Antimalarial alkaloid from Hypoestes forskaolii.

Following on from previous studies, we brought further our quest for anti-malarial agents isolated from plants grown in the Saudi Arabian Peninsula. Methanolic extracts were prepared from eighteen Saudi plants and then tested in vitro to assess their anti-malarial effects on Plasmodium falciparum K1, (a chloroquine-resistant strain) as well as their cytotoxicity on MRC5 (human diploid embryonic lung cell line) cells. Moderate anti-malarial activity was observed in extracts prepared from Hypoestes forskaolii (Vahl) R.

In vitro anti-influenza virus activity of a cardiotonic glycoside from Adenium obesum (Forssk.).

Methanolic extracts of six Saudi plants were screened for their in vitro antiviral activity using influenza virus A/PR/8/34 (H1N1) and MDCK cells in an MTT assay. The results indicated that the extracts of Adeniumobesum and Tephorosianubica possessed antiviral activity (99.3 and 93.

Antitrypanosomal activity of some pregnane glycosides isolated from Caralluma species.

Pregnane glycosides previously isolated from genus Caralluma (C. Penicillata, C. tuberculata and C.

Antiplasmodial and antitrypanosomal activity of plants from the Kingdom of Saudi Arabia.

The antiplasmodial and antitrypanosomal activity of the methanol extracts of 42 plants collected from the Kingdom of Saudi Arabia and some fractions obtained thereof were evaluated. The antiplasmodial activity was tested in vitro against chloroquine-resistant strain (K1) and sensitive strain (FCR3), and the antitrypanosomal activity was tested in vitro against Trypanosoma brucei brucei GUTat 3.1 strain.

Acylated pregnane glycosides from Caralluma tuberculata and their antiparasitic activity.

Five pregnane glycosides were isolated from Caralluma tuberculata (1-5), in addition to a known one (russelioside E, 6). The structures of the isolated compounds were elucidated by the analysis of NMR data and FAB-MS experiments. All the isolated compounds were tested for their antimalarial and antitrypanosomal activities as well as their cytotoxicity against human diploid embryonic cell line (MRC5).

In vitro antimalarial activity of prenylated flavonoids from Erythrina fusca.

Ethyl acetate (EtOAc) extract from the stem bark of Erythrina fusca showed a antimalarial activity against the multi-drug-resistant strain (K1) of Plasmodium falciparum, and six flavonoids, lupinifolin (1), citflavanone (2), erythrisenegalone (3), lonchocarpol A (4), liquiritigenin (5), and 8-prenyldaidzein (6), were isolated from the extract. Diprenylated flavanone 4 showed a notable antimalarial activity (IC(50); 1.6 microg/mL); however 1 and 3 did not show the activity, even though these compounds possessed prenylated substitution.

Antimalarial activity of biflavonoids from Ochna integerrima.

During the screening of antimalarial substances, the 80% EtOH extract from the outer bark of Ochna integerrima Merr. (Ochnaceae) was shown to have a good anti-malarial activity (IC50 value: 6.5 microg/mL) whereas extracts from the inner barks of O.