Dipterocarpus alatus (Dipterocarpaceae) is a medicinal plant whose use is well known for the treatment of genito-urinary diseases. However, there is no report of its cytotoxic potential. In this study, the chemical composition, antioxidant and cytotoxic activities of extracts of the leaves, bark, twigs and oleo-resin from D. alatus are investigated. Cytotoxicity was measured by the neutral red (NR) assay against HCT116, SKLU1, SK-MEL2, SiHa and U937 cancer cell lines and antioxidant capacity was evaluated by DPPH, ABTS radical scavenging, and ferric reducing antioxidant power (FRAP) assays. The chemical composition was analyzed by gas chromatography–mass spectrometry (GC-MS). Leaf, bark and twig extracts exhibited stronger antioxidant activity than oleo-resin, with bark extract showing the highest antioxidant activity and the highest total phenolic content. All samples showed more cytotoxic activity against the U937 cell line than HCT116, SKLU1, SK-MEL2 and SiHa cells with oleo-resin being more cytotoxic than melphalan against U937 cells. Chemical composition analysis of oleo-resin by GC-MS showed that the major components were sesquiterpenes, namely α-gurjunene (30.31%), (-)-isoledene (13.69%), alloaromadendrene (3.28%), β-caryophyllene (3.14%), γ-gurjunene (3.14%) and spathulenol (1.11%). The cytotoxic activity of oleo-resin can be attributed to the sesquiterpene content, whereas the cytotoxic and antioxidant activities of leaf, bark and twig extracts correlated to total phenolic content.
A CE assay for the simultaneous determination of charged and uncharged potential impurities (1S,2S-(1)-norpseudoephedrine, 1R,2S-(À)-norephedrine, phenylacetone and phenylacetone oxime) of dexamphetamine sulfate including the stereoisomer levoamphetamine was developed and validated. The optimized background electrolyte consisted of a 50 mM sodium phosphate buffer, pH 3.0, containing 80 mg/mL sulfobutylether-b-CD and 25 mg/mL sulfated b-CD. Separations were performed in 40.2/35 cm, 50 mm id fused-silica capillaries at a temperature of 201C and an applied voltage of -10 kV. 1R,2S-(À)-ephedrine was used as internal standard. The assay was validated in the range of 0.05-1.0% for the related substances and in the range of 0.05-5.0% for levoamphetamine. The LOD was 0.01-0.02% depending on the analyte. The assay also allowed the separation of the E,Z-stereoisomers of phenylacetone oxime. The effect of the degree of substitution of sulfobutylether-b-CD was investigated. In commercial samples of dexamphetamine sulfate between 3.2 and 3.7% of levoamphetamine were found. Furthermore, phenylacetone and phenylacetone oxime could be observed at the LOD, indicating the synthetic origin of the investigated samples. The effect in attention deficit hyperactivity disorder is believed to be mediated via several mechanisms including the binding of the drug to the pre-synaptic dopamine transporter inducing a reversed transport process as well as stimulation of pre-synaptic inhibitory autoreceptors, resulting in reduced activity in dopaminergic and noradrenergic pathways [4]. Dexamphetamine can be synthesized by various methods, for example, starting from chiral precursors such as D-phenylalanine [5] or from chiral b-hydroxyphenylethylamines such as 1R,2S-(À)-norephedrine or 1S,2S-(1)-norpseudoephedrine [6,7]. Alternatively, the compound can be obtained from racemic amphetamine synthesized from phenylacetone (1-phenyl-2-propanone, benzyl methyl ketone) by Leuckart reaction or by reduction of the oxime [8,9] followed by fractional crystallization with L-(1)-tartaric acid [10]. Thus, charged as well as neutral starting materials or synthetic by-products as well as the enantiomer levoamphetamine (2R-(À)-amphetamine) may be present as related substances in the drug.Dexamphetamine sulfate is described in monographs by the United States Pharmacopeia 32 (USP 32) [11]
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