Elucidating Pharmacological Activities of Volatile Chemotypes in Essential Oil of Morina longifolia

Abstract

Morina longifolia(Himalayan Whorlflower) is a glabrous herb, found at an altitude of 3000 – 4000 m in the regions of Himalaya, Kashmir, and Bhutan. Previous reports have shown that the parts of this plant like leaves and flowers have been used for healing wound, improving digestion, and enhancing appetite. However, what compound or phytochemicals promote the medicinal use of this plant has not been elucidated and what other uses in medicine are also largely unknown. Therefore, the objective of this study was to characterize phytochemicals in the essential oil of Morina longifolia using GC‐MS (gas chromatography‐mass spectrometry) and to evaluate their bioactivity against bacteria, fungi, and oxidants. The results obtained from the GC‐MS analysis identified 23 compounds, including α‐copaene (49.19%), caryophyllene (20.03%), δ‐cadinene (10.49%), and α‐humulen (4.10%), with higher concentrations in the plant essential oil. We found that essential oil at concentrations of 0.125 mg/mL to 1 mg/mL was able to control the growth of bacterial and fungal strains. Among the bacteria strains, Kocuria rhizophila(MTCC 1541), Micrococcus luteus(MTCC 1541) and Salmonella typhi(NCTC 786) were sensitive at high concentrations, as their growth was inhibited by oil at concentrations of 0.5 to 1%. The oil also inhibited the growth of fungal strains including Aspergillus niger(MTCC 1344) at a high concentration of 0.5 to 1%, while Candida albicans(MTCC 227) growth was inhibited at a low concentration of 0.125 to 0.250%. In addition, we found free radical scavenging activity (FRSA) of M. longifolia essential oil which was in the range of 10.19 – 89.15%. Using ferric chloride (FeCl3) reducing method to access the reducing power activities of M. longifolia essential oil, our results revealed M. longifolia has more than 50% reduction potential at the concentration of 0.75 mg/ml and confirmed its antioxidant properties. Finally, a 0.50 mg/mL IC50 value was obtained indicating a scavenging of nitric acid activities, at 54.21%. The present study identified the significance of M. longifoliaand its potential use as a source of antimicrobial and antioxidant compounds which could act as an alternative against the menace of growing antibiotic resistance.