Browsing by Author "Thitima Lhinhatrakool"

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    Anti-inflammatory 12,20-Epoxypregnane and 11,12-seco-Pregnane Glycosides from the Stems of Hoya kerrii
    (2017-06-23) Chonticha Seeka; Samran Prabpai; Palangpon Kongsaeree; Supinya Tewtrakul; Thitima Lhinhatrakool; Somyote Sutthivaiyakit; Ramkhamhaeng University; Mahidol University; Prince of Songkla University; Rangsit University
    © 2017 The American Chemical Society and American Society of Pharmacognosy. Five 12,20-epoxypregnane glycosides (1-3, 5, and 6) and two 11,12-seco-pregnane glycosides (4 and 7) with spirodilactone motifs, as well as spirodilactone cleavage products 8 and 9, were isolated from the stems of Hoya kerrii. The relative configurations of the three related skeletons were supported by ROESY experiments and X-ray crystallographic analyses. The isolates were evaluated for their anti-inflammatory activity based on the inhibition of NO production in RAW264.7 cells, and some showed IC50values ranging from 12.6 to 96.5 μM. The most potent compound, 9a, was also examined for its anti-inflammatory mechanism against mRNA expression and was found to down-regulate mRNA expression of iNOS and COX-2 in a dose-dependent manner.
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    Antiplasmodial sesquiterpene alkaloids from the roots of maytenus mekongensis
    (2011-06-24) Thitima Lhinhatrakool; Samran Prabpai; Palangpon Kongsaeree; Somyote Sutthivaiyakit; Ramkhamhaeng University; Mahidol University
    Eight new sesquiterpene alkaloids (1 - 8) and four known sesquiterpene alkaloids (9 - 12) have been isolated from the roots of Maytenus mekongensis. Structures were determined using extensive spectroscopic methods. The relative configuration of 7-epi-mekongensine (2) was established by single-crystal X-ray crystallographic analysis. The alkaloids were evaluated for antiplasmodial activity against Plasmodium falciparum, K1 strain, and for cytotoxicity using a panel of cell lines. © 2011 The American Chemical Society and American Society of Pharmacognosy.