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A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed to distinguish Asian ginseng (Panax ginseng C. A. Meyer) and North American ginseng (Panax quinquefolius L.). The method is based on the baseline chromatographic separation of ginsenoside Rf and 24(R)-pseudoginsenoside F11, two potential chemical markers present in ginseng root methanolic extracts, and their unambiguous on-line identification using tandem mass spectrometry. Consistent with the literature, 24(R)-pseudoginsenoside F11 was detected in abundance in North American ginseng roots in excess of 0.1% (w/w) of the dried root. In contrast to some reports, 24(R)-pseudoginsenoside F11 was also identified in Asian ginseng roots at trace levels using LC-MS-MS but at less than 0.0001% (w/w). Besides showing identical tandem mass spectra to authentic 24(R)-pseudoginsenoside F11, the corresponding compound in Asian ginseng root coeluted with standard under different HPLC conditions, thus confirming this compound as 24(R)-pseudoginsenoside F11. Another ginsenoside often used to distinguish Asian and North American ginseng, ginsenoside Rf, was found in abundance in Asian ginseng roots at more than 0.021% (w/w). In Asian ginseng roots, the ratio of ginsenoside Rf to 24(R)-pseudoginsenoside F11 exceeded 700:1. The limit of detection of ginsenoside Rf or 24(R)-pseudoginsenoside F11 was 120 pg injected on-column, and the limit of quantification was 240 pg on-column. In summary, LC-MS-MS analysis of ginseng products for the presence and ratio of ginsenoside Rf and 24(R)-pseudoginsenoside F11 may be used for the unambiguous identification of Asian and North American ginsengs.

Inflammatory conditions as they occur during periodontal disease often result in decreased alveolar bone levels and a loss of connective tissue homeostasis. Here we have focused on the effect of microRNA-138 (miR-138) as a potential regulator of periodontal stem cells as they affect homeostasis during inflammatory conditions. Our data indicate that miR-138 was significantly upregulated in our periodontal disease animal model. Interaction of miR-138 with a predicted targeting site on the osteocalcin (OC) promoter resulted in a 3.7-fold reduction of luciferase activity in promoter assays compared with controls; and miR-138 overexpression in periodontal progenitors significantly inhibited OC (3.4-fold), Runx2 (2.8-fold), and collagen I (2.6-fold). Moreover, treatment with inflammatory modulators such as interleukin (IL)-6 and lipopolysaccharide (LPS) resulted in a significant 2.2-fold (IL-6) or 1.9-fold (LPS) increase in miR-138 expression, while OC and Runx2 expression was significantly decreased as a result of treatment with each inflammatory mediator. Further defining the role of miR-138 in the OC-mediated control of mineralization, we demonstrated that the LPS-induced downregulation of OC expression was partially reversed after miR-138 knockdown. LPS, miR-138 mimic, and OC small interfering RNA inhibited osteoblast differentiation marker alkaline phosphatase activity, while miR-138 inhibitor and OC protein addition enhanced alkaline phosphatase activity. Supporting the role of OC as an essential modulator of osteoblast differentiation, knockdown of miR-138 or addition of OC protein partially rescued alkaline phosphatase activity in periodontal ligament (PDL) cells subjected to LPS treatment. Our data establish miR-138 inhibitor as a potential therapeutic agent for the prevention of the bone loss associated with advanced periodontal disease.

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