Three phenylpropanoid glycosides (salidroside, syringin and coniferin) and one lignan (phillyrin) isolated from the leaves of Phillyrea latifolia L. (Oleaceae) were tested for interactions with the cyclo-oxygenase and 5-lipoxygenase pathways of arachidonate metabolism in calcium-stimulated mouse peritoneal macrophages and human platelets, and for their effects on cell viability. These compounds are capable of exerting inhibitory actions on enzymes of the arachidonate cascade. Phillyrin, salidroside and syringin exert a preferential effect on the cyclo-oxygenase pathway, inhibiting release of the cyclo-oxygenase metabolites prostaglandin E₂ (IC₅₀ values 45.6 μM, 72.1 μM and 35.5 μM, respectively) and to a lesser extent reducing thromboxane B₂ levels (IC₅₀ values 168 μM, 154 μM and 29.3 μM, respectively). In contrast, coniferin can be classified as a ”dual inhibitor”, since it produces reduction in generation of both cyclo-oxygenase (IC₅₀ values 75.2 μM for prostaglandin E₂ and 619 μM for thromboxane B₂) and 5-lipoxygenase metabolites, but the effects are greater against leukotriene C₄ (IC₅₀ value 63.6 μM). Structure-activity relationships of the three phenylpropanoid glycosides are discussed. Thus, like some other compounds found in medicinal herbs, our molecules possess an array of potentially beneficial anti-eicosanoid properties which may, alongside other constituents, contribute to the claimed therapeutic properties of the plant from which they are derived.

As part of our screening of antiviral agents from medicinal plants, 11 compounds from plant origin (Bupleurum rigidum and Scrophularia scorodonia), three saikosaponins, seven iridoids and one phenylpropanoid glycoside were tested in vitro against herpes simplex type I (HSV-1), vesicular stomatitis virus (VSV) and poliovirus type 1. Five of these compounds showed antiviral activity against VSV. The percentages of cellular viability at the non-toxic limit concentrations of the active compounds were: verbascoside 53.6 % at 500 μg/ml, 8-acetylharpagide 32.1 % at 500 μg/ml, harpagoside 43.3 % at 450 μg/ml, scorodioside 47.8 % at 500 μg/ml and buddlejasaponin IV 56.9 % at 25 μg/ml. Although none of the saikosaponins were active against HSV-1, the iridoid scorodioside showed moderate in vitro anti-HSV-1 activity (30.6 % at 500 μg/ml). However, none of the compounds tested in this survey had any effect against poliovirus.

Seven iridoid glycosides isolated from different extracts of Scrophularia scorodonia L., namely bartsioside, aucubin, harpagide, harpagoside, 8-acetylharpagide, scorodioside and scropolioside B, had been evaluated for their in vitro anti-inflammatory activity in cellular systems generating COX and LOX metabolites. Structure-activity relationships obtained from in vitro screening results were discussed. Most compounds assayed did not exhibit any significant effect on PGE₂- and LTC₄-release from calcium ionophore-stimulated mouse peritoneal macrophages. In the LTC₄-assay, only aucubin showed a significant effect, with an IC₅₀ value of 72 μM. Harpagoside and harpagide also inhibited release of LTC₄, but neither effect reached statistical significance. The release of PGE₂ by mouse peritoneal macrophages stimulated with calcium ionophore was inhibited by harpagoside and 8-acetylharpagide, but this effect is not statistically significant. However, most iridoids assayed showed a significant effect on TXB₂-release from calcium ionophore-stimulated human platelets, with inhibition percentages slightly lower than the reference drug ibuprofen. Only harpagide, scorodioside and scropolioside B had no significant effect on TXB₂-release. Our results indicate that selective inhibition of the TX-synthase enzyme may be the primary target of action of most of these iridoids, and one of the mechanisms through which they exert their anti-inflammatory effects. COX:cyclooxygenase5-LOX:5-lipoxygenaseAA:arachidonic acidPGs:prostaglandinsTXs:thromboxanesLTs:leukotrienesNSAIDs:non-steroidal anti-inflammatory drugsHETEs:hydroxy-eicosatetraenoic acidsNDGA:nordihydroguaiaretic acidDMSO:dimethyl sulfoxideEDTA:ethylenediaminotetraacetic acidMTT:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromideELISA:enzyme-linked immunosorbent assayPBS:Dulbecco's phosphate-buffered salineDMEM:Dulbecco's modified Eagle's mediumFCS:fetal calf serumPMA:phorbol myristate acetatePKC:protein kinase C

Scrophularia species have been used since ancient times as folk remedies for some medical treatments including scrophula, scabies, tumours and inflammatory affections. Some compounds isolated from these species, such as iridoids and phenylpropanoids, are considered responsibles for these activities. This review summarizes mainly the biological activity associated with this genus.