Polyphenols & Aging & Hormesis Baste on 15 Feb 2007 04:52 pm
Neurohormesis: Paracelsus Revisited?!
Source: Trends in Neuroscience (2006), 29: 632-639
Article Type: Review
Authors: MP Mattson, A Cheng
Image taken from: http://www.bad-bad.de/gesch/paracel.gif
Recently, the hormesis theory is gaining momentum for explaining the health-beneficial effects of diets rich in fruits and vegetables. Actually, one of the first to describe hormetic effects of any substance applied to living things has been Paracelsus, one of the most famous scientists of the 16th century.
What is hormesis? The term describes the induction of health-beneficial effects due to the low-dose presence of agents that are toxic at higher concentrations (adaptive response). In this regard, phytochemicals (such as polpyhenols) can be considered as mild stressors provoking the up-regulation of the endogenous antioxidant network. This in turn would enable an organism to better cope with an increasing production of reactive oxidative and nitrosative species (ROS and RNS), for example in disease states. Consequently, the detrimental degeneration of proteins, fatty acids, sugars and DNA would be avoided. In the long run, this could finally lead to a healthier aging process, characterised by a lower burden of chronic, lifestyle maladies. Mattson and Cheng support this concept by summarising recent data obtained with, amongst others, the neurohormetic phytochemicals resveratrol and curcumin in vitro and in vivo.
Personally, I feel quite comfortable with this theory. However, whether it will help to answer the recurring question of whether an increase/decrease in biomarkers such as antioxidant capacity or antioxidant enzyme activity upon incubation/intake of phytochemicals is actually beneficial or detrimental, only time will tell.
For further reading, I recommend: Arumugam et al., 2006 and Hipkiss, 2006 and Hayes, 2007.
on 16 Feb 2007 at 11:00 am 1.Graeme SMITH said …
First of all, great weblog. I really enjoy the read. I catch it on Google Reader
Hormesis and modulation of both the physiological and psychological systems by applying small stressors with exercise and/or diet is quiet an interesting subject.
I’ve seen a fair bit of work published over the last year about adaptogenic compounds that act to activate various cellular signalling pathways, strengthening the system and protecting against stress.
Two compounds that come to mind are Rhodiola Rosea and Ashwagandha.
Here’s a paper published just last month….
Phytother Res. 2007 Jan;21(1):37-43.
Adaptogenic and central nervous system effects of single doses of 3% rosavin and 1% salidroside Rhodiola rosea L. extract in mice.
* Perfumi M,
* Mattioli L.
Department of Experimental Medicine and Public Health, University of Camerino, Via Scalzino 3, 62032 Camerino (MC), Italy. marina.perfumi@unicam.it
Rhodiola rosea L., or ‘golden root’, is a popular plant in traditional medicine in Eastern Europe and Asia, with a reputation for improving depression, enhancing work performance, eliminating fatigue and treating symptoms of asthenia subsequent to intense physical and psychological stress. Due to these therapeutic properties, R. rosea is considered to be one of the most active adaptogenic drugs. To confirm and extend results obtained in the few preclinical and clinical studies available in English language journals, the purpose of the present study was to re-investigate the effects produced by a single oral administration of an R. rosea hydroalcohol extract (containing 3% rosavin and 1% salidroside) on the central nervous system in mice. The extract was tested on antidepressant, adaptogenic, anxiolytic, nociceptive and locomotor activities at doses of 10, 15 and 20 mg/kg, using predictive behavioural tests and animal models. The results show that this R. rosea extract significantly, but not dose-dependently, induced antidepressant-like, adaptogenic, anxiolytic-like and stimulating effects in mice. This study thus provides evidence of the efficacy of R. rosea extracts after a single administration, and confirms many preclinical and clinical studies indicating the adaptogenic and stimulating effects of such R. rosea extracts. Moreover, antidepressant-like and anxiolytic-like activities of R. rosea were shown in mice for the first time.
PMID: 17072830 [PubMed - in process]
and here’s a paper about ashwagandha
Pharmacol Biochem Behav. 2003 Jun;75(3):547-55.
Adaptogenic activity of Withania somnifera: an experimental study using a rat model of chronic stress.
* Bhattacharya SK,
* Muruganandam AV.
Department of Pharmacology, Postgraduate Institute of Basic Medical Sciences, Calcutta University, 244 B Acharya JC Bose Road, Calcutta 700 020, India.
Withania somnifera (WS) Dunal is classified in Ayurveda, the ancient Hindu system of medicine, as a rasayana, a group of plant-derived drugs reputed to promote physical and mental health, augment resistance of the body against disease and diverse adverse environmental factors, revitalise the body in debilitated conditions and increase longevity. These attributes are remarkably similar to the properties ascribed to adaptogens like Panax ginseng (PG) in contemporary medicine. As such, the adaptogenic activity of a standardised extract of WS roots was investigated against a rat model of chronic stress (CS). The stress procedure was mild, unpredictable footshock, administered once daily for 21 days to adult male Wistar rats. CS induced significant hyperglycaemia, glucose intolerance, increase in plasma corticosterone levels, gastric ulcerations, male sexual dysfunction, cognitive deficits, immunosuppression and mental depression. These CS induced perturbations were attenuated by WS (25 and 50 mg/kg po) and by PG (100 mg/kg po), administered 1 h before footshock for 21 days. The results indicate that WS, like PG, has significant antistress adaptogenic activity, confirming the clinical use of the plant in Ayurveda.
PMID: 12895672 [PubMed - indexed for MEDLINE]
and finally here’s another worth while read
Mech Ageing Dev. 2004 Apr;125(4):285-9.
Aging, anti-aging, and hormesis.
* Rattan SI.
Department of Molecular Biology, Danish Centre for Molecular Gerontology, University of Aarhus, Gustav Wieds Vej, DK-8000 Aarhus-C, Denmark. rattan@imsb.au.dk
As a result of almost 50 years of efforts in collecting descriptive data, biogerontologists are now able to construct general principles of aging and to explore possibilities of gerontomodulation. Most of the data indicate that aging is characterized by a stochastic accumulation of molecular damage and a progressive failure of maintenance and repair, and the genes involved in homeodynamic pathways are the most likely candidate virtual gerontogenes. Several approaches are being tried and tested to modulate aging in a wide variety of organisms, but with the ultimate aim of improving the quality of human life in old age. These approaches include gene therapy, hormonal supplementation, nutritional modulation, and intervention by antioxidants and other molecules. A recent approach is that of applying hormesis in aging research and therapy, which is based on the principle of stimulation of maintenance and repair pathways by repeated exposure to mild stress.
PMID: 15063104 [PubMed - indexed for MEDLINE]