Cytotoxic, Anti-inflammatory and Antioxidant Activities of Heliotropium indicum Extracts

Heliotropium indicum Linn., or ‘Indian heliotrope’ is very common in India with a long history of traditional medicinal uses in many countries in the world. In Thailand, the plant has been traditionally use to cure various diseases such as fever, insect bites, stings, diarrhea, skin rashes, menstrual disorder and urticaria. In addition, the plant is commonly used by Thai folk doctors as a component in remedies for treatment of lung cancer.

In the present study, we investigated cytotoxicity against two types of lung cancer cell lines (A549 and NCI-H226), anti-inflammatory effect and antioxidant activity of Heliotropium indicum extracts.

The water and ethanolic extracts of Heliotropium indicum were tested. The cytotoxic activity against two types of human lung cancer cell lines (A549 and NCI-H226) was evaluated by sulforhodamine B (SRB) assay. The antiinflammatory effect was investigated on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. LPS-induced nitric oxide (NO) production was determined by Griess reagent. The antioxidant activity was performed by 1, 1-diphenyl-picrylhydrazyl (DPPH) radical scavenging method.

The ethanolic extract showed cytotoxic activity only against NCI-H226 (IC50 = 51.90±2.35 μg/ml) whereas the water extract had no cytotoxic activity against both A549 and NCI-H226 (IC50 >100 μg/ml). For anti-inflammatory effect, the results revealed that the ethanolic extract exhibited the most potent inhibitory activity on nitric oxide production (IC50 = 24.17±2.12 μg/ml), followed by Indomethacin (positive control) with an IC50 value of 34.67±6.23 μg/ml while water extract was apparently inactive (IC50 >100 μg/ml). For antioxidant activity, the ethanolic extract showed high antioxidant activity (EC50 = 28.91±4.26 μg/ml) but the water extract showed no antioxidant activity (EC50 >100 μg/ml).

These results can support using Heliotropium indicum Linn. for component in lung cancer remedy by Thai folk doctors. However, more studies are required.