Wolfberry is mainly produced in Zhongning County, Ningxia, China and also planted in several provinces such as Inner Mongolia, Xinjiang, Gansu and Shanxi. It is often born in the hillside, saline-alkali soil and hilly land. It can be sown during whole year, mainly in the spring from last third of March to first third of April ^[1][2].

Wolfberry from Ningxia or Zhongning: It refers to wolfberry produced in Ningxia province or Zhongning County, Ningxia. This area is gentle slope hilly and plain area, with deep soil stratum, which is compatible for both warm and cold condition and rich in selenium. In terms of climate, with the annual average temperature of 9.2°C, the production area, belonged to drought climate in the middle temperate zone, has adequate sunlight, drought with inadequate rain, and large temperature difference between day and night.

According to the shapes and characters of wolfberry, it can be divided into 12 varieties, including white-lined wolfberry, wolfberry with rolled leaf, wolfberry with wooden club-like fruit, wolfberry with pointed tip and yellow leaf, wolfberry with round head and yellow leaf, wolfberry with pointed tip and round fruit, wolfberry with hemp leaf, wolfberry with yellow fruit, wolfberry with small yellow fruit, wolfberry with cannabis leaf, wolfberry with round fruit, and wolfberry with pinhead fruit.

The shape of wolfberry is generally long oval or elliptical, slightly flat, with the length of 0.6-2 cm and diameter of 3-8 cm. The color of its surface is bright red or dark red, with slight glossiness, irregularly wrinkles and slightly pointed tip. It has the style marks with small convex shape and white peduncle marks at the base. The skin is pliable and shriveled, and the flesh is thick, soft and sticky, with the seeds inside. The flavor is slight with sweet and slightly sour taste.

Wolfberry from Ningxia or Zhongning: Its shape is elliptical and flat rather than round, long but not thin. It has obvious stalk marks with white color. The color of the surface is dark red or purplish red. The water content of wolfberry from Zhongning is 12-13%, which is not easy to agglomerate. After extrusion into blocks, it is still loose after pressure release. The floating rate is high after soaking in water. In terms of taste, it has thin skin and thick flesh with sweet and slightly bitter taste. It is the only variety listed in Chinese Pharmacopoeia.

Wolfberry from Xinjiang: Its shape is elliptical or oval, with fewer wrinkles, less seeds and thick flesh. The color of the surface is dark red to purple. It has higher sugar content and sweet taste, which is easy to agglomerate and easy to sink after soaking in water.

Wolfberry from Qinghai: Its shape is large and long, with fewer wrinkles. The color of the surface is dark red to purple. It has higher sugar content, with sweet and chewy taste, which is easy to agglomerate and easy to sink after soaking in water.

Wolfberry from Gansu: Its shape is flat spindle or long flat oval, with thin and wrinkled skin, small seed and thick flesh. The color of the surface is red-orange or red. It has sweet and slightly bitter taste, high sugar content, which is easy to agglomerate.

Wolfberry from Inner Mongolia: Its shape is obround, with fewer wrinkles and heavier seed. The color of the surface is dark red. It is easy to sink after soaking in water, whose soup is slightly red in color. It has high sugar content and sweet taste, which is easy to agglomerate.

Wolfberry is one of the precious traditional Chinese medicines, with long history of medicinal and therapeutic food, and a good product for prolonging life. The discovery of wolfberry can be traced back to the period before the 6th century BC. In the Book of Songs, it described that “Do not pick Qi on my tree”, where “Qi” refers to wolfberry. Wolfberry were applied for both medicinal and edible purposes, found in Shen Nong Ben Cao Jing, which meant every parts of wolfberry are treasure. “Gou-qi plant was divided  Qi-gen, Di-gu, Qi-ji, and Di-fu. After long terms of usage, it could strong bones and muscles, reduce body weight and prolong life.” It shows that, in history, people have a deep understanding of the health care function of wolfberry. In the Ming Dynasty, Li Shizhen gave a detailed description of wolfberry in Compendium of Materia Medica and explained the efficacy and usage of its sprout, fruit and root respectively. For the medical applications, wolfberry is good at moistening Yin, strengthening essence and nourishing blood.

Yin deficiency and troubled cough: It can be treated with wolfberry accompanied with several medicines, such as anemarrhena asphodeloides bunge, fritillaria thun-bergli, ophiopogon japonicas and radix Stemonae, to achieve the effect of moistening lung, promoting the secretion of saliva and reinforcing Yin deficiency ^[3].

Liver-Kidney Yin deficiency, dry and painful eyes or blurred vision: Wolfberry has the relieving effect, which can be made into Qi Ju Di Huang Pill with other medicines such as chrysanthemum and rehmanniae, recorded in Yi Gi, to clear liver and nourish kidney ^[3].

Diabetes: The steamed wolfberry can be chewed to promote the secretion of saliva and relieve thirsty. If it can be taken with other materials at the same time, such as dried rehmannia root, astragalus membranaceus, radix trichosanthis and thizoma dioscoreae, the effect is better ^[3].

1. Polysaccharides

Water-soluble polysaccharides are considered as the most important bioactive components of wolfberry, mainly composed of pectin polysaccharide, glucan, xylan and arabinogalactan. It was proved that lycium barbarum polysaccharides significantly inhibited tumor spread and promote antibody generation in spleen cells and phagocytosis of macrophages ^[5][6][7]. In addition, it was found through animal experiments that the anticancer property of lycium barbarum polysaccharides showed on significantly inhibiting the proliferation of lung cancer cells ^[7][8][11].

2. Phenols

Wolfberry is a good source of phenols, including phenolic acids, flavonoids, phenyl propanoids and coumarins. The experiments confirmed that phenol extracted from wolfberry had good anti-oxidant and anti-bacterial effects on multiple Gram-negative and positive bacteria ^[10]. The studies showed that flavonoids and other phenols  inhibited the formation of reactive oxygen species and increase the expression of anti-oxidant enzymes, such as catalase, glutathione peroxidase and superoxide dismutase ^[9][10]. In addition, phenol with low molecular weight improved the antioxidant activity of lycium barbarum polysaccharides ^[10].

The preparation and processing of wolfberry were recorded began in Song Dynasty. After Ming Dynasty, its processing methods were increased significantly. According to statistics, there are more than 20 methods of the preparation and processing of wolfberry in ancient China ^[4]. The followings are relatively common processing methods.

Wolfberry: Remove the impurities and remove the residual fruit stem and pedicle ^[3].

Wolfberry after frying: Fry wolfberries gently until they have burnt spots on the surface, remove and let them cool ^[3].

Wolfberry after frying with salt: Put the salt in the wok, fry it with gentle heat, put wolfberries in, fry them again until it is swollen and yellow in color, then sieve out the salt ^[3].

There are records in Supplementary Records of Famous Physicians, Collected Works of Materia Medica, and Materia Medica Companion that the drug property of wolfberry is cold in nature and non-toxic. However, in Collected Works of Materia Medica, it also pointed out that “wolfberry cannot be treated with the patient either the spleen and stomach are prone to cold phlegm or diarrhea is occurred from time to time”. That means it should be taken carefully for the patient with spleen deficient and diarrhea ^[3]. Wolfberry is listed as both food and medicine in Circular of Ministry of Health on further regulating the raw material management of healthcare product and food, released by National Health Commission of the People’s Republic of China.

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