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1.
Tuchinda P Kornsakulkarn J Pohmakotr M Kongsaeree P Prabpai S Yoosook C Kasisit J Napaswad C Sophasan S Reutrakul V 《Journal of natural products》2008,71(4):655-663
Chemical investigation of the aerial parts of Phyllanthus acutissima resulted in the isolation of five new dichapetalin-type triterpenoids, acutissimatriterpenes A-E ( 1- 5), and two new lignans, acutissimalignans A ( 6) and B ( 7), along with two known lignans and three known ellagic acid derivatives. The structures of 1- 7 were determined mainly on the basis of spectroscopic methods. The compounds obtained were evaluated for cytotoxic and anti-HIV-1 activities. 相似文献
2.
Kanokmedhakul S Kanokmedhakul K Prajuabsuk T Panichajakul S Panyamee P Prabpai S Kongsaeree P 《Journal of natural products》2005,68(7):1047-1050
Three new azadirachtin derivatives, named azadirachtins O-Q (1-3), along with the known azadirachtin B (4), azadirachtin L (5), azadirachtin M (6) 11alpha-azadirachtin H (7), 11beta-azadirachtin H (8), and azadirachtol (9) were isolated from seed kernels of Azadirachta excelsa. Their structures were established by spectroscopic techniques, and the structure of 3 was confirmed by X-ray analysis. Compounds 1-7 and 9 exhibited toxicity to the diamondback moth (Plutella xylostella) with an LD50 of 0.75-1.92 microg/g body weight, in 92 h. 相似文献
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Albericio F Arvidson PI Bisetty K Giralt E Govender T Jali S Kongsaeree P Kruger HG Prabpai S 《Chemical biology & drug design》2008,71(2):125-130
The synthesis and X-ray structure of two diasteriomeric heptapeptides [Ac-Ala-Ala-Ala-(R/S)-Cage-Ala-Ala-Ala-NH2] with a trishomocubane amino acid as a beta-turn scaffold are reported. The amino acid was synthesized as a racemate and two diastereomeric peptides were obtained. The two peptides were separated by preparative high-pressure liquid chromatography and crystals suitable for X-ray analysis were grown for both diasteriomeric peptides. In general, both the peptides satisfy the criteria for beta-turn conformations. Five of the six Ala residues of both cage peptide crystals satisfy the criteria for 3(10)-helix characteristics and the cage amino acid residue satisfied the alpha-helix classification. These experimental results confirm previous theoretical studies in our laboratory which predicted that the cage moiety would be a strong/active beta-turn inducer. 相似文献
5.
Lhinhatrakool T Prabpai S Kongsaeree P Sutthivaiyakit S 《Journal of natural products》2011,74(6):1386-1391
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. 相似文献
6.
Sadeq A. Al‐Maweri Saman Warnakulasuriya Abdulaziz Samran 《Journal of investigative and clinical dentistry》2018,9(1)
Khat or qat (Catha edulis) is a plant that grows in East Africa and southern Arabia. The leaves and twigs of this small tree are chewed by several millions of people worldwide for their stimulating amphetamine‐like effects. The reported prevalence of khat chewing in Europe and the USA is on the rise, especially with global migration. Long‐term khat chewing has several detrimental general and oral health effects. The aim of the present study was to review the current literature regarding khat use and its association with oral and dental diseases, with particular emphasis on its link with oral keratotic white lesions and oral cancer. We searched the literature to identify all relevant articles. Studies showed that khat is associated with several oral and dental conditions, including keratotic white lesions, mucosal pigmentation, periodontal disease, tooth loss, plasma cell stomatitis, and xerostomia. There are limited data on the incidence of dental caries among khat chewers. The evidence that khat chewing is a risk factor for oral cancer is still weak, and is mainly based on anecdotal case reports and uncontrolled studies. 相似文献
7.
Kongsaeree P Prabpai S Sriubolmas N Vongvein C Wiyakrutta S 《Journal of natural products》2003,66(5):709-711
Three novel dihydroisocoumarin derivatives (1-3) with antimalarial, antituberculous, and antifungal activities have been isolated by bioassay-guided fractionation from an endophytic fungus, Geotrichum sp., collected from Crassocephalum crepidioides. Structures were established as 7-butyl-6,8-dihydroxy-3(R)-pent-11-enylisochroman-1-one (1), 7-but-15-enyl-6,8-dihydroxy-3(R)-pent-11-enylisochroman-1-one (2), and 7-butyl-6,8-dihydroxy-3(R)-pentylisochroman-1-one (3) using spectroscopic data. 相似文献
8.
Shadi El Bahra Klaus Ludwig Abdulaziz Samran Sandra Freitag-Wolf Matthias Kern 《Dental materials》2013
Objectives
The aim of this study was to evaluate the linear and volumetric dimensional changes of six denture base resins processed by their corresponding injection-molding systems at 3 time intervals of water storage.Materials and methods
Two heat-curing (SR Ivocap Hi Impact and Lucitone 199) and four auto-curing (IvoBase Hybrid, IvoBase Hi Impact, PalaXpress, and Futura Gen) acrylic resins were used with their specific injection-molding technique to fabricate 6 specimens of each material. Linear and volumetric dimensional changes were determined by means of a digital caliper and an electronic hydrostatic balance, respectively, after water storage of 1, 30, or 90 days. Means and standard deviations of linear and volumetric dimensional changes were calculated in percentage (%). Statistical analysis was done using Student's and Welch's t tests with Bonferroni–Holm correction for multiple comparisons (α = 0.05).Results
Statistically significant differences in linear dimensional changes between resins were demonstrated at all three time intervals of water immersion (p ≤ 0.05), with exception of the following comparisons which showed no significant difference: IvoBase Hi Impact/SR Ivocap Hi Impact and PalaXpress/Lucitone 199 after 1 day, Futura Gen/PalaXpress and PalaXpress/Lucitone 199 after 30 days, and IvoBase Hybrid/IvoBase Hi Impact after 90 days. Also, statistically significant differences in volumetric dimensional changes between resins were found at all three time intervals of water immersion (p ≤ 0.05), with exception of the comparison between PalaXpress and Futura Gen.Significance
Denture base resins (IvoBase Hybrid and IvoBase Hi Impact) processed by the new injection-molding system (IvoBase), revealed superior dimensional precision. 相似文献9.
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Hemtasin C Kanokmedhakul S Kanokmedhakul K Hahnvajanawong C Soytong K Prabpai S Kongsaeree P 《Journal of natural products》2011,74(4):609-613
Three new sesquiterpenes, named phomoarcherins A-C (1-3), and four known compounds, kampanol A (4), R-mevalonolactone, ergosterol, and ergosterol peroxide, were isolated from the endophytic fungus Phomopsis archeri. These structures were established on the basis of spectroscopic evidence. The structure and absolute configuration of 1 were confirmed by X-ray crystallographic analysis of its p-bromobenzoate derivative (1a). Compounds 1-4 showed cytotoxicity against five cholangiocarcinoma cell lines (0.1-19.6 μg/mL), while 1 and 2 exhibited weak cytotoxicity against the KB cell line with IC(50) values of 42.1 and 9.4 μg/mL, respectively. In addition, compound 2 showed antimalarial activity against Plasmodium falciparum with an IC(50) value of 0.79 μg/mL. 相似文献