Bioassay guided fractionation of Boenninghausenia sessilicarpa (Rutaceae) resulted in the isolation of a new dimeric coumarin glucoside 9′-methoxyl rutarensin (1) and a cytotoxic compound rutamarin (4), as well as an antivirus component leptodactylone (8), together with six known coumarins. Their structures were elucidated by 1D- and 2D NMR spectroscopy and ESI-MS analyses, respectively. Rutamarin (4) showed significant inhibitory activities against A-549, Bel-7402, HepG-2 and HCT-8 tumour cell lines with IC₅₀s of 1.318, 2.082, 2.306 and 2.497 μg/ml. In addition, leptodactylone (8) showed potent protective activity on cells infected by SARS-CoV with ratio of 60% at 100 μg/ml.

Four new chromone glycosides allo-aloeresin D (2), C-2′-decoumaroyl-aloeresin G (8), 2′-O-coumaroyl-(S)-aloesinol (9), 2′-O-[p-methoxy-(E)-cinnamoyl]-(S)-aloesinol (10) and nine known chromone glycosides (1, 3 - 7, 11 - 13) were isolated from two Aloe spp. plants, A. vera and A. nobilis. Among them, 1 and 8 showed significant inhibitory activity against BACE1 (β-secretase) with IC₅₀ values of 39.0 and 20.5 × 10^-6 M, as well as inhibition of Aβ_{1 - 42} production by 7.4 and 12.3 %, respectively, in B103 neuroblastoma cells at 30 ppm. The preliminary structure-activity relationships of Aloe chromone glucosides were also discussed.

Bioassay-guided fractionation of the ethanol extract of Senecio scandens led to the isolation of four new compounds 1–4. These compounds were obtained as tautomeric mixture of α/β epimers, but their structures were confirmed unambiguously by 1D and 2D NMR spectra and LC NMR technology. ¹H NMR spectra of pure 1α and 1β were furnished by HPLC NMR technology. Compounds 1–4 exhibited moderate cytotoxicities against five tumor cell lines.

A simple, rapid, accurate, and selective quantitative nuclear magnetic resonance method for the determination of tadalafil in bulk drugs and its tablets was established and evaluated. Spectra were obtained in dimethylsulfoxide-d₆ using 2,4-dinitrotoluene as the internal standard. In this study, the method’s linearity, range, limit of quantification, stability, precision, and accuracy were validated. The results were consistent with those obtained from high-performance liquid chromatography analysis. Thus, the proposed method is a useful and practical tool for the determination of tadalafil in bulk drugs and its tablets.

A convenient method for the synthesis and enantiomeric resolution of ( +/- )-pinocembrin has been developed. This route involves the hydrogenation of 5,7-dihydroxyflavone, the derivatization of racemic pinocembrin with chiral amine, and the separation of the diastereoisomers due to their different physical properties.