Micronutrients and phytochemicals
Wolfberries contain many nutrients and phytochemicals including
11 essential and 22 trace dietary minerals
18 amino acids
6 essential vitamins
8 polysaccharides and 6 monosaccharides
5 unsaturated fatty acids, including the essential fatty acids, linoleic acid and alpha-linolenic acid
beta-sitosterol and other phytosterols
5 carotenoids, including beta-carotene and zeaxanthin (below), lutein, lycopene and cryptoxanthin, a xanthophyll
numerous phenolic pigments (phenols) associated with antioxidant properties
Select examples given below are for 100 grams of dried berries.
Calcium. Wolfberries contain 112 mg per 100 gram serving, providing about 8-10% of the Dietary Reference Intake (DRI).
Potassium. Wolfberries contain 1,132 mg per 100 grams dried fruit, giving about 24% of the DRI.
Iron. Wolfberries have 9 mg iron per 100 grams (100% DRI).
Zinc. 2 mg per 100 grams dried fruit (18% DRI).
Selenium. 100 grams of dried wolfberries contain 50 micrograms (91% DRI)
Riboflavin (vitamin B2). At 1.3 mg, 100 grams of dried wolfberries provide 100% of DRI.
Vitamin C. Vitamin C content in dried wolfberries has a wide range (from different sources) from 29 mg per 100 grams to as high as 148 mg per 100 grams (respectively, 32% and 163% DRI).
Wolfberries also contain numerous phytochemicals for which there are no established DRI values.
Examples:
Beta-carotene: 7 mg per 100 grams dried fruit.
Zeaxanthin. Reported values for zeaxanthin content in dried wolfberries vary considerably, from 2.4 mg per 100 grams to 82.4 mg per 100 grams to 200 mg per 100 grams. The higher values would make wolfberry one of the richest edible plant sources known for zeaxanthin content. Up to 77% of total carotenoids present in wolfberry exist as zeaxanthin.
Polysaccharides. Polysaccharides are a major constituent of wolfberries, representing up to 31% of pulp weight.
Wolfberry polysaccharides
One study published in the Journal of Ethnopharmacology found that:
Endogenous lipid peroxidation, and decreased antioxidant activities, as assessed by superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (TAOC), and immune function were observed in aged mice and restored to normal levels in Lycium polysaccharide-treated groups. Antioxidant activities of Lycium barbarum polysaccharides were found to be comparable with normal antioxidant, vitamin C. Furthemore, adding vitamin C to the polysaccharide treatment further increased in vivo antioxidant activity of the polysaccharides.
Criticism
Marketers of some wolfberry products claim that polysaccharides have specific physiological roles mediated by specialized cell receptors "master" control properties over other bioactive chemicals and cells. Characteristic spectral peaks are claimed to define one berry's geographic origin from another.
These assertions are an important marketing message for wolfberry products branded as Tibetan Goji Berries or Himalayan Goji Juice. Such statements, however, have no scientific evidence published under peer-review and are not compliant with regulatory guidelines for marketing natural food products (see below, Marketing claims under scrutiny in Europe, Canada and the United States).
Functional food and beverage applications
It is often cultivated for a variety of food and beverage applications within China, but increasingly today for export as dried berries, juice, and pulp or grounds. Wolfberries are prized for their versatility of color and nut-like taste in common meals, snacks, beverages, and medicinal applications. A major effort is underway in Ningxia, China to process wolfberries for “functional” wine.
Marketing literature for wolfberry products including several "goji juices" suggest that wolfberry polysaccharides have extensive biological effects and health benefits, although none of these claims has been supported by peer-reviewed research.
A May 2008 clinical study published by the peer-reviewed Journal of Alternative and Complementary Medicine indicated that parametric data, including body weight, did not show significant differences between subjects receiving Lycium barbarum berry juice and subjects receiving the placebo; the study concluded that subjective measures of health were improved and suggested further research in humans was necessary. This study, however, was subject to a variety of criticisms concerning its experimental design and interpretations.
Published studies have also reported possible medicinal benefits of Lycium barbarum in animal models, especially due to its antioxidant properties, including potential benefits against cardiovascular and inflammatory diseases, vision-related diseases (such as age-related macular degeneration and glaucoma), having neuroprotective properties or as an anticancer and immunomodulatory agent.
Wolfberry leaves may be used to make tea, together with Lycium root bark (called dìgupí; ? ? ? in Chinese), for Traditional Chinese medicine (TCM). A glucopyranoside (namely (+)-Lyoniresinol-3a-O-ß-d-glucopyranoside) and phenolic amides (dihydro-N-caffeoyltyramine, trans-N-feruloyloctopamine, trans-N-caffeoyltyramine and cis-N-caffeoyltyramine) isolated from wolfberry root bark have inhibitory activity in vitro against human pathogenic bacteria and fungi.
Safety issues
Two published case reports described elderly women who experienced increased bleeding, expressed as an elevated INR, after drinking quantities of wolfberry tea. Further in vitro testing revealed that the tea inhibited warfarin metabolism, providing evidence for possible interaction between warfarin and undefined wolfberry phytochemicals.
Atropine, a toxic alkaloid found in other members of the Solanaceae family, occurs naturally in wolfberry fruit. The atropine concentrations of berries from China and Thailand are variable, with a maximum content of 19 ppb, below the likely toxic amount.
