Cholinesterase, α-glucosidase, tyrosinase and urease inhibitory activities of compounds from fruits of C.H. Wright (Violaceae).

From fruits, 3-Nor-4β-friedelan-24-ol () and 3-decyl-6,7,8-trimethoxy-2H,5H-furo[4,3,2-de]isochromene-2,5-dione (), new derivatives alongside, 28-hydroxyfriedelan-3-one (), friedelin (), 3,3',4,4',5'-pentamethylcoruleoellagic acid (), hexamethylcoruleoellagic acid (), 3',4,4',5,5'-pentamethylcoruleoellagic acid (), and fatty compounds were isolated and characterized using HRESIMS, EIMS, 1D and 2D NMR. enzyme inhibition of compounds and were evaluated on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-glucosidase, urease and tyrosinase. Against AChE and BChE, the phenolic compounds and had good activity probably due to the phenolic nature and methoxy substituents.

Chemical constituents from leaves and trunk bark of (Violaceae).

Two new coruleoellagic acid derivatives, 3,4',5,5',-tetramethylcoruleoellagic acid ; 3',4,4',5,5'-pentamethylcoruleoellagic acid and a new friedelane-type triterpene derivative rinol , were isolated from leaves and trunk bark of (Violaceae) along with seven known compounds including 3,3',4,4',5'-pentamethylcoruleoellagic acid , hexamethylcoruleoellagic acid 28-hydroxyfriedelin friedelin friedelan-3-ol scopoletin and β-sitosterol-3--β-D-glucopyranoside Their structures were elucidated by means of spectroscopic methods including IR, 1D and 2D NMR in conjunction with mass spectrometry. Crude extracts of leaves and trunk bark as well as compounds were evaluated for their antibacterial activities against 7 pathogenic bacterial strains ( ATCC49619, ATCC 43300, ATCC 700603, ATCC 49247, ATCC 25922, HM601, BAA 977). Compound displayed noteworthy activity against with MIC value of 9.

New lupan-type triterpenoids.

Three new lupan-type triterpernoid derivatives, namely globimetulin A (1), B (2) and C (3), were isolated from the shoot of Globimetula dinklagei (Loranthaceae), a hemiparasitic plant growing on Manihot esculenta, along with five known compounds: friedelin (4), friedelan-3-ol (5), 28-hydroxyfriedelin (6), 4-hydroxy-3,5-dimethoxybenzoic acid (7) and (1R,5S,7S)-7-[2-(4-hydroxyphenyl)ethyl]-2,6-dioxabicyclo[3.3.1]nonan-3-one (8).

Antibacterial activity of some natural products against bacteria expressing a multidrug-resistant phenotype.

The present study assessed the antimicrobial activities of various natural products belonging to the terpenoids, alkaloids and phenolics against a collection of Gram-negative multidrug-resistant (MDR) bacteria. The results demonstrated that most of the compounds were extruded by bacterial efflux pumps. In the presence of the efflux pump inhibitor phenylalanine arginine β-naphthylamide (PAβN), the activities of laurentixanthone B (xanthone), plumbagin (naphthoquinone), 4-hydroxylonchocarpin (flavonoid) and MAB3 (coumarin) increased significantly against all studied MDR bacteria.

Antimicrobial and antileishmanial xanthones from the stem bark of Allanblackia gabonensis (Guttiferae).

The phytochemical study of stem bark of Allanblackia gabonensis has resulted in the isolation and characterisation of one new xanthone derivative, named allanxanthone D, together with 10 known compounds, including 6 xanthones derivatives, allanxanthone A, 1,5-dihydroxyxanthone, 1,7-dihydroxyxanthone and 1,3,6,7-tetrahydroxy-2-(3-methylbut-2-enyl)xanthone, forbexanthone, 6-deoxyisojacareubin, one polyisoprenylated benzophenone, guttiferone F, one flavanol, epicathechin, two phytosterols, beta-sitosterol and campesterol. The structures of these compounds were established on the basis of one- and two-dimensional NMR homo- and hetero-nuclear evidence. These compounds were evaluated for their activity against Leishmania amazonensis in vitro and antimicrobial activities against a range of Gram negative and Gram positive bacteria.