarkers, with the histopathological assessment of heart, kidney, spleen, and liver, were investigated. The gene expression level of inflammation biomarkers (Tumour Necrosis Factor-alpha (TNF-α) and interleukin-1 (IL-1)), apoptosis factor (Caspase3), glucose regulatory genes (Glucose transporter (GLUT) 4 and 2), and lipid regulatory gene (Adenosine 50-monophosphate protein-kinase (AMPK)) were investigated.

Results

Administration of AGR to STZ-diabetic mice decreased blood glucose level (p < 0.01), normalized the lipid profile (p < 0.01), improved the serum level of kidney (p < 0.01) and liver biomarkers (p < 0.01), and normalized Kidney hypertrophy (p < 0.01), inflammation (p < 0.001), and apoptosis (p < 0.01). The AGR effect was better at 100 mg/kg than Metformin (100 mg/kg) on healing T2DM condition in mice.

Conclusion

AGR possesses anti-inflammatory, antioxidant, anti-hyperglycemic, anti-hyperlipidemic, and anti-glycation activity, thus exhibiting a protective function in STZ-induced diabetic mice. Further in vitro and in vivo works are necessary, especially to elucidate the mechanism of action of AGR at the cellular and molecular levels.