Effects of Rosa canina: a placebo or a future possible drug?
Rosa canina, also referred to as the dog rose, is a permanent scrambling or climbing species of rose that is indigenous to Europe, south-western Asia and northern Africa. Generally, the plant is found to be growing up to three meters or around 10 feet in length. Some plants may even grow longer and reach the apex of taller trees growing nearby. Rosa canina plants bear hooked thorns on the stem and these aid the plants in climbing. The plant has pinnate leaves, with each leaf having two to three pairs of jagged leaflets. Usually, the blooms of Rosa canina are pink, but they may also be found in white. The flowers are around 4 cm to 6 cm in diameter, each having five petals.
The flowers develop into reddish-orange colored fruits, also known as hips.
The most important parts of the dog rose are its fruits or hips, which possess high medicinal value. The fruits or hips of Rosa canina are usually vivid red and harvested during the fall. They are widely used for their medicinal properties.
The fruits or hips of the dog rose enclose an assortment of vitamins and added essential nourishments. For instance, the hips of Rosa canina enclose rich amounts of vitamin C. In addition, the fruits also contain different amounts of vitamins A, B1, B2, B3 and K. The other ingredients contained in the dog rose fruits are tannins, flavonoids, vanillin, polyphenols, carotenoids and essential oil. Each of these elements contained in the Rosa canina hips have significant roles in the human body.
As mentioned above, the dog rose or Rosa canina is native to Europe and the temperate climatic zones of Asia and northern Africa. Usually, the dog rose plant grows in hedgerows or a row of bushes forming a hedge and also as thickets or a thick coppice. Apart from this, the dog rose plants may also be found growing naturally in open areas, such as meadows, pastures and wasteland. The fruits or hips of the dog rose are collected during fall.
Rosa canina or the dog rose plants thrive well in damp soils and also grows fine in heavy clay soils. The plants of this species of rose have a preference for circumneutral soil as well as sunlight areas with their roots growing in the shade. However, if the dog rose is cultivated in darkness or profound shadow, they do not bear flowers and fruits. Although, the plants grow well in damp soil conditions, they are averse to soggy soils or arid areas. The plants have the aptitude to withstand exposure to marine conditions. While the fruits or hips of the dog rose draw several species of birds towards them, numerous insects and gall wasps inhabit the plants. The flowers of the dog rose are very aromatic, while the leaves when smashed or bruised, emit an excellent scent. Rosa canina or the dog rose has the aptitude to grow excellently in the company of parsley, lupins, alliums and mignonette. If garlic plants are grown in the vicinity of the dog rose, they help in protecting the plants of this rose species from diseases as well as invasion of insects. However, the growth of dog rose plants is very poor when they are near any boxwood plants.
There are quite a number of people who like to use a combination of the Rosa canina or the dog rose petals and hips/fruits. When the petals and hips are used in blend, they are said to function as a diuretic, astringent, a laxative as well as a stimulant or tonic. However, when the hips are used separately, people assert that they are effective in treating diarrhea, trivial contagions, cold, gastritis and scurvy. In addition, presently several studies are being conducted to find whether the hips of Rosa canina are able to prevent or overturn the development of cancer cells.
All said and done, using the dog rose or Rosa canina also has its downsides. There is a number of side effects related to the use of Rosa canina, but most of them are comparatively insignificant or having less adversity. For instance, a beneath the fleshy tissues of the hips you will find a layer resembling fine bristles or hair. If this hair-like layer of the Rosa canina fruit is consumed, it may cause irritation in the mouth as well as the digestive tract.
Effect and Efficacy Profiles
In traditional medicine, 2–5 g of the plant material is used to prepare an aqueous extract, e.g. for a cup of tea, taken 3 to 4 cups per day.
Optimum temperature and infusion periods to achieve the maximum content of vitamin C in the tea from dried or divided frozen fruit were found to be 60 °C and 360 min (dried fruit) and 60 °C and 270 min, respectively (Yavru and Kadioglü, 1997).
However, in commercial products, e.g.soups, only minor amounts of folate and vitamin C were found, probably because the duration of the preparation and high temperatures might have destroyed both active constituents (Stralsjö et al., 2003).
The ischemia/reperfusion injury in the mouse colon is another established model to study the antioxidative effect of agents. The rose hip powder containing 863 mg% vitamin C and 82% carbohydrates, had a significantly additive effect on the Lactobacillus plantarum DSM 9843-inhibitory effect on caecal malondialdehyde (MDA) as an index of lipid peroxidation. A positive correlation between MDA and Enterobacteriaceae count was found. The authors concluded that rose hip and L. plantarum should be used as a pre-treatment to tissue injuries, e.g. colon surgery, organ transplantation and vascular surgery (Hakansson et al., 2006).
The chemoluminescence assay is another measure of oxygen radical generation by activated polymorphonuclear neutrophils (PMN). Rose hip and seed aqueous extract at concentrations of 500 μg/mL and higher inhibited chemoluminescence of PMN activated by opsonized zymosan and also chemotaxis of the human cells.
A galactolipid was identified as the co-active ingredient for the inhibitory effect on chemotaxis in PMN (Larsen et al., 2003).
An aqueous extract prepared from rose hip seed did not inhibit the prostaglandin biosynthesis and platelet activating factor-induced exocytosis of elastase (Tunon et al., 1995). However, a recent short communication reported that if rose hip and seed were extracted with organic solvents (e.g. methanol, dichloromethane and hexane) both COX-1 (sheep seminal vesicles) and COX-2 (human recombinant) were inhibited in vitro. However, the aqueous extract was also ineffective in these tests.
In Rosa canina root, constituents with inhibitory effects on inflammatory mediators of cartilage destruction, such as Il-1R, Il-1 and TNF-R were found (Yesilada et al., 1997).
In a cross-over human pharmacological study, in which the volunteers first received 45 g rose hip and seed powder over 28 days and thereafter 10 g powder per day, it was shown that the antiinflammatory effect in terms of ex vivo/in vitro chemotaxis of PMN was dose-dependent (Winther et al., 1999). Moreover, C-reactive protein (a marker of inflammation) as well as creatinine values decreased significantly. After stopping the intake of the powder, these values increased to the pre-values again (Kharazmi and Winther, 1999; Winther et al., 1999).
Effects on body fat, plasma and biliary lipids
An 80% acetone extract from rose hip and seed (50 mg/kg) or seed (12.5 and 25 mg/kg) were found to show substantial inhibitory effect on the gain of body weight and/or weight of visceral fat (total weight of epididymal, mesenteric and paranephric fats) without affecting food intake in mice for 2 weeks after administration of the extracts and with no obvious toxic effect (Ninomiya et al., 2007).
In addition, plasma triglyceride and free fatty acid levels were significantly reduced on day 14 following the rose hip and seed or the rose hip seed lipophilic extract. As main constituent, trans-tiliroside was identified, that inhibited dose-dependently body weight gain and visceral fat weight in a dose of 0.1–10 mg/kg/day.
Anti-ulcerogenic and probiotic effects
An aqueous extract prepared from 10 g rose hip seed with a yield of 21% in a dose of 2 g/kg prevented gastrointestinal lesions caused by 96% ethanol if administered 15 min prior to the ethanol administration. The ulcer index, defined as the sum of lesions in mm, was zero (Gürbütz et al., 2003).
In a human pharmacological investigation, 22 healthy volunteers received a proprietary rose hip drink over 3 weeks and another 26 volunteers, a rose hip drink containing oats fermented with Lactobacillus plantarum 9843. In both groups, the numbers of faecal bifidobacteria and lactobacilli were significantly increased.
During the period of intake, the volunteers receiving the fermented drink experienced a significant increase in stool volume and a significant decrease in flatulence and slightly softer stools, whereas the stool volume was slightly decreased during the intake of proprietary rose hip drink (Johannson et al., 1998).
Effect on blood glucose
The effects of aqueous and ethanol extracts on blood glucose were investigated in rabbits.
For the constituent trans-tiliroside a blood glucose lowering effect after glucose loading (1 g/kg i.p.) was demonstrated in doses up to 10 mg/kg/day (Ninomiya et al., 2007).
Effects on urine excretion and composition
Grases and coworkers (1992) did not observe any diuretic effect during 12 days and no effect on creatinine, phosphate and oxalate concentrations and excretion when water was replaced by a rose hip seed infusion 5 g/L (prepared with boiling water and filtered) in rats receiving a balanced diet. However, calciuria decreased and citraturia increased, indicating a possible beneficial effect of rose hip seed tea in calcium oxalate urolithiasis. While magnesium chloride decreases urine pH, such an acidifying effect was not observed during concomitant administration of the rose hip seed infusion (Grases et al., 1992).
Anti-mutagenic and anti-cancerogenic effects
Raw, boiled juice, boiled leaves and dried seeds of rose hip were not found to be mutagenic in Salmonella typhimurium TA 100.
Dried rose hip seed (100 g) was extracted with petroleum ether, with ethanol 95% and water, with yields of 0.3%, 5.9% and 10%, respectively. Whereas the aqueous rose hip seed extract showed only a poor cytotoxic effect on Yoshida ascites sarcoma cells (LD50 > 10 mg/ mL), the ethanol and petroleum ether extracts demonstrated a significant cytotoxic effect with LD50 values of 3.9 and 1.2 mg/mL, respectively, indicating a possible anticancerogenic effect (Trovato et al., 1996).
Methanol, dichloromethane and n-hexane rose hip seed extracts were assessed for their antibacterial activity against 11 pathogenic Gram-positive and Gram-negative bacterial species. Only the methanol extract demonstrated a weak antibacterial effect and only against E. coli 8110 (Kumarasamy et al., 2002).
Two polyphenols were isolated: tellimagrandin I was more effective than rugosin B and had a synergistic effect to oxacillin in reducing the MIC in methicillin-resistant Staphylococcus aureus.
Tellimagrandin I also significantly reduced the MIC of tetracycline in some strains of methicillin-sensitive Staphylococcus aureus (Shiota et al., 2000).
The petroleum ether, ethanol and aqueous extracts investigated in the study on the cytotoxic effects of rose hip seed (Trovato et al., 1996) were also tested for their antimycotic activity on strains of Candida albicans. The ethanol rose hip seed extract had a modest but significant antimycotic effect (Trovato et al., 2000).
Although evidence of the effectiveness is only moderate for osteoarthritis (two exploratory clinical studies of good quality, Chrubasik et al., 2006) and poor for rheumatoid arthritis and chronic low back pain (one exploratory study only for each indication) there is no doubt of the overall anti-inflammatory and analgesic potential of LitozinR. Studies that objectify the effect sizes are urgently needed to assure clinical significance before the rose hip and seed powder may be considered in treatment guidelines. As a specific adverse event in rare cases, allergy may occur. Allergy with generalized exanthema and gastrointestinal complaints may even occur after drinking rose hip tea (Lleonart et al., 2007).
Otherwise, only minor gastrointestinal adverse events have been observed, mainly due to inappropriate concomitant liquid consumption.
As generally suggested for plant intake, a gap of 2 h should be considered between the intake of powder and the intake of other medications so as not to risk any interaction in absorption.
The topical use of rose hip seed oil in eczema, trophic ulcers of the skin, neurodermitis, cheilitis etc may also be promising.
Since the content of bioactive constituents in the oils prepared with ultrasound, microwave, suband supercritical fluid extraction was different, clinical studies are necessary to determine which oil is the best for topical use. Contact allergy to rose oil of other species, e.g. the flower petals of Rosa damascena, has been observed (Cockayne and Gawkrodger, 1997) and might therefore also be possible with topical use of Rosa canina oil.
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Stralsjö L, Alklint C, Olsson ME, Sjöholm I. 2003. Total folate content and retention in rosehips (Rosa ssp.) after drying. J Agric Food Chem 51: 4291–4295.
Hakansson A, Stene C, Mihaescu A et al. 2006. Rose hip and Lactobacillus plantarum DSM 9843 reduce ischemia/ reperfusion injury in the mouse colon. Dig Dis Sci 51: 2094–2101.
Larsen E, Kharazmi A, Christensen LP, Christensen SB. 2003. An anti-inflammatory galactolipid from rose hip (Rosa canina) that inhibits chemotaxis of human peripheral blood neutrophils in vitro. J Nat Prod 66: 994–995.
Tunon H, Olavsdotter C, Bohlin L. 1995. Evaluation of anti-inflammatory activity of some Swedish medicinal plants. Inhibition of prostaglandin biosynthesis and PAF-induced exocytosis. J Ethnopharmacol 48: 61–76.
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Johansson ML, Nobaek S, Berggren A et al. 1998. Survival of Lactobacillus plantarum DSM 9843 (299v), and effect on the short-chain fatty acid content of faeces after ingestion of a rose-hip drink with fermented oats. Int J Food Microbiol 42: 29–38.
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