Rosa roxburghii

Rosa roxburghii, (the burr rose, chestnut rose, or chinquapin rose), is a species of flowering plant in the family Rosaceae, native to the eastern Himalayas, Tibet, and central and southern China. In the wild it is found in thickets, mountain forests, on slopes, and alongside streams, typically 500 to 1400 m above sea level. A diffuse shrub capable of reaching 8 m but usually shorter, it is available from commercial suppliers. In China, it is cultivated for its vitamin C-rich hips on 170,000 ha, mostly in Guizhou.

It was dedicated to William Roxburgh, a Scottish physician and botanist who was director of the Calcutta Botanical Garden.

Three forms have been recognized: Rosa roxburghii f. roxburghii, which has double or semi-double, reddish or pink flowers 5 – in diam.,Rosa roxburghii f. normalis Rehder & E. H. Wilson (in Sargent, Pl. Wilson. 2: 318. 1915), which has simple, pink flowers 4 – in diam. and also, Rosa roxburghii f. hirtula (Regel) (Rehder and Wilson), flowers single, pale pink or lilac-pink from Japan.

Taxonomy
R. roxburghii is also known commonly as the 'Sweet Chestnut Rose', the 'Chestnut Rose', the 'Burr Rose', and the 'Chinquapin Rose'.

It gets its common name 'Chestnut Rose' from the large burred hips that look like chestnuts.

It was originally found in China in the early 1800s, where it had been growing for generations, and it is rarely grown in European gardens. It was then introduced to the botanic garden in Calcutta around 1824.

In 1823, Trattinick changed the name of a species of rose. It was originally named Rosa microphylla by Dr. William Roxburgh (1751-1815) in 1820, because René Louiche Desfontaines had previously applied the name microphylla to an unrelated European species of rose in 1798. It then became Rosa roxburghii, and Trattinick published this name change in 'Rosacearum monographia' on page 233 in 1823. Rosacearum monographia (or The 'Monograph of the Rose Family') covered generic and species descriptions of plants in the rose family, although it was not illustrated.

The specific epithet was spelled roxbourgii in the protologue, but roxburghii is more commonly used.

The etymological root of the binomial name Rosa is from the ancient Latin name for the rose. The Latin specific epithet of Roxburghii was named after John Roxburgh (1770s–1820s), an occasional overseer of Calcutta Botanic Garden.

It was verified as Rosa roxburghii by United States Department of Agriculture and the Agricultural Research Service on 15 February 1996, and is listed as Rosa roxburghii in the Encyclopedia of Life.

Rosa roxburghii f. normalis is an accepted name by the RHS and listed in the RHS Plant Finder book.

It is also often sold under name Rosa roxburghii 'plena'. Normally, advertised as a medium pink double form, but a deeper pink version is available from nurseries.

It belongs to the section 'Microphyllae' which also includes the Japanese species, R. hirtula.

After gene sequencing was carried out it was found that R. roxburghii is closely related to Rosa odorata var. gigantea.

Distribution and habitat
Rosa roxburghii is native to temperate areas of eastern Asia, within China and Japan.

Range
Found within China, it is found in the provinces of Anhui, Zhejiang, Fujian, Hunan, Hubei, Gansu, Jiangxi, Guizhou, Shaanxi, Sichuan, Yunnan, Guangxi and Xinjiang.

Habitat
It is found growing in various habitats including; Mountain forests, thickets, slopes, stream sides, semi-arid river valleys, waysides, and on roadsides. In China, it is commonly found on banks between rice fields, where it can obtain plenty of water during the summer.

They can be found at an altitude of 500 - 2500 m above sea level.

Uses
Rosa roxburghii has various uses including; as an ornamental (within gardens), as a food source with (edible fruit, or fruit drink) and also medicinal use (in folklore and scientific research).

The edible fruit are very rich in vitamins and have a sweet, sour taste; they are used medicinally and to ferment wine. The roots are also used medicinally. The species is also cultivated for ornament, for its showy flowers, or as a hedge because of its abundant prickles.

Food source
Rosa roxburghii and Rosa sterilis both have edible fruit and have been eaten since 1765 A.D.

The fruit / rosehips can be eaten raw or cooked, and has a sweet sour taste. The fruit is very rich in vitamins, including Vitamin E. and rich in vitamin C, The content of Vitamin C is much higher than other kinds of fruits such as grape, apple, pear and dahurian rose fruit. The vitamin content is 5-7 % (per 100 mg of fruit). It also has higher content vitamin P than other common vegetables and fruits. Unusually for a fruit, it is also a known source of essential fatty acids.

In 2016, the phytochemical characteristics of the fruit were investigated. A total of 135 volatile compounds were identified, a total of 59 compounds in methanol extracts were identified, including 13 organic acids (including ascorbic acid), 12 flavonoids, 11 triterpenes, nine amino acids, five phenylpropanoid derivatives, four condensed tannins, two stilbenes, two benzaldehyde derivatives and one benzoic acid derivative. Roxbins A and B were also found in the fruit.

There is only a thin layer of edible flesh surrounding the many seeds. It can be ground into a powder, and mixed with flour or added to other foods as a supplement. Be sure to remove the seed hairs. In China, it is the commercial source of rosehip powder.

R. roxburghii fruit has seen a rise in patent applications for methods to produce juice. The juice, wine, and the preserved fruit can be used as a dietary supplement, in many health-related industries. A rose jelly formula has been found.

While being edible, there are some hazards of eating Rosa roxburghii. There is a layer of hairs around the seeds just beneath the flesh of the fruit. These hairs can cause irritation to the mouth and digestive tract if ingested.

Medicinal use
It is used in Chinese traditional medicine, and called 'Cili', and used as fruit juice remedy.

In Compendium of Materia Medica (written in 1578), the fruits can alleviate mental depression and remove stagnated food.

It is used in health supplements because of its strong anti-oxidation, circulatory and cardiovascular tonic properties, gastrointestinal, urinary, and reproductive functions, including anti-aging, free radical scavenging, immunologic regulation, stress tolerance, anti-inflammation, anti-virus, anti-aging, anti-fatigue effects and to enhance immunity. Also has anti-mutagenic, anti-atherogenic and anti-tumor effects, as well as genoprotective and radioprotective activities. Due to being rich in tannins it is also used as an astringent.

A controlled feeding study in 2005 found that a supplement increases plasma antioxidant capacity and glutathione redox state.

In modern medicine, it has been undergoing various experimental tests and pharmacological studies, including gene sequencing, extracts have demonstrated anti-arteriosclerosis activity and benefits for cholesterol levels that support its use for cardiovascular disorders. Also seems to have rejuvenation, immune supportive and anti-cancer effects.