Scientific Name(s): Lycium barbarum L., Lycium chinense Mill., Lycium halimifolium Mill., Lycium vulgare Dunal.
Common Name(s): Barbary wolfberry, Chinese desert thorn, Chinese wolfberry, Desert-thorn, Duke of Argylls tea tree, Fructus Lycii Chinensis, Goji, Goji berry, Gou Qi Zi, Gouqizi, Himalayan goji, Kuko, LYCH, Matrimony vine, Ningxia, Red diamonds, Tibetan goji, Wolfberry
Two closely related species, L. barbarum and L. chinense, collectively produce the berries considered to be goji, wolfberries, or Gou Qi Zi. They are botanically related to the tomato and are deciduous woody perennials. Primarily cultivated in China, these species grow from 1 to 3 m in height; the L. barbarum tends to be the taller of the two.1 The 5-petaled flowers are lavender to light-purple in color, and the lanceolate/ovate leaves appear alternately or in bundles on the shoot. The tender, oblong berries, which must be picked carefully or shaken from the vine when ripe, are a bright orange-red color and contain between 10 to 60 yellow seeds. The berries ripen from July to October in the Northern Hemisphere. A process of slow drying is undertaken to preserve the fruit, which then appear similar in size and texture to a raisin.2 The leaves are used to make tea, and the bark is extensively used in traditional Chinese medicines.1 Synonyms are Lycium halimifolium Mill.; Lycium vulgare Dunal.
Gou Qi Zi is listed in the Pharmacopeia of the People's Republic of China (2000)3 and use of the berries dates back 2,300 years. Traditional use has included preventing conditions such as diabetes, hyperlipidemia, cancer, hepatitis, immune disorders, thrombosis, and male infertility.4, 5 In traditional Chinese medicine it is used for its anti-aging properties and tranquilizing and thirst quenching effects, as well as its ability to increase stamina. Goji is a core ingredient in most herbal eye remedies. Further uses have included nourishing the blood, enriching the yin, and as a tonic for the liver, kidneys, and lungs.6, 7, 8, 9
Major compounds isolated from the berries include the carotenoids beta-carotene, lutein, lycopene, zeaxanthin, zeaxanthin dipalmitate, polysaccharides (comprising 30% of the pulp), vitamins (ascorbic acid, glucopyranosyl ascorbic acid, tocopherol), fatty acids, betaine, and peptidoglycans.7, 9, 10, 11, 12
Neutral volatile compounds identified include steroids, glycolipids (including the cerebrosides), glycosides, glucopyranosides, and alkaloids (spermine alkaloid, polyhydroxylated alkaloids).13, 14 Flavonoids, phenolic amides, cyclic peptides, and sesquiterpenes have also been described.14 Additionally, rutin, chlorogenic acid, and lyciumosides have been identified in the leaf15 and phenolic amides identified in the root bark.16, 17
The berries contain dietary amounts of calcium, potassium, iron, zinc, and selenium, as well as riboflavin and vitamin C. Concern has been raised about the amount of atropine present in berries; only trace amounts were found and at levels considered insignificant (up to a maximum of 19 ppb w/w).3
Uses and Pharmacology
High quality, clinical trials are lacking.
Potent superoxide anion scavenging activity has been demonstrated for the polysaccharide extract of Goji berries.4, 14, 18 Activity of polysaccharide extract 500 mg has been estimated to be greater than vitamin C 500 mg.4
In older mice, the decreased activity of enzymes in the brain, liver, and heart consequent to oxidative stress was enhanced by administration of polysaccharides extracted from Lycium fruits, lending support to the traditional anti-aging use of Gou Qi Zi.4
Lycium fruit has been used traditionally to treat infertility. In mice with heat- and time-damaged seminiferous tubules, the polysaccharide extract of the berries inhibited apoptosis and reversed morphological damage.8, 19, 20 Protection against DNA-induced seminiferous tubule damage was also demonstrated in mice, and these actions are attributed to anti-oxidative activity.8 Doxorubicin-induced cardiac oxidative stress was decreased in rats pretreated with the aqueous extract of L. barbarum21 and anti-oxidative effects on human dermal fibroblasts have been demonstrated.22
Cardiometabolic risk factors
A meta-analysis of randomized controlled trials investigating the effects of L. barbarum on cardiometabolic risk factors identified 7 trials (N=548) that met eligibility criteria. The majority of the studies were of low-quality and were conducted in healthy subjects in China; however, 2 were conducted in patients with type 2 diabetes. Interventions included the fruit, fruit juice, and the polysaccharide extract. Overall, no significant differences were found on risk factors of noncommunicable diseases but when stratified by age and duration of intervention, significant improvements were noted. In participants at least 60 years of age or when the duration of the intervention was not less than 3 months, L. barbarum supplementation resulted in significant reductions in total cholesterol and triglycerides. Compared to healthy subjects, those with type 2 diabetes exhibited more of a reduction in fasting glucose.41
Experiments investigating the effect of berry polysaccharides have found enhanced spontaneous electrical activity in the hippocampus, and a decreased stroke index and neurological score in ischemia and reperfusion models.8 Neuronal death and apoptosis have been prevented, in animal experiments.8 In rats, beta-amyloid peptide neurotoxicity has been prevented, suggesting a role for the berry in Alzheimer disease.7, 33
Inhibition of monoamine oxidase B, which is elevated in neurodegenerative disease and aging, has been demonstrated with Lycium.34
A double-blind, randomized, placebo-controlled trial enrolling 67 adults with type 2 diabetes was conducted by the Nanjing Center for Disease Control and Prevention in China to evaluate the hypoglycemic effect of L. barbarum polysaccharide (LBP), used traditionally in Chinese medicine to treat various diseases that manifest with frequent drinking and urination. Administration of 300 mg/day of LBP for 3 months resulted in significant improvements in glucose area under the curve, insulinogenic index, serum glucose, and high-density lipoprotein levels; however, these effects were only significant in patients not currently taking hypoglycemic medications. Insulin response to a meal was not changed and no significant changes were noted for other lipid parameters or adipokines (ie, toxic necrosis factor [TNF]-alpha, leptin, interleukin-6). No adverse events were reported.40
Pretreatment with an aqueous extract of the L. chinense fruits decreased hepatic enzyme levels (aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase) in rats with carbon tetrachloride-induced hepatic injury. Histological changes were also decreased.26 Similar results were obtained for zeaxanthin extract against induced hepatic fibrosis in rats.11Lycium compounds with potential hepato-protective (possibly antioxidant) effects have been identified.5, 17, 26
Experiments investigating the potential of L. barbarum and L. chinense in cancer treatment focus on immune-enhancing and direct effects. The weight of the thymus and spleen in rats was increased, as was macrophage activity, with administration of a polysaccharide extract.4, 27, 28 Increased cytotoxic T lymphocyte and tumor necrosis factor activity have occurred in animal experiments and in human mononuclear cells in vitro.8, 27, 29 Protection from the effects of myelosuppression has been reported.30
Aqueous extracts inhibit proliferation and induce apoptosis in hepatocellular cancer in rats and human hepatoma cell lines.31, 32 Growth of sarcoma in mice was suppressed28, 29 while an observational study suggested a benefit for cancer patients taking L. barbarum polysaccharides.29
Effects on the eye are thought to be related to antioxidant activity.8, 23 The berries are rich in zeaxanthin and increased plasma zeaxanthin levels have been demonstrated with berry consumption.2, 8 Lutein content in the berries is somewhat lower.2, 9 Fifteen grams of berries per day for 28 days increased total and lipid-standardized plasma zeaxanthin levels.2 Bioavailability of zeaxanthin is variable and experiments have been conducted to increase the availability using milk-based and emulsion formulations.12, 35
Increased survival of retinal ganglion cells has been demonstrated in experiments in rats with induced glaucoma.23 No effect on ocular pressure was found. The effect did not appear to be dose-dependent, and a prolonged effect (4 weeks) was demonstrated.8
Data are lacking to guide dosage in the clinical setting. Fifteen grams of berries per day increased plasma zeaxanthin levels in healthy adults.2
Pregnancy / Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking.
There are case reports of elevated international normalized ratio values in patients taking warfarin.29, 37 In these reports, the patients consumed herbal tea made from the berries or bark of L. barbarum estimated to equate to 6 to 18 g of berries/day.37
In vitro experiments suggest the potential for monoamine oxidase B inhibition, the clinical importance of which is unknown.34
Varying degrees of hypersensitivity reactions have been reported, including a case report of anaphylaxis. A 37-year-old Italian man, with known allergies to pollen since childhood, experienced goji berry-dependent exercise-induced anaphylaxis that was effectively treated with epinephrine, fluids, and corticosteroids. Subsequent skin prick tests were positive for grass, ragweed, mugwort, pellitory, birch, olive tree, tomato, peanut, and hazelnut.39
Data are lacking.
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