The Anti-Obesity and Anti-Inflammatory Capabilities of Pterostilbene and its Colonic Metabolite Pinostilbene Protect against Tight Junction Disruption from Western Diet Feeding

Hepatoprotective effect of dietary pterostilbene against high-fat-diet-induced lipid accumulation exacerbated by chronic jet lag via SIRT1 and SIRT3 activation

Hepatic lipid metabolism is modulated by the circadian rhythm; therefore, circadian disruption may promote obesity and hepatic lipid accumulation. This study aims to investigate dietary pterostilbene (PSB) 's protective effect against high-fat-diet (HFD)-induced lipid accumulation exacerbated by chronic jet lag and the potential role of gut microbiota therein. Mice were treated with a HFD and chronic jet lag for 14 weeks. The experimental group was supplemented with 0.25% (w/w) PSB in its diet to evaluate whether PSB had a beneficial effect. Our study found that chronic jet lag exacerbates HFD-induced obesity and hepatic lipid accumulation, but these adverse effects were significantly mitigated by PSB supplementation. Specifically, PSB promoted hepatic lipolysis and β-oxidation by upregulating SIRT1 expression, which indirectly reduced oxidative stress caused by lipid accumulation. Additionally, the PSB-induced elevation of SIRT1 and SIRT3 expression helped prevent excessive autophagy and mitochondrial fission by activating Nrf2-mediated antioxidant enzymes. The result was evidenced by the use of SIRT1 and SIRT3 inhibitors in in vitro studies, which demonstrated that activation of SIRT1 and SIRT3 by PSB is crucial for the translocation of PGC-1α and Nrf2, respectively. Moreover, the analysis of gut microbiota suggested that PSB's beneficial effects were partly due to its positive modulation of gut microbial composition and functionality. The findings of this study suggest the potential of dietary PSB as a candidate to improve hepatic lipid metabolism via several mechanisms. It may be developed as a treatment adjuvant in the future.

Hypoglycemic effects and associated mechanisms of resveratrol and related stilbenes in diet

Hyperglycemia has become a global health problem due to changes in diet and lifestyle. Most importantly, persistent hyperglycemia can eventually develop into type II diabetes. While the usage of current drugs is limited by their side effects, stilbenes derived from fruits and herbal/dietary plants are considered as important phytochemicals with potential hypoglycemic properties. Herein, the most common stilbenoids in consumed foods, i.e. resveratrol, pterostilbene, piceatannol, oxyresveratrol, and 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucopyranoside (THSG), are reviewed in this paper. These stilbenes are found to regulate glucose homeostasis via (a) modulation of feeding behaviour and nutrition absorption; (b) restoration of insulin signalling by enhancing insulin production/insulin sensitivity; (c) improvement of gut permeability, gut microbial profile and resulting metabolomes; and (d) amelioration of circadian rhythm disruption. In this review, we have summarized the underlying mechanisms for the hypoglycemic effects of the five most common dietary stilbenoids listed above, providing a comprehensive framework for future study and applications.

Natural compounds as obesity pharmacotherapies

Obesity has become a serious global public health problem, affecting over 988 million people worldwide. Nevertheless, current pharmacotherapies have proven inadequate. Natural compounds have garnered significant attention due to their potential antiobesity effects. Over the past three decades, ca. 50 natural compounds have been evaluated for the preventive and/or therapeutic effects on obesity in animals and humans. However, variations in the antiobesity efficacies among these natural compounds have been substantial, owing to differences in experimental designs, including variations in animal models, dosages, treatment durations, and administration methods. The feasibility of employing these natural compounds as pharmacotherapies for obesity remained uncertain. In this review, we systematically summarized the antiobesity efficacy and mechanisms of action of each natural compound in animal models. This comprehensive review furnishes valuable insights for the development of antiobesity medications based on natural compounds.

Pinostilbene inhibits full-length and splice variant of androgen receptor in prostate cancer

Prostate cancer is the most prevalent cancer in men worldwide and is promoted by the sex hormone androgen. Expression of androgen from the testis can be significantly reduced through castration. However, as most prostate cancer patients acquire castration resistance, additional therapeutic solutions are necessary. Although anti-androgens, such as enzalutamide, have been used to treat castration-resistant prostate cancer (CRPC), enzalutamide-resistant CRPC (Enz-resistant CRPC) has emerged. Therefore, development of novel treatments for Enz-resistant CRPC is urgent. In this study, we found a novel anti-androgen called pinostilbene through screening with a GAL4-transactivation assay. We confirmed that pinostilbene directly binds to androgen receptor (AR) and inhibits its activation and translocalization. Pinostilbene treatment also reduced the protein level and downstream gene expression of AR. Furthermore, pinostilbene reduced the protein level of AR variant 7 in the Enz-resistant prostate cancer cell line 22Rv1 and inhibited cell viability and proliferation. Our results suggest that pinostilbene has the potential to treat Enz-resistant CRPC.

Pterostilbene Enhances Thermogenesis and Mitochondrial Biogenesis by Activating the SIRT1/PGC-1α/SIRT3 Pathway to Prevent Western Diet-Induced Obesity

SCOPE

Sirtuin 1/peroxisome proliferator-activated receptor gamma co-activator 1 alpha (SIRT1/PGC-1α) pathway activation is known to promote thermogenesis and mitochondrial biogenesis. Pterostilbene (PSB) and pinostilbene (PIN), the methylated analogs of resveratrol, are potential candidates to enhance thermogenesis and mitochondrial biogenesis.

METHOD AND RESULTS

A model of Western diet-induced obesity in mice is designed. Either PSB or PIN is supplemented in the diet for 16 weeks. Both samples can significantly reduce body weight gain but only PSB can decrease inguinal adipose tissue weight. Besides, both samples can promote lipolysis but only PSB supplementation activates the SIRT1/PGC-1α/SIRT3 pathway to enhance mitochondrial biogenesis and thermogenesis in the inguinal adipose tissue. In addition, although both samples exert a modulatory effect on gut microbiota but significant increments in fecal isobutyric acid, valeric acid, and isovaleric acid are only observed in the PSB group, functioning as gut microbial metabolites.

CONCLUSION

Overall, these findings suggest PSB and PIN as potential candidates for the improvement of obesity and gut microbiota dysbiosis. With its higher stability, PSB exerts a greater effect than PIN by promoting thermogenesis and mitochondrial biogenesis via SIRT1 activation.

Antiobesity pathways of pterostilbene and resveratrol: a comprehensive insight

It may not always be possible for obese individuals to limit energy intake or to provide and/or maintain greater energy expenditure through exercise and physical activity. Therefore, the search for effective methods for obesity continues. Recently, the anti-obesity effect of stilbenes has attracted attention. In this review, aim was evaluating the effect of pterostilbene and resveratrol against obesity and the possible mechanisms in this effect. Dietary phytochemicals can induce body weight loss by increasing basal metabolic rate and thermogenesis and/or altering lipid metabolism. Stilbenes are products of the plant phenylpropanoid pathway. Very important mechanisms for the anti-obesity impact belonging to resveratrol as well as pterostilbene include thermogenic activation in brown adipose tissue alongside the browning of white adipose tissue. Considering nutrition and dietary habits, which have an important place in lifestyle changes for both the prevention and the treatment of obesity, pterostilbene and resveratrol, which are polyphenols and stilbenes, are seen as promising. However, optimal dose, duration, mechanism, long-term safety, side effects, combination, elucidation of genomic interactions, and lifestyle modifications should be considered.

The Role of Mitochondria in Phytochemically Mediated Disease Amelioration

Mitochondrial dysfunction may cause cell death, which has recently emerged as a cancer prevention and treatment strategy mediated by chemotherapy drugs or phytochemicals. However, most existing drugs cannot target cancerous cells and may adversely affect normal cells via side effects. Mounting studies have revealed that phytochemicals such as resveratrol could ameliorate various diseases with dysfunctional or damaged mitochondria. For instance, resveratrol can regulate mitophagy, inhibit oxidative stress and preserve membrane potential, induce mitochondrial biogenesis, balance mitochondrial fusion and fission, and enhance the functionality of the electron transport chain. However, there are only a few studies suggesting that phytochemicals could potentially protect against the cytotoxicity of some current cancer drugs, especially those that damage mitochondria. Besides, COVID-19 and long COVID have also been reported to be correlated to mitochondrial dysfunction. Curcumin has been reported bringing a positive impact on COVID-19 and long COVID. Therefore, in this study, the benefits of resveratrol and curcumin to be applied for cancer treatment/prevention and disease amelioration were reviewed. Besides, this review also provides some perspectives on phytochemicals to be considered as a treatment adjuvant for COVID-19 and long COVID by targeting mitochondrial rescue. Hopefully, this review can provide new insight into disease treatment with phytochemicals targeting mitochondria.

Piceatannol and 3'-Hydroxypterostilbene Alleviate Inflammatory Bowel Disease by Maintaining Intestinal Epithelial Integrity and Regulating Gut Microbiota in Mice

Inflammatory bowel disease has become a significant health concern across the globe, causing frequent and long-term harm to the digestive system. This study evaluated the effect of piceatannol (PIC) and 3'-hydroxypterostilbene (HPSB) on dextran sulfate sodium (DSS)-induced colitis in mice and investigated whether their effects are exerted through the amelioration of gut barrier dysfunction to reduce the severity of colitis. The findings showed that both PIC and HPSB attenuated inflammation by inhibiting the TNF-α/NF-κB/MLC pathway and reducing NLRP3 inflammasome activation. However, PIC was comparably effective in modulating tight junctions. The results may be attributed to the effect of PIC on reducing cell apoptosis-associated protein expression, including Bax/Bcl-2 and caspase-3 activation. Furthermore, microbiota analysis revealed that both PIC and HPSB increased representative probiotic species, including Akkermansiaceae and Lactobacillus intestinalis, and exhibited inhibitory effects on several bacterial species (Spiroplasmataceae and Acholeplasmataceae). Based on linear discriminant analysis effect size, butyrate-producing bacteria were identified as a biomarker in the PIC group. Overall, the results demonstrated that PIC repressed inflammation, inhibited cell apoptosis, and regulated microbiota composition. Consequently, PIC is more effective in maintaining gut barrier integrity than HPSB, and it is a promising ingredient in the development of functional food for colitis prevention.

Synergistic effects of natural products in combination with anticancer agents in prostate cancer: A scoping review

Background: Prostate cancer is the second most common cancer in men and has the fourth highest mortality among men worldwide. Different combination therapies for cancer are being tested, and among them, the integration of natural products is increasing. This study reviews research on the combination of anticancer drugs and natural products for the treatment of prostate cancer and suggests future directions in this field.

Methods: Articles were identified by searching the PubMed, Embase, and Cochrane Library databases. Search keywords included the following: “Antineoplastic agents,” “Anticancer drug,” “Phytotherapy,” “Natural product,” “Drug synergism,” and “Synergistic effect”. The selection process focused on whether the differences in efficacy of anticancer drugs were evaluated when combined with natural products.

Results: Nineteen studies were included. All 19 studies evaluated efficacy in vitro, as well as 10 in vivo. There were 13 studies on a single compound extracted from natural products, three studies on mushroom and herb extracts, and three studies on herbal medicines consisting of three herbs, and a dietary supplement containing 10 herbs. Cancer cell lines used were PC-3 in nine studies, LNCaP in six studies, C4-2 in five studies, DU-145 in four studies, and 22Rv1 in two studies. Anti-cancer drugs co-administered were as follows: docetaxel in nine studies, doxorubicin and enzalutamide in three studies, paclitaxel and suberoylanilide hydroxamic acid in two studies, and cisplatin, vincristine, and bicalutamide in one study each.

Conclusion: Although prostate cancer is prevalent worldwide, there are relatively few studies on the use of natural products with anticancer agents as treatment. Since it has reported that the efficacy of anticancer drugs is enhanced by coadministration of natural products, it is necessary to conduct further studies on this.