Rosa canina pseudo fruits, often referred to as rose hips, have been used as herbal medicine for more than 2,000 years, yet research has only recently begun to clarify specific mechanisms by which this plant product affects human health. Numerous compounds have been identified, and speculations of their bioactivity have implicated flavonoids, carotenoids, and fatty acids (FAs). With more than 4,500 representatives, flavonoids have been subjected to comprehensive research, with results that suggest various individual structures may be health-promoting compounds, also in rose hips. The importance of carotenoids from R. canina is currently being debated, because the demonstration of specific bioactivity among this group is presently less clear. The benefits of specific FAs have been investigated for decades, and several types of FAs are termed “essential” for human health. The specific mechanisms for bioactivity associated with three FAs that are abundant in R. canina fruits have been clarified in research. For example, linoleic acid, α-linolenic acid (mostly present in the seeds from R. canina) and a galactolipid ((2S)-1,2-di-O-[(9Z,12Z,15Z)-octadeca-9-12-15-trienoyl]-3-O-β-d-galactopyranosyl glycerol), referred to as GOPO, have been shown to have anti-inflammatory properties. The aim of this review is to critically analyze the published literature on rose hip research, with emphasis on the broadness and varying significance of the publications. Initially, we describe the chemical ingredients of R. canina pseudo fruits, with some focus on what ingredients are found in the whole pseudo fruit and what we know is confined to the seeds (achene seeds), and/or the shells (hypanthium). Then, we evaluate important papers describing the in vitro investigations of the bioactivity and impacts of the constituents of rose hip.

Objective: To evaluate the effects of a rose hip powder (Hyben Vital^®) made from seeds and shells on cell senescence, skin wrinkling, and aging. Methods: A total of 34 healthy subjects, aged 35–65 years, with wrinkles on the face (crow’s-feet) were subjected to a randomized and double-blinded clinical study of the effects of the rose hip powder, as compared to astaxanthin, a well-known remedy against wrinkles. During the 8-week study, half of the participants ingested the standardized rose hip product, while the other half ingested astaxanthin. Objective measurements of facial wrinkles, skin moisture, and elasticity were made by using Visioscan, Corneometer, and Cutometer at the beginning of the study, after 4 weeks, and after 8 weeks. Evaluation of participant satisfaction of both supplements was assessed using questionnaires. In addition, the effect of the rose hip preparation on cell longevity was measured in terms of leakage of hemoglobin through red cell membranes (hemolytic index) in blood samples kept in a blood bank for 5 weeks. Significance of all values was attained with P≤0.05. Results: In the double-blinded study, the rose hip group showed statistically significant improvements in crow’s-feet wrinkles (P<0.05), skin moisture (P<0.05), and elasticity (P<0.05) after 8 weeks of treatment. A similar improvement was observed for astaxanthin, with P-values 0.05, 0.001, and 0.05. Likewise, both groups expressed equal satisfaction with the results obtained in their self-assessment. The rose hip powder further resulted in increased cell longevity of erythrocyte cells during storage for 5 weeks in a blood bank. Conclusion: Results suggest that intake of the standardized rose hip powder (Hyben Vital^®) improves aging-induced skin conditions. The apparent stabilizing effects of the rose hip product on cell membranes of stored erythrocyte cells observed in this study may contribute to improve the cell longevity and obstructing skin aging.

The introduction of glucagon-like peptide 1 (GLP-1)-based therapies has greatly improved the management of type 2 diabetes (T2D), as they ensure good blood glucose control and promote weight loss. Ingestion of standardized herbal remedies that promote the same endogenous metabolic processes affected by the GLP-1-based treatments could provide cheaper alternatives in low- and middle-income countries, where there is currently an increase in the incidence of T2D. The focus in this study was to determine quality control parameters and the prime factors for the Rauvolfia-Citrus tea (RC-tea), as used in Nigerian traditional medicine to treat T2D. We have previously shown that the RC-tea that is made by boiling leaves of Rauvolfia vomitoria Afzel. and fruits of Citrus aurantium L. causes normalization of blood glucose and reduction of ectopic lipid accumulation in genetic diabetic (BKS-db) db ) mice and in humans with T2D. The standardized RC-tea was made by boiling 40 g dried R. vomitoria foliage and 200 g fresh C. aurantium fruits per litre. The resulting golden-brown extract is free of microbial contamination, has pH 5 and contains ca. 230 mg naringin (marker compound for C. aurantium) ) and 25 mg robinin (marker compound for R. vomitoria) ) per litre. In addition, the herbal extract has the characteristic HPLC-DAD fingerprint where the marker compounds, naringin and robinin have retention times of approximately 26.3 min and 26.9 min, respectively, when using the outlined column and gradient elution conditions. Comparative evaluations of the antidiabetic effects of the standardized RC-tea and boiling water-extracts made with C. aurantium fruits alone (CA), R. vomitoria foliage alone (RV) and a combination of CA and RV, (CA + RV) in BKS-db db mice, indicate that components from R. vomitoria foliage drive the reductions in ectopic lipid accumulation, since CA-treated mice lacked this effect. However, the normalization of blood glucose arises from combination of components from the two source plant materials as administration of either CA or RV resulted in hypoglycaemia. Interestingly, treatment with the CA + RV mixture, generated by mixing individually produced CA and RV plant extracts, resulted in hyperglycaemia, possibly due to drug-drug interactions of the blood glucose-reducing components in either plant extract. Hence, our data show that the best antidiabetic outcome results from the traditional practice of boiling R. vomitoria foliage and C. aurantium fruits together.

Ashwagandha (Withania somnifera L.) root powder and extracts have long been used in Ayurvedic medicine to improve sleep and anxiety. Recent scientific investigations into its efficacy have shown promise for relief from anxiety, insomnia and stress and for improving the immune system. It has also been suggested that oxygen uptake in the cardiovascular system, muscle strength, cognitive function, the reproductive system and the aging process significantly benefit from ashwagandha treatment. Since the herbal remedy is taken daily by millions of people in India, China and parts of the West, it is interesting that there are very few case reports of side effects directly attributed to the treatment, suggesting that the administration of ashwagandha preparations may be safe. Currently, neither the European Medicines Agency nor the FDA considers ashwagandha as a drug or general health supplement. Therefore, ashwagandha products are marketed in the West as dietary supplements so that users may be exposed to unscrupulous vendors. In this narrative/literature review, scientific findings from basic research and human clinical trials on herbal remedies, spanning the period from 1994 to date, were critically evaluated for the purpose of highlighting knowledge gaps to provide context for new research. Such investigations will provide evidence for the efficacy and safety of ashwagandha treatment, thus making the herbal preparations more accessible to a wider audience.

Background: Large positive responses to placebo are common in clinical trials and pose a major challenge when evaluating different treatments, including new foods. Standard between-group comparisons may fail to detect true effects when placebo improvements are significant. We aimed to demonstrate how a simple dose–response correlation method can help differentiate genuine positive responses from those experienced with placebo through secondary analysis of a randomized controlled clinical trial of powdered Rosa-canina fruits. Methods: Data were reanalyzed from a multicenter, double-blind, randomized, placebo-controlled trial (N = 120; ClinicalTrials.gov NCT01459939) evaluating the effects of standardized Rosa-canina powder in hip and knee osteoarthritis (OA). Participants received fixed doses, leading to variability in mg/kg exposure due to different body weights. Pearson correlations between dose/kg and changes in WOMAC pain and function at 6 and 12 weeks were calculated separately for the active and placebo groups. Standard between-group comparisons were also performed. Results: Both groups showed significant improvement, over 50%, with no statistically significant differences between them in WOMAC pain or function. However, only the active group, which received a food supplement, exhibited a consistent negative correlation between body weight and symptom improvement at 6 and 12 weeks, suggesting greater benefit with higher dose per kilogram of body weight. No dose–response relationship was observed in the placebo recipients. Therefore, weight-stratified plots revealed an exposure–response gradient in the active group. Conclusions: Dose–response correlation analysis uncovered positive effects of Rosa-canina as a nutrient that were not detectable through standard between-group comparisons. This is consistent with findings from earlier rose-hip research. This low-cost, easy-to-implement method may help distinguish active effects from placebo responses in trials with large nonspecific improvements. Incorporating such analyses could improve the identification of nutrients containing biologically active preparations and support dose selection in future clinical research.