Effect of the Lycium Barbarum Polysaccharides on Age-related oxidative Stress

Author: Luigi Scavino
Date: 24/02/2015


Goji berry (or wolfberry) is the fruit of Lycium barbarum and Lycium chinense, two closely related species in the family Solanaceae. The family also includes the potato, tomato, eggplant, chili pepper, tobacco and belladonna. The two species are native to Asia.

Since the early 21st century, interest has increased for wolfberries for their novelty and nutrient value. They have been termed a superfruit, which has led to a profusion of consumer products. In traditional medicine, the whole fruit or its extracts have numerous implied health effects.

Goji, 2015

The wide-ranging properties of the Goji berry can be explained by its composition: it is extremely rich in vitamins (A, C, B1, B2, B3, B12), minerals (calcium, phosphorus, potassium, iron, zinc, selenium, manganese, copper, chromium), aminoacids (18, among essential and not essential), sterols, vegetable fatty acids, betaine, flavonoids, carotenoids (beta-carotene, lutein, lycopene).

Valori nutrizionali del Goji, 2015

Because of this, Lycium barbarum fruits have a large variety of biological activities and pharmacological functions and play an important role in preventing and treating various chronic diseases, such as diabetes, hyperlipidemia, cancer, hepatitis, hypo-immunity function, thrombosis, and male infertility.

Goji Berry Health Properties, 2014

During the nineties the discovery of new biochemical compounds in goji berries has increased the interest in these small red fruits. In particular, 4 polysaccharides (complex sugars) unique in nature were found: that is precisely why they took the name from the berries: LBP, Lycium Barbarum Polysaccharides.

These polysaccharides, present in large quantities in goji berries (up 31% of the weight of the dried berries) are particularly valuable because the capacity to exercise an important antioxidation effect.

Gli LBP delle Bacche di Goji, 2015

Aging is a progressive deterioration of physiological function that impairs the ability of an organism to maintain homeostasis and consequently increases the organism's susceptibility to disease and death. Nearly all organisms manifest functional declines as a result of aging. It is widely accepted that disorganizing free radical reactions linked to oxygen metabolism or oxidative stress play an important role not only in normal aging but also in many age-related degenerative processes.
Oxidative stress is described generally as a condition under which increased production of free radicals, reactive species (including singlet oxygen and reactive lipid peroxidation products, such as reactive aldehydes and peroxides), and oxidant-related reactions occur that result in damage.
It is well recognized that free radical scavengers or antioxidants plays a important role in slowing down biological aging. The evidence suggests that Lycium barbarum is effective to be an anti-aging agent as well as nourishment of eyes, livers and kidneys. The anti-aging property of Lycium barbarum is found in the polysaccharides isolated from the red-colored fruits and has been investigated in different models. For example, extracts of Lycium barbarum have anti-decrepit effect in brain and heart tissues by increasing the activity of superoxide dismutase.

Oxidation of lipids produces lipid peroxides that can reduce membrane fluidity, inactivate membrane-bound proteins and decompose into cytotoxic aldehydes such as malondialdehyde or hydroxynonenal. Accumulation of hydroxynonenal increases with age in several tissues and the level of malondialdehyde and hydroxynonenal-conjugated collagen protein increases with age a lot of tissues, too. It was also observed an increase in the levels of MDA, a marker of lipid peroxidation in the test organs of aged people. Hence, lipid oxidation is closely associated to aging. On the contrary, LBP treatment demonstrated decreased level of lipid peroxides and this could be in part due to reduced formation of lipid peroxides from age-dependent free radicals.
A vast number of evidence implicates that aging is associated with a decrease in antioxidant status and that age-dependent increases in lipid peroxidation are a consequence of diminished antioxidant protection.

The major antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) are regarded as the first line of the antioxidant defense system against reactive oxygen species generated in vivo during oxidative stress.
SOD dismutates superoxide radicals to form hydrogen peroxide, which in turn is decomposed to water and oxygen by GSH-Px and CAT, thereby preventing the formation of hydroxyl radicals. Therefore, these enzymes act cooperatively at different sites in the metabolic pathway of free radicals.
Age-induced oxidative injury was found to reduce the total antioxidant capacity (TAOC), which reflects the non-enzymatic antioxidant defense system, as well as antioxidant enzyme levels (SOD, CAT, GSH-Px) in test organs of aged. Due to depletion in antioxidant levels, the free radicals are not neutralized and aged organs show enhanced susceptibility to lipid peroxidation.
The observation that LBP treatment significantly restores the marker enzymes activity of aged people compared to aged control suggests the reversal by these drugs administration of age-induced oxidation.
The enhanced activity of SOD, CAT and GSH-Px and increased TAOC in the aging people can be very effective in scavenging the various types of oxygen free radicals and their products. So the inhibitory effect of the Lycium barbarum polysaccharides on lipid peroxidation might be, at least in part, attributed to its influence on the antioxidant enzymes and non-enzymatic system.
It was also reported that, in general, the age-related changes in the activities of SOD, GSH-Px, and CAT were paralleled by a similar change in the relative level of the mRNA expressions coding for these enzymes in brain, hepatocytes, and kidney. It also was shown that aging decreased the mRNA expressions of SOD and GSH-Px but did not change CAT. Some studies also revealed the discrepancy between the activity and mRNA expression of either SOD or GSH-Px. This may suggest that the activities of antioxidant enzymes in aged tissues could be controlled by translational process and/or post-translational process, but not by transcriptional process. It is possible that the effect of the Lycium barbarum polysaccharides on SOD, CAT and GSH-Px was associated with its effect on translational process and/or post-translational process of these antioxidant enzymes.

Effect of the Lycium Barbarum Polysaccharides on Age-related oxidative Stress, 2006

The influence of the Lycium barbarum polysaccharides on the LPF in aged mice was also investigated. LPF is an important marker for oxidative damage. The deposition of LPF in animals tissues usually increased significantly with age. Large deposits of the pigment, which can contain toxic compounds such as the amphiphilic pyridinium bisretinoid, A2E, may be deleterious to cell function and contribute to disease progression.
It was showed that its content increased continuously with age in mice, as found in several other species. Therefore, it was confirmed age-dependent accumulation of LPF. An alternative possibility is that lipofuscin is continually turned-over in tissues, the characteristic age-related accumulation being due to imbalance between rate of formation and rate of degradation or elimination, with more being produced than is removed. Likewise, the Lycium barbarum polysaccharides effectively reduced its content in aged tissues. We assume that the inhibition of the Lycium barbarum polysaccharides against the LPF deposition is indirectly achieved by its scavenging free radical and stimulating antioxidant enzymes activity. Moreover, addition of vitamin C to polysaccharides can significantly and dose-dependently raise antioxidant activity of polysaccharides.

A Study of four Antioxidation Effects of Lycium Barbarum Polysaccharides in Vitro, 2013

2015-02-25T13:42:21 - Luigi Scavino
2015-02-24T14:32:16 - Luigi Scavino
AddThis Social Bookmark Button