• Nutrition Research and Practice
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• 제18권1호
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• pp.33-45
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• 2024

BACKGROUND/OBJECTIVES: Onion, particularly onion peel, is a quercetin-rich food with, anti-inflammatory and immunomodulatory effects. However, the effect of onion peel extract (OPE) in humans is unclear. Thus, the present study aimed to investigate whether OPE improves natural killer (NK) cell activity and cytokine concentration in a randomized double-blind placebo-controlled trial. SUBJECTS/METHODS: Eighty participants aged 19-64 yrs old with a white blood cell count of 4,000-10,000 cells/µL, symptoms of upper respiratory infection at least once within the previous 12 mon, and perceived stress scale (PSS) over 14 were included. Participants were randomly assigned to take either 1,000 mg/day OPE or a placebo for 8 weeks. RESULTS: Compliance were 87.4 ± 8.6% and 86.9 ± 79.0% in OPE and placebo groups. Compared to the placebo, OPE supplementation improved "Hoarseness" (P = 0.038) of the Wisconsin Upper Respiratory Symptom Survey (WURSS)-21 symptom, and stress scores (P = 0.001; 0.021) of PSS. Supplementation of OPE had no significant effect on NK cell activity and concentrations of cytokines such as interleukin (IL)-2, IL-6, IL-12, IL-1β, interferon-γ, and tumor necrosis factor-α. At baseline, the WURSS-21 symptom and PSS score (P = 0.024; 0.026) were higher in the OPE group than the placebo group. Among participants with higher than median WURSS-21 symptom score, OPE supplementation increased NK cell activity (P = 0.038). Supplementation of OPE had no significant effects on safety measurements and adverse events. CONCLUSIONS: The present study suggested that OPE supplementation improves NK cell activity in participants with moderate upper respiratory symptoms without any significant adverse effects.

• 대한한의학회지
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• 제29권2호
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• pp.165-181
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• 2008

Objectives: This study was conducted to help clinical studies for treating the common cold with Oriental medicine. We inspected tendencies of clinical studies of the common cold in western medicine and analyzed the assessing instruments for it by scrutinizing PubMed publications for the last five years. Materials and Methods: We inspected 32 theses and scrutinized their objectives, periods, participants, materials and methods, the instrument of assessment for the studies, and validity, reliability, criteria and symptom score for questionnaires, results and JADAD score. Results: 1. The median for total period of study was 7 months, the median for days of treatment was 7.5, and most studies were carried out during the winter/spring period, because of the enhanced risk of cold infections. 2. The studies focused on unorthodox medicines or new drug products, such as antipyretic analgesics (e.g. paracetamol), decongestant and bronchodilator (e.g. ephedrine), echinacea, antioxidants (e.g. zinc), probiotic bacteria and so on. 3. All theses except one had subjectscomposed of cold patients who were infected naturally. The median number of subjects for final analysis was 187. 4. 27 studies used survey as the instrument of assessment. Among these, only one thesis was verified for validity. 5. The mean of JADAD score was 4.41, suggesting most of theses of worth. 7 studies were assessed as ineffective. Conclusion: Recent studies of the common cold are focused on unorthodox medicines or new drug products, and it is necessary to provide an objective instrument for assessing common cold treatments.