Chebulinic acid and Boeravinone B act as anti-aging and anti-apoptosis phyto-molecules during oxidative stress

Potential inhibitors of RPS6KB2 and NRF2 in head and neck squamous cell carcinoma

Among the major altered pathways in head and neck squamous cell carcinoma, AKT/mTORC1/S6K and NRF2/KEAP1 pathway are quite significant. The overexpression and overstimulation of proteins from both these pathways makes them the promising candidates in cancer therapeutics. Inhibiting mTOR has been in research from past several decades but the tumour heterogeneity, and upregulation of several compensatory feed-back mechanisms, encourages to explore other downstream targets for inhibiting the pathway. One such downstream effectors of mTOR is S6K2. It is reported to be overexpressed in cancers such as head and neck cancer, breast cancer and prostate cancer. In case of NRF2/KEAP1 pathway, nuclear factor erythroid 2-related factor 2 (NFE2L2 or NRF2) is overexpressed in ∼90% of head and neck squamous cell carcinoma (HNSCC) cases. It associates with poor survival rate and therapeutic resistance in HNSCC treatment. NRF2 pathway is the primary antioxidant pathway in the cell which also serves pro-tumorigenic functions, such as repression of apoptosis, cell proliferation support and chemoresistance. The aim of this work was to explore S6K2 and NRF2 and identify novel and potential inhibitors against them for treating head and neck squamous cell carcinoma. Since the crystal structure of S6K2 was not available at the time of this study, we modelled its structure using homology modelling and performed high throughput screening, molecular dynamics simulations, free energy calculations and protein-ligand interaction studies to identify the inhibitors. We identified natural compounds Crocin and Gypenoside XVII against S6K2 and Chebulinic acid and Sennoside A against NRF2. This study provides a significant in-depth understanding of the two studied pathways and therefore can be used in the development of potential therapeutics against HNSCC.Communicated by Ramaswamy H. Sarma.

Boeravinone B, a natural rotenoid, inhibits osteoclast differentiation through modulating NF-κB, MAPK and PI3K/Akt signaling pathways

Osteoporosis is a major public health concern, which requires novel therapeutic strategies to prevent or mitigate bone loss. Natural compounds have attracted attention as potential therapeutic agents due to their safety and efficacy. In this study, we investigated the regulatory activities of boeravinone B (BOB), a natural rotenoid isolated from the medicinal plant Boerhavia diffusa, on the differentiation of osteoclasts and mesenchymal stem cells (MSCs), the two main cell components responsible for bone remodeling. We found that BOB inhibited osteoclast differentiation and function, as determined by TRAP staining and pit formation assay, with no significant cytotoxicity. Furthermore, our results showing that BOB ameliorates ovariectomyinduced bone loss demonstrated that BOB is also effective in vivo. BOB exerted its inhibitory effects on osteoclastogenesis by downregulating the RANKL/RANK signaling pathways, including NF-κB, MAPK, and PI3K/Akt, resulting in the suppression of osteoclast-specific gene expression. Further experiments revealed that, at least phenomenologically, BOB promotes osteoblast differentiation of bone marrow-derived MSCs but inhibits their differentiation into adipocytes. In conclusion, our study demonstrates that BOB inhibits osteoclastogenesis and promotes osteoblastogenesis in vitro by regulating various signaling pathways. These findings suggest that BOB has potential value as a novel therapeutic agent for the prevention and treatment of osteoporosis. [BMB Reports 2023; 56(10): 545-550].

Chebulinic acid alleviates LPS-induced inflammatory bone loss by targeting the crosstalk between reactive oxygen species/NFκB signaling in osteoblast cells

Chebulinic acid (CA), a plant ellagitannin derived from Triphala, is reported to exhibit both anti-inflammatory & anti-oxidant activity apart from anti-tumour property. However, its role in inflammatory bone loss conditions was unexplored. We hypothesized that CA may prevent the bone loss under inflammatory conditions induced by lipopolysaccharide (LPS) in 10-week-old male C57BL/6J mice. Micro-CT analysis and histomorphometric evaluations were carried out where it was found that CA significantly improved the bone micro-architectures by enhancing trabecular connectivity and strength of the bone. CA also increased the bone regeneration as examined by calcein labelling and ex-vivo mineralisation along with maintaining the bone serum markers. Further, CA ameliorated the reduction in osteoblast cell differentiation, proliferation and viability after LPS stimulation. DCFDA and Mitosox staining revealed that CA presented remarkable protective effects against LPS treatment by attenuating oxidative stress, both at cellular & mitochondrial levels. In addition, CA significantly decreased the production of pro-inflammatory cytokines, and down-regulated the phosphorylation of NFκB and IκBα, indicating that CA could attenuate the inflammatory impairment to primary osteoblast cells by suppressing the NFkB signalling pathway. Taken together, the protective role of CA against LPS-induced bone loss & inhibitory effect on total ROS levels hold promise as a potential novel therapeutic strategy for the inflammatory diseases in bones.

Ex Vivo and In Vitro Antiaging and Antioxidant Extract Activity of the Amelanchier ovalis from Siberia

Phenolic acids are biologically active substances that prevent aging and age-related diseases, e.g., cancer, cardiovascular diseases, Alzheimer's disease, Parkinson's disease, etc. Cellular senescence is related to oxidative stress. The Siberian Federal District is rich in medicinal plants whose extracts contain phenolic acids. These plants can serve as raw materials for antiaging, antioxidant food supplements, and Amelanchier ovalis is one of them. In the present research, we tested the phytochemical profile of its extract for phenolic acids. Its geroprotective and antioxidant properties were studied both ex vivo and in vitro using Saccharomyces cerevisiae Y-564 as a model organism. The chromotographic analysis revealed gallic, p-hydroxybenzoic, and protocatechuic acids, as well as derivatives of chlorogenic and gallic acids. The research involved 0.25, 0.5, and 1.0 mg/mL extracts of Amelanchier ovalis, all of which increased the growth and lifespan of yeast cells. In addition, the extracts increased the survival rate of yeast under oxidative stress. An in vitro experiment also demonstrated the antioxidant potential of Amelanchier ovalis against ABTS radicals. Therefore, the Amelanchier ovalis berry extract proved to be an excellent source of phenolic acids and may be recommended as a raw material for use in antioxidant and geroprotective food supplements.

Targeting aging mechanisms: pharmacological perspectives

Geroprotectors slow down aging and promote healthy longevity in model animals. Although hundreds of compounds have been shown to extend the life of laboratory model organisms, clinical studies on potential geroprotectors are exceedingly rare, especially in healthy elders. This review aims to classify potential geroprotectors based on the mechanisms by which they influence aging. These pharmacological interventions can be classified into the following groups: those that prevent oxidation; proteostasis regulators; suppressors of genomic instability; epigenetic drugs; those that preserve mitochondrial function; inhibitors of aging-associated signaling pathways; hormetins; senolytics/senostatics; anti-inflammatory drugs; antifibrotic agents; neurotrophic factors; factors preventing the impairment of barrier function; immunomodulators; and prebiotics, metabiotics, and enterosorbents.

Field study on the soil bacterial associations to combined contamination with heavy metals and organic contaminants

The understanding of soil microbial associations to combined contamination would substantially benefit the restoration of damaged ecosystems, which is currently limited at the field scale. In this study, we investigated the soil bacterial associations to combined contamination with metals (Cd, Cu, Hg, Pb, and Zn), polyaromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs). Samples were collected from field sites under five land-use patterns with electronic waste recycling. Results showed that the contents of Cd (0.22-12.86 mg/kg), Cu (17-14,136 mg/kg), Pb (4.6-77,014 mg/kg), Hg (0.28-22 mg/kg), Zn (26-42,495 mg/kg), PAHs (4.6-1753 μg/kg), and PBDEs (1.9-1079 μg/kg) varied significantly across sites. We observed positive correlations between catalase activity and heavy metals, indicative of a resistance response to the oxidative stress induced by metals. Furthermore, the bacterial community diversity was found to be determined primarily by PBDEs, whereas acenaphthylene, available phosphorus, and 2,2',3,3',4,5,6-heptabrominated diphenyl ether (BDE-183) were the three major drivers affecting community composition. The co-occurrence network constructed for bacterial communities exposed to combined contamination was non-random with scale-free, small-world and modularity features. We further proposed functional roles of the modules including stress resistance, hydrocarbon degradation, and nutrient cycling. Overall, the findings of redundancy analysis, variation partition analysis and the co-occurrence network indicated that soil bacterial community under combined contamination cooperated to survive. Members including Rhodoplanes and Nitrospira were capable of degrading PAHs and PBDEs in various pathways, while others, including Acinetobacter, Citrobacter, and Pseudomonas, reduced the metal toxicity to the community. Our findings provide new insights into the responses of soil bacteria, particularly in terms of inter-specific relationships, under combined contamination at the field scale.

A Bioactive compound Shatavarin IV-mediated longevity as revealed by dietary restriction-induced autophagy in Caenorhabditis elegans

Plant-based dietary supplements that delay aging are of significant interest now a days because these naturally occurring bioactive molecules effectively provide pharmaceuticals/neutraceuticals to deal with diseases related to the advanced life expectancy. In this paper, we aimed to investigate the effect of Shatavarin IV (SIV), a steroidal saponin isolated from Asparagus racemosus Willd. on dietary restriction (DR) induced longevity in Caenorhabditis elegans. SIV significantly increased the lifespan to 18% which is independent of antimicrobial activity and reduced the aging by-product, lipofuscin along with increased locomotion, and chemotaxis behavior in wild type worms. The longevity effect has been dependent on eat-2, which was further validated via reduced pharyngeal pumping rate that established the effect similar to DR induced longevity. Moreover, like eat-2 mutant worms, SIV reduces the total progeny number of wild type worm along with a significant alleviation of stored fat, which reconfirms the involvement of eat-2 mediated longevity. Further, it was also observed that DR induced longevity mechanism by SIV requires mTOR which works in PHA-4/FOXA dependent manner. In addition to this, the role of autophagy mechanism concerning SIV mediated DR was confirmed via bec-1, unc-51, and lgg-1. The longevity effect achieved by SIV was also dependent on SKN-1/NRF-2 and partially dependent on DAF-16/FOXO. Furthermore, the DR-induced longevity by SIV was found to be independent of hsf-1 exhibiting non-significant alteration in the mRNA expression of downstream target genes hsp-16.2 and hsp-70. Altogether, this study provides first-hand information on the pro-longevity effect of SIV in worms that have been mediated by the DR-regulating gene induced autophagy.

Potential protective roles of phytochemicals on glutamate-induced neurotoxicity: A review

Glutamate, as an essential neurotransmitter, has been thought to have different roles in the central nervous system (CNS), including nerve regeneration, synaptogenesis, and neurogenesis. Excessive glutamate causes an up-regulation of the multiple signaling pathways, including phosphoinositide-3 kinase/protein kinase B (PI3K/Akt), Akt/mammalian target of rapamycin (mTOR) protein, mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK)1/2, and autophagy that are involved in neurodegenerative diseases pathophysiology. There are numerous findings on curcumin, astaxanthin, thymoquinone, and berberine, as natural products, which have outstanding effects in cell signaling far beyond their anti-oxidant activity, considering as a potential therapeutic target for glutamate excitotoxicity. Herein, we address the role of glutamate as a potential target in neurodegenerative diseases and discuss the protective effects of certain phytochemicals on glutamate-induced neurotoxicity.