Prenylated phenylpropenes from Coleonema pulchellum with antimicrobial activity

(±)-Zanthonitidumines A and B: Two new benzophenanthridine alkaloids enantiomers from Zanthoxylum nitidum and their anti-inflammatory activity

Two new benzophenanthridine alkaloids enantiomers (±)-zanthonitidumines A (1) and B (2), along with seven known analogues (3-9), were isolated from Zanthoxylum nitidium. Their structures were elucidated on the basis of extensive spectroscopic techniques and ECD data. Compound 2 exhibited the most significant inhibition of IL-6 generation as well as TNF-α release which suggest that it may be a potential anti-inflammatory agent.

Bioactive prenylated C6-C3 derivatives from the stems and leaves of Illicium fargesii

Seventeen new prenylated C₆-C₃ derivatives, namely, illifargeins A-M (1-13), including three pairs of enantiomers (1, 5, and 12) and one norillifargeal A (14), together with eight known analogues (15-22), were isolated from the stems and leaves of Illicium fargesii. The structures of the new compounds were elucidated using spectroscopic data (UV, IR, 1D and 2D NMR, and HRESIMS). Their absolute configurations were determined by using experimental and calculated ECD data analysis, as well as a modified Mosher's method. Compounds 1a, 1b, 2, 3, 5a, 7, 10, 11, 15, 16, 19, and 20 showed potential activity against Coxsackie virus B3, with IC₅₀ values ranging from 6.23 to 33.33 µM. Compounds 9 and 15 exhibited potential activity against influenza virus A, with IC₅₀ values of 11.11 and 19.24 µM, respectively. Compounds 2, 3, and 18 exhibited potential anti-oxidant activity, with IC₅₀ values ranging from 1.43 to 6.71 µM.

Antioxidant Activity of Metabolites from Coleonema Album (Rutaceae)

Coleonema album, a member of the South African ‘Fynbos’ biome, was evaluated for its antioxidant and free radical scavenging activity. Ethanol- and acetone-based extracts from plant material obtained from two different geographical areas were analysed. A bioassay-guided fractionation methodology was followed for screening of active compounds. The 1,1-diphenyl-2-picrylhydrazyl (DPPH)-TLC method revealed the presence of a number of antioxidants which were quantified by the DPPH-spectrophotometric assay and the oxygen radical absorbance capacity (ORAC) assay. The C. album extracts possessed significant in vitro antioxidant activity, a large portion of which appeared to be contributed by the phenolic compounds. In contrast, the reducing power of the extracts could not be correlated with the observed antioxidant activity. Identification and structural information of the active components were obtained by a combination of preparative TLC and LC-MS which revealed the presence of coumarin aglycones and glycosides. The results of this study indicate that C. album contains strong antioxidants that warrant further investigation into the relationship between the structure and activity of the active coumarin metabolites.

Antifungal and antioxidant activities of Coleonema album and C. pulchellum against skin diseases

CONTEXT

Coleonema album (Thunb) Bart. & H. L. Wendl (Rutaceae) has been used in the formulation of skincare products, and the Khoisan people rub it on their skin to add luster. Coleonema pulchellum I. Williams has received less attention in the South African traditional medicine.

OBJECTIVE

This study investigates the antifungal and antioxidant activities of C. album and C. pulchellum essential oil (EO) and leaf extracts; and analyzes the chemical components of their EOs.

MATERIALS AND METHODS

Antifungal activity of leaf extracts was determined using the microdilution method with griseofulvin and ketoconazole as controls. Antifungal capacity of EO was investigated using the 'Volatile release plate method'. Trichophyton rubrum (ATCC 28188) and T. mentagrophytes (ATCC 9533) mycelia (0.3 cm diameter) were placed on fresh yeast malt agar in Petri dishes with filter paper (impregnated with 20 μL of EO) on the lid for direct exposure to EO volatiles while plates without EO were used as controls. The incubation time was seven days. Antioxidant activities of the leaf extracts were determined.

RESULTS

Methanol leaf extract of C. pulchellum inhibited the growth of three fungi tested with MIC values of 195, 391 and 49 μg/mL for Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum gypseum, respectively. Terpenes formed the major components of the EO. The EO from both plants inhibited the growth of T. rubrum in vitro.

DISCUSSION AND CONCLUSION

This study revealed the therapeutic value of C. pulchellum. Coleonema album and C. pulchellum should be considered as potential plants for skin ointment from natural origin.

Rotenoids, Flavonoids, and Chalcones from the Root Bark of Millettia usaramensis

Five new compounds, 4-O-geranylisoliquiritigenin (1), 12-dihydrousararotenoid B (2), 12-dihydrousararotenoid C (3), 4'-O-geranyl-7-hydroxyflavanone (4), and 4'-O-geranyl-7-hydroxydihydroflavanol (5), along with 12 known natural products (6-17) were isolated from the CH2Cl2/MeOH (1:1) extract of the root bark of Millettia usaramensis ssp. usaramensis by chromatographic separation. The purified metabolites were identified by NMR spectroscopic and mass spectrometric analyses, whereas their absolute configurations were established on the basis of chiroptical data and in some cases also by X-ray crystallography. The crude extract was moderately active (IC50 = 11.63 μg/mL) against the ER-negative MDB-MB-231 human breast cancer cell line, and accordingly compounds 6, 8, 9, 10, 12, and 16 also showed moderate to low cytotoxic activities (IC50 25.7-207.2 μM). The new natural product 1 exhibited antiplasmodial activity with IC50 values of 3.7 and 5.3 μM against the chloroquine-sensitive 3D7 and the chloroquine-resistant Dd2 Plasmodium falciparum strains, respectively, and was also cytotoxic to the HEK293 cell line.

New phenylpropenoids, bis(1-phenylethyl)phenols, bisquinolinone alkaloid, and anti-inflammatory constituents from Zanthoxylum integrifoliolum

Five new compounds, including two new phenylpropenoids, (R,E)-1-[4-(3-hydroxyprop-1-enyl)phenoxy]-3-methylbutane-2,3-diol (1) and 4-hydroxy-3-(3-methyl-2-butenyl)cinnamyl alcohol (2), two new bis(1-phenylethyl)phenols, 2,6-bis(1-phenylethyl)phenol (3) and 2,4-bis(1-phenylethyl)phenol (4), and a new bisquinolinone alkaloid, 18-demethylparaensidimerin C (5), together with 17 known compounds have been isolated from the stem wood of Zanthoxylum integrifoliolum. The structures of these new compounds were determined through spectral analyses including extensive 2D nuclear magnetic resonance data. Among the isolates, N-methylflindersine (7), (-)-simulanol (10), and evofolin-C (16) exhibited potent inhibition against N-formylmethionylleucylphenylalanine-induced superoxide production with IC(50) values less than 12 microM.

Diterpenoid, steroid, and triterpenoid agonists of liver X receptors from diversified terrestrial plants and marine sources

It has been demonstrated that liver X receptors (LXR) play a significant role in cholesterol homeostasis. Agonists of LXR are expected to increase cellular cholesterol efflux, lower LDL, and raise HDL levels. Screening of a natural product library of plant extracts using a LXR-SPA binding assay and bioassay-guided fractionation of a number of plant and marine gorgonian extracts led to the isolation of a number of active compounds. These included acanthoic acid (1) and alcohol (2), viperidone (3), polycarpol (4), rosacea acid (5), a cycloartane derivative (6), a new cycloartane analogue (7), betulinic acid (8), and gorgostane derivatives (9, 10, and 11). Of these compounds, 1, 4, and 11 exhibited potent binding affinity for alpha-receptor with IC(50) values of 0.25, 0.12, and 0.07 microM, respectively. Functionally they also showed strong coactivator association stimulation for LXRalpha receptor with EC50 values of 0.18, 0.03, and 0.05 microM, respectively. They also exhibited 15-, 8-, and 13-fold induction of the alpha-receptor in a transactivation assay in HEK-293 cells, respectively. In general these compounds were selective for the LXR alpha-receptor over the beta-receptor in all assays and were much better stimulators of the alpha-receptor than the endogenous steroid ligands.

A new prenylated arylnaphthalene lignan from Haplophyllum myrtifolium

A novel prenylated arylnaphthalene lignan, 7-O-(3-methyl-2-butenyl)isodaurinol, was isolated from Haplophyllum myrtifolium and identified on the basis of detailed spectral analyses, including 2D-NMR spectrometry. The known furoquinoline alkaloids, dictamnine, robustine, gamma-fagarine and skimmianine, the aryltetralin lignan (-)-1beta-polygamain and the flavone chrysosplenetin were isolated from the same source.

Eight new prenylcoumarins from Phebalium clavatum

The aerial parts of Phebalium clavatum yielded eight new 3-prenylated coumarins, phebaclavin A-H (1-8). Their structures were established on the basis of their NMR and mass spectral data. In addition, seven known compounds were also isolated, including two 8-geranyloxy linear furocoumarins previously obtained from Phebalium tuberculosum ssp. megaphyllum, included in the same section of the genus.