Many natural products could serve as the starting point in the development of modern medicines because of their numerous biological and pharmacological activities. However, some of them are known to carry toxicological properties as well. In order to achieve a safe treatment with plant products, numerous research studies have recently been focused on both pharmacology and toxicity of medicinal plants. Moreover, these studies employed efforts for alternative biological assays. Brine Shrimp Lethality Assay is the most convenient system for monitoring biological activities of various plant species. This method is very useful for preliminary assessment of toxicity of the plant extracts. Rapidness, simplicity and low requirements are several advantages of this assay. However, several conditions need to be completed, especially in the means of standardized experimental conditions (temperature, pH of the medium, salinity, aeration and light). The toxicity of herbal extracts using this assay has been determined in a concentration range of 10, 100 and 1000 µg/ml of the examined herbal extract. Most toxicity studies which use the Brine Shrimp Lethality Assay determine the toxicity after 24 hours of exposure to the tested sample. The median lethal concentration (LC 50 ) of the test samples is obtained by a plot of percentage of the dead shrimps against the logarithm of the sample concentration. LC 50 values are estimated using a probit regression analysis and compared with either Meyer's or Clarkson's toxicity criteria. Furthermore, the positive correlation between Meyer's toxicity scale for Artemia salina and Gosselin, Smith and Hodge's toxicity scale for higher animal models confirmed that the Brine Shrimp Lethality Assay is an excellent predictive tool for the toxic potential of plant extracts in humans.

Evaluation of the antioxidant potential of methanol extract of Chenopodium botrys L. (Amaranthaceae) collected from six different locations in Republic of Macedonia was performed. Several methods were used for testing the antioxidative activity: 1) 2,2-diphenyl1-picrylhydrazyl (DPPH) radical scavenging assay, 2) ferric reduction power assay (FRAP), 3) inhibition of H2 O2 activity, 4) non-sitespecific hydroxyl radical-catalyzed 2-deoxy-D-ribose degradation (NSSOH) and 5) site-specific hydroxyl radical-catalyzed 2-deoxy-D-ribose degradation (SSOH). The IC50 values ranged from 0.26-3.10 mg/mL, 3.01-12.71 mg/mL and 2.60-12.29 mg/mL, for DPPH, NSSOH and SSOH assays, respectively. The H2 O2 inhibition activity and the ferric reducing power capacity were from 28.84-46.56% and 26.14- 43.40%, respectively. The obtained data establish the antioxidant potency in concentration-dependent manner. Additionally, total phenols (TPC) and total flavonoid content (TFC) were determined. The estimated values ranged from 27.77-71.25 mg GAE/g DW and from 7.35- 16.33 mg QE/g DW, respectively

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Methanolic extracts from Juniperus communis L. berries collected from five different localities in the Republic of Macedonia were evaluated for their cytotoxicity by Brine shrimp lethality assay. The obtained cytotoxic activity is descending as follows: Pelister (128 μg/ mL) > Jakupica (221 μg/mL) > Prilep (662 μg/mL) > Demir Hisar (863 μg/mL) > Makedonski Brod (969 μg/mL). Berries collected from mountain areas (Pelister and Jakupica) demonstrated prominent cytotoxic effects, while berries collected from localities near urban areas exhibited lower cytotoxicity. Variations in their bioactivity are probably due to their complex phytochemical composition, which may vary with different ecological and geographical conditions.