Effect of geranylated dihydrochalcone from Artocarpus altilis leaves extract on Plasmodium falciparum ultrastructural changes and mitochondrial malate: Quinone oxidoreductase.

Nearly half of the world's population is at risk of being infected by Plasmodium falciparum, the pathogen of malaria. Increasing resistance to common antimalarial drugs has encouraged investigations to find compounds with different scaffolds. Extracts of Artocarpus altilis leaves have previously been reported to exhibit in vitro antimalarial activity against P. falciparum and in vivo activity against P. berghei. Despite these initial promising results, the active compound from A. altilis is yet to be identified. Here, we have identified 2-geranyl-2', 4', 3, 4-tetrahydroxy-dihydrochalcone (1) from A. altilis leaves as the active constituent of its antimalarial activity. Since natural chalcones have been reported to inhibit food vacuole and mitochondrial electron transport chain (ETC), the morphological changes in food vacuole and biochemical inhibition of ETC enzymes of (1) were investigated. In the presence of (1), intraerythrocytic asexual development was impaired, and according to the TEM analysis, this clearly affected the ultrastructure of food vacuoles. Amongst the ETC enzymes, (1) inhibited the mitochondrial malate: quinone oxidoreductase (PfMQO), and no inhibition could be observed on dihydroorotate dehydrogenase (DHODH) as well as bc1 complex activities. Our study suggests that (1) has a dual mechanism of action affecting the food vacuole and inhibition of PfMQO-related pathways in mitochondria.

Alkaloid and benzopyran compounds of Melicope latifolia fruit exhibit anti-hepatitis C virus activities.

BACKGROUND: New agents for developing alternative or complementary medicine to treat the hepatitis C virus (HCV) are still needed due to high rates of HCV infection globally and the current limitations of available treatments. Treatment of HCV with a combination of direct acting antivirals have been shown to be approximately 90% effective but will be limited in the future due to the emergence of drug resistance and high cost. The leaves of Melicope latifolia have previously been reported to have anti-HCV activity and are a potential source of bioactive compounds for future novel drug development. This study aimed to evaluate the efficacy of the extract of M. latifolia fruit to treat HCV and to isolate its active compounds. METHOD: M. latifolia fruit was extracted using methanol and purified using vacuum liquid chromatography (VLC) and Radial Chromatography. The anti-HCV activity was analyzed using cell culture lines Huh7it-1 and JFH1 (genotype 2a). Time-of-addition and immunoblotting studies were performed to identify the mode of action of the isolated active compounds. The structures of the active compounds were determined using nuclear magnetic resonance (NMR) spectra, UV, IR, and Mass Spectra. RESULTS: Six known compounds were isolated from M. latifolia fruit: O-methyloktadrenolon, alloevodionol, isopimpinellin, alloxanthoxyletin, methylevodionol, and N-methylflindersine. N-methylflidersine was the most active compound with IC50 value of 3.8 µg/ml while methylevodionol, isopimpinellin, and alloevodionol were less active. O-methyloktadrenolon and alloxanthoxyletin were moderately active with IC50 values of 10.9 and 21.72 µg/ml, respectively. N-methylflidersine decreased level of HCV NS3 protein expression in the cells. CONCLUSION: The alkaloid compound, N-methylflindersine which was isolated from M. latifolia possesses anti-HCV activity through post-entry inhibition and suppressed NS3 protein expression.

Two new 2-arylbenzofurans from Sesbania grandiflora L. and their cytotoxicity towards cancer cell.

Two new 2-arylbenzofurans, sesbagrandiflorain D (1) and E (2) along with two known 2-arylbenzofurans, spinosan A (3) and spinosan B (4) were isolated from the stem bark of Sesbania grandiflora L. The structure of two new compounds established by HRESIMS, 1 D NMR (1H, 13C) and 2 D NMR (HMQC, HMBC) spectra. Compounds (1-4) assayed for their cytotoxicity towards three human cancer cells (MCF-7, HeLa, and WiDr). Compound 1 showed very high activity against MCF-7 and WiDr with an IC50 value of 0.06 and 0.60 µg/mL, respectively.

Mesucalophylloidin, a new isoprenylated 4-phenylcoumarin from Mesua calophylloides (Ridl.) Kosterm.

A new isoprenylated 4-phenylcoumarin derivative, mesucalophylloidin (1) along with three known compounds, mammea A/BA cyclo F (2), calolongic acid (3) and isocalolongic acid (4) were isolated from the stem bark of Mesua calophylloides (Ridl.) Kosterm. Structures of all the compounds were elucidated using extensive spectroscopic methods, including UV, IR, HRESIMS, 1D and 2D NMR. Compounds 1-4 were evaluated for their cytotoxicity against P-388 cells, showing that compound 1 gave moderate activity with IC50 6.26 µg/mL.

Airlanggins A-B, two new isoprenylated benzofuran-3-ones from the stem bark of Calophyllum soulattri.

Two new isoprenylated benzofuran 3-ones, airlanggin A (1) and B (2) along with two known xanthones, ananixanthone (3) and trapezifolixanthone (4) were isolated from the stem bark of Calophyllum soulattri. Structures of all the compounds were elucidated using extensive spectroscopic methods, including UV, IR, HRESIMS, 1D and 2D NMR. Compounds 1-4 were evaluated for their cytotoxicity against P-388 cells, showing that compound 3 was the most active with IC50 0.68 µg/mL and compound 1 showed moderate activity with IC50 5.80 µg/mL.

Flavonoid and stilbene derivatives from Macaranga trichocarpa.

A new farnesylated flavonol (4'-O-methylmacagigantin) and a new geranylated stilbene (macatrichocarpin H), together with eight known phenolic compounds, have been isolated from the leaves of Macaranga trichocarpa. Structures of these compounds were determined based on NMR and mass spectrroscopic data. Cytotoxic properties of the isolated compounds were tested against P-388 cells showing that mactrichocarpin G was the most active compound with IC50 was 3.5µM.

Dihydroflavonol and flavonol derivatives from Macaranga recurvata.

Two new dihydroflavonol derivatives, macarecurvatins A and B, have been isolated from the leaves of Macaranga recurvata (Euphorbiaceaae), along with the known compounds diisoprenylaromadendrin, glyasperin A and broussoflavonol F. The structures of the new compounds were determined on the basis of spectroscopic evidence. Upon cytotoxic evaluation against P-388 cells, macarecurvatin B showed strong activity with an IC50 of 0.83 microM.

Geranylated flavonols from Macaranga rhizinoides.

Two geranylated and methylated flavonol derivatives, macarhizinoidins A (1) and B (2), along with a known phenolic compound methyl 4-isoprenyloxycinnamate (3), have been isolated from the methanol extract of the leaves M. rhizinoides. The structures of these compounds were identified based on their spectroscopic data. On cytotoxic evaluation against murine leukemia P-388 cells, compounds 1-2 showed IC50 values of 11.4 and 13.9 microM, respectively, while compound 3 was inactive.