Recently goji plants and berries have been widely promoted. According to many internet sites, it is one of the novel “superfruits” with a multitude of human health benefits, including antioxidant activity, anti-aging properties, enhanced immunity to bacterial, fungal, and vision-related diseases, and improved mental capacity. These purported benefits are associated with the amino acids, minerals, and vitamin content of the berries. Juice, dried goji berries, and teas from plant leaves are a few of products frequently advertised.
Goji berries are harvested from shrubs of the genus Lycium. This plant belongs to the nightshade family (Solanaceae) which includes other commercially important vegetables such as tomato, potato, eggplant, peppers, ornamentals (nicotiana, petunia), and weeds (nightshade, groundcherry, and jimsonweed). Lycium plants are commonly known as matrimony-vine, wolf berry, Duke of Argyll’s teaplant, box thorn, bocksdorn, and ning xia gou qi. While there are about one hundred different species of Lycium, some of the more common species in the United States are L. barbarum, L. halimifolium, and L. chinense. All of these species are sold as goji berry plants. L. barbarum plants are suited to hardiness zone 8 in the Southwestern U.S. and have one-inch long, linear leaves with pale rose flowers.
In contrast, the range of L. halimifolium is from Virginia to Missouri, Kansas, and Oklahoma, north to Ontario and west to Minnesota. It can be found growing in several counties throughout Missouri, usually in abandoned sites, old fields, roadsides, and along railroad tracks. These shrubs are usually about three to five feet tall and have arching spiny or spineless branches that grow up to ten feet long. Leaves are grayish-green color, lanceolate, and 2.5 inches in length (Figure 1 a). One to three lilac-colored flowers develop at nodes (Figure 1 b). In Missouri, plants flower from May through September, with the small quarter-inch- long red berries (Figure 1c) present in July through October. This species escapes cultivation and becomes a nuisance. Young shoots and leaves may poison sheep and cattle when eaten.
L. chinense shrubs are similar to those of L. halimifolium with arching branches up to twelve feet long, but they are generally spineless with ovate leaves up three inches in length. Flowers are purplish colored and the elongated berries are orange to scarlet, about one inch long. These naturalized plants are most commonly found in eastern North America. When purchasing plants, species may be incorrectly identified.
While the health benefits of goji berry seem enticing, scientific evidence of supporting these claims is not available. In 2006, the U.S. Food and Drug Administration sent warning letters to two goji juice distributors in violation of marketing their product as a drug intended for the prevention or cure of disease, when goji juice is not generally recognized as safe and effective for various health benefits. One published study revealed that wolfberry tea inhibited warfarin metabolism. Goji berries also contain the alkaloid atropine, which has medicinal properties, but can also produce adverse health effects when consumed in large quantities. Atropine concentrations in berries are not commonly measured, but one study reported that berries tested from China and Thailand had variable atropine contents up to 19 ppb. Until more information is available, more common blueberries, cranberries, blackberries, raspberry, pomegranates, strawberries, oranges, mangoes, apples, and tomatoes have many similar health attributes that have been more thoroughly tested.
REVISED: September 30, 2015