The untapped potential of spermidine alkaloids: Sources, structures, bioactivities and syntheses

A Spermidine Derivative Ameliorates Dextran Sulfate Sodium-Induced Colitis in Mice by Inhibiting the MAPK4/AKT Signaling Pathway

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by recurrent episodes and an inability to achieve a complete cure. The spermidine derivative (di-p-coumaroyl-caffeoyl spermidine, SPDD), as a key alkaloid, exhibits unique health benefits. However, it has not yet been reported whether SPDD can improve dextran sulfate sodium (DSS)-induced colitis in mice. Herein, we investigated the effects and mechanisms of SPDD on DSS-induced colitis in mice. SPDD was successfully purified from rose bee pollen and was found to have a protective effect on colitis, evidenced by reduced disease activity index (DAI) scores and colonic inflammation, increased colonic length and upregulated the expression of tight junction proteins (TJs) in the model (p < 0.05). Importantly, the IL-17 signaling pathway showed significant enrichment by RNA sequencing (RNA-seq) technology with SPDD treatment, which resulted in the downregulation of MAPK4 expression (p < 0.05). Furthermore, SPDD weakened the interaction between MAPK4 and AKT, resulting in a decrease in the phosphorylation level of AKT, thereby reducing the expression of IL-6, IL-1β, iNOS, and COX-2, and alleviating colitis (p < 0.05). In addition, SPDD treatment also ameliorated TNF-α-induced inflammation in Caco-2 cells. Overall, our study demonstrated that SPDD reversed colonic inflammation in colitis mice through the MAPK4/AKT pathway and might be a promising candidate for UC intervention.

Achieving healthy aging through gut microbiota-directed dietary intervention: Focusing on microbial biomarkers and host mechanisms

BACKGROUND

Population aging has become a primary global public health issue, and the prevention of age-associated diseases and prolonging healthy life expectancies are of particular importance. Gut microbiota has emerged as a novel target in various host physiological disorders including aging. Comprehensive understanding on changes of gut microbiota during aging, in particular gut microbiota characteristics of centenarians, can provide us possibility to achieving healthy aging or intervene pathological aging through gut microbiota-directed strategies.

AIM OF REVIEW

This review aims to summarize the characteristics of the gut microbiota associated with aging, explore potential biomarkers of aging and address microbiota-associated mechanisms of host aging focusing on intestinal barrier and immune status. By summarizing the existing effective dietary strategies in aging interventions, the probability of developing a diet targeting the gut microbiota in future is provided.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three key notions: Firstly, gut microbiota has become a new target for regulating health status and lifespan, and its changes are closely related to age. Thus, we summarized aging-associated gut microbiota features at the levels of key genus/species and important metabolites through comparing the microbiota differences among centenarians, elderly people and younger people. Secondly, exploring microbiota biomarkers related to aging and discussing future possibility using dietary regime/components targeted to aging-related microbiota biomarkers promote human healthy lifespan. Thirdly, dietary intervention can effectively improve the imbalance of gut microbiota related to aging, such as probiotics, prebiotics, and postbiotics, but their effects vary among.

Spermidine Exerts Protective Effects in Random-Pattern Skin Flap Survival in Rats: Possible Involvement of Inflammatory Cytokines, Nitric Oxide, and VEGF

BACKGROUND

Distal necrosis and inflammation are two of the most common health consequences of random-pattern skin flaps survival (SFS). Anti-inflammatory effects of spermidine have been identified in various studies. On the other hand, considering the involvement of the nitric oxide molecule in the spermidine mode of action and also its role in skin tissue function, we analyzed the possible effects of spermidine on the SFS and also, potential involvement of nitrergic pathway and inflammatory cytokine in these phenomena.

METHODS

Each rat was pretreated with either a vehicle (control) or various doses of spermidine (0.5, 1, 3, 5, 10 and 30 mg/kg) and then was executed a random-pattern skin flap paradigm. Also, spermidine at the dose of 5 mg/kg was selected and one group rats received spermidine 20 min prior to surgery and one additional dose 1 day after operation. Then, 7 days after operations, interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon-gamma (IFN-γ), and nitrite levels were inquired in the tissue samples by ELIZA kit. Vascular endothelial growth factor expression was assessed by DAPI staining and fluorescent microscopes. The concentrations of three polyamines, including spermidine, spermine, and cadaverine, were analyzed using HPLC.

RESULTS

Pretreatment with spermidine 5 mg/kg improved SFS considerably in microscopic skin H&E staining analysis and decreased the percentage of necrotic area. Moreover, spermidine exerted promising anti-inflammatory effects via the modulation of nitric oxide and reducing inflammatory cytokines.

CONCLUSIONS

Spermidine could improve skin flaps survival, probably through the nitrergic system and inflammation pathways. This preclinical study provides level III evidence for the potential therapeutic effects of spermidine on SFS in rats, based on the analysis of animal models. Further studies are needed to confirm these findings in clinical settings.

LEVEL OF EVIDENCE III

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Polyamine-containing natural products: structure, bioactivity, and biosynthesis

Covering: 2005 to August, 2023Polyamine-containing natural products (NPs) have been isolated from a wide range of terrestrial and marine organisms and most of them exhibit remarkable and diverse activities, including antimicrobial, antiprotozoal, antiangiogenic, antitumor, antiviral, iron-chelating, anti-depressive, anti-inflammatory, insecticidal, antiobesity, and antioxidant properties. Their extraordinary activities and potential applications in human health and agriculture attract increasing numbers of studies on polyamine-containing NPs. In this review, we summarized the source, structure, classification, bioactivities and biosynthesis of polyamine-containing NPs, focusing on the biosynthetic mechanism of polyamine itself and representative polyamine alkaloids, polyamine-containing siderophores with catechol/hydroxamate/hydroxycarboxylate groups, nonribosomal peptide-(polyketide)-polyamine (NRP-(PK)-PA), and NRP-PK-long chain poly-fatty amine (lcPFAN) hybrid molecules.