The paper includes two studies. For antiviral flavonoids from Alkanna orientalis: Alkanna orientalis (L) Boiss. (Boraginaceae) is a perennial herb distributed in Arabia and southern Sinai Peninsula, used in Arabia for sore throat. Previous studies isolated flavonoids and pyrrolizidine alkaloids from the plant from southern Sinai Peninsula. As part of efforts to isolate natural bioactive agents, an ethanolic extract of A. orientalis collected from Saudi Arabia showed good activity against Coxsackie virus. Bioassay-guided fractionation yielded six known 3-methoxyflavones responsible for the activity, identified as kaempferol 3,7-dimethyl ether (kumatakenin) (1), kaempferol 3,4'-dimethyl ether (ermanin) (2), 6-methoxykaempferol 3,7-dimethyl ether (penduletin) (3), 6-methoxyquercetin 3,3'-dimethyl ether (jaceidin) (4), 6-methoxykaempferol 3-methyl ether (5), and kaempferol 3-methyl ether (isokaempferide) (6). Compounds 1—4 and 6 were first isolated from this plant. Plant material was collected from Abha, Saudi Arabia in March 1990 (voucher at King Saud University). Dried aerial parts (2 kg) were extracted with ethanol (yield 246.7 g); 40 g of the extract was chromatographed on a C18 column (MeOH/H2O) and active fractions purified on silica gel 60 column (chloroform-acetone gradient) to obtain the six flavonoids, identified by spectral data (1H-NMR, 13C-NMR, MS). The six 3-methoxyflavones tested on Vero cells infected with Coxsackie virus B3 had IC50 (μg/ml) of 6, 1.2, <2, <2, 3.4, and 0.94 for compounds 1—6 respectively; chloroquine (positive control) had IC50 = 10 μg/ml. For cytotoxic components of Artemisia princeps: Extracts of Artemisia princeps Pampan (Asteraceae) are used in Chinese traditional medicine for inflammation, diarrhoea, and circulatory disorders (dismenorrhea, haematunia, haemorrhoids). As part of searching for potent antitumor substances, the extracts showed significant cytotoxicity against cultured human tumor cell lines in vitro. Phytochemical investigation via cytotoxicity-oriented fractionation combined with the SRB method (adopted by NCI for antitumor screening) isolated four active constituents responsible for cytotoxicity against five human tumor cell lines.