The nitric oxide-producing properties of Ulmi radicis cortex extract

Effects of 4-Week Intervention with Ulmus macrocarpa Hance Extract on Immune Function Biomarkers in Healthy Adults: A Randomized Controlled Trial

Ulmus macrocarpa extract has been shown to have immune-related effects in animals, but no studies have yet been performed in humans. This randomized, double-blind, placebo-controlled trial was conducted to determine the effect of short-term administration of Ulmus macrocarpa Hance extract (UME) on immune function biomarkers and its safety in human subjects. Fifty-eight subjects were randomly assigned to a UME group or a placebo group. Subjects in the UME group were given 500 mg per day of UME orally for 4 weeks. Mean fluorescence intensity (MFI) of tumor necrotic factor-α increased only in the UME group at 1 week (P = 0.027). The MFI of interleukin-2 decreased less significantly in the UME group than in the placebo group at 1 week (P = 0.028). However, unfortunately, at 4 weeks, no intergroup differences were detected in MFIs of cytokine. In conclusion, administration of UME for 1 week increased serum TNF-α and sustains IL-2 in human, which suggests that UME increases Th1-related immune function in the short term in healthy people. However, additional studies are needed to confirm the results of this first-stage study and further trials are required to decide on optimal dosage and duration of administration. This trial is registered with ClinicalTrials.gov Identifier: NCT02414412.

Nitric oxide, human diseases and the herbal products that affect the nitric oxide signalling pathway

1. Nitric oxide (NO) is formed enzymatically from l-arginine in the presence of nitric oxide synthase (NOS). Nitric oxide is generated constitutively in endothelial cells via sheer stress and blood-borne substances. Nitric oxide is also generated constitutively in neuronal cells and serves as a neurotransmitter and neuromodulator in non-adrenergic, non-cholinergic nerve endings. Furthermore, NO can also be formed via enzyme induction in many tissues in the presence of cytokines. 2. The ubiquitous presence of NO in the living body suggests that NO plays an important role in the maintenance of health. Being a free radical with vasodilatory properties, NO exerts dual effects on tissues and cells in various biological systems. At low concentrations, NO can dilate the blood vessels and improve the circulation, but at high concentrations it can cause circulatory shock and induce cell death. Thus, diseases can arise in the presence of the extreme ends of the physiological concentrations of NO. 3. The NO signalling pathway has, in recent years, become a target for new drug development. The high level of flavonoids, catechins, tannins and other polyphenolic compounds present in vegetables, fruits, soy, tea and even red wine (from grapes) is believed to contribute to their beneficial health effects. Some of these compounds induce NO formation from the endothelial cells to improve circulation and some suppress the induction of inducible NOS in inflammation and infection. 4. Many botanical medicinal herbs and drugs derived from these herbs have been shown to have effects on the NO signalling pathway. For example, the saponins from ginseng, ginsenosides, have been shown to relax blood vessels (probably contributing to the antifatigue and blood pressure-lowering effects of ginseng) and corpus cavernosum (thus, for the treatment of men suffering from erectile dysfunction; however, the legendary aphrodisiac effect of ginseng may be an overstatement). Many plant extracts or purified drugs derived from Chinese medicinal herbs with proposed actions on NO pathways are also reviewed.

Release of intermediate reactive hydrogen peroxide by macrophage cells activated by natural products

By determining the hydrogen peroxide (H2O2) released in cultures of peritoneal macrophage cells from Swiss mice, we evaluated the action of 27 vegetable compounds (pristimerin, tingenone, jatrophone, palustric acid, lupeol, cladrastin, ocoteine, boldine, tomatine, yohimbine, reserpine, escopoletin, esculine, plumericin, diosgenin, deoxyschizandrin, p-arbutin, mangiferin, and others) using a 2 mg/ml solution of each compound (100 microg/well). Macrophages are cells responsible for the development of the immunological response reaction, liberating more than one hundred compounds into the extracellular environment. Among these are the various cytokines and the intermediate compounds of nitrogen (NO) and oxygen (H2O2). This coordinated sequence of biochemical reactions is known as the "oxidative burst." When we compared the results with those obtained with zymosan (an important stimulator of H2O2) we observed that the compounds showing the highest activity were substances 2 (tingenone), 16 (reserpine) and 20. Other substances such as compounds 1, 4, 5, 6, 8, 12, 13, 14, 15, 17, 19, 23, 24, 26, and 27 also showed a certain activity, but with less intensity than the aforementioned ones. Compounds 3, 7, 9, 10, 11, 18, 21, 22 and 25 presented no activity. These results suggest that natural products (mainly tingenone and reserpine and others) with different chemical structures are strong immunological modulators. However, further tests are needed to determine the 'oxidative burst' in future studies.