Eugenol Elicits Prolongevity by Increasing Resistance to Oxidative Stress in C. elegans.

AIMS: To analyze the efficacy of eugenol on longevity by assessing its antioxidant effect using Caenorhabditis elegans as an animal model. BACKGROUND: Eugenol is a major polyphenolic component of Ocimum sanctum (Tulsi) which attributes wide pharmacological activities and can serve as a biomarker. However, the possible effect of eugenol on longevity in Caenorhabditis elegans has not been reported. OBJECTIVE: The objective of this investigation was to provide the first scientific based results about the effect of eugenol on longevity, slowing down of paralysis in Alzheimer's model and the mechanism behind it in Caenorhabditis elegans animal model system. METHODS: The phenolic components of methanolic extract of Ocimum sanctum were analyzed by RP-HPLC. Worms were exposed to different concentrations of extract and one of its components - eugenol. Lifespan, health span, survival in CL4176 Alzheimer's model and molecular mechanism were analyzed. RESULTS: Extract of Ocimum sanctum and eugenol increased lifespan and provided indemnity against pro-oxidants. It also significantly improved healthy ageing and slowed the progression of neurodegeneration in CL4176 Alzheimer's model of the worm by increasing survival against prooxidants and slowing down the paralysis. Longevity effect was independent of the DAF-16 as observed by using DAF-16::GFP and daf-16 null mutant strains. These results implicate eugenol as a potent therapeutic compound that may curtail ageing and age related disorders like- Alzheimer's disease. CONCLUSION: The present work demonstrated eugenol as a potential anti-ageing compound that may curtail ageing, improve heath span by enhancing resistance to oxidative stress and exerts its effect independent of DAF-16 pathway. So, it can be assumed that eugenol can be beneficial to humans as well, albeit further research is necessary before declaring it for human consumption.

Silymarin extends lifespan and reduces proteotoxicity in C. elegans Alzheimer's model.

Aging is a process of progressive decline in physiological functions resulting in increased vulnerability to diseases and death. Aging results in increased rates of age related disorders like neurodegenerative diseases, cardiovascular diseases, diabetes, cancer, arthritis etc. Modulation of insulin signaling, protein aggregation, stress, free radical damage and inflammation are the major causes for deleterious changes resulting in aging. Many studies are being undertaken to find novel compounds which can improve a typical human life span and aid in healthy aging. We investigated the potential of one such compound silymarin for its anti-aging effect. Silymarin is a flavanone derivative extracted from the seeds of the milk thistle Silybum marianum. It is widely used for the treatment of liver diseases in clinical practice. We tested the anti-aging efficacy of silymarin using the Caenorhabditis elegans model system. Our results demonstrate that C. elegans treated with 25µM and 50µM silymarin concentration resulted in an increase in mean lifespan by 10.1% and 24.8% respectively compared to untreated control. Besides increased lifespan, silymarin treated aged animals showed better locomotion rate, higher response to stimuli and improved tolerance to stress compared to untreated control. We also checked the potential of silymarin to slow the progression of neurodegenerative disorder like Alzheimer's disease (AD) by using CL4176 C. elegans model for AD. C. elegans CL4176 transgenic animal induces expression of amyloid beta-protein (Aß1-42) in muscle tissues when subjected to temperature of 23°C and above resulting in worm paralysis. CL4176 animals treated with silymarin showed delayed paralysis via enhancing resistance to oxidative stress. These results suggested that silymarin is a potential hormetin for preventing aging and age-related diseases.

Phycoerythrin extends life span and health span of Caenorhabditis elegans.

In the present study, we tested the antioxidant activity of phycoerythrin (PE, an oligomeric light harvesting protein isolated from Lyngbya sp. A09DM) to curtail aging effects in Caenorhabditis elegans. Purified PE (100 µg/ml) dietary supplement was given to C. elegans and investigated for its anti-aging potential. PE treatment improved the mean life span of wild type (N2)-animals from 15 ± 0.1 to 19.9 ± 0.3 days. PE treatment also moderated the decline in aging-associated physiological functions like pharyngeal pumping and locomotion with increasing age of N2 worms. Moreover, PE treatment also enhanced the stress tolerance in 5-day-aged adults with increase in mean survival rate from 22.2 ± 2.5 to 41.6 ± 2.5% under thermo stress and from 30.1 ± 3.2 to 63.1 ± 6.4% under oxidative (hydrogen peroxide)-stress. PE treatment was also noted to moderate the heat-induced expression of human amyloid-beta(Aß1-42) peptide and associated paralysis in the muscle tissues of transgenic C. elegans CL4176 (Alzheimer's disease model). Effectiveness of PE in expanding the life span of mutant C. elegans, knockout for some up (daf-2 and age-1)- and down (daf-16)-stream regulators of insulin/IGF-1 signaling (IIS), shows the independency of PE effect from DAF-2-AGE-1-DAF-16 signaling pathway. Moreover, the inability of PE in expanding the life span of hsf-1 knockout C. elegans(sy441) suggests the dependency of PE effect on heat shock transcription factor (HSF-1) controlling stress-induced gene expression. In conclusion, our results demonstrated a novel anti-aging activity of PE which conferred increased resistance to cellular stress resulting in improved life span and health span of C. elegans.

Characterization of two novel biovar of Agrobacterium tumefaciens isolated from root nodules of Vicia faba.

A total of eight strains of bacteria were isolated from the root nodule of Vicia faba on the selective media of Rhizobium. Two of these strains produced phenotypically distinct mucoid colonies (one slow growing and the other fast growing) and were examined using a polyphasic approach for taxonomic identification. The two strains (MTCC 7405 and MTCC 7406) turned out to be new strains of biovar 1 Agrobacterium rather than Rhizobium, as they showed growth on alkaline medium as well as on 2% NaCl and neither catabolized lactose as the carbon source nor oxidized Tween-80. The distinctness between the two strains was marked with respect to their growth on dextrose and the production of lysine dihydrolase, ornithine decarboxylase and DNA G + C content. 16S rDNA sequencing and their comparison with the 16S rDNA sequences of previously described agrobacteria as well as rhizobia strains confirmed the novelty of the two strains. Both of the strains clustered with strains of Agrobacterium tumefaciens in the 16S rDNA-based phylogenetic tree. The phenotypic and biochemical properties of the two strains differed from those of the recognized biovar of A. tumefaciens. It is proposed that the strains MTCC 7405 and MTCC 7406 be classified as novel biovar of the species A. tumefaciens (Type strains MTCC 7405 = DQ383275 and MTCC 7406 = DQ383276).