Potential Anti-inflammatory Effects of the Fruits of Paulownia tomentosa.

As part of an ongoing search for new natural products from medicinal plants to treat respiratory disease, six new compounds, a dihydroflavonol (1) and five C-geranylated flavanones (3, 6, 8, 13, and 14), and 13 known compounds were isolated from mature fruits of Paulownia tomentosa. The structures of the new compounds were determined via interpretation of their spectroscopic data (1D and 2D NMR, UV, IR, ECD, and MS). In biological activity assays with human alveolar basal epithelial cells, the expression of TNF-α-induced proinflammatory cytokines (IL-8 and IL-6) was reduced significantly by the EtOAc fraction of a P. tomentosa extract as well as by the new compounds isolated from this fraction. Furthermore, the majority of the isolates (1-19 except 5-7) were found to inhibit human neutrophil elastase (HNE) activity, with IC50 values ranging from 2.4 ± 1.0 to 74.7 ± 8.5 µM. In kinetic enzymatic assays with the HNE substrate MeOSuc-AAPV-pNA, compound 17 exhibited the highest inhibitory activity (Ki = 3.2 µM) via noncompetitive inhibition. These findings suggest that the flavanone constituents of P. tomentosa fruits may be valuable for the development of new drug candidates to treat airway inflammation.

Biophysical insight into structure-function relation of Allium sativum Protease Inhibitor by thermal, chemical and pH-induced modulation using comprehensive spectroscopic analysis.

In this study, we have analyzed the structural and functional changes in the nature of Allium sativum Protease Inhibitor (ASPI) on undergoing various denaturation with variable range of pH, temperature and urea (at pH 8.2). ASPI being anti-tryptic in nature has native molecular mass of ∼15kDa. The conformational stability, functional parameters and their correlation were estimated under different conditions using circular dichroism, fluorescence and activity measurements. ASPI was found to fall in belongs to α+ß protein. It demonstrated structural and functional stability in the pH range 5.0-12.0 and up to70°C temperature. Further decrease in pH and increase in temperature induces unfolding followed by aggregation. Chemical induced denaturation was found to be cooperative and transitions were reversible and sigmoid. Tm (midpoint of denaturation), ΔCp (constant pressure heat capacity change) and ΔHm (van't Hoff enthalpy change at Tm were calculated to be 41.25±0.2°C, 1.3±0.07kcalmol-1K-1 and 61±2kcalmol-1 respectively for thermally denatured ASPI earlier. The reversibility of the protein was confirmed for both thermally and chemically denatured ASPI. The results obtained from trypsin inhibitory activity assay and structural studies are found to be in a significant correlation and hence established structure-function relationship of ASPI.

Phileucin - A Cyclic Dipeptide Similar to Phevalin (Aureusimine B) from Streptomyces coelicolor M1146.

Overexpression of a putative type III polyketide synthase (PKSIII) from the marine myxobacterium Enhygromyxa salina SWB007 in Streptoinyces coelicolor MI 146 led to the accumulation of a novel monoketopiperazine consisting of phenylalanine and isoleucine. This compound was named phileucin and shows high structural similarity to phevalin (aureusimine B). The protease inhibiting activity was tested against human cathepsin L, human leukocyte elastase; bovine trypsin and bovine chymotrypsin. In contrast to phevalin, no protease inhibition was observed.

Triterpenoids as neutrophil elastase inhibitors.

Neutrophile elastase has the capacity to degrade elastin, a protein found in the connective tissue of the lungs. Unchecked elastase leads to pulmonary pathologies. Therefore, the development of elastase inhibitors is currently actively pursued in the therapeutic field. Several triterpenoids have been reported as inhibitors against elastase or its release. Such compounds could be valuable for the design of new drugs. This review is aimed at giving a comprehensive insight into the recent work performed in the field of triterpenoid-induced elastase inhibition.

[Heterologous expression, purification, and properties of a chymotrypsin inhibitor isolated from potatoes].

The PKPIJ-B gene encoding a chymotrypsin inhibitor from a subfamily of potato Kunitz-type proteinase inhibitors (PKPI) in potatoes (Solanum tuberosum L. cv. Yubilei Zhukova) was cloned into a pET23a vector and then expressed in Escherichia coli. The recombinant PKPIJ-B protein obtained in the inclusion bodies was denatured, purified by high-performance liquid chromatography (HPLC) on Mono Q under denaturing conditions, and renaturated. The renaturated protein was additionally purified using HPLC on DEAE-ToyoPearl. The PKPIJ-B protein efficiently suppressed chymotrypsin activity, had a weaker effect on trypsin, and inhibited the growth and development of phytopathogenic microorganisms affecting potato plants.

Anti-neutrophilic inflammatory secondary metabolites from the traditional Chinese medicine, Tiankuizi.

Through bioassay-guided fractionation, thirteen compounds (1-13) were isolated from the dry root of Semiaquilegia adoxoides, known as Tiankuizi in traditional Chinese medicine (TCM). Among these, four benzoic acid derivatives (1, 2, 4, 5), one 4,6-dimethoxy-5-methyl-2H-pyran-2-one (10) and one 1,2,3-propanetriol (13) were found for the first time in S. adoxoides. This is the first record of compound 10 from a natural source. 4-Hydroxybenzoic acid (1) and 3,4-dihyroxybenzoic acid (2) showed selective inhibition against elastase release and superoxide anion generation, with IC50 values of 3.20 and 6.21 microg/mL, respectively. Compound 1 had 7-fold better activity than the positive control against elastase release induced by human neutrophils. Overall, our studies demonstrated Tiankuizi (S. adoxoides) as a potential TCM and isolates 1 and 2 as promising lead compounds for neutrophilic inflammatory diseases.

Hydoroxyhibiscone A, a novel human neutrophil elastase inhibitor from Hibiscus syriacus.

In an ongoing investigation of compounds from natural products that exhibit anti-aging properties, hydroxyhibiscone A (1), a new furanosesquiterpenoid, together with hibiscone D (2), was isolated from the root bark of Hibiscus syriacus. Utilizing UV, IR, NMR, and MS spectroscopic analyses, these chemical structures were revealed. Compounds 1 and 2 were found to possess significant anti-aging properties on the human neutrophil elastase (HNE) assay, exhibiting HNE inhibitory activities with IC50 values of 5.2 and 4.6 micronM, respectively.

New polyketides from the marine-derived fungus Phaeosphaeria spartinae.

The fungus Phaeosphaeria spartinae is an endophyte of the marine alga Ceramium sp. Investigation of this marine-derived fungus led to the isolation of the new natural products spartinol A (1), B (2), C (3) and D (4). The structures of these closely related compounds were established from extensive spectroscopic investigations. Compound 3 showed weak inhibition of human leukocyte elastase (HLE).

Neutrophil elastase inhibitor, sivelestat sodium hydrate prevents ischemia-reperfusion injury in the rat bladder.

In the present study, we evaluated the effect of neutrophil elastase inhibitor, sivelestat sodium hydrate on ischemia-reperfusion injury in the rat bladder. Rat abdominal aorta was clamping with a small clip to induce ischemia-reperfusion injury in the bladder. Eight-week-old male Sprague Dawley rats were divided into four groups; sham-operated control rats, 30 min ischemia-60 min reperfusion (IR) rats, and IR rats treated with 15 or 60 mg/kg of sivelestat sodium hydrate. Sixty minutes prior to induction of ischemia, sivelestat sodium hydrate was administrated intraperitoneally. Real-time monitoring of blood flow and nitric oxide (NO) release were measured simultaneously with a laser Doppler flowmeter and an NO-selective electrode, respectively. The NO2-NO3 and malonaldehyde (MDA) concentrations were measured in the experimental urinary bladders. Clamping of the abdominal aorta, blood flow was rapidly decreased and NO release was gradually increased. After removing the clip, blood flow was rapidly increased and NO release was gradually returned to the basal level. These movements of blood flow and NO release were inhibited by treatment with sivelestat sodium hydrate in a dose-dependent manner. Both NO2-NO3 and MDA concentrations in the bladder were increased by induction of IR, and NO2-NO3 and MDA concentrations were decreased by treatment with high dose of sivelestat sodium hydrate significantly. Our data indicated that sivelestat sodium hydrate could inhibit increasing NO2-NO3 and MDA concentrations by IR, and it has potentiality protective effects on IR injury in the rat urinary bladder.

Natural compounds as inhibitors of human neutrophil elastase.

The imbalance between human neutrophil elastase (HNE) and endogenous serine proteinase inhibitors is considered to cause a variety of HNE-mediated inflammatory disorders. Thus, HNE has been the object of intensive research to find potent inhibitors that target its destructive and pro-inflammatory action. This review focuses on natural compounds which have been demonstrated to inhibit the enzyme itself or its release from neutrophils. Some of the natural compounds discussed here may serve as lead structures suitable to be used for the development of semi-synthetic inhibitors, but up to now none has been found active enough to be directly used in therapy.