Xianglong Wu

The importance of the prenyl group in the activities of osthole in enhancing bone formation and inhibiting bone resorption in vitro.

Osteoporosis treatment always aimed at keeping the balance of bone formation and bone resorption. Recently, prenyl group in natural products has been proposed as an active group to enhance the osteogenesis process. Osthole has both the prenyl group and bone-protective activities, but the relationship is still unknown. In this study we found that osthole exerted a potent ability to promote proliferation and osteogenic function of rat bone marrow stromal cells and osteoblasts, including improved cell viability, alkaline phosphatase activity, enhanced secretion of collagen-I, bone morphogenetic protein-2, osteocalcin and osteopontin, stimulated mRNA expression of insulin-like growth factor-1, runt-related transcription factor-2, osterix, OPG (osteoprotegerin), RANKL (receptor activator for nuclear factor-κB ligand), and the ratio of OPG/RANKL, as well as increasing the formation of mineralized nodules. However, 7-methoxycoumarin had no obvious effects. Osthole also inhibited osteoclastic bone resorption to a greater extent than 7-methoxycoumarin, as shown by a lower tartrate-resistant acid phosphatase activity and lower number and smaller area of resorption pits. Our findings demonstrate that osthole could be a potential agent to stimulate bone formation and inhibit bone resorption, and the prenyl group plays an important role in these bone-protective effects.

Astragaloside II induces osteogenic activities of osteoblasts through the bone morphogenetic protein-2/MAPK and Smad1/5/8 pathways

Radix Astragalus has been identified to exert beneficial effects in preventing postmenopausal bone loss. However, the active ingredients and mechanism of action remain unknown. In this study, we examined the effect of Astragaloside II (AST II), which is a monomer of Astragalus saponin, on the viability, proliferation, differentiation and maturation of rat primary osteoblasts, as well as its relevant molecular mechanism. We found that AST II exhibits a significant induction of proliferation, differentiation and mineralization in primary osteoblasts. AST II stimulates osteoblast differentiation at various stages, from early to late stage of differentiated osteoblasts. Furthermore, induction of differentiation by AST II is associated with increased expression of bone morphogenetic protein-2 (BMP-2), activation of Smad1/5/8, ERK1/2 and p38, and increased expression of core-binding factor 1 (Cbfa1)/Runx2. BMP antagonist (Noggin) blocks the effect of AST II on cell differentiation, and Smad1/5/8, p38, Cbfa1 expression, but only partly decreases ERK1/2 activation. This indicates that BMP-2 is essential in AST II-mediated osteoblast differentiation and Smad1/5/8, p38, Cbfa1 activation, and is partly involved in ERK1/2 activation. In conclusion, although in vivo studies are required in the future, as a phyto-saponin of Radix Astragalus, AST II may become a novel candidate that is beneficial for stimulating the osteoblastic activity resulting in bone formation, which has not been recognized and reported previously.

Synthesis, crystal structure and anti-fatigue effects of some benzamide derivatives.

A series of benzamide derivatives such as 1-(1,3-benzodioxol-5-ylcarbonyl) piperidine (1-BCP) were synthesized by the reaction of substituted benzoic acids with piperidine, morpholine or pyrrolidine using a novel method. The crystals of these benzamide derivatives were obtained by recrystallization. Structures of target and intermediate compounds were determined via FT-IR, 1H-NMR and elemental analysis and X-ray crystallography of select examples. The crystal structures of these compounds have potential applications to identify the binding site for allosteric modulators of the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor. The anti-fatigue effects of the benzamide derivatives in weight-loaded forced swimming mice were investigated in a swimming endurance capacity test used as an indicator of fatigue. The swimming times to exhaustion were longer in the b3, d3, and e3 groups than in the caffeine group (p < 0.05). In conclusion, b3, d3 and e3 enhanced the forced swimming capacity of mice. The mechanism of the anti-fatigue effects will be studied in the future.

A comparative study on the effect of promoting the osteogenic function of osteoblasts using isoflavones from Radix Astragalus.

Radix Astragalus has been shown to exert beneficial effects regarding the prevention postmenopausal osteoporosis. However, its mechanism of action remains to be investigated. Calycosin, formononetin, and calycosin‐7‐O‐β‐d‐glucoside are the main isoflavone constituents of Astragalus. In this study, the abilities of these 3 compounds to promote osteogenic function of osteoblasts were compared, and the structure–activity relationships of these osteotrophic isoflavones were determined. Calycosin exhibited a greater effect than formononetin and calycosin‐7‐O‐β‐d‐glucoside regarding improvements in osteogenic function of osteoblasts, as demonstrated by cell proliferation, alkaline phosphatase activity, collagen I and osteocalcin secretion, and the number and area of mineralized bone nodules. This suggests that calycosin may be better than formononetin and calycosin‐7‐O‐β‐d‐glucoside at preserving bone mass. In addition, calycosin, formononetin, and calycosin‐7‐O‐β‐d‐glucoside stimulate the expression of bone morphogenetic protein 2 and runt‐related transcription factor 2 proteins, which indicates that all 3 agents may promote the osteogenesis of osteoblasts via regulation of bone morphogenetic protein 2 expression. In conclusion, calycosin may be the best candidate, with higher osteogenic activity than formononetin and calycosin‐7‐O‐β‐d‐glucoside. The higher osteogenic activity of calycosin could be attributable to the superiority of its chemical structure (a hydroxyl group at position C3 of Ring B and no glucosyl group).

Synthesis, crystal structure, and antinociceptive effects of some new riluzole derivatives

Nine N-alkylated derivatives of riluzole were synthesized in order to obtain new compounds with potential antinociceptive activity. Riluzole was firstly transformed into (6-trifluoromethoxy-benzothiazol-2-yl)-hydrazine, then it was chlorinated by SOCl2 to obtain 2-chloro-6-trifluoromethoxy-benzothiazole. This intermediate product was treated with nine alkylamines to give N-alkylated derivatives of riluzole respectively. The structures of compounds were confirmed by means of elemental analysis, IR, 1H NMR, and 13C NMR. The synthetic route was optimized and four novel crystals were obtained by recrystallization. This study investigated the antinociceptive activity of some N-alkylated derivatives of riluzole by hot plate test in mice. The relationship between antinociceptive activity and the doses of 4b, 4c, 4h, 4g, and riluzole had been studied. Compared with the control group (0 mg/kg), the effects of compounds 4b and 4h showed a significant increase (13.78 ± 2.89 s, 12.89 ± 2.94 s, respectively). Compound 4c showed extreme significant increase (18.07 ± 3.08 s) in the time mice spent on the hot plate. The compounds 4b, 4c, and 4h had increased the latency time compared to the blank solvent group. They have potential application in developing new drug candidates with antinociceptive activity.

Reaction-based fluorescent probes for rapid detection of hydrogen sulfide in vivo

In this work, a series of novel fluorescent probes based on the fluorophores 3-benzothiazolyl-7-hydroxycoumarin/7-hydroxycoumarin were developed for detection of H2S. The probes exhibited excellent specific responses to H2S over other related competing species, including reactive sulfur, nitrogen and oxygen species. Moreover, the further successful imaging of the targetable fluorescent probe for sensing H2S in vivo was exciting and revealed that this targetable probe could serve as an efficient tool to study H2S-related chemical biology in physiological and pathological events.