Phytochemicals as Prebiotics and Biological Stress Inducers.

Phytochemicals in fruits and vegetables produce health benefits, but questions remain regarding their bioavailability, molecular targets, and mechanism of action. Here, we address these issues by considering the prebiotic and biological properties of phytochemicals. A fraction of phytochemicals consumed orally passes through the gut lumen, where it modulates the composition of the gut microbiota and maintains intestinal integrity. Phytochemicals and microbiota-derived metabolites that are absorbed by the organism comprise compounds that, at low doses, induce stress resistance mechanisms, including autophagy, DNA repair, and expression of detoxifying and antioxidant enzymes. We propose that these mechanisms improve cellular and organ function and can account for the promiscuous bioactivities of phytochemicals, despite their limited bioavailability and extremely varied chemical structures.

Emerging use of senolytics and senomorphics against aging and chronic diseases.

Senescence is a state of cell cycle arrest that plays an important role in embryogenesis, wound healing and protection against cancer. Senescent cells also accumulate during aging and contribute to the development of age-related disorders and chronic diseases, such as atherosclerosis, type 2 diabetes, osteoarthritis, idiopathic pulmonary fibrosis, and liver disease. Molecules that induce apoptosis of senescent cells, such as dasatinib, quercetin, and fisetin, produce health benefits and extend lifespan in animal models. We describe here the mechanism of action of senolytics and senomorphics, many of which are derived from plants and fungi. We also discuss the possibility of using such compounds to delay aging and treat chronic diseases in humans.

Gut commensal Parabacteroides goldsteinii plays a predominant role in the anti-obesity effects of polysaccharides isolated from Hirsutella sinensis.

OBJECTIVE: The medicinal fungus Ophiocordyceps sinensis and its anamorph Hirsutella sinensis have a long history of use in traditional Chinese medicine for their immunomodulatory properties. Alterations of the gut microbiota have been described in obesity and type 2 diabetes. We examined the possibility that H. sinensis mycelium (HSM) and isolated fractions containing polysaccharides may prevent diet-induced obesity and type 2 diabetes by modulating the composition of the gut microbiota. DESIGN: High-fat diet (HFD)-fed mice were treated with HSM or fractions containing polysaccharides of different molecular weights. The effects of HSM and polysaccharides on the gut microbiota were assessed by horizontal faecal microbiota transplantation (FMT), antibiotic treatment and 16S rDNA-based microbiota analysis. RESULTS: Fraction H1 containing high-molecular weight polysaccharides (>300 kDa) considerably reduced body weight gain (∼50% reduction) and metabolic disorders in HFD-fed mice. These effects were associated with increased expression of thermogenesis protein markers in adipose tissues, enhanced gut integrity, reduced intestinal and systemic inflammation and improved insulin sensitivity and lipid metabolism. Gut microbiota analysis revealed that H1 polysaccharides selectively promoted the growth of Parabacteroides goldsteinii, a commensal bacterium whose level was reduced in HFD-fed mice. FMT combined with antibiotic treatment showed that neomycin-sensitive gut bacteria negatively correlated with obesity traits and were required for H1's anti-obesogenic effects. Notably, oral treatment of HFD-fed mice with live P. goldsteinii reduced obesity and was associated with increased adipose tissue thermogenesis, enhanced intestinal integrity and reduced levels of inflammation and insulin resistance. CONCLUSIONS: HSM polysaccharides and the gut bacterium P. goldsteinii represent novel prebiotics and probiotics that may be used to treat obesity and type 2 diabetes.

Antiaging effects of bioactive molecules isolated from plants and fungi.

Aging is influenced by many lifestyle choices that are under human control, including nutrition and exercise. The most effective known antiaging intervention consists of calorie restriction (CR), which increases lifespan in yeasts, worms, fruit flies, mice, and nonhuman primates. CR also improves healthspan by preventing the development of various aging-related diseases such as cancer, cardiovascular disease, diabetes, and neurodegeneration. Many compounds isolated from plants and fungi prolong lifespan and prevent age-related diseases in model organisms. These plant and fungal compounds modulate the same cellular and physiological pathways as CR, including those involving insulin and insulin-like growth factor-1, mammalian target of rapamycin, and sirtuins. Modulation of these aging-related pathways results in the activation of various cellular processes such as autophagy, DNA repair, and neutralization of reactive oxygen species. Together, these cellular processes are believed to delay aging and prevent chronic diseases by improving bodily functions and stress resistance. We review here the mechanisms of action of plant and fungal molecules possessing antiaging properties and discuss the possibilities and challenges associated with the development of antiaging compounds isolated from natural products.

Effects of obesity on depression: A role for inflammation and the gut microbiota.

Depression is a mental disorder associated with environmental, genetic and psychological factors. Recent studies indicate that chronic neuro-inflammation may affect brain physiology and alter mood and behavior. Consumption of a high-fat diet leads to obesity and chronic systemic inflammation. The gut microbiota mediates many effects of a high-fat diet on human physiology and may also influence the mood and behavior of the host. We review here recent studies suggesting the existence of a link between obesity, the gut microbiota and depression, focusing on the mechanisms underlying the effects of a high-fat diet on chronic inflammation and brain physiology. This body of research suggests that modulating the composition of the gut microbiota using prebiotics and probiotics may produce beneficial effects on anxiety and depression.

Hirsutella sinensis polysaccharides and Parabacteroides goldsteinii reduce lupus severity in imiquimod-treated mice.

BACKGROUND: The incidence of autoimmune diseases is increasing in developed countries, possibly due to the modern Western diet and lifestyle. We showed earlier that polysaccharides derived from the medicinal fungus Hirsutella sinensis produced anti-inflammatory, anti-diabetic and anti-obesity effects by modulating the gut microbiota and increasing the abundance of the commensal Parabacteroides goldsteinii in mice fed with a high-fat diet. METHODS: We examined the effects of the prebiotics, H. sinensis polysaccharides, and probiotic, P. goldsteinii, in a mouse model of imiquimod-induced systemic lupus erythematosus. RESULTS: The fungal polysaccharides and P. goldsteinii reduced markers of lupus severity, including the increase of spleen weight, proteinuria, and serum levels of anti-DNA auto-antibodies and signal transducer and activator of transcription 4 (STAT4). Moreover, the polysaccharides and P. goldsteinii improved markers of kidney and liver functions such as creatinine, blood urea nitrogen, glomerulus damage and fibrosis, and serum liver enzymes. However, the prebiotics and probiotics did not influence gut microbiota composition, colonic histology, or expression of tight junction proteins in colon tissues. CONCLUSIONS: Our results indicate that H. sinensis polysaccharides and the probiotic P. goldsteinii can reduce lupus markers in imiquimod-treated mice. These prebiotics and probiotics may therefore be added to other interventions conducive of a healthy lifestyle in order to counter autoimmune diseases.

Gut barrier disruption and chronic disease.

The intestinal barrier protects the host against gut microbes, food antigens, and toxins present in the gastrointestinal tract. However, gut barrier integrity can be affected by intrinsic and extrinsic factors, including genetic predisposition, the Western diet, antibiotics, alcohol, circadian rhythm disruption, psychological stress, and aging. Chronic disruption of the gut barrier can lead to translocation of microbial components into the body, producing systemic, low-grade inflammation. While the association between gut barrier integrity and inflammation in intestinal diseases is well established, we review here recent studies indicating that the gut barrier and microbiota dysbiosis may contribute to the development of metabolic, autoimmune, and aging-related disorders. Emerging interventions to improve gut barrier integrity and microbiota composition are also described.

Recent advances in the field of caloric restriction mimetics and anti-aging molecules.

Caloric restriction (CR) mimetics are molecules that produce beneficial effects on health and longevity in model organisms and humans, without the challenges of maintaining a CR diet. Conventional CR mimetics such as metformin, rapamycin and spermidine activate autophagy, leading to recycling of cellular components and improvement of physiological function. We review here novel CR mimetics and anti-aging compounds, such as 4,4'-dimethoxychalcone, fungal polysaccharides, inorganic nitrate, and trientine, highlighting their possible molecular targets and mechanisms of action. The activity of these compounds can be understood within the context of hormesis, a biphasic dose response that involves beneficial effects at low or moderate doses and toxic effects at high doses. The concept of hormesis has widespread implications for the identification of CR mimetics in experimental assays, testing in clinical trials, and use in healthy humans. We also discuss the promises and limitations of CR mimetics and anti-aging molecules for delaying aging and treating chronic diseases.

Ganoderma lucidum stimulates autophagy-dependent longevity pathways in Caenorhabditis elegans and human cells.

The medicinal fungus Ganoderma lucidum is used as a dietary supplement and health tonic, but whether it affects longevity remains unclear. We show here that a water extract of G. lucidum mycelium extends lifespan of the nematode Caenorhabditis elegans. The G. lucidum extract reduces the level of fibrillarin (FIB-1), a nucleolar protein that correlates inversely with longevity in various organisms. Furthermore, G. lucidum treatment increases expression of the autophagosomal protein marker LGG-1, and lifespan extension is abrogated in mutant C. elegans strains that lack atg-18, daf-16, or sir-2.1, indicating that autophagy and stress resistance pathways are required to extend lifespan. In cultured human cells, G. lucidum increases concentrations of the LGG-1 ortholog LC3 and reduces levels of phosphorylated mTOR, a known inhibitor of autophagy. Notably, low molecular weight compounds (<10 kDa) isolated from the G. lucidum water extract prolong lifespan of C. elegans and the same compounds induce autophagy in human cells. These results suggest that G. lucidum can increase longevity by inducing autophagy and stress resistance.

Could nasal nitric oxide help to mitigate the severity of COVID-19?

The nasal cavity and turbinates play important physiological functions by filtering, warming and humidifying inhaled air. Paranasal sinuses continually produce nitric oxide (NO), a reactive oxygen species that diffuses to the bronchi and lungs to produce bronchodilatory and vasodilatory effects. Studies indicate that NO may also help to reduce respiratory tract infection by inactivating viruses and inhibiting their replication in epithelial cells. In view of the pandemic caused by the novel coronavirus (SARS-CoV-2), clinical trials have been designed to examine the effects of inhaled nitric oxide in COVID-19 subjects. We discuss here additional lifestyle factors such as mouth breathing which may affect the antiviral response against SARS-CoV-2 by bypassing the filtering effect of the nose and by decreasing NO levels in the airways. Simple devices that promote nasal breathing during sleep may help prevent the common cold, suggesting potential benefits against coronavirus infection. In the absence of effective treatments against COVID-19, the alternative strategies proposed here should be considered and studied in more detail.

Plant and fungal products that extend lifespan in Caenorhabditis elegans.

The nematode Caenorhabditis elegans is a useful model to study aging due to its short lifespan, ease of manipulation, and available genetic tools. Several molecules and extracts derived from plants and fungi extend the lifespan of C. elegans by modulating aging-related pathways that are conserved in more complex organisms. Modulation of aging pathways leads to activation of autophagy, mitochondrial biogenesis and expression of antioxidant and detoxifying enzymes in a manner similar to caloric restriction. Low and moderate concentrations of plant and fungal molecules usually extend lifespan, while high concentrations are detrimental, consistent with a lifespan-modulating mechanism involving hormesis. We review here molecules and extracts derived from plants and fungi that extend the lifespan of C. elegans, and explore the possibility that these natural substances may produce health benefits in humans.

Hormetic Effects of Phytochemicals on Health and Longevity.

Caloric restriction, intermittent fasting, and exercise activate defensive cellular responses such as autophagy, DNA repair, and the induction of antioxidant enzymes. These processes improve health and longevity by protecting cells and organs against damage, mutations, and reactive oxygen species. Consuming a diet rich in vegetables, fruits, and mushrooms can also improve health and longevity. Phytochemicals such as alkaloids, polyphenols, and terpenoids found in plants and fungi activate the same cellular processes as caloric restriction, fasting, and exercise. Many of the beneficial effects of fruits and vegetables may thus be due to activation of stress resistance pathways by phytochemicals. A better understanding of the mechanisms of action of phytochemicals may provide important insights to delay aging and prevent chronic diseases.

Antrodia cinnamomea induces anti-tumor activity by inhibiting the STAT3 signaling pathway in lung cancer cells.

We examined the effects of an Antrodia cinnamomea ethanol extract (ACEE) on lung cancer cells in vitro and tumor growth in vivo. ACEE produced dose-dependent cytotoxic effects and induced apoptosis in Lewis lung carcinoma (LLC) cells. ACEE treatment increased expression of p53 and Bax, as well as cleavage of caspase-3 and PARP, while reducing expression of survivin and Bcl-2. ACEE also reduced the levels of JAK2 and phosphorylated STAT3 in LLC cells. In a murine allograft tumor model, oral administration of ACEE significantly inhibited LLC tumor growth and metastasis without affecting serum biological parameters or body weight. ACEE increased cleavage of caspase-3 in murine tumors, while decreasing STAT3 phosphorylation. In addition, ACEE reduced the growth of human tumor xenografts in nude mice. Our findings therefore indicate that ACEE inhibits lung tumor growth and metastasis by inducing apoptosis and by inhibiting the STAT3 signaling pathway in cancer cells.

Antrodia cinnamomea produces anti-angiogenic effects by inhibiting the VEGFR2 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: The medicinal mushroom Antrodia cinnamomea has been used to treat cancer but its anti-angiogenic effects have not been studied in detail. AIM OF THE STUDY: The main objective of this study was to determine the molecular mechanism of activity underlying the anti-angiogenic effects of A. cinnamomea. MATERIALS AND METHODS: The effects of an A. cinnamomea ethanol extract (ACEE) on cell migration and microvessel formation were investigated in endothelial cells in vitro and Matrigel plugs implanted into mice in vivo. Activation of intracellular signaling pathways was examined using Western blotting. Protein expression was assessed using immunohistochemistry in a mouse model of lung metastasis. RESULTS: We show that treatment with ACEE inhibits cell migration and tube formation in human umbilical vein endothelial cells (HUVECs). ACEE suppresses phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2) and expression of pro-angiogenic kinases in vascular endothelial growth factor (VEGF)-treated HUVECs, in addition to reducing expression of Janus kinase 2 (JAK2) and phosphorylation of signal transducer and activator of transcription 3 (STAT3). ACEE treatment inhibits VEGF-induced microvessel formation in Matrigel plugs in vivo. In addition, ACEE significantly reduces VEGFR2 expression in Lewis lung carcinoma cells and downregulates the expression of cluster of differentiation 31 (CD31) and VEGFR2 in murine lung metastases. CONCLUSION: These results indicate that A. cinnamomea produces anti-angiogenic effects by inhibiting the VEGFR2 signaling pathway.

Immunomodulatory Properties of Plants and Mushrooms.

Plants and mushrooms are used for medicinal purposes and the screening of molecules possessing biological activities. A single plant or mushroom may produce both stimulatory and inhibitory effects on immune cells, depending on experimental conditions, but the reason behind this dichotomy remains obscure. We present here a large body of experimental data showing that water extracts of plants and mushrooms usually activate immune cells, whereas ethanol extracts inhibit immune cells. The mode of extraction of plants and mushrooms may thus determine the effects produced on immune cells, possibly due to differential solubility and potency of stimulatory and inhibitory compounds. We also examine the possibility of using such plant and mushroom extracts to treat immune system disorders.

Myths and Realities Surrounding the Mysterious Caterpillar Fungus.

The caterpillar fungus Ophiocordyceps sinensis is a medicinal mushroom increasingly used as a dietary supplement for various health conditions, including fatigue, chronic inflammation, and male impotence. Here, we propose strategies to address the existing challenges related to the study and commercial production of this mysterious fungus.

Anti-obesogenic and antidiabetic effects of plants and mushrooms.

Obesity is reaching global epidemic proportions as a result of factors such as high-calorie diets and lack of physical exercise. Obesity is now considered to be a medical condition, which not only contributes to the risk of developing type 2 diabetes mellitus, cardiovascular disease and cancer, but also negatively affects longevity and quality of life. To combat this epidemic, anti-obesogenic approaches are required that are safe, widely available and inexpensive. Several plants and mushrooms that are consumed in traditional Chinese medicine or as nutraceuticals contain antioxidants, fibre and other phytochemicals, and have anti-obesogenic and antidiabetic effects through the modulation of diverse cellular and physiological pathways. These effects include appetite reduction, modulation of lipid absorption and metabolism, enhancement of insulin sensitivity, thermogenesis and changes in the gut microbiota. In this Review, we describe the molecular mechanisms that underlie the anti-obesogenic and antidiabetic effects of these plants and mushrooms, and propose that combining these food items with existing anti-obesogenic approaches might help to reduce obesity and its complications.

Corrigendum: Ganoderma lucidum reduces obesity in mice by modulating the composition of the gut microbiota.

This corrects the article DOI: 10.1038/ncomms8489.

Isolation, Culture and Characterization of Hirsutella sinensis Mycelium from Caterpillar Fungus Fruiting Body.

The caterpillar fungus Ophiocordyceps sinensis (previously called Cordyceps sinensis) has been used for centuries in Asia as a tonic to improve health and longevity. Recent studies show that O. sinensis produces a wide range of biological effects on cells, laboratory animals and humans, including anti-fatigue, anti-infection, anti-inflammatory, antioxidant, and anti-tumor activities. In view of the rarity of O. sinensis fruiting bodies in nature, cultivation of its anamorph mycelium represents a useful alternative for large-scale production. However, O. sinensis fruiting bodies harvested in nature harbor several fungal contaminants, a phenomenon that led to the isolation and characterization of a large number of incorrect mycelium strains. We report here the isolation of a mycelium from a fruiting body of O. sinensis and we identify the isolate as O. sinensis' anamorph (also called Hirsutella sinensis) based on multi-locus sequence typing of several fungal genes (ITS, nrSSU, nrLSU, RPB1, RPB2, MCM7, ß-tubulin, TEF-1α, and ATP6). The main characteristics of the isolated mycelium, including its optimal growth at low temperature (16°C) and its biochemical composition, are similar to that of O. sinensis fruiting bodies, indicating that the mycelium strain characterized here may be used as a substitute for the rare and expensive O. sinensis fruiting bodies found in nature.

Pinicolol B from Antrodia cinnamomea induces apoptosis of nasopharyngeal carcinoma cells.

ETHNOPHARMACOLOGICAL RELEVANCE: The medicinal mushroom Antrodia cinnamomea possesses anticancer properties but the active compounds responsible for these effects are mostly unknown. AIM OF THE STUDY: We aimed to identify novel A. cinnamomea compounds that produce cytotoxic effects on cancer cells. MATERIALS AND METHODS: Using ethanol extraction and chromatography, we isolated the lanostanoid compound lanosta-7,9(11),24-trien-3ß,15α,21-triol (1) from cultured A. cinnamomea mycelium. Cytotoxicity and pro-apoptotic effects of compound 1 were evaluated using the MTS assay and flow cytometry analysis, respectively. RESULTS: Compound 1 produced cytotoxic effects on the nasopharyngeal carcinoma cell lines TW02 and TW04, with IC50 values of 63.3 and 115.0µM, respectively. On the other hand, no cytotoxic effects were observed on non-tumorigenic nasopharyngeal epithelial cells (NP69). In addition, compound 1 induced apoptosis in TW02 and TW04 cells as revealed by flow cytometry analysis. CONCLUSIONS: Our results demonstrate for the first time the presence of pinicolol B in A. cinnamomea mycelium and suggest that this compound may contribute to the anticancer effects of A. cinnamomea.