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Chemical investigation of the methanol extract from the leaves of H. roeperianum led to the isolation of a new tetraoxygenated xanthone along with eleven known compounds including six xanthones, one polyketide, one flavonoid, one ferulic acid derivative and two pentacyclic triterpenoids. Their structures were established on the basis of 1D- and 2D-NMR, UV, IR, and MS experiments, and by comparison of their spectroscopic data with those of similar compounds reported in the literature. The new xanthone was tested against a panel of eight bacterial strains including six Gram-negative and two Gram-positive bacteria. As results, it exhibited weak antibacterial activity with MIC values ranging from 64 to 128 µg/mL.

The chemical investigation of Anonidium mannii root extract by column chromatography techniques led to the isolation of eight compounds among which two previously unreported compounds; a lanostane-type triterpene, lanosta-7,9(11),23-triene-3β,15α-diol 1 and an alkaloid, 9-hydroxy-8-methoxyphenanthridin-6( 5H )-one 2 along with six known compounds: lanosta-7,9(11),24-triene-3β,21-diol 3 , oxoanolobine 4 , 3, 4-dihydroxybenzoic acid 5, stigmasterol 6, β - sitosterol 7 and 3-O-β-D-glucopyranosyl-β-stigmasterol 8. Their structures were established from spectral data, mainly HR-ESIMS, 1 D and 2 D NMR and by comparison with literature data. The crude root and stem bark extracts (AMR and AMB) and the isolated compounds ( 1-8 ) were tested against nine Gram-negative bacteria using rapid p -iodonitrotetrazolium chloride ≥97% (INT) microdilution technique. It was found that AMR, AMB and compound 5 were active against the nine tested bacteria with MIC values ranging from 64 to 1024 µg/mL. Compounds 1-4 had selective antibacterial activities whilst 6-8 were not active.

A new caffeate derivative from the ethanol extract of the stem bark of Cassia sieberiana DC. is described herein along with the known secondary metabolites spectaline ( 2 ), iso -6-cassine ( 3 ), 3- O -methyl- chiro -inositol ( 4 ), monobehenin ( 5 ), octyl nonadecyloate ( 6 ), β -sitosterol ( 7 ), stigmasterol ( 8 ) and sitosterol 3- O - β -D-glucopyranoside ( 9 ). The chemical structures were elucidated by means of various spectroscopic and spectrometric techniques. Extract and isolated compounds were devoid of inhibitory action against the herein selected bacterial strains (MICs > 256 μg/mL) but showed capacities to reduce 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (EC 50  < 3 μg/mL) considerably better than the "gold standard" trolox (EC 50 6.47 ± 0.48 μg/mL).