Current Bioactive Compounds 2017, 13, 3-17
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Send Orders for Reprints to [email protected] 3 Current Bioactive Compounds 2017, 13, 3-17 REVIEW ARTICLE ISSN: 1573-4072 eISSN: 1875-6646 Realizing the Potential of Health-Promoting Rosehips from Dogroses (Rosa sect. Caninae) Hilde Nybom* and Gun Werlemark Balsgård, Department of Plant Breeding, Swedish University of Agricultural Sciences, Fjälkestadsvägen 459, SE29194 Kristianstad, Sweden Abstract: Systematics and Genetics: Medicinal effects of rosehips are attributed mainly to dogroses, i.e. species in Rosa sect. Caninae. These are mostly pentaploid and have a unique meiosis with asymmetrical chromosome distribution. Offspring in reciprocal crosses differ widely since seedlings resemble the seed parent more than the pollen parent. Chemical Contents: Flesh (shells) of rosehips from dogroses contain high levels of antioxidants, mainly polyphenols and ascorbic acid, as well as carotenoids and vitamins B and E. The seeds are rich in polyun- saturated fatty acids and are used for skin treatment and cosmetics. Both shells and seeds, separately or A R T I C L E H I S T O R Y together, are used for health-promoting food and food additives. Received: March 9, 2016 Revised: May 25, 2016 Medicinal Effects: The most well-documented studies concern the positive effects on inflammatory proc- Accepted: May 31, 2016 esses, especially in patients suffering from osteoarthritis. The exact medicinal role of different rosehip DOI: compounds have not been investigated in detail, and the relative importance of fruit flesh versus seed is 10.2174/15734072126661606070906 35 also not yet determined. Plant Production and Breeding: Rosehips are mainly harvested by hand from wild or naturalized dogrose bushes. Once the key compounds have been identified, commercial output of rosehips with pre- dictable quality would be facilitated by careful optimization of plant material, cultivation conditions, and post-harvest and processing procedures. Some cultivars have been bred in Europe but breeding goals have not been clearly defined and commercial production is limited. Modern genomic tools have improved breeding programs in many crops but polyploidy and the canina meiosis present considerable challenges for research and breeding in dogroses. Keywords: Antioxidant, functional food, medicinal plant, phytotherapy, plant breeding, plant taxonomy. 1. INTRODUCTION The well-known genus Rosa contains numerous species of commercial interest. Several wild species have contrib- uted to the highly appreciated and economically important ornamental rose cultivars, and, in the case of R. damascena, also to the rose oil industry. Other rose species have re- mained more anonymous but some have considerable poten- tial due to their fruits: the rosehips. Commercially marketed rosehips are obtained from several different species. One important group is the dogroses, all of which belong to the section Caninae (Fig. 1). These are long-lived woody peren- nials, found mainly in woodland margins and in disturbed habitats such as roadsides and open pastures. *Address correspondence to this author at the Balsgård, Department of Plant Breeding, Swedish University of Agricultural Sciences, Fjälkestadsvägen 459, SE29194 Kristianstad, Sweden; Tel: +46 703 444 369; E-mail: Fig. (1). Rosehips of the dogrose species Rosa dumalis. Photo Staf- [email protected] fan Andersson. 1875-6646/17 $58.00+.00 © 2017 Bentham Science Publishers Current Bioactive Compounds 4 Current Bioactive Compounds 2017, Vol. 13, No. 1 Nybom and Werlemark Dogroses were sometimes cultivated in the Middle Ages difficult group to classify. Numerous dogrose taxa have been for use as medicinal plants, using almost all parts of the defined according to morphological characters such as leaflet plants: rosehips, seeds, petals, leaves and roots. Presently, shape, hip shape, length of pedicel, presence or absence of dogroses are sometimes planted as ornamentals, especially in glandular hair, shape of prickles, persistence of sepals, shape public areas where they are appreciated for their hardiness of style head orifice, leaf pubescence, and plant shape. At the and soundness. In addition, dogroses are used as rootstocks end of the 19th century, the total number of taxa described, for the budding of ornamental roses, but they are gradually including varieties, reached 4266 [2]. being replaced by rootstocks derived from other species with Section Caninae is divided into a number of subsections; superior characteristics. In the last two decades, modern sci- Trachyphyllae with R. marginata (syn. R. jundzillii) as the ence has, however, shown that rosehips from dogroses con- only species, Rubrifoliae with R. glauca (syn. R. rubrifolia) tain compounds of interest for functional food and nutraceu- ticals as well as for medicinal drugs. Efforts are now being as the only species, Vestitae with, e.g., R. mollis, R. sher- ardii, R. tomentosa and R. villosa (syn. R. pomifera), Ru- made to identify the active ingredients and their mode of bigineae with, e.g., R. agrestis, R. inodora, R. micrantha and action. R. rubiginosa, Tomentellae with R. balsamica and R. abiet- Objectives of this review include: ina, and Caninae with, e.g., R. canina, R. corymbifera, R. dumalis, R. montana and R. stylosa. Occasionally, R. stylosa 1. An overview of the complex taxonomy of dogroses is instead treated within its own subsection, Stylosae. since proper determination of the analysed plant mate- rial is essential for future optimization of commercially 2.2. DNA-Based Dogrose Taxonomy manufactured and marketed products, Morphological characters are generally insufficient for 2. An insight into the unique transmittal of chromosomes, unambiguous classification of dogroses, even when applied and therefore also traits, from parents to offspring since to plants in comparative garden trials [3, 4]. In dogroses, this has profound effects on the origination of dogrose many taxa have, however, turned out to be even more diffi- plants and their use, cult to distinguish when analysed with DNA markers, and 3. An account of chemical compounds with a potential samples from closely related species often overlap to a high role in the health-promoting effects of rosehips, degree. In one AFLP-based study conducted on >900 dogrose specimens sampled in a transect across Europe, the 4. Short descriptions of some of the studies that have re- three major subsections Caninae, Rubigineae and Vestitae ported medicinal effects of dogroses, and were clearly discriminated [5]. Some support was also indi- 5. Efforts to link the above-mentioned research areas, and cated for the smaller subsections Trachyphyllae, Rubrifoliae suggest how improvements towards well-informed and Stylosae, all of which have been hypothesized to derive utilization of rosehips can be achieved. from crosses between dogroses and taxa in other sections. Within the subsections, many species overlapped consid- 2. ROSE TAXONOMY erably. In dogroses, geographic distances often appear to be Proper inventorizing and evaluation of genetic resources at least as important as morphology-based classification in are a cornerstone in plant domestication. For the develop- explaining genotypic similarities between analyzed speci- ment of rosehip-based health-promoting products, potentially mens [4, 5]. Possibly, such species have arisen multiple valuable species should be collected and analysed. The genus times in multiple locations and are, therefore, polyphyletic. Rosa is however quite complex, and delimitation of sections In another study, AFLP and DNA microsatellite (SSR) and species is controversial. Numerous taxa have been de- markers were applied to discriminate among three species scribed at different ploidy levels, and inter-taxon hybridiza- within the subsection Vestitae [6]. Again, considerable over- tion is common. Although a modern classification of roses is lap was reported but clustering of the samples reflected dif- needed, the well-known Rehder system updated by Wisse- ferences in ploidy level (all species contained both tetra- and mann [1] is still much used. Three small subgenera, Hulthe- pentaploid specimens) more than in species affiliation or mia, Hesperhodos and Plathyrhodon, and one large, Rosa, geographical origin. are recognized. 3. CYTOLOGY AND REPRODUCTION Subgenus Rosa is further subdivided into 10 different sections. One of the largest is section Caninae, dogroses, The basic chromosome number in the genus Rosa is x = with approximately 50 species. The other sections are 7. Diploid rose species have two sets of chromosomes, 2n = Pimpinellifoliae (15 species), Gallicanae (one species and 2x = 14. In meiosis, these 14 chromosomes pair up to form several hybrid taxa), Carolinae (about five species), Rosa seven bivalents as expected, and inheritance is asymmetri- (about 80 species, formerly known as section Cinna- cally biparental. Many rose species as well as almost all or- momeae), Synstylae (about 25 species), Indicae (three spe- namental cultivars are instead tetraploid, with 2n = 4x = 28. cies), Banksianae (possibly two species), Laevigatae (one These can form bivalents or multivalents, but inheritance is species) and Bracteatae (one or two species). still symmetrically biparental. 2.1. Classical Dogrose Taxonomy 3.1. Canina Meiosis Medicinal effects of rosehips are mostly ascribed to the Dogroses are usually pentaploid (2n = 5x = 35) although dogroses but these have unfortunately proved to be the most some are tetraploid or hexaploid. All dogroses have peculiar Health-Promoting Rosehips