Source dependent variation in phenolics, antioxidant and antimicrobial activity of Paeonia emodi in west Himalaya,...

Paeonia emodi is one of the ethno therapeutically important Himalayan plants used to cure various diseases. However, a systematic investigation of the effect of altitude on phytochemical, antioxidant, and antimicrobial activity has not been reported so far. The present study assessed the variation in the bioactive compounds, antioxidant and antimicrobial activity of the leaf, and rhizome of P. emodi collected from different altitudes. Phytochemicals such as phenols, flavonoids, flavanol, tannins, emodin, and paeoniflorin were found in all the sampled populations, but the quantity varied significantly across the altitude. In leaf, phenolics, flavonoids, and tannins content positively correlated with altitude (p < 0.01), but flavanol did not show any connection. Similarly, in the rhizome, positive relation with altitude (p < 0.01) was observed in phenol, flavonoids, and paeoniflorin. Antioxidant activity measured by 1, 1-diphenyl- 2 picrylhydrazyl (DPPH) and nitric oxide assays showed a positive correlation (p < 0.05) with altitude. 2, 2-azinobis (3-ethylbenzothiazoline-6-sulphonic acid), ferric reducing antioxidant power, and hydroxyl ion assays did not show any relation with altitude. Antimicrobial activity was higher in the case of rhizome for the minimum inhibitory concentration and positively correlated with phenolics, flavonoids, and flavanol (p < 0.05). The present study further revealed that the secondary metabolites in the leaf and rhizome extracts of P. emodi are an excellent source of antioxidant and antimicrobial activity, thus validating the species' therapeutic potential.

The online version contains supplementary material available at 10.1007/s12298-022-01242-z.