Mass spectrometry imaging: new eyes on natural products for drug research and development.

Natural products (NPs) and their structural analogs represent a major source of novel drug development for disease prevention and treatment. The development of new drugs from NPs includes two crucial aspects. One is the discovery of NPs from medicinal plants/microorganisms, and the other is the evaluation of the NPs in vivo at various physiological and pathological states. The heterogeneous spatial distribution of NPs in medicinal plants/microorganisms or in vivo can provide valuable information for drug development. However, few molecular imaging technologies can detect thousands of compounds simultaneously on a label-free basis. Over the last two decades, mass spectrometry imaging (MSI) methods have progressively improved and diversified, thereby allowing for the development of various applications of NPs in plants/microorganisms and in vivo NP research. Because MSI allows for the spatial mapping of the production and distribution of numerous molecules in situ without labeling, it provides a visualization tool for NP research. Therefore, we have focused this mini-review on summarizing the applications of MSI technology in discovering NPs from medicinal plants and evaluating NPs in preclinical studies from the perspective of new drug research and development (R&D). Additionally, we briefly reviewed the factors that should be carefully considered to obtain the desired MSI results. Finally, the future development of MSI in new drug R&D is proposed.

Transcutaneous electrical stimulation at auricular acupoints innervated by auricular branch of vagus nerve pairing tone for tinnitus: study protocol for a randomized controlled clinical trial.

BACKGROUND: Subjective tinnitus is a phantom sensation experienced in the absence of any source of sound. Its mechanism remains unclear, and no approved drugs are available. Vagus nerve stimulation (VNS) is an exciting new method to treat tinnitus, but direct electrical stimulation of the cervical vagus has disadvantages. This randomized controlled clinical trial aims to overcome these limitations by stimulating the auricular branch of vagus nerve (ABVN) on the outer ear. Since the ABVN is the only peripheral branch of the vagus nerve distributed on the ear's surface, it should be possible to achieve analogous efficacy to VNS by activating the central vagal pathways. However, researches have indicated that the curative effect lies in a combination of auditory and vagal nerve stimulation. Moreover, from traditional Chinese theory, auricular acupoints used to treat tinnitus are mainly in the regions supplied by the ABVN. Whether stimulation at the auricular acupoints is due to unintentional stimulation of vagal afferent fibers also needs evidence. METHODS/DESIGN: A total of 120 subjects with subjective tinnitus are randomized equally into four groups: (1) electrical stimulation at auricular acupoints (CO10, CO11, CO12, and TF4) innervated by the ABVN; (2) electrical stimulation at auricular acupoints (CO10, CO11, CO12, and TF4) innervated by ABVN pairing tones; (3) electrical stimulation at auricular acupoints innervated by non-ABVN pairing tones; (4) electrical acupuncture. Patients will be treated for 30 minutes every other day for 8 weeks. The primary outcome measure is the Tinnitus Handicap Inventory. The secondary outcome measure combines a visual analogue scale to measure tinnitus disturbance and loudness with the Hospital Anxiety and Depression Scale. Assessment is planned at baseline (before treatment) and in the 4th and 8th week, with further follow-up visits after termination of the treatment at the 12th week. Any adverse events will be promptly documented. DISCUSSION: Completion of this trial will help to confirm whether ABVN or the combination of ABVN and sound stimulus plays a more important role in treating tinnitus. Moreover, the result of this clinical trial will enhance our understanding of specific auricular acupoints. TRIAL REGISTRATION: Chinese Clinical Trials Register ChiCTR-TRC-14004940.

The effect of high speed shearing on disaggregation and degradation of pectin from creeping fig seeds.

The effect of high speed shearing (HSS) on disaggregation and degradation of pectin from creeping fig seeds was investigated. It was found that disaggregation and degradation occurred during the whole shearing process. When pectin solution was sheared at 24,000 rpm for less than 8h, degradation happened but disaggregation was dominant during this period. After 8h, degradation became obvious, however, a small amount of aggregates remained even after 24h treatment, indicating that HSS may not eliminate aggregates efficiently. The presence of aggregates is one of the most probable causes for the inaccurate determination of molecular weight of pectin. A new method was proposed for calculating more accurately the molecular weight based on the change of the reducing sugar content and the variation of molecular weight. Determination of unsaturated uronide and FT-IR spectra analysis indicated that neither ß-elimination nor demethoxylation occurred during the HSS, and no new functional group was formed during the HSS process.

Extraction of pectin from Premna microphylla turcz leaves and its physicochemical properties.

Premna microphylla turcz leaves (PMTL) have been used for preparing a "green tofu" by Chinese for a long history. Chemical composition analysis indicated alcohol insoluble solids (AIS) of PMTL contained high amount of pectin. Water, ammonium oxalate, hydrochloric acid and sodium hydroxide were used to extract different pectic fractions sequentially. Ammonium oxalate was found to be the most effective extracting agent, reflecting on a high yield (20.61%) and a significant change of morphology of AIS. The resulted oxalate-soluble pectin (OXSP) showed high galacturonic acid content (76.15%) and average molecular weight (980.67kDa), low neutral sugar content (6.41%) and degree of methoxylation (14.90%). All of the characteristics have contributed excellent gelling and thickening properties of OXSP. These results may allow an improved use of PMTL as a resource of low-methoxyl pectin, and observation of the morphology of residues can be helpful for evaluating the efficiency of extracting agents.

Pectic-oligosaccharides prepared by dynamic high-pressure microfluidization and their in vitro fermentation properties.

Pectic-oligosaccharides (POSs) were prepared from apple pectin by dynamic high-pressure microfluidization (DHPM). Operating under selected conditions (pectin concentration 1.84%, solution temperature 63 °C, DHPM pressure 155MPa and number of cycles 6 passes), 32.92% of the pectin was converted into POS. The resulting POS contains 29.56% galacturonic acid and 58.53% neutral sugars. The prebiotic properties of POS were then evaluated using a fecal batch culture fermentation. The POS increased the number of Bifidobacteria and Lactobacilli, and produced a higher concentration of acetic, lactic, and propionic acid than their parent pectin. Furthermore, POS decreased the number of Bacteroides and Clostridia while their parent pectin increased them. Moreover, the effects of POS on the growth of these bacteria and production of short-chain fatty acids are comparable to those of the most studied prebiotic, fructooligosaccharide. These results indicated that the POS prepared by DHPM has a potential to be an effective prebiotic.

Effects of electro-acupuncture on IGF-I expression in spared dorsal root ganglia and associated spinal dorsal horn in cats subjected to adjacent dorsal root ganglionectomies.

The effects of electro-acupuncture (EA) on insulin-like growth factor-I (IGF-I) expression in the spared dorsal root ganglia (DRG) and associated spinal dorsal horns were explored in cats subjected to unilateral removal of L(1)-L(5) and L(7)-S(2) DRG, sparing the L(6) DRG. Immunohistochemistry revealed the presence of IGF-I immunoreactive products in the L(6) DRG neurons and some neurons and glial cells in the spinal cord. Western blot demonstrated that the level of IGF-I was significantly up-regulated both in the spared DRG and the dorsal horns of L(3) and L(6) cord segments at both 7 and 14 days post operation following EA. The present findings demonstrated the association between neuroplasticity and IGF-I expression, suggesting the possible role of IGF-I in EA promoted spinal cord plasticity.