Evaluation of the genotoxic and antigenotoxic potential of Melissa officinalis in mice

Melissa officinalis (L.) (Lamiaceae), a plant known as the lemon balm, is native to the east Mediterranean region and west Asia. Also found in tropical countries, such as Brazil, where it is popularly known as “erva-cidreira” or “melissa”, it is widely used in aqueous- or alcoholic-extract form in the treatment of various disorders. The aim was to investigate in vivo its antigenotoxicity and antimutagenicity, as well as its genotoxic/mutagenic potential through comet and micronucleus assaying. CF-1 male mice were treated with ethanolic (Mo-EE) (250 or 500 mg/kg) or aqueous (Mo-AE) (100 mg/kg) solutions of an M. officinalis extract for 2 weeks, prior to treatment with saline or Methyl methanesulfonate (MMS) doses by intraperitoneal injection. Irrespective of the doses, no genotoxic or mutagenic effects were observed in blood and bone-marrow samples. Although Mo-EE exerted an antigenotoxic effect on the blood cells of mice treated with the alkylating agent (MMS) in all the doses, this was not so with Mo-AE. Micronucleus testing revealed the protector effect of Mo-EE, but only when administered at the highest dose. The implication that an ethanolic extract of M. officinalis has antigenotoxic/antimutagenic properties is an indication of its medicinal relevance

Artificial substrate bioassay for testing oviposition of southern green stink bug conditioned by soybean plant chemical extracts.

A laboratory bioassay was developed for testing oviposition preference of southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), toward chemicals extracted from soybean, Clycine max (L.) Merrill, pods and leaves. In this bioassay, an artificial substrate (cheesecloth) was stretched over a wooden ring (embroidery hoops), treated with plant extracts or chromatographic fractions, and then exposed to adult stink bugs to assess oviposition preference. The methanol extract of pods stimulated the greatest oviposition. After a chromatographic separation on a reverse phase open column, the most active fraction derived from this extract was that eluted with 20 methanol in water. After subjecting this fraction to chromatography on silica, the greatest activity occurred in the fraction eluted with 60 methanol in methylene chloride. Further fractionation of this material by thin layer chromatography gave no single fraction with demonstrated activity, but the recombined fractions were again active, indicating that multiple components are probably involved in eliciting oviposition. Antennectomized females did not differentiate treated versus untreated substrates, but females with the hairs of the genitalia coated did, indicating that the oviposition-eliciting compounds were sensed by the antennae, rather than by hairs of the genital plaques