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Plants & People: The Intersection of Botany and Human Experience

Biogeography and Evolution of Lycium Species

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Goji Berries: The Key to Eternal Youth? Goji Berries have become a symbol of the Superfood movement which has continued to gain traction in the US and across the world. Although they have served as a token of this emerging trend, goji berries have been renowned in Asia for their nutritious qualities for many centuries. Its use has been documented for almost 2000 years in traditional Chinese medicine (Gross et al., 2006). The goji industry has skyrocketed during the 21st century as they’ve been recognized for their nutritious qualities. Goji berries have a rich cultural history which has contributed to their claim to fame. In 2003, health writer Earl Mindell distributed a booklet which suggested that goji berries had anti-cancer properties - this drove their entry into the Superfood market. His claims were based on the myth of Li Qing Yuen; the herbalist supposedly consumed goji berries daily which allowed him to live 256 years (Earl Mindell and Rick Handel, 2003). While Mindell’s booklet was full of false exaggerations, there is merit to many of his claims regarding the nutritional benefits of goji berries. Two species are colloquially known as goji berries: Lycium barbarum and Lycium chinense. Their unique vegetative and reproductive morphology makes harvesting the berries labor intensive. Both the goji berry and immature leaves from L. chinense and L. barbarum are eaten by many for their health benefits - while the benefits have been known for centuries, the underlying macromolecular structure that dictates these properties is only being explored in more recent decades. By Ismael Rodriguez & Catherine Nordstrom #Goji
Goji Berry: Lycium barbarum & Lycium chinense
As the range of L. barbarum and L. chinense has radiated out from China across Asia and Europe, many names have been given to both the plant and berry. In Mandarin, 枸杞子 (gǒuqǐzi) is the name for the berry. The colloquial term we use now, “goji” is a mispronunciation of the Pinyin name for the berry. Many other names have been given, including kuko no mi (クコの実) or kuko no kajitsu (クコの果実) in Japanese, gugija (hangul: 구기자; hanja: 枸杞子) in Korean, kỷ tử (杞子) or cẩu kỷ (枸杞) in Vietnamese, and dre-tsher-mai-dre-bu in Thai; English names include wolfberry, matrimony vine, The Duke of Argyll’s Tea Tree, among others. L. bararum was first given its scientific name in 1753 and L. chinense was named in 1768 (USDA ARS, 2022).
Morphology
Lycium barbarum and Lycium chinense are deciduous woody perennial plants which grow to heights of around 1-3 meters, L. chinense is generally a bit shorter and is primarily grown in southern China, while L. barbarum is taller and grown in the Ningxia Hui Autonomous Region of northern China and they are slightly taller (ChemEurope). Both species have robust root structures so they are often used as barriers for erosion. They are in the Solanaceae family along with many other plant foods like tomato, eggplant, and peppers (Britannica, 2017). Leaves grow in alternate arrangements or in groups of one to three leaves. They are generally a lanceolate shape with blunt or rounded tips. On average, the leaves are 7 cm long and 3.5 cm wide.

One to three flowers are bunched at the ends of stems that are 1-2 cm long. The calyx has short bell-shaped leaves and it is eventually broken when the berry begins to grow. The corolla of the goji flower is lavender and is 9-14cm long - each flower has five petals and stamens. The stalks of the stamens are longer than the anthers. The pistil is 8-11.5 mm long and the stamens are 3-8mm long (Government of South Australia, 2007). L. barbarum and L. chinense are self-pollinating, but they can also be cross-pollinated by insects. They have a long flowering period, so they are appreciated by many pollinators. Flowering occurs from June through September and berry maturation from August to October, with some variation due to climate differences (Queensland Government, 2016).

The goji berries themselves are generally a vibrant red color, though there are some interesting color variations among specifically cultivated strains. They only reach a length of around 0.7-2cm, the berries of L. chinense smaller than those of L. barbarum. There are varying numbers of seeds, but it is generally within ten to thirty seeds (Bernardello L, 1986) - L. chinense has more seeds, making it the more bitter species of goji berry.
Nutritional Qualities
Goji berries have been used for centuries for their medicinal qualities, but studies on the exact nutritional profile could not be done until more recent years. The figure to the left was a part of a series of microscopic analyses that utilized histochemical and fluorescence assays to examine the distribution of bioactive compounds inside of Lycium barbarum berries. Assorted lipids, essential oils, and terpenoids were found throughout the mesocarp, endocarp, and seeds. Polysaccharides, including pectins and mucilage, were also found throughout the entire berry. Polyphenols, tannins, lignins, alkaloids, and flavonoids were also found in various components of the goji berries. The orange color of the berry is also indicative of a high density of carotenoids within the pericarp cells (Konarska, 2018). The USDA FoodData Central most recent information on the nutritional content of goji berries concluded that 28g of dried goji berries has approximately 4g Protein, 0.1 Total lipids, 21.6g Carbohydrates, 3.6g of Fiber, 12.8g Sugar, 53.2mg Calcium, 1.9mg Iron, 83.4mg Sodium, 13.6mg Vitamin C, 7500 IU Vitamin A, as trace amounts of other minerals and cellular compounds (Fooddata Central Search, 2019).
Goji berries have a very similar nutritional profile compared to other berries, but they do have a notably high protein content. The Goji Berry has vitamin C levels comparable to that of lemons or strawberries. It also has an extraordinary amount of Zeaxanthin which is antioxidant that serves as a filter for your eyes, protecting them from sunlight damage. Along the same lines, the berry contains ascorbic acid and the enzyme SOD. Together, these two work to better cardiovascular health. However, these benefits are not as helpful for those who are already experiencing health problems, rather they work better as a preventative and overall health boost. While there are other health benefits associated with Goji Berry, these are the ones with most scientific support. The other benefits lack the research to solidify them.
Evolutionary History & Ecology
Although the exact domestication history of the Goji Berry is unknown, gene mapping has allowed for a map showing the likely evolution and spread of the Lycium genus. Analysis of almost 3 million single nucleotide polymorphisms (SNPs) across 13 species of Lycium suggests that the North American clade is result of a migratory event from Asia to North America. Two other species, Lycium depressum of Asia, and Lycium ruthenicum of Africa, Europe, and Asia, differentiated prior to this migratory event. The SNPs are also indicative of the clusters of polymorphisms that are desirable within edible Lycium species like Lycium barbarum and Lycium chinense (Cao et al, 2021).

Although they are native to China, L. barbarum and L. chinense now have a range that spans across Asia and southeast Europe. L. Barbarum and L. Chinense are used almost interchangeably, but L. Barbarum is often referred to as the superior species in quality of berry. It also grows further North than its counterpart. L. Barbarum was likely domesticated in Zhongning County- a county in northern China that borders the Yellow River – seasonal flooding leaves mineral-rich silt deposits which fertilizes the crops (Gong Y, et al. 2015). This is where Goji Berries thrived as a wild species. From 220 BCE to 900 CE, Chinese Dynasties built an irrigation system that went from the Yellow River to the Ningxia Region. This passed right through Zhongning County and brought extra nutrients to the wild plants. As a result, the farmers in the area took the largest, richest, and reddest berries for themselves; storing the seeds for future harvest. Around the time this irrigation channel was under construction, the Goji berry was also growing in popularity as a medicinal herb and was likely further farmed for its utility. As farmers picked out the best specimens and planted those seeds, the Goji berry diverged from its ancient, wild relative. As farmers kept up the practice of selecting for the best berries, they eventually separated the Goji Berry plants into an estimated 10 landraces known today.

These landraces may seem insignificant as they are all Goji Plants, but the quality of berry varies from one landrace to the next. Recently, the Goji Berry skyrocketed as a cure-all type of food and has also grown in popularity outside of China. This caused a rush in which farmers all over the globe have attempted to cultivate Goji Plants for their lucrative yields. However, cultivation is tough outside of the native Chinese soil and yields are usually smaller and finicky outside of China. Therefore, 45% of Goji Berries are still harvested in China where the best environment and landraces produce the most nutritious berries. The optimal conditions for the best berries are sunny yet moist conditions with fertile, silt soil. The best method to farming the Goji plants is as follows: plant Goji cuttings about two meters apart during Autumn, trim to promote branch growth for the first two years, water generously, allow plenty of sunlight, harvest from June - October as needed. The plants are fragile for the first two years and need constant attention, but they will become drought resistant after two years as they begin to produce berries. It is recommended to harvest by hand since the berries will easily bruise and leak with any rough handling. Also, one should prune the plants so that they grow only one vertical stem trimmed to a comfortable height for harvesting and produce lateral branches. Practices vary depending on location, but those listed above have worked well in areas such as China, Tibet, Mongolia, Canada, and a diversifying array of new areas worldwide. After harvest, most berries are dried for preservation as they may be shipped to other continents and regions.

Many Traditional Chinese Medicine handbooks and guides through the centuries have utilized Lycium barbarum and Lycium chinense within their recipes - it is classed as a "tonic herb for yin deficiency" among other plants and animal parts like Snow ear mushroom, egg yolk, and monk fruit (Chinese Herbal Medicine Database). Traditionally, the berry is often boiled within a soup or tea along with other healing herbs in order to treat different ailments like liver problems or dry skin (食材, 2022). While it is often added as a medicinal ingredient, goji berries are a flavorful addition to both sweet and savory recipes because of their unique flavor. It is described as a sweet cherry tomato, reminiscent of a cranberry once they are dried (Chaey, 2015). Other parts of the Goji Plant are eaten such as the leaves and shoots - while the leaves serve as both a vegetable and loose-leaf tea, the shoots are only eaten as a vegetable. Records from the Han Dynasty also refer to a method of consumption still popular today: gǒuqǐ jiǔ, or 'wolfberry wine'. It is still a popular beverage today, especially in the Ningxia region of China (中国酿造枸杞酒的历史, 2007). As the industry has globalized, goji berries can now be consumed via pills, juices, powdered spices, topical lotions, and teas.
References
Gross, Paul M.; Xiaoping Zhang; and Richard Zhang (2006). Wolfberry: Nature's Bounty of Nutrition & Health. Charleston, South Carolina, United States: BookSurge Publishing. ISBN 1419620487. ISBN 9781419620485.

Earl Mindell and Rick Handel (2003), "Goji: The Himalyan Health Secret". Momentum Media, 58 pages. ISBN 978-0967285528

(USDA ARS, 2022) USDA, Agricultural Research Service, National Plant Germplasm System. 2022.

Germplasm Resources Information Network (GRIN Taxonomy). National Germplasm Resources Laboratory, Beltsville, Maryland. URL: https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=22939. Accessed 23 May 2022.

Britannica, The Editors of Encyclopaedia. "list of plants in the family Solanaceae". Encyclopedia Britannica, 29 Jun. 2017, https://www.britannica.com/topic/list-of-plants-in-the-family-Solanaceae-2026039. Accessed 23 May 2022.

Government of South Australia (2007), "Lycium barbarum". Online fact sheet on Electronic Flora of South Australia (eFloraSA). Accessed on 2018-05-04.

Bernardello L. Revisión taxonómica de las especies sudamericanas de Lycium (Solanaceae) Bol Acad Nac Cien Córdoba Ar. 1986;57:173–356. [Google Scholar]

Queensland Government (2016), "Lycium barbarum". Online fact sheet on Weeds of Australia website. Accessed on 2018-05-04.

Gong, Y., Yu, Z., Yao, Q., Chen, H., Mi, T., & Tan, J. (2015). Seasonal Variation and Sources of Dissolved Nutrients in the Yellow River, China. International journal of environmental research and public health, 12(8), 9603–9622. https://doi.org/10.3390/ijerph120809603

CalFlora: Information on California plants for education, research and conservation. (2000) The CalFlora Database, Berkeley.
Ma, Zheng Feei, et al. “Goji Berries as a Potential Natural Antioxidant Medicine: An Insight into Their Molecular Mechanisms of Action.” Oxidative Medicine and Cellular Longevity, Hindawi, 9 Jan. 2019, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6343173/.

Gao, Qiutao. “Home - Books - NCBI.” National Center for Biotechnology Information, U.S. National Library of Medicine, Jan. 2011, https://www.ncbi.nlm.nih.gov/books.
Gong, Haiguan. “Germplasm Resources and Strategy for Genetic Breeding of Lycium Species: A Review.” Research Gate, Feb. 2022.
Konarska, A. Microstructural and histochemical characteristics of Lycium barbarum L. fruits used in folk herbal medicine and as functional food. Protoplasma 255, 1839–1854 (2018). https://doi.org/10.1007/s00709-018-1277

“Fooddata Central Search - Goji Berries, Dried.” FoodData Central, 1 Apr. 2019, https://fdc.nal.usda.gov/fdc-app.html#/food-details/173032/nutrients.

Chaey, Christina. “All about Dried Goji Berries, the Superfood Raisin.” Bon Appétit, Bon Appétit, 11 June 2015, https://www.bonappetit.com/test-kitchen/ingredients/article/goji-berries

“Chinese Herbal Medicine Database.” Tonic Herbs for Yin Deficiency, Me & Qi, https://www.meandqi.com/herb-database?category=tonic+herbs+for+yin+deficiency.

“食材.” 美食天下, https://www.meishichina.com/YuanLiao/GouQi/.

中国酿造枸杞酒的历史, 2007/3/14, https://web.archive.org/web/20151001104023/http://confucianism.com.cn/minsu/show.asp?id=19521

Cao, You-Long & Li, Yan-long & Fan, Yun-Fang & Li, Zhen & Yoshida, Kouki & Wang, Jie-Yu & Ma, Xiaokai & Wang, Ning & Mitsuda, Nobutaka & Kotake, Toshihisa & Ishimizu, Takeshi & Tsai, Kun-Chan & Niu, Shance & Zhang, Diyang & Sun, Wei-Hong & Luo, Qing & Zhao, Jian-Hua & Yin, Yue & Zhang, Bo & Liu, Zhong-Jian. (2021). Wolfberry genomes and the evolution of Lycium (Solanaceae). Communications Biology. 4. 10.1038/s42003-021-02152-8.