Chemical composition and biological activities of Nepeta hindostana (Roth) Haines, Nepeta graciliflora Benth. and Nepeta cataria L. from India

Intraditional medicine system, Nepeta species are widely used to reduce chicken pox, tuberculosis, malaria, pneumonia, influenza, measles, stomach disorders, eye complaints, respiratory disorders, asthma, colds, coughs etc. The aim of the present study was to evaluate the chemical composition and biological activities of the essential oils from three species of genus Nepeta viz: Nepeta hindostana (Roth) Haines (NHO), Nepeta graciliflora Benth (NGO) and Nepeta cataria L (NCO).

The essential oils were analysed by the combination of GC and GC-MS. Antioxidant activity was tested by using reducing power assay, metal chelating of Fe2 +assay, and DPPH radical scavenging assay. In-vitro antinflammatory activity was evaluated using albumin denaturation assay and anti-diabetic activity was determined by using α-amylase assay.

The major components present in NCO, NHO and NGO were cis-nepetalactone (69.78%), β-farnesene (43.41%) and sesquisabinene (28.75%), respectively. NCO showed the highest percentage inhibition of DPPH radical (IC50=5.89 µl/ml) followed by NHO (IC50=8.63 µl/ml) and then NGO (IC50=13.81 µl/ml). In terms of reducing power assay and metal chelating of Fe2+  assay, the highest antioxidant activity was also shown by NCO. Among the tested essential oil, NCO showed highest in-vitro anti-inflammatory potential (IC50 18.463±0.14 µg/ml) followed by NGO and NHO with IC50 22.035±0.11 µg/ml and 26.17±0.14 µg/ml, respectively. NHO showed maximum antidiabetic activity with IC50 8.92±0.10 µg/ml of α-amylase.

On the basis of present research work it is marked that the essential oil of Nepeta hindostana (Roth) Haines, Nepeta graciliflora Benth. and Nepeta cataria L. is a potent antioxidant, anti-inflammatory and anti-diabetic agent indicating their potentiality in the field of food, pharmaceutical and cosmetic industry