Age is the leading risk factor for many of the most prevalent and devastating diseases including neurodegenerative diseases. A number of herbal medicines have been used for centuries to ameliorate the deleterious effects of ageing-related diseases and increase longevity. Oxidative stress is believed to play a role in normal ageing as well as in neurodegenerative processes. Since many of the constituents of herbal extracts are known antioxidants, it is believed that restoring oxidative balance may be one of the underlying mechanisms by which medicinal herbs can protect against ageing and cognitive decline. Based on the premise that astrocytes are key modulators in the progression of oxidative stress associated neurodegenerative diseases, 13 herbal extracts purported to possess anti-ageing properties were tested for their ability to protect U373 human astrocytes from hydrogen peroxide induced cell death. To determine the contribution of antioxidant activity to the cytoprotective ability of extracts, total phenol content and radical scavenging capacities of extracts were examined. Polygonum multiflorum, amongst others, was identified as possessing potent antioxidant and cytoprotective properties. Not surprisingly, total phenol content of extracts was strongly correlated with antioxidant capacity. Interestingly, when total phenol content and radical scavenging capacities of extracts were compared to the cytoprotective properties of extracts, only moderately strong correlations were observed. This finding suggests the involvement of multiple protective mechanisms in the beneficial effects of these medicinal herbs.
► Oxidative stress plays a role in neurodegenerative processes. ► Thirteen herbal extracts tested for protection against H2O2 induced cell death. ► Polygonum multiflorum was the most potent antioxidant and cytoprotectant. ► Total phenol content was strongly correlated with antioxidant capacity. ► Antioxidant activity is moderately correlated with cytoprotective ability.
For millennia, herbal medicines consisting of whole herbs or plant parts such as leaves, stems, roots and seeds have been used in traditional Chinese medicine (TCM) for the treatment of specific ailments, to maintain and restore body balance and to increase longevity (Suk, 2005). Many of the drugs available in Western medicine have been directly isolated from plants or are hemi-synthetic molecules based on the molecular scaffolds of natural products. While Western medicine mainly focuses on the identification and isolation of single active constituents from plants that interact with single therapeutic targets, TCM aims to reverse the underlying “imbalance” between the body and the environment that is thought to cause disease (Cheng, 2000). This often involves the use of complex mixtures of herbs containing multiple chemical groups and compounds with diverse biological and pharmacological actions. It is believed that compounds not only act synergistically with other compounds from the same plant, but also may enhance the activity or counteract the toxicity of compounds from other plants (Howes and Houghton, 2003). A recent study, investigating the antioxidant properties of a herb which is used extensively in TCM, Polygonum multiflorum, found that the radical scavenging abilities of two of its main active components, emodin and quercetin, were lower than crude leaf, stem and root extracts of the herb (Lin et al., 2010). Furthermore, while studies with traditional herbal medicines such as Fuzhisan (Bi et al., 2011) and herbal extracts such as Panax ginseng(Lee et al., 2008) have shown success in slowing cognitive decline; results of clinical trials with single “active” compounds, such as curcumin from Curcuma longa (Hamaguchi et al., 2011) and huperzine A fromHuperzia serrata (Rafii et al., 2011) have not been successful.
Full Article can be found here http://www.sciencedirect.com/science/article/pii/S0197018612002860
Cytoprotective properties of traditional Chinese medicinal herbal extracts in hydrogen peroxide challenged human U373 astroglia cells
- Megan L. Steelea,
- John Truongc, 1,
- Suresh Govindaraghavana, d, 2,
- Lezanne Ooia,
- Nikolaus J. Sucherc, 1,
- Gerald Müncha, b, ,
- a Dept. of Pharmacology, School of Medicine, University of Western Sydney, Campbelltown, NSW, Australia
- b Molecular Medicine Research Group, University of Western Sydney, Campbelltown, NSW, Australia
- c CompleMed, University of Western Sydney, Campbelltown, NSW, Australia
- d LIPA Pharmaceuticals, Minto, NSW, Australia