Inhibitors of bone resorption from Halenia corniculata

Chemical constituents of Lomatogonium carinthiacum and Halenia corniculata

Objective

To study the chemical constituents from traditional Chinese (Mongolian) medicine, Lomatogonium carinthiacum and Halenia corniculate.

Methods

The chemical constituents were isolated and purified by silicagel column, Sephadex LH-20, ODS and high performance liquid chromategramphy. The structures were identified by NMR and MS analysis technics.

Results

Twelve compounds were isolated and identified as isovitexin (1), Luteolin-5-O-β-D-glucoside (2), Isosaponarin (3), Luteolin-7-O-β-D-glucoside (4,7), 1,4,8-Trimethoxy-xanthone-6-O-β-D-glucoronyl-(1 → 6)O-β-Dglucoside (5), friginosideD (6), 1-hydroxy-2,3,5-trimethoxyxanthone (8), 1-hydroxy-2,3,4,5-tetramethoxyxanthone (9), 1-hydroxy-2,3,4,7-tetramethoxyxanthone(10), 1-hydroxy-2,3,4,5,7-pentamethoxyxanthone (11) and usnic acid (12).

Conclusion

Compounds 6 and 12 are obtained from L. carinthiacum and H. corniculate for the first time.

New bone-generative effect of Salvia officinalis L. in the expanded midpalatal suture : An in vivo and in vitro study

PURPOSE

The aims of this study were to evaluate the effects of systemic administration of Salvia officinalis Linnaeus (L.) leaf extract on new bone formation in the expanded premaxillary suture in rats in vivo and to examine the antioxidant effects and phenolic profile of Salvia officinalis (SO) leaf and root extracts in vitro.

METHODS

Fourteen male Sprague Dawley rats were allocated to two groups: SO group (n = 7) and control group (n = 7). An open-loop spring was attached to the upper incisors of each rat to expand the premaxillae. A 5-day expansion period followed by a 12-day retention period was observed. The rats in the SO group received systemic administration of 20 mg SO/kg/day via the orogastric route for 17 days. Histomorphometric examinations were carried out to examine the amount of new bone formation, number of capillaries, and intensity of inflammatory cell response. Immunohistochemical analysis was conducted to examine the number of osteoblasts and osteoclasts. Leaf and root extracts of SO were also analyzed for antioxidant activity and phenolic compounds in vitro.

RESULTS

Statistical analysis showed that the following were higher in the SO group than in the control group: new bone formation, number of osteoblasts and osteoclasts, intensity of inflammatory cell response (neutrophils, lymphocytes, and macrophages), and number of capillaries. The major compound identified in SO leaf extract was rosmarinic acid, while luteolin derivatives, salvianolic acid F, and medioresinol were also present.

CONCLUSIONS

Salvia officinalis L. from leaf extract provided antioxidant effects and stimulated enhanced new bone formation in the expanded midpalatal suture after maxillary expansion in rats.

V-ATPases and osteoclasts: ambiguous future of V-ATPases inhibitors in osteoporosis

Vacuolar ATPases (V-ATPases) play a critical role in regulating extracellular acidification of osteoclasts and bone resorption. The deficiencies of subunit a3 and d2 of V-ATPases result in increased bone density in humans and mice. One of the traditional drug design strategies in treating osteoporosis is the use of subunit a3 inhibitor. Recent findings connect subunits H and G1 with decreased bone density. Given the controversial effects of ATPase subunits on bone density, there is a critical need to review the subunits of V-ATPase in osteoclasts and their functions in regulating osteoclasts and bone remodeling. In this review, we comprehensively address the following areas: information about all V-ATPase subunits and their isoforms; summary of V-ATPase subunits associated with human genetic diseases; V-ATPase subunits and osteopetrosis/osteoporosis; screening of all V-ATPase subunits variants in GEFOS data and in-house data; spectrum of V-ATPase subunits during osteoclastogenesis; direct and indirect roles of subunits of V-ATPases in osteoclasts; V-ATPase-associated signaling pathways in osteoclasts; interactions among V-ATPase subunits in osteoclasts; osteoclast-specific V-ATPase inhibitors; perspective of future inhibitors or activators targeting V-ATPase subunits in the treatment of osteoporosis.

Determination of xanthones and flavonoids of methanol extracts obtained from different parts of the plants of three Gentianaceae species

Gentianopsis barbata, Halenia corniculata, and Gentianella acuta were widely distributed throughout China and commonly used in traditional Chinese medicine. However, owing to similar living environments and morphological features, locals often had trouble distinguishing between these three species. In this present study, chromatograms at 350 nm were obtained and the composition and content of their chemical compounds determined using HPLC-DAD/ESI-MS². In total, 35 chemical compounds were detected, 32 of which were identified, 25 of which were xanthones, 6 flavonoids, and 1 chlorogenic acid. The 350 nm chromatograms of these three species displayed evident differences. The individual compounds and their occurrence and content in different parts of the plant within different species were included in our results. This basic data will be useful for future pharmacological study. The total compositions of flavonoids and xanthones were approximately comparable in G. barbata and H. corniculata. Meanwhile, xanthones were predominant in G. acuta. From the perspective of chemical compound compositions, the leaf is recommended as the most valuable medicinal section for each of these three species.

Concise Approach to 1,4-Dioxygenated Xanthones via Novel Application of the Moore Rearrangement

The rapid synthesis of 1,4-dioxygenated xanthones and related natural products employing the Moore rearrangement as a key transformation has been developed. The approach features an acetylide stitching step to unite a substituted squaric acid with a protected hydroxy benzaldehyde derivative to provide a key intermediate that undergoes facile Moore rearrangement to deliver a hydroxymethyl aryl quinone. Subsequent oxidation, hydroxy group deprotection and cyclization then affords highly functionalized xanthones. The utility of the approach was demonstrated by its application to a concise and efficient synthesis of the naturally-occurring xanthone 1. The structure of a natural product that had been named dulcisxanthone C was also corrected to that of the xanthone 1.

General and expedient synthesis of 1,4-dioxygenated xanthones

A facile entry to 1,4-dioxygenated xanthones having a variety of substitution patterns and substituents was developed that features a novel application of the Moore cyclization using substrates that were readily assembled in a highly convergent fashion by an acetylide stitching process. The practical utility of the methodology was demonstrated by an efficient synthesis of a naturally occurring xanthone and correction of the structure of dulcisxanthone C.

The effects of luteolin on osteoclast differentiation, function in vitro and ovariectomy-induced bone loss

Flavonoids, a group of polyphenolic compounds abundant in plants, are known to prevent bone loss in ovariectomized (OVX) animal models. Inhibition of osteoclast differentiation and bone resorption is considered as an effective therapeutic approach in the treatment of postmenopausal bone loss. Luteolin, a plant flavonoid, has potent anti-inflammatory properties both in vivo and vitro. In this study, we found that luteolin markedly decreased the differentiation of both bone marrow mononuclear cells and Raw264.7 cells into osteoclasts. Luteolin also inhibited the bone resorptive activity of differentiated osteoclasts. We further investigated the effects of luteolin on ovariectomy-induced bone loss using micro-computed tomography, biomechanical tests and serum markers assay for bone remodeling. Oral administration of luteolin (5 and 20 mg/kg per day) to OVX mice caused significant increase in bone mineral density and bone mineral content of trabecular and cortical bones in the femur as compared to those of OVX controls, and prevented decreases of bone strength indexes induced by OVX surgery. Serum biochemical markers assays revealed that luteolin prevents OVX-induced increases in bone turnover. These data strongly suggest that luteolin has the potential for prevention of bone loss in postmenopausal osteoporosis by reducing both osteoclast differentiation and function.