Separation of Dihydro-Isocoumarins and Dihydro-Stilbenoids from Hydrangea macrophylla ssp. serrata by Use of Counter-Current Chromatography.

Previously, different Hydrangea macrophylla ssp. serrata cultivars were investigated by untargeted LC-MS analysis. From this, a list of tentatively identified and unknown compounds that differ significantly between these cultivars was obtained. Due to the lack of reference compounds, especially for dihydro-isocoumarins, we aimed to isolate and structurally characterise these compounds from the cultivar 'Yae-no-amacha' using NMR and LC-MS methods. For purification and isolation, counter-current chromatography was used in combination with reversed-phase preparative HPLC as an orthogonal and enhanced purification workflow. Thirteen dihydro-isocoumarins in combination with other metabolites could be isolated and structurally identified. Particularly interesting was the clarification of dihydrostilbenoid glycosides, which were described for the first time in H. macrophylla ssp. serrata. These results will help us in further studies on the biological interpretation of our data.

Modulation of central corneal thickness by various riboflavin eyedrop compositions in porcine corneas.

PURPOSE: To evaluate the modulatory effect of various riboflavin 0.1% and 0.2% compositions on the central corneal thickness (CCT) in fresh porcine corneas. SETTING: Department of Ophthalmology, Johannes Gutenberg University of Mainz, Mainz, Germany. DESIGN: Experimental study. METHODS: The CCT in freshly enucleated porcine globes was measured by ultrasound pachymetry before and after (if applicable) deepithelialization and every 10 minutes thereafter during 120 minutes of eyedrop application. In Groups 1 and 2 (controls), no eyedrops were applied. In Groups 3 and 4, isotonic riboflavin eyedrops were used. In Groups 5 to 9, hypotonic riboflavin eyedrops were given. In Groups 10 and 11, preparations for transepithelial crosslinking were applied. In Groups 2 to 9, deepithelialization was performed. The final CCT in the groups was compared by analysis of variance. RESULTS: One hundred ten freshly enucleated porcine globes were used. The mean final CCT compared with preoperative values was 97% ± 4% (SD) in Group 1, 91% ± 4% in Group 2, 66% ± 5% in Group 3, 151% ± 13% in Group 4, 65% ± 2% in Group 5, 105% ± 3% in Group 6, 120% ± 4% in Group 7, 130% ± 4% in Group 8, 132% ± 4% in Group 9, 114% ± 2% in Group 10, and 114% ± 4% in Group 11. The differences between Group 1 and each of Groups 3, 4, 5, 7, 8, and 9 were statistically significant (P<.05). CONCLUSION: There was considerable variation in the final CCT as a result of varying riboflavin eyedrop compositions. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.